LiPos and charger, this good?
09-20-2009, 07:26 AM
#1
Senior Member
Thread Starter
Join Date: Aug 2009
Location: Washington, MO
Posts: 101
Likes: 0
Received 0 Likes
on
0 Posts
LiPos and charger, this good?
Ok, so after the problems I had with my 9.6v NiMh burning up motors, I have decided to go with a couple of LiPos. Getin set up to go brushless next year. So here is what I have to pede's, bought one off ebay with the Oroin Method R 19t, 3 bodies, an extra set of wheels and tires<to be used on my older pede> but no batteries or charger. I also bought a C027 for $20 shipped, and boy have I got into the doghouse spending all that money. LOL
So with these two pedes an motors I was thinking of buyin 2s LiPos and a charger maybe 2 batts for each truck so me an my son can run together. Would these batteries be good for my motors? http://www.hobbycity.com/hobbycity/s..._hardcase_packand I was thinking this for a charger just in hopes to keep the cost down. http://www.hobbycity.com/hobbycity/s...rger_1-6_Cells But as i dont know the first thing about LiPos or chargers for that matter I wanted to ask you guys first.
So with these two pedes an motors I was thinking of buyin 2s LiPos and a charger maybe 2 batts for each truck so me an my son can run together. Would these batteries be good for my motors? http://www.hobbycity.com/hobbycity/s..._hardcase_packand I was thinking this for a charger just in hopes to keep the cost down. http://www.hobbycity.com/hobbycity/s...rger_1-6_Cells But as i dont know the first thing about LiPos or chargers for that matter I wanted to ask you guys first.
09-20-2009, 08:12 AM
#2
RE: LiPos and charger, this good?
I'd go with these 30c batts.................same price, softcase which is Ok when properly fit into a battery tray.
http://www.hobbycity.com/hobbycity/s..._30C_Lipo_Pack
Im not familiar with the quality of the charger, however if you click on the review tab at the bottom they are all fairly good reviews. They say the balancer is just a little off, not a huge deal really.
Im guessing your esc doesnt have a built in lipo cutoff, if not here is one that can be easily installe :
http://www3.towerhobbies.com/cgi-bin...&I=LXPGM8&P=ML
http://www.hobbycity.com/hobbycity/s..._30C_Lipo_Pack
Im not familiar with the quality of the charger, however if you click on the review tab at the bottom they are all fairly good reviews. They say the balancer is just a little off, not a huge deal really.
Im guessing your esc doesnt have a built in lipo cutoff, if not here is one that can be easily installe :
http://www3.towerhobbies.com/cgi-bin...&I=LXPGM8&P=ML
09-20-2009, 10:53 AM
#3
Senior Member
My Feedback: (1)
Join Date: Jun 2009
Location: Great Falls,
MT
Posts: 2,482
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
if the pede's are XL-5 then novak says the cut off wont work:
" This is the Novak Smart Stop 2-Cell LiPo Cut-Off Module.
**This module is NOT compatible with the Traxxas XL-5 ESC with the**
**BLUE case #3018X (TRAM3028), see COMMENTS below.**"
" This is the Novak Smart Stop 2-Cell LiPo Cut-Off Module.
**This module is NOT compatible with the Traxxas XL-5 ESC with the**
**BLUE case #3018X (TRAM3028), see COMMENTS below.**"
09-20-2009, 12:16 PM
#4
Senior Member
Thread Starter
Join Date: Aug 2009
Location: Washington, MO
Posts: 101
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
Yes its an XL-5 ESC, so now I'd need batteries, charger, new ESC, and a cut off?? Damn, might have to wait awhile longer to go LiPo an buy some cheap NiMh's =/
09-20-2009, 12:36 PM
#5
RE: LiPos and charger, this good?
Yeah...............i forgot the Pede had an XL-5.............i think there is another Cutoff that will work, i'll do some checkin'. If so you wont need a new esc, just a compatible cutoff..............so, batts, charger and a cutoff ($25-30).
09-21-2009, 02:58 AM
#6
Senior Member
Join Date: Mar 2007
Location: Yuma,
AZ
Posts: 295
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
I have an Imax B6AC. Good little charger considering what it can do. You really gotta watch the temps on it as it doesn't have a fan like an Accucell. The balancer works ok, and it's an easy to use device. Small, portable, does all the chemistries, built in balancer, AC/DC compatible. Very good features for the price....
Now the downsides (sorry if I'm raining on your parade a bit here): The charger might not last that long as it burns out easily if it gets overheated, the balancer isn't the best out there, no internal fan (already mentioned), 50W maximum charge rate even though it can do up to 6S batteries, AC function charges at a slightly lower power level than DC (the internal DC power supply isn't the best).
Honestly, it's hard to beat for the money. Just realize that it if cooks outside of 90 days after you buy it, you own an $85 paperweight unless you can con the repair dept. to replace it for cheap free.I really liked mine, but it died maybe 5 months after I got it. When it was working, it seemed a bit limited in its charge capabilites, but as long as you aren't charging more than one battery at a time, or less than a 3S, 5000, you should be ok. It worked great for charging my 2200's for my Trex 450, but when I went to charge my 6S packs for my Atom 500, it could only charge at maybe 1/2C.
Now the downsides (sorry if I'm raining on your parade a bit here): The charger might not last that long as it burns out easily if it gets overheated, the balancer isn't the best out there, no internal fan (already mentioned), 50W maximum charge rate even though it can do up to 6S batteries, AC function charges at a slightly lower power level than DC (the internal DC power supply isn't the best).
Honestly, it's hard to beat for the money. Just realize that it if cooks outside of 90 days after you buy it, you own an $85 paperweight unless you can con the repair dept. to replace it for cheap free.I really liked mine, but it died maybe 5 months after I got it. When it was working, it seemed a bit limited in its charge capabilites, but as long as you aren't charging more than one battery at a time, or less than a 3S, 5000, you should be ok. It worked great for charging my 2200's for my Trex 450, but when I went to charge my 6S packs for my Atom 500, it could only charge at maybe 1/2C.
09-21-2009, 09:00 AM
#7
Senior Member
Thread Starter
Join Date: Aug 2009
Location: Washington, MO
Posts: 101
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
I'll be honest, I have no clue what a balancer dose LOL. Guess I have ALOT of research to do before I go LiPo, cause I didnt even know I needed a cutoff. Guess my best bet with very limited funds and winter just around the conor is to buy a couple of cheap NiMh's. Probebly go with somethin like this http://www3.towerhobbies.com/cgi-bin...?&I=LXXUP5&P=7 . Not the best I know but i need to buy at least 2 batt's so my son an I can run for a bit together.
09-21-2009, 09:51 AM
#8
RE: LiPos and charger, this good?
Since you are considering nimh now,
Here is a decent deal, I like the batts personally, have owned 6 of them for around a year now and they are still goin strong, includes a charger too.
http://www.all-battery.com/two84v380...rtcharger.aspx
Here is a decent deal, I like the batts personally, have owned 6 of them for around a year now and they are still goin strong, includes a charger too.
http://www.all-battery.com/two84v380...rtcharger.aspx
09-21-2009, 10:17 AM
#9
Senior Member
Join Date: Oct 2006
Location: longmont,
CO
Posts: 215
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
get the zippy hardcase 30c. i have one and its is awesome and it can do a lot of current. my stock slash came alive with this pack.
09-21-2009, 10:35 AM
#10
RE: LiPos and charger, this good?
if you are ordering from hobbycity they have a cheap voltage warning device http://www.hobbycity.com/hobbycity/s...idproduct=7224
I do not have one but the reviews are ok
I do not have one but the reviews are ok
09-21-2009, 11:46 AM
#11
Senior Member
Thread Starter
Join Date: Aug 2009
Location: Washington, MO
Posts: 101
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
Hmmm so that warning device, the batteries and a charger are all I really need to run the 2s? Not goin 3s yet as i still have brushed motors I dont want to fry. If this is the case than I might be able to swing LiPo in a month !!! O an Rebuilder that is a good deal, but I already have a charger, but I am gonna check the site for cheap batteries as i am most likely gonna need a pair of NiMh's till xmas. Unless I get REALLY lucky LOL. I am just tired of sitin here lookin at my truck and not being able to run it LOL.
09-21-2009, 12:13 PM
#12
RE: LiPos and charger, this good?
ORIGINAL: Hotroder383
Hmmm so that warning device, the batteries and a charger are all I really need to run the 2s? Not goin 3s yet as i still have brushed motors I dont want to fry. If this is the case than I might be able to swing LiPo in a month !!! O an Rebuilder that is a good deal, but I already have a charger, but I am gonna check the site for cheap batteries as i am most likely gonna need a pair of NiMh's till xmas. Unless I get REALLY lucky LOL. I am just tired of sitin here lookin at my truck and not being able to run it LOL.
Hmmm so that warning device, the batteries and a charger are all I really need to run the 2s? Not goin 3s yet as i still have brushed motors I dont want to fry. If this is the case than I might be able to swing LiPo in a month !!! O an Rebuilder that is a good deal, but I already have a charger, but I am gonna check the site for cheap batteries as i am most likely gonna need a pair of NiMh's till xmas. Unless I get REALLY lucky LOL. I am just tired of sitin here lookin at my truck and not being able to run it LOL.
09-21-2009, 12:20 PM
#13
Senior Member
Join Date: Mar 2007
Location: Yuma,
AZ
Posts: 295
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
Lipos don't take a ton of research, but they're not as plug in, walk away, come back in four hours and put on the next battery. You'll find they're a bit easier to deal with than NiMh's because they charge much quicker, don't build up a memory, last longer, give you better power, and can be incredibly cheap! I have a 2S 4000 25C, and hey were maybe $30 apiece. Only real downside to running Lipos is you have to time your runs or have some kind of battery monitor if you're not good about disciplining yourself. As long as you keep the pack above the rated voltage, you'll be fine.
Balancing is exactly what it sounds like: you do it to keep the cells at the same voltage to avoid over-working/charging/discharging the cells (remember the warning about not mixing Alkaline batteries in your CD players and tape decks. Same concept, as you can damage or explode the cells). A lot of people freak out about Lipos when they really don't need to. Once you get it in your head how you should run them, they become second nature, and useless items like a battery monitors or low voltage cutoffs are a waste of your money.
I wrote up a small battery/electronics concept guide for someone else in another thread. I'll see if I can find it again and re-post it here or give you a link.
Balancing is exactly what it sounds like: you do it to keep the cells at the same voltage to avoid over-working/charging/discharging the cells (remember the warning about not mixing Alkaline batteries in your CD players and tape decks. Same concept, as you can damage or explode the cells). A lot of people freak out about Lipos when they really don't need to. Once you get it in your head how you should run them, they become second nature, and useless items like a battery monitors or low voltage cutoffs are a waste of your money.
I wrote up a small battery/electronics concept guide for someone else in another thread. I'll see if I can find it again and re-post it here or give you a link.
09-21-2009, 12:42 PM
#14
Senior Member
Join Date: Mar 2007
Location: Yuma,
AZ
Posts: 295
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
Have a look at these batteries. Half the price of the 5000's most guys recommend, not too much for your brushed setups, perfect for when you first get into brushless, great run-times, and more than enough to go bashing around with for you and your son:
http://www.hobbycity.com/hobbycity/s...25C_Car_Lipoly
This is the one I use in my SC10, and it keeps the pace with most of the other cars on the track. Plus you can go with the super high Kv motors and gain the speed lost by only using 2S Lipos and you keep your costs really low. Only time you'd really need the higher cell setup is if you're serious about racing and truly need every bit of performance you can get. Otherwise, backyard bashing and a little rub racing will be a waste of your money getting the more expensive ones (especially seeing you're in the doghouse enough just getting the buggies!).
The Accucell-6 is a great little charger too. Cheap, reliable, highly capable, and very portable. Makes for the second best charger I've ever owned, right behind the Accucell-8150. They're both virtually the same thing, just the 8150 can do more and faster.
http://www.hobbycity.com/hobbycity/s...idProduct=7028
So for about $200.48, you can get 4 batteries and two chargers delivered to your house (or $212.29 for EMS express). While that may sound pretty steep up front, it's the best deal you're going to get with the Lipo setup that you want to have. Even if you went with the NiMh setup mentioned before, It'll take about 2-1/2 hours to charge each battery (max charge rate is 1.8A) and with 3800's, you'll be looking at 12-15 minutes of run-time from each one. With the Lipos, they only take an hour to charge and can be charged several times a day. Decisions, decisions!!!!
http://www.hobbycity.com/hobbycity/s...25C_Car_Lipoly
This is the one I use in my SC10, and it keeps the pace with most of the other cars on the track. Plus you can go with the super high Kv motors and gain the speed lost by only using 2S Lipos and you keep your costs really low. Only time you'd really need the higher cell setup is if you're serious about racing and truly need every bit of performance you can get. Otherwise, backyard bashing and a little rub racing will be a waste of your money getting the more expensive ones (especially seeing you're in the doghouse enough just getting the buggies!).
The Accucell-6 is a great little charger too. Cheap, reliable, highly capable, and very portable. Makes for the second best charger I've ever owned, right behind the Accucell-8150. They're both virtually the same thing, just the 8150 can do more and faster.
http://www.hobbycity.com/hobbycity/s...idProduct=7028
So for about $200.48, you can get 4 batteries and two chargers delivered to your house (or $212.29 for EMS express). While that may sound pretty steep up front, it's the best deal you're going to get with the Lipo setup that you want to have. Even if you went with the NiMh setup mentioned before, It'll take about 2-1/2 hours to charge each battery (max charge rate is 1.8A) and with 3800's, you'll be looking at 12-15 minutes of run-time from each one. With the Lipos, they only take an hour to charge and can be charged several times a day. Decisions, decisions!!!!
09-21-2009, 01:09 PM
#15
Senior Member
Join Date: Mar 2007
Location: Yuma,
AZ
Posts: 295
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
Ok, found it. I wrotethis a while back, so some of the info might be a little off-topic, but it gets the point across. Long read, but might help you out just a bit more in your thoughts about going Lipo:
. . . .it's a good idea to stay away from cheap stuff UNLESS it's been proven otherwise.I for one took the risk and can happily say I came out the victor on that challenge.
The Accucell-6 and Accucell-8150 are top-notch performers. I like the 8150 a lot more because it can handle the bigger stuff or charging multiple batteries at once. ***You can charge 2S on it, but you have to plug it into the 3S port, but select 2S.Funny little part I just recently learned, but figured I'd mention it foreveryone'sinformation.*** ->(updated from the original post)
Anyways, they're both well worth the money and I'd put them up against any premium charger with utmost confidence.
All About Lipos: (Long and boring, but worth the read if you care to learn!)
"C" ratings tell you roughly what amperage (or current)you can expect to getout ofa battery (not the power). Power is measured in watts and is calculated by multiplying the voltage by the current. You can determine the amperage output of the packby multiplying the rated capacity of the pack by the marked C rating. Take a 5,000,25Cbattery for example. Itwill give you: [1,000milliamps = 1 full amp, so...]5A X 25C =125Amps of current. If that battery was a 3S (three cell) Lipo, you'd take the full charge of 12.60V X 5A= 63watts of power. Any time you change the C rating, Voltage, or capacity size of the battery, you have to modify that part of the equation to extract the value.
The voltages of the batteries are added when they are linked in series. Each Lipo cell has a nominal voltage (or rated voltage) of 3.7V per cell, and a full charge of 4.20V per cell.A battery pack is labeled with the nominal or rated voltage (e.g; 1S = 3.7V, 2S = 7.4V, 3S= 11.1V, 4S = 14.8V, 5S = 18.5V, 6S = 22.2V, etc...[full charge would be 4.2V, 8.4V, 12.60V, 16.8V, 21V, and 25.2V respectively]). The voltage dictates how fast your motor will spin (theoretically at least). Avoiding slippage; final drive ratios; gear ratios; and motor turns/Kv ratings (of which, there is no real way to determine the speed of the motor by the # of turns and there is no correlation of turns to a Kv rating. Kv's just happen to be the best way to determine the speed); the higher the voltage, the faster the motor will spin. Coincidentally or in addition to, the higher the Kv, the faster the motor will spin as well. I'm not quite familiar enough with turns to quote how they work, but the lower the number, the faster I believe. (brushless) motors can spin up to about 76,000rpm's before they are no longer safe to operate(it's actually the bearings that can't spin fast enough). If the motor can stay under this speed limit, then you can use the motor with said voltage. (You can swap out bearings to ceramics and raise that limit to over 100,000rpm's, but heat would be a large concern going that fast)
For instance: The VXL 3500 motor is quite popular for 1/10th cars. It's rated at 3500Kv. You multiply the Kv rating by the voltage to get your theoretical maximum speed. So, on 2S, you'd get 8.4V X 3500Kv =29,400rpm. 3S = 44,100rpm's. 4S = 58,800rpm. 5S = 73,500rpm. 6S = 88,200rpm. So, theoretically, the highest number of cells you could use with a VXL 3500 motor is 5 cells. Keep in mind, at this voltage, it would be pretty easy to heat the motor up very quickly, so you would either have to gear the motor down, add heatsinks and/or a fan, or drastically reduce your run times in order to keep the heat in check. Not to mention the car would probably destroy itself with all that power anyways! If you moved up your Kv to say the Mamba 5700Kv, the max voltage you could run on that would be 12.60V or a 3S Lipo. The reason the 6900Kv, 7700Kv and 9000Kv motors are only rated for 2S use is they exceed the 76,000rpm speed limit by a good margin on 3S and above (6900 on 3S = 86,940rpm's alone!)
Lipos should be stored at half-charge unless you are ready to run them within a couple days of full charge. Keeping it fully charged and not using it will deteriorate the life-span of the battery and degrade its performance. Also, keeping them out of high temps when storing will keep the life-span up. Lipos don't like to work when they are cold, so you should keep them in your pockets of in a heated spot until you want to run them in the colder months. However, they should never be run above 140-160 degrees. Doing so means you are either overdrawing them (get a higher C pack or reduce load/gearing/drag), or they need more ventilation.
Running no more than 80% of the battery's capacity out will keep the battery going stronger and longer. You multiply the rated capacity of the battery by .80 to find the maximum you should be putting back into the battery. for example: 5,000 battery again, times .80 (5000 X .80 = 4,000mA). So you should never have to put back in more tha 4,000 milliamps back into a 5000 pack, or else you are damaging it (you're not really hurting it too bad, but you are wearing it out a lot quicker by over-discharging it). I usually never let the battery go below the rated voltage, seeing the voltage is a good indicator of how much charge you have left on the battery. (e.g.-if you have an 11.1 or 3S battery, anywhere between 11.1V and 12.60V is considered a partial charge. 11.85V is the median charge [or 50% charge], and therefore the storage charge amount)
A Lipo should also never be dishcarged below 3.1V per cell (might be 3.3V/cell. Can't remember off the top of my head) and anything below 2.7V per cell should be considered lost, or a dead cell. It might not be recoverable beyond that (kinda like a lead acid battery).
***The trick to recovering a deep discharge (some of the smart chargers won't charge over-discharged lipo's): (Please us this info with EXTREME caution) Put the battery on NiMh charge for acouple* minutes just to get the voltage bumped up enough to allow the charger to accept it.After that, switch back to Lipo balance charge and fill it up very slowly for the next few cycles. Monitor it's progress before going wild with it, else it could burst or puff on you. *leaving it on NiMh charge for too long could damage the battery and/or charger. Avoid doing this longer than 5 to 10 minutes. If it's not recovered enough by then, toss the pack. It's probably toast!
Balance charging is essential when using Lipos. if your charger does not have a built in balancer, you can get aftermarket ones that work with, but independantly fromyour charger (astro-Blinky, Thunder-Power TP-205, TP-210, Hyperion, etc...). They basically burn off the extravoltage/milliamps of cells that are higher than the others and makes them stay level throughout the charge cycle as well as ensuring none of the cells goes over the 4.20V/cell mark (which could lead to the battery going bad or exploding). It takes a great deal of overcharging to get a battery to explode though. Despite all the fear and hype of how dangerous they are, they're really not that bad. Just a force not to be reconed with if it actually does catch fire or bursts. Most of the old stories you hear came from when no one knew about balancing and/or the chargers did not have proper cut-offs built in to prevent such occurances. Also, many people just walkedout of the room or away from their cars with the batteries charging andun-attended, resulting inwhole housesand vehicles going up in flames.The majority ofchargers have some major safety stuff built in now, so I wouldn't be too uptight about them, just don't walk away from them while charging.
If a battery Puffs on you, gives up the magic smoke, drops a cell, loses almost all power due to age, or is damaged beyond wise use (we call it getting Taco'd in the helicopter community); drop the battery in a bucket of salt-water and let it self discharge overnight. After that you can safely drop it in the trash once you've removed the solder contacts and the main leads. It's perfectly harmless to the environment (unless you throw out the lead solder along with it!).
Capacity: Bigger number on the side of the package = more energy storage = more power (both current and voltage sustaining characteristics) = longer run-times = happy camper!!! (or pissed off dude when you break something 5 minutes into a 30 minute battery!).
Well, I think that's about boring enough and covers just about everything I can think of concerning Lipo's (at the moment at least). I'm sure I could drone on longer, but I'll either wait until tomorrow or someone else will pipe up with what I forgot to mention. Cheers!
. . . .it's a good idea to stay away from cheap stuff UNLESS it's been proven otherwise.I for one took the risk and can happily say I came out the victor on that challenge.
The Accucell-6 and Accucell-8150 are top-notch performers. I like the 8150 a lot more because it can handle the bigger stuff or charging multiple batteries at once. ***You can charge 2S on it, but you have to plug it into the 3S port, but select 2S.Funny little part I just recently learned, but figured I'd mention it foreveryone'sinformation.*** ->(updated from the original post)
Anyways, they're both well worth the money and I'd put them up against any premium charger with utmost confidence.
All About Lipos: (Long and boring, but worth the read if you care to learn!)
"C" ratings tell you roughly what amperage (or current)you can expect to getout ofa battery (not the power). Power is measured in watts and is calculated by multiplying the voltage by the current. You can determine the amperage output of the packby multiplying the rated capacity of the pack by the marked C rating. Take a 5,000,25Cbattery for example. Itwill give you: [1,000milliamps = 1 full amp, so...]5A X 25C =125Amps of current. If that battery was a 3S (three cell) Lipo, you'd take the full charge of 12.60V X 5A= 63watts of power. Any time you change the C rating, Voltage, or capacity size of the battery, you have to modify that part of the equation to extract the value.
The voltages of the batteries are added when they are linked in series. Each Lipo cell has a nominal voltage (or rated voltage) of 3.7V per cell, and a full charge of 4.20V per cell.A battery pack is labeled with the nominal or rated voltage (e.g; 1S = 3.7V, 2S = 7.4V, 3S= 11.1V, 4S = 14.8V, 5S = 18.5V, 6S = 22.2V, etc...[full charge would be 4.2V, 8.4V, 12.60V, 16.8V, 21V, and 25.2V respectively]). The voltage dictates how fast your motor will spin (theoretically at least). Avoiding slippage; final drive ratios; gear ratios; and motor turns/Kv ratings (of which, there is no real way to determine the speed of the motor by the # of turns and there is no correlation of turns to a Kv rating. Kv's just happen to be the best way to determine the speed); the higher the voltage, the faster the motor will spin. Coincidentally or in addition to, the higher the Kv, the faster the motor will spin as well. I'm not quite familiar enough with turns to quote how they work, but the lower the number, the faster I believe. (brushless) motors can spin up to about 76,000rpm's before they are no longer safe to operate(it's actually the bearings that can't spin fast enough). If the motor can stay under this speed limit, then you can use the motor with said voltage. (You can swap out bearings to ceramics and raise that limit to over 100,000rpm's, but heat would be a large concern going that fast)
For instance: The VXL 3500 motor is quite popular for 1/10th cars. It's rated at 3500Kv. You multiply the Kv rating by the voltage to get your theoretical maximum speed. So, on 2S, you'd get 8.4V X 3500Kv =29,400rpm. 3S = 44,100rpm's. 4S = 58,800rpm. 5S = 73,500rpm. 6S = 88,200rpm. So, theoretically, the highest number of cells you could use with a VXL 3500 motor is 5 cells. Keep in mind, at this voltage, it would be pretty easy to heat the motor up very quickly, so you would either have to gear the motor down, add heatsinks and/or a fan, or drastically reduce your run times in order to keep the heat in check. Not to mention the car would probably destroy itself with all that power anyways! If you moved up your Kv to say the Mamba 5700Kv, the max voltage you could run on that would be 12.60V or a 3S Lipo. The reason the 6900Kv, 7700Kv and 9000Kv motors are only rated for 2S use is they exceed the 76,000rpm speed limit by a good margin on 3S and above (6900 on 3S = 86,940rpm's alone!)
Lipos should be stored at half-charge unless you are ready to run them within a couple days of full charge. Keeping it fully charged and not using it will deteriorate the life-span of the battery and degrade its performance. Also, keeping them out of high temps when storing will keep the life-span up. Lipos don't like to work when they are cold, so you should keep them in your pockets of in a heated spot until you want to run them in the colder months. However, they should never be run above 140-160 degrees. Doing so means you are either overdrawing them (get a higher C pack or reduce load/gearing/drag), or they need more ventilation.
Running no more than 80% of the battery's capacity out will keep the battery going stronger and longer. You multiply the rated capacity of the battery by .80 to find the maximum you should be putting back into the battery. for example: 5,000 battery again, times .80 (5000 X .80 = 4,000mA). So you should never have to put back in more tha 4,000 milliamps back into a 5000 pack, or else you are damaging it (you're not really hurting it too bad, but you are wearing it out a lot quicker by over-discharging it). I usually never let the battery go below the rated voltage, seeing the voltage is a good indicator of how much charge you have left on the battery. (e.g.-if you have an 11.1 or 3S battery, anywhere between 11.1V and 12.60V is considered a partial charge. 11.85V is the median charge [or 50% charge], and therefore the storage charge amount)
A Lipo should also never be dishcarged below 3.1V per cell (might be 3.3V/cell. Can't remember off the top of my head) and anything below 2.7V per cell should be considered lost, or a dead cell. It might not be recoverable beyond that (kinda like a lead acid battery).
***The trick to recovering a deep discharge (some of the smart chargers won't charge over-discharged lipo's): (Please us this info with EXTREME caution) Put the battery on NiMh charge for acouple* minutes just to get the voltage bumped up enough to allow the charger to accept it.After that, switch back to Lipo balance charge and fill it up very slowly for the next few cycles. Monitor it's progress before going wild with it, else it could burst or puff on you. *leaving it on NiMh charge for too long could damage the battery and/or charger. Avoid doing this longer than 5 to 10 minutes. If it's not recovered enough by then, toss the pack. It's probably toast!
Balance charging is essential when using Lipos. if your charger does not have a built in balancer, you can get aftermarket ones that work with, but independantly fromyour charger (astro-Blinky, Thunder-Power TP-205, TP-210, Hyperion, etc...). They basically burn off the extravoltage/milliamps of cells that are higher than the others and makes them stay level throughout the charge cycle as well as ensuring none of the cells goes over the 4.20V/cell mark (which could lead to the battery going bad or exploding). It takes a great deal of overcharging to get a battery to explode though. Despite all the fear and hype of how dangerous they are, they're really not that bad. Just a force not to be reconed with if it actually does catch fire or bursts. Most of the old stories you hear came from when no one knew about balancing and/or the chargers did not have proper cut-offs built in to prevent such occurances. Also, many people just walkedout of the room or away from their cars with the batteries charging andun-attended, resulting inwhole housesand vehicles going up in flames.The majority ofchargers have some major safety stuff built in now, so I wouldn't be too uptight about them, just don't walk away from them while charging.
If a battery Puffs on you, gives up the magic smoke, drops a cell, loses almost all power due to age, or is damaged beyond wise use (we call it getting Taco'd in the helicopter community); drop the battery in a bucket of salt-water and let it self discharge overnight. After that you can safely drop it in the trash once you've removed the solder contacts and the main leads. It's perfectly harmless to the environment (unless you throw out the lead solder along with it!).
Capacity: Bigger number on the side of the package = more energy storage = more power (both current and voltage sustaining characteristics) = longer run-times = happy camper!!! (or pissed off dude when you break something 5 minutes into a 30 minute battery!).
Well, I think that's about boring enough and covers just about everything I can think of concerning Lipo's (at the moment at least). I'm sure I could drone on longer, but I'll either wait until tomorrow or someone else will pipe up with what I forgot to mention. Cheers!
09-21-2009, 01:41 PM
#16
Senior Member
Thread Starter
Join Date: Aug 2009
Location: Washington, MO
Posts: 101
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
That is awsome Skunk!! Thanks a TON! Thanks to everyone who gave me info on this, I really do appreciate it! $220 is a bit of cash BUT if I can use all of it when I go brushless next year then it isnt so bad. I will just have to save up for a few weeks to get it. I had a blonde moment, sitin here lookin at my 9.6v battery moanin about not being able to use it when it hit me like a lighting bolt. Take a cell out an make it a 8.4 dummy!! So thats what I did, spent a good 15 mins out playin with the truck, seems to have lost a little speed with the C027 VS the Titan but didnt over heat and had gobs more torque wich was good as I live on a hill an run mostly in grass. Thanks again to all for the info!! It helps a guy like me out ALOT!!
09-21-2009, 01:44 PM
#17
RE: LiPos and charger, this good?
ORIGINAL: Skunkworx
Lipos don't take a ton of research, but they're not as plug in, walk away, come back in four hours and put on the next battery. You'll find they're a bit easier to deal with than NiMh's because they charge much quicker, don't build up a memory, last longer, give you better power, and can be incredibly cheap! I have a 2S 4000 25C, and hey were maybe $30 apiece. Only real downside to running Lipos is you have to time your runs or have some kind of battery monitor if you're not good about disciplining yourself. As long as you keep the pack above the rated voltage, you'll be fine.
Balancing is exactly what it sounds like: you do it to keep the cells at the same voltage to avoid over-working/charging/discharging the cells (remember the warning about not mixing Alkaline batteries in your CD players and tape decks. Same concept, as you can damage or explode the cells). A lot of people freak out about Lipos when they really don't need to. Once you get it in your head how you should run them, they become second nature, and useless items like a battery monitors or low voltage cutoffs are a waste of your money.
I wrote up a small battery/electronics concept guide for someone else in another thread. I'll see if I can find it again and re-post it here or give you a link.
Lipos don't take a ton of research, but they're not as plug in, walk away, come back in four hours and put on the next battery. You'll find they're a bit easier to deal with than NiMh's because they charge much quicker, don't build up a memory, last longer, give you better power, and can be incredibly cheap! I have a 2S 4000 25C, and hey were maybe $30 apiece. Only real downside to running Lipos is you have to time your runs or have some kind of battery monitor if you're not good about disciplining yourself. As long as you keep the pack above the rated voltage, you'll be fine.
Balancing is exactly what it sounds like: you do it to keep the cells at the same voltage to avoid over-working/charging/discharging the cells (remember the warning about not mixing Alkaline batteries in your CD players and tape decks. Same concept, as you can damage or explode the cells). A lot of people freak out about Lipos when they really don't need to. Once you get it in your head how you should run them, they become second nature, and useless items like a battery monitors or low voltage cutoffs are a waste of your money.
I wrote up a small battery/electronics concept guide for someone else in another thread. I'll see if I can find it again and re-post it here or give you a link.
09-21-2009, 03:34 PM
#18
Senior Member
Join Date: Mar 2007
Location: Yuma,
AZ
Posts: 295
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
Vigelence is free dude. Why pay for something that shouldn't cost you a dime? It's not like a timer is hard to set on a watch. Besides that, youget touse your battery at peak performance instead of draining it until it's almost dead and have nothing left anyways. Plus it takes less time to charge your packs back up if you only use 70-80% of its capacity. You do it however you like. I found them to be too much of a pain because you almost never use the same batteries, and even the variations between the same exact (brand and/or make) batteries can cause it to over-discharge. You ca use them in conjunction with a good routine as an absolute backup, but usually they're not a very good means of keeping your batteries safe.
09-22-2009, 12:00 PM
#19
Senior Member
Join Date: Jan 2009
Location: , PHILIPPINES
Posts: 248
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
ORIGINAL: Skunkworx
Vigelence is free dude. Why pay for something that shouldn't cost you a dime? It's not like a timer is hard to set on a watch. Besides that, you get to use your battery at peak performance instead of draining it until it's almost dead and have nothing left anyways. Plus it takes less time to charge your packs back up if you only use 70-80% of its capacity. You do it however you like. I found them to be too much of a pain because you almost never use the same batteries, and even the variations between the same exact (brand and/or make) batteries can cause it to over-discharge. You ca use them in conjunction with a good routine as an absolute backup, but usually they're not a very good means of keeping your batteries safe.
Vigelence is free dude. Why pay for something that shouldn't cost you a dime? It's not like a timer is hard to set on a watch. Besides that, you get to use your battery at peak performance instead of draining it until it's almost dead and have nothing left anyways. Plus it takes less time to charge your packs back up if you only use 70-80% of its capacity. You do it however you like. I found them to be too much of a pain because you almost never use the same batteries, and even the variations between the same exact (brand and/or make) batteries can cause it to over-discharge. You ca use them in conjunction with a good routine as an absolute backup, but usually they're not a very good means of keeping your batteries safe.
It's better to be safe than sorry dude. And your timer method will only work in the track. When bashing or crawling, you need some sort of lipo cutoff or alarm.
09-23-2009, 06:06 AM
#20
Senior Member
Join Date: Mar 2007
Location: Yuma,
AZ
Posts: 295
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
Not sure how it would make a difference. It will work well for both applications seeing you'll run them harder at the track in most cases, so that would put you on the conservative side when bashing.I just don'tsee why they become such a necessary thing when you can easily (and more safely) do without them. The point of timing your runs is to establish just how much you can use the battery. If you go out and do high-speed stuff for one battery, then the next you are just toodling around, your battery will be more than safe because your times will be set for high drains/slightly lower run-times. So when you're not going break-neck speeds, it uses less energy, therefore, being safer than an LVC that will allow you to go as high as 90%-95% discharge before kicking in. It's a highly proven fact that if you routinely go over 80% discharge, it will kill your battery much sooner. Just about every LVC/monitor I've ever seen on the market will either cut out way too soon (not necessarily a bad thing on this one), or way too late (which is very, and much morecommon) and that's why I made my statement that they are pretty much worthless. If you HAVE to use one, I suppose it couldn't hurt as an extremebackup. But if it's going to cost you the price of a battery, I'd take the extra battery and my chances! If it was only $5 instead of 5 times that amount, we'd have an entirely different conversation. On top of all that, it's not like you're only going to be able to use a 4000+ battery for 5 minutes. You get at least 10-15 minutes of solid, hard running (andpossibly longer in a lot of cases) and that's within the 'overly conservative' timed method.
As I said before, to each his own.
As I said before, to each his own.
09-23-2009, 07:35 AM
#21
Senior Member
Join Date: Jan 2009
Location: , PHILIPPINES
Posts: 248
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
ORIGINAL: Skunkworx
Not sure how it would make a difference. It will work well for both applications seeing you'll run them harder at the track in most cases, so that would put you on the conservative side when bashing. I just don't see why they become such a necessary thing when you can easily (and more safely) do without them. The point of timing your runs is to establish just how much you can use the battery. If you go out and do high-speed stuff for one battery, then the next you are just toodling around, your battery will be more than safe because your times will be set for high drains/slightly lower run-times. So when you're not going break-neck speeds, it uses less energy, therefore, being safer than an LVC that will allow you to go as high as 90%-95% discharge before kicking in. It's a highly proven fact that if you routinely go over 80% discharge, it will kill your battery much sooner. Just about every LVC/monitor I've ever seen on the market will either cut out way too soon (not necessarily a bad thing on this one), or way too late (which is very, and much more common) and that's why I made my statement that they are pretty much worthless. If you HAVE to use one, I suppose it couldn't hurt as an extreme backup. But if it's going to cost you the price of a battery, I'd take the extra battery and my chances! If it was only $5 instead of 5 times that amount, we'd have an entirely different conversation. On top of all that, it's not like you're only going to be able to use a 4000+ battery for 5 minutes. You get at least 10-15 minutes of solid, hard running (and possibly longer in a lot of cases) and that's within the 'overly conservative' timed method.
As I said before, to each his own. [img][/img]
Not sure how it would make a difference. It will work well for both applications seeing you'll run them harder at the track in most cases, so that would put you on the conservative side when bashing. I just don't see why they become such a necessary thing when you can easily (and more safely) do without them. The point of timing your runs is to establish just how much you can use the battery. If you go out and do high-speed stuff for one battery, then the next you are just toodling around, your battery will be more than safe because your times will be set for high drains/slightly lower run-times. So when you're not going break-neck speeds, it uses less energy, therefore, being safer than an LVC that will allow you to go as high as 90%-95% discharge before kicking in. It's a highly proven fact that if you routinely go over 80% discharge, it will kill your battery much sooner. Just about every LVC/monitor I've ever seen on the market will either cut out way too soon (not necessarily a bad thing on this one), or way too late (which is very, and much more common) and that's why I made my statement that they are pretty much worthless. If you HAVE to use one, I suppose it couldn't hurt as an extreme backup. But if it's going to cost you the price of a battery, I'd take the extra battery and my chances! If it was only $5 instead of 5 times that amount, we'd have an entirely different conversation. On top of all that, it's not like you're only going to be able to use a 4000+ battery for 5 minutes. You get at least 10-15 minutes of solid, hard running (and possibly longer in a lot of cases) and that's within the 'overly conservative' timed method.
As I said before, to each his own. [img][/img]
The timer method is more consistent in the track because your throttle input is consistent throughout the run. I have a 23T motor in my touring car and it takes about 5 minutes to discharge my Orion 3800 30C lipo to 80% capacity (as recommend by Orion to increase number of cycles). Now when you go bashing in the parking lot or crawling on the rocks, how do you determine how long you should run? Throttle input will be varied, and there is no way to accurately predict how the battery discharges. So should I stop playing after 5 minutes "to be safe"? Or stop and check the voltage every now and then with a volt meter? And it's such a hassle to stop the timer every time you stop to check your car or take a break.
$25 to protect my $100 Orion packs plus the convenience and peace of mind is well worth it. Running lipos without an LVC is like driving a car without a fuel gauge. You can do it, but it's too much of a hassle, and it's stupid.
09-23-2009, 08:02 AM
#22
Senior Member
Thread Starter
Join Date: Aug 2009
Location: Washington, MO
Posts: 101
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
Peace brothers, Peace. I have run a car w/o a fuel gauge, in fact i am driveing one right now LOL. But thats beside the point, if skunk dosent want to run any type of timer or voltage cut off its his right. Myself I am gonna go with one of them cheap alarms just because I have NO experince with LiPo's. But I will also be testing my battery during the run just to get a feel for how long I should be able to use said battery. I wont take out a stop watch but keep an eye on my watch. Between that and the alarm I should be good. =)
09-23-2009, 09:27 AM
#23
Senior Member
Join Date: Jan 2009
Location: , PHILIPPINES
Posts: 248
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
I had a car too with a defective fuel gauge, and stupid me ran out of gas more than once [:@] Anyway the timer method will work if you're careful, I for one do not use a cutoff at the track. But for someone new to lipos, a cutoff or alarm is highly recommended. Peace 
03-18-2010, 10:49 AM
#24
Junior Member
Join Date: Feb 2010
Location: Smithville, IN
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
RE: LiPos and charger, this good?
Well, I left a lipo in my Super Cub LP after I crashed it about a week ago. According to my multimeter, I have .1 volt, .44 volts, and .75 volts in a 3S. The charger won't even acknowledge it exists. I suppose this ones toast as the Super Cub's receiver is always on when the battery is plugged in.
