Which Charger?
07-20-2013, 02:23 PM
#27
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RE: Which Charger?
ORIGINAL: mark IX
Rob2160, awesome video, thanx a lot....... That charger looks quite simple to use, do you know if the Accucel 8 has a function to trickle charge NiCd/NiMH batteries as well?
Thanx, Mark
Rob2160, awesome video, thanx a lot....... That charger looks quite simple to use, do you know if the Accucel 8 has a function to trickle charge NiCd/NiMH batteries as well?
Thanx, Mark
I have only used it for NiCds a few times (for an old Tamiya RC car that uses a flat pack of NiCds)
You can set the charge rate right down to 0.1 amp.
If you set a higher rate, it automatically reduces as the batteries become full.
One feature that worked really well was the "Cycle" which automatically charged and discharged the NiCd pack a number of times (user selected)
This brought the old Tamiya Battery back to life after many years of no use.
It also has a "storage" feature for LiPo which charges only to a lower voltage which is supposed to extend the life of LiPo batteries if you don't use them for a while
07-21-2013, 02:18 PM
#28
RE: Which Charger?
The only concern I have with that HK power supply (PS) is that it is 25A and the charger I have in mind says use a 30A min PS. I found this one on Amazon: 12V 30A DC Universal Regulated Switching Power Supply 360W
Specifications: -
Input Voltage: 115V/230VAC(90¡«132VAC/180¡«264VAC) -
Output Voltage: 12V DC -
Output Current: 0~29.2A -
Protection: Shortage Protection, Overload Protection, Over Voltage Protection
Weight: 660g
Size: 215*114*50mm
Shell Material: Aluminum
Safety Compliance: FCC / CE -Connection
AC power input -COM: DC power output "-" -V:
DC power output "+" -+V / ADJ: Adjust the output voltage (10%)
Note: -1. In-door use only, for this switch power supply is not waterproof. -2. 110V/230V is selected by switch. Before power on please check input voltage avoiding damage.
Thanx, Mark
) then you don't need to have 30 amps or better in a PS.
07-21-2013, 05:41 PM
#30
RE: Which Charger?
What I really need to know is the relationship between battery capacity, voltage, charge current required, and the charge time needed. There must be some cook book formula (equations, etc.) i.e. choosing a power supply 101, that is used to calaulate this out. That way, I can size the PS based on the batteries I'm trying to charge. [
]
Thanx, Mark
] Thanx, Mark
07-21-2013, 09:34 PM
#31
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RE: Which Charger?
ORIGINAL: mark IX
What I really need to know is the relationship between battery capacity, voltage, charge current required, and the charge time needed. There must be some cook book formula (equations, etc.) i.e. choosing a power supply 101, that is used to calaulate this out. That way, I can size the PS based on the batteries I'm trying to charge. []
Thanx, Mark
What I really need to know is the relationship between battery capacity, voltage, charge current required, and the charge time needed. There must be some cook book formula (equations, etc.) i.e. choosing a power supply 101, that is used to calaulate this out. That way, I can size the PS based on the batteries I'm trying to charge. [
] Thanx, Mark
http://www.rchelicopterfun.com/rc-lipo-batteries.html
The charger you are looking at is only 150 Watt x 2 - so any 350 Watt power supply should work fine.
Now I can size the charger and PS with the confidence I need. Although it looks like the ones I've chosen will suit my needs quite well.
07-23-2013, 04:06 PM
#34
RE: Which Charger?
There is one question I had about the charger I showed earlier. Then spec below says the charge current range is .1 to 7A. Would that be total current betwwen the two ports (its a dual charger) or does each port have a .1 to 7A range? Anybody know, Turnigy is not responding................
Thanx, Mark
Specs:
Charging Output: 2 x 150W (300w Total)
Input Voltage: 11~18v DC
Charge Current Range: 0.1~7.0A
07-23-2013, 04:45 PM
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RE: Which Charger?
ORIGINAL: mark IX
There is one question I had about the charger I showed earlier. Then spec below says the charge current range is .1 to 7A. Would that be total current betwwen the two ports (its a dual charger) or does each port have a .1 to 7A range? Anybody know, Turnigy is not responding................
Thanx, Mark
Specs:
Charging Output: 2 x 150W (300w Total)
Input Voltage: 11~18v DC
Charge Current Range: 0.1~7.0A
There is one question I had about the charger I showed earlier. Then spec below says the charge current range is .1 to 7A. Would that be total current betwwen the two ports (its a dual charger) or does each port have a .1 to 7A range? Anybody know, Turnigy is not responding................
Thanx, Mark
Specs:
Charging Output: 2 x 150W (300w Total)
Input Voltage: 11~18v DC
Charge Current Range: 0.1~7.0A
That current range will be for each port -
However, it will be like the Accucell 8 in that the maximum current will not exceed the 150 Watts per port
For example.. you are charging a 3 S battery and you set 7 amps as the charge rate.
12 volts (Average voltage during charge for a 3 S) x 7 amps = 84 Watts
This is well under the 150 Watt capacity - which means the charger will happily charge at 7 amps..
If you have a 6 S battery and you set 7amp as the charge rate...
24 volts x 7 amps = 168 Watts. The charger won't allow this.. it will automatically limit the charge rate to a lower figure that is not more than 150 Watts
On my Accucell 8 - when I set 7amps charge rate on a 6 S battery it peaks at about 6.7 amps and lowers slowly to about 6.3 amps as the battery charges.
The charger is always adjusting the charge amps to maintain no more than 150 Watts.. (I think you can see it on my earlier video)
So if your charger is 150 W and 7amp, you will only get the full 7amps charging 1-5S batteries,
Hope that makes sense..
07-23-2013, 06:44 PM
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RE: Which Charger?
ORIGINAL: mark IX
Rob, yes it does make sense. Thanx again....... So the amperage the charger will allow the battery to charge at, is related to how long it takes that particular battery to fully charge, correct?
Thanx, Mark
Rob, yes it does make sense. Thanx again....... So the amperage the charger will allow the battery to charge at, is related to how long it takes that particular battery to fully charge, correct?
Thanx, Mark
Think of it as a water tank being filled.. its the same principle..
5000 mah / or a 5000 litre pool...
If you charge at 5 amps.. that is 5000 milliamps per hour.. so it will take an hour to fill..
Just like putting 5000 liters an hour into a 5000 liter pool.. - that would take 1 hour...
That is charging at 1C
Charge a 5000 Mah Battery at 10 amps, it would only take 30 minutes ( 10 amps is 10000 millamps per hour) so it would take 1/2 an hour..
Charge a 5000 Mah battery at 1 amp... (1000 mah per hour ) and you guessed it.. it will take 5 hours..
Just like putting 1000 liters an hour into a 5000 liter pool...
Just remember 1 amp = 1000 milliamps per hour.. the math is pretty easy..
07-23-2013, 11:21 PM
#38
Senior Member
RE: Which Charger?
The basics of charging are fairly simple.
A 5AH (5000mah) battery charging at 1C would indeed require a 5A charge current.
Since W=IxE, a batteries voltage must be considered when looking at the wattage rating.
Lipo and other fairly common RC batteries are charged with what is basically a charger that changes from a constant current charger to a constant voltage charger. When the battery reaches the desired voltage, the charger either stops charging, or goes to a very low charge rate, referred to as trickle charge.
From this point, things start getting murky!
As batteries charge the voltage tends to rise, and at some point, the charge current starts decreasing.
Lead Acid batteries as well as some others, can tolerate a "trickle charge", and in some cases, it might even be desired.
Lipos seem to be happiest at a "storage" level (3.7-3.85 V per cell) for well, long term storage, which is any period over just a couple of days.
Since Lipos are perhaps pickier than the other common types - - - and of major concern these days,
Remember that the Lipos often do better with balance charging, and a battery is no better than the weakest cell.
A well balanced/matched Lipo can be balanced charged much faster than one that is not.
Some of my mediocre Lipos spend almost as much time balancing in the latter part of the charge process as they did to reach 80-90% of charge. A well balanced/matched battery seems to take less than 10% of the total charge time to balance and complete the charge.
What are rule of thumb charge rates?
Lead acid (Car Battery, etc) usually 1/10 C, unless otherwise stated.
What usually occurs is that when the Pb battery is partially charged, it will increase in voltage to the point that a voltage between 13.8 and 14.4V causes the charger to limit current to between a trickle charge rate or just a few amperes.
NiCads and NMIH are similar, and temperature rise is one of the factors that can be used. The charge/discharge/charge cycling can increase the storage capability.
LIFe batteries are another critter, and have a fairly flat voltage over the useful charge range. This is both a blessing and a curse.
(It makes it harder to determine charge level)
LiPos are quite useful because they have a low internal resistance, and have an energy density about twice that or above compared to the other
types. This can be quite useful for providing power to electric motors spinning a propeller, and can also provide high peak currents when needed. This peak current capability helps prevent "brownouts" caused by such things as electric retracts, digital servos,and the like.
Back to LiPo voltage per cell
4.2v is considered the nominal full charge. in theory this is really closer to 4.35v. However, our chargers need a safety range for
multiple reasons. (Accuracy, temperature, and variation in LiPos.)
LiPo Minimum safe voltage - Currently usually considered to be between 3.2 to about 3.4. older and smaller lipos may have a lower safe voltage of down to 2.75V or so. New Lipo types may have a higher minimum voltage of about 3.6v
Variation between cells - - less than 10mv is good, more than 15-20 mv is not so good. 20 mv or more can easily cause balance problems, and a loss of overall battery capability in usable mah.
When figuring cell resistance- - An indication of cell quality
Under load, a weak cell in a series of cells drops it's voltage compared to the other cells.
Under charge, things can get complicated. A saving factor is the low charge rate, compared to the usual high discharge rate (for LiPos)
Since the same current flows through series connected cells, the voltage variance between cells is an indication of the charge in each cell, as well as the cell resistance.
Cell resistance may be/is dynamic. The end result is that a cell that is not well matched with the others will show a different voltage, and have a different charge percentage.
A 5AH (5000mah) battery charging at 1C would indeed require a 5A charge current.
Since W=IxE, a batteries voltage must be considered when looking at the wattage rating.
Lipo and other fairly common RC batteries are charged with what is basically a charger that changes from a constant current charger to a constant voltage charger. When the battery reaches the desired voltage, the charger either stops charging, or goes to a very low charge rate, referred to as trickle charge.
From this point, things start getting murky!
As batteries charge the voltage tends to rise, and at some point, the charge current starts decreasing.
Lead Acid batteries as well as some others, can tolerate a "trickle charge", and in some cases, it might even be desired.
Lipos seem to be happiest at a "storage" level (3.7-3.85 V per cell) for well, long term storage, which is any period over just a couple of days.
Since Lipos are perhaps pickier than the other common types - - - and of major concern these days,
Remember that the Lipos often do better with balance charging, and a battery is no better than the weakest cell.
A well balanced/matched Lipo can be balanced charged much faster than one that is not.
Some of my mediocre Lipos spend almost as much time balancing in the latter part of the charge process as they did to reach 80-90% of charge. A well balanced/matched battery seems to take less than 10% of the total charge time to balance and complete the charge.
What are rule of thumb charge rates?
Lead acid (Car Battery, etc) usually 1/10 C, unless otherwise stated.
What usually occurs is that when the Pb battery is partially charged, it will increase in voltage to the point that a voltage between 13.8 and 14.4V causes the charger to limit current to between a trickle charge rate or just a few amperes.
NiCads and NMIH are similar, and temperature rise is one of the factors that can be used. The charge/discharge/charge cycling can increase the storage capability.
LIFe batteries are another critter, and have a fairly flat voltage over the useful charge range. This is both a blessing and a curse.
(It makes it harder to determine charge level)
LiPos are quite useful because they have a low internal resistance, and have an energy density about twice that or above compared to the other
types. This can be quite useful for providing power to electric motors spinning a propeller, and can also provide high peak currents when needed. This peak current capability helps prevent "brownouts" caused by such things as electric retracts, digital servos,and the like.
Back to LiPo voltage per cell
4.2v is considered the nominal full charge. in theory this is really closer to 4.35v. However, our chargers need a safety range for
multiple reasons. (Accuracy, temperature, and variation in LiPos.)
LiPo Minimum safe voltage - Currently usually considered to be between 3.2 to about 3.4. older and smaller lipos may have a lower safe voltage of down to 2.75V or so. New Lipo types may have a higher minimum voltage of about 3.6v
Variation between cells - - less than 10mv is good, more than 15-20 mv is not so good. 20 mv or more can easily cause balance problems, and a loss of overall battery capability in usable mah.
When figuring cell resistance- - An indication of cell quality
Under load, a weak cell in a series of cells drops it's voltage compared to the other cells.
Under charge, things can get complicated. A saving factor is the low charge rate, compared to the usual high discharge rate (for LiPos)
Since the same current flows through series connected cells, the voltage variance between cells is an indication of the charge in each cell, as well as the cell resistance.
Cell resistance may be/is dynamic. The end result is that a cell that is not well matched with the others will show a different voltage, and have a different charge percentage.
07-24-2013, 08:13 PM
#40
Senior Member
RE: Which Charger?
Actually, space, weight, and CG permitting, I'd rather use two or three battery packs to reach 6 to 8Cells.
Why?
A bad cell only takes out a part of the total, instead of the whole pack.
The larger batteries have started to be built as a combination of say a 4Cell and 2Cell or a second 4Cell pack to meet shipping regulations.
Many of the chargers will charge up to 6Cell batteries, but not 8Cells.
Two, three, or four cell packs are easier to replace, due to availability and cost of a single pack.
Why?
A bad cell only takes out a part of the total, instead of the whole pack.
The larger batteries have started to be built as a combination of say a 4Cell and 2Cell or a second 4Cell pack to meet shipping regulations.
Many of the chargers will charge up to 6Cell batteries, but not 8Cells.
Two, three, or four cell packs are easier to replace, due to availability and cost of a single pack.
08-12-2013, 01:39 PM
#43
http://www.hobbyking.com/hobbyking/s...dProduct=42483
yup, they do, their links are different for the USA warehouse VS the international.
Hobby King does not have a great customer service track record IN MY OPINION, (I've placed dozens of orders with them, but their site can be a bit quirky.)
that being said I do still order from them. they seem to have customers that love or hate them.
(I show that charger in the USA warehouse for ~ $41 plus $12 for Priority mail shipping.)
yup, they do, their links are different for the USA warehouse VS the international.
Hobby King does not have a great customer service track record IN MY OPINION, (I've placed dozens of orders with them, but their site can be a bit quirky.)
that being said I do still order from them. they seem to have customers that love or hate them.
(I show that charger in the USA warehouse for ~ $41 plus $12 for Priority mail shipping.)
08-12-2013, 01:42 PM
#45
here's the link for the 110V input power supply in the usa warehouse...
http://www.hobbyking.com/hobbyking/s...dProduct=19680
(you may now see what I meant about their site being a bit quirky... )
http://www.hobbyking.com/hobbyking/s...dProduct=19680
(you may now see what I meant about their site being a bit quirky... )
08-12-2013, 04:36 PM
#46
I just visited HK's website and..... naturally, I have to pick the charger that is not available in the USA warehouse!!! Looks like I'll have to deal with the S&H at the international warehouse........ BTW, I'm getting the power supply at Amazon.
Mark
Mark
09-25-2013, 02:01 PM
#47
Ok, guys I got my new Turnigy Mega 300w 8s Dual Balance Charger/Discharger, from Hobby King. It's about a month old and I finally had some time to try it out. Well it doesn't seem to be working!!!
Prob #1 - I can't seem to get the display screen to take me to the "user setup" screen to do the initial setup. The buttons cycle thru the batt types, size, etc but no user set up screen
Prob #2 - None of the buttons for the 2nd port will respond when I touch them.
Not sure if Prob #2 is related to Prob #1. There does not seem to be a reset button anywhere. The directions don't have a very good trouble shooting section. I wonder if I should contact Turnigy directly or go thru HK customer support.
Does anyone have any experirnce with this particular charger?
Thanx, Mark
Prob #1 - I can't seem to get the display screen to take me to the "user setup" screen to do the initial setup. The buttons cycle thru the batt types, size, etc but no user set up screen
Prob #2 - None of the buttons for the 2nd port will respond when I touch them.
Not sure if Prob #2 is related to Prob #1. There does not seem to be a reset button anywhere. The directions don't have a very good trouble shooting section. I wonder if I should contact Turnigy directly or go thru HK customer support.
Does anyone have any experirnce with this particular charger?
Thanx, Mark
09-25-2013, 02:31 PM
#48
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The peril of hobby king, I think you have to post the charger too china even though its bought in a different warehouse. It may of changed now but that's how it used to be.
Hopefully its just the manual isn't that good and you can figure it out to work.
Hopefully its just the manual isn't that good and you can figure it out to work.
