Batteries and charging question
 

Hi all,

so I can fly on one batteries pack 500 mAh about 3-4 safe flights? I just want to fly more without wondering if there is enough power up there.

is the setting in the picture works?

Can this charger in the picture to charge Rx batteries between flights from a 12V cell? Or there is a better way to do it?

Are these hydrimax any good for 10 flights?

its just after the Field box discussion is this the right panel?

Thanks
Alex

RE: Batteries and charging question
 

yes it will work ok.
If you're thinking of changing batteries at the field ,to fly more. I wouldnt . the battery pack is a big part of weight and balance.
Use the field charger instead.
10 flights will be a chore

RE: Batteries and charging question
 

Yes, the charger will work. Another option is to buy NiMH battery packs instead of NiCad. You can buy a NiMH pack that will provide over 2000 mah and will be the same size as the 500 mah NiCad pack.

RE: Batteries and charging question
 

I got a Load Voltage checker from Tower to check batteries between flights. It's made by hobbico. If you get a volt meter I would make sure it checks under load. Another way if you don't have a load checker is to turn things on and move controls. Then turn off and check voltage. This should take care of any "surface voltage"

I found it is just easier to get the load volt meter.

Just my 2 cents.

P.S. I learned the hard way not to just take it off the charger and check voltage with a digital volt meter. The result was lost control midflight. This was after the battery read 5.2 volts as soon as it came off the charger. (I didn't have it plugged in more than 3 hours) And it was dead before this. The dang weather was perfect and I didn't use my head before leaving the house.

Del

RE: Batteries and charging question
 

Ok piper_chuck said get NiMH battery with 2000 mah on average how long will the battery last? Bare with me I'm new.:D

RE: Batteries and charging question
 

Thanks Guys.

piper_chuck, what kind of charger do i need for 2000 mAh Nimh?

Thanks

Alex

RE: Batteries and charging question
 

Your TX charger will work, you just need to let it charge MUCH longer.

RE: Batteries and charging question
 

If your using the Spectrum radio like I have they charge at 50ma. That 40 hrs to charge 2000 ma pack [X(] I bought a charger and a 1650 ma pack for the plane as 30+ hrs to charge was a bit much.

RE: Batteries and charging question
 

I have one JR charger that outputs at 150mA for the TX connector.

For the larger packs a higher output will be better, but you do not want to over do it too.

RE: Batteries and charging question
 

[8D] Thanks alot Guys, it helped, now i need to figuer out how to install all these things on a future field box

Alex

RE: Batteries and charging question
 

First, you should be able to get more then three or 4 flights off your existing pack. buy a loaded volt meter as suggested earlier. Tower has one for $10 and the correct cables for your radio. Don't even think of charging a pack more then 700 ma with a 50 ma charger, it will never charge fully and you will crash. Use the volt meter on every flight untill you get an idea how much you can fly in reality before spending a bunch of money. Make sure you give a good overnight to your batteries before you go fly and never use a fast field charger if you can avoid it, your batteries will be happier. If you need to ,you can go to a 1000-1200 ma pack but remember your transmitter will run out of juice to. Make sure to charge whatever you end up with a 10% charge rate.

RE: Batteries and charging question
 

Be carefull of accepting any advice on getting X number of flights from a given pack.

The big variable is how stiff your linkages are and if you have anything binding esp. if it causes servos to stall. We have a standard trainer set up that we recommend to beginners. Set up with everything free I will fly for 1.5 hours before recharging. A binding set up will have gone to low battery before the hour is reached.

RE: Batteries and charging question
 

It also depends on the duration of your flights, if they are mostly simple circuits, or extreme aerobatics (more servo movement)and number of servos in the model.
The 2000mah Rx Nimh pack is a good suggestion. You want to be able to charge it at arount 150 - 200ma's.
Another advantage of Nimh over NiCd is the metal hydride cells do not develop a memory like nicads do.

RE: Batteries and charging question
 

Give up on that memory thing, its a hold over from the Sixties when NASA was doing very precise charge and discharging of batteries to the same point. Not a problem these days. Nicads are generally still considered the most reliable battery out there and will take more abuse and have a lower internal resistance. Not to say that the other options won't work just fine. The downside to Nicads is weight and they are more toxic. I just don't see a need to spend money untill you really need to, If you need to, thats great, but lets see if you need to first.

RE: Batteries and charging question
 

Thanks P-40 DRIVER

i must be hooked up to this hobby sooner then i tought i would be.

I have more RC equipment then i need for this first plane.

whats you said is true.

i'll wait with it.

thanks again

From too many trees i cant see the forest.

Alex

RE: Batteries and charging question
 

It's impossible to say exactly. The reason is the type of flying you're doing, lazy circles in the sky will use much less power than aerobatics, the size of the plane, and the number of servos will all determine the amount of battery used. I bring a battery tester to the field and check the voltage BEFORE the first flight and then regularly throughout the day. When the voltage gets to a certain point I stop flying the plane. Testing the voltage is easier if you install the switch and charging jack in something like this: http://www2.towerhobbies.com/cgi-bin...&I=LXJ778&P=ML

RE: Batteries and charging question
 

The guideline I've seen for nimh batteries is that they charge at about 67% efficiency. This means that you need to put in about 1/3 more power than their capacity. So, if the pack was completely dead, you would need to add around 2600 mah to fully charge it. Divide this by the rate of your charger to get the time.

Having said this, it's obvious that the battery would not be fully dead when you begin charging it, so you will need less time. If you keep the charging current low, below the 10% capacity of the battery level, then you minimize the risk of damage from charging too fast or over charging due to leaving the charger on too long.

When I made the switch from standard battery packs to larger capacity and started using some 5 cell packs for certain planes and boats, I decided it was time to get a better charger too. I found there are lots of good chargers out there. I ended up with the [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXEYD4&P=ML]Hobbico Accucycle Elite[/link]. The reason I chose it was because it comes with a 110 volt power supply but can also work off of a 12 volt source, can charge/discharge 2 different batteries at the same time, and includes a digital display to report the status/results of the charge/discharge. I use the discharge capability to occasionally test the capacity of the battery.

RE: Batteries and charging question
 

P-40, intresting that you should say this. The Spectrum radio's (DX7) come with an 1100 ma batt & 1500 ma in the Tx. Spectrum has actually been picked on for this and newer models will have a 100 ma charger. I did head the warnings I read here and ordered the battery monitor someone posted a link to [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&W=001349828&I=LXHDJ2&P=K]monitor[/link] On a personal note, I went to the 1600 ma pack due to wanting 6.0v

RE: Batteries and charging question
 

Really? Gosh, I better tell my wal wart charger it's not up to the task! [X(]

Sarcasm aside, I've seen this assertion several times. The 10% figure is not a MINIMUM, it's a guideline MAXIMUM for safe slow-charging. Staying at, or below, 10% provides relatively fool proof charging. Going above 10% can be done, but requires closer monitoring or a charger that can detect peak and shut off or switch to a lower current. I've charged plenty of 2000+ mah batteries on the standard wall wart charger that puts out less than 100 mah. While this is not a particularly fast method, if given enough time they do reach full capacity.

RE: Batteries and charging question
 

Yup...

Heck I regularly charge 27Ah (that's right AMP not MILLIAMP) sealed batteries with a 150mAh charger.

It takes a long time ( more than four days ) for a full charge after a long weekend at the field, but I don't have to worry about damaging the batteries as this is practically a trickle charge.

This is how I regularly charge my field box batteries, that I purchased from UPS vendors. In turn I found that the UPS's charge the batteries at this rate too.

And yes I've verified full charge and capacity with my ICE charger just to assure myself that the 27Ah battery was being fully charged.

I also charge my 2000mAh NIMH batteries with 50 & 100mAh chargers just fine too.

Also verified to obtain full capacity through actual tests.

RE: Batteries and charging question
 

You might want to check out "SR Batteries" website, They build batteries for the aerospace industry, RC just being a side line for them and do some reading. Thats where my info came from amoung other sources. Its not that this or that might or might not work, Its about taking the least risk to get the job done without wasting a bunch of money. Nicads are still the most reliable battery out there, charge at a 10% rate, and use a loaded volt meter to check condition before every flight and chances of failure will be greatly reduced. Very cheap and reliable.

RE: Batteries and charging question
 

Yeah, been there, seen that... understand the logic, but you can nevertheless safely charge at the lower current w/o damaging the batteries and at the same time getting full power from the charge.

It just takes longer... as long as you are over the self discharge rates.

RE: Batteries and charging question
 

just turning on the radio and moving servos is NOT enough. nicads by nature give almost full power -right up until the moment they die! you need to use a ESV -Expanded Scale Voltmeter- lots of hobby companies make them- they are all over the place at swaps for about $5. field chargers can be used & there are several types-peak detection, constant volt types. as long as you do not charge at excessively high rates you will likely not damage your batteries. continued fast charging( complete charge in 15 min or so ) can cause venting as timing at this rate is very critical. you should still check with ESV. depending on the battery condition, type & # of servos 3-4 flights should be the minimum # . ive gotten 10 long flights on 3 channel planes easily - yes, it was ready for recharge.

RE: Batteries and charging question
 

Thanks i'll look into it

Alex

RE: Batteries and charging question
 

I had a 700ma 9.6 volt battery in my futaba radio charging it fully would get me 22 mins of the radio being on. Not flying. Bought a triton cycled it a few times now i can get 90 mins out of it...........That must be lack of memory in a nicad...HA HA ...It can't remember how it use to work when it was new. It has been replaced by a Nimh....Just my 2 cents