Choice of battery.

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Choice of battery.

Postby talisman » Mon Aug 20, 2012 4:34 am

Seems to me that if I use the Trustfire A123 cells from DXtreme that I can rely on their over and undercharge protection and their inherent reliability to not need a special charger or balancer and can use my NIMH charger Any comment.
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Re: Choice of battery.

Postby cynr100 » Mon Aug 20, 2012 11:01 am

The Trustfires are Li-Io or LiFE, if you have a good Li-Po charger you should be able to set it up for LiFE, Accucel 6 has this ability by changing the battery voltage under Li-po from 3.7v to 3.3v.
I'm running some Samsung INR18650 Li-Io 1300mAh cells ,I have wired and packed, for my Tx batteries.

Not sure how much DX want for their Trustfires, you might want to check this out instead, if it suits your application:

http://www.hobbyking.com/hobbyking/stor ... _Pack.html

As to using a NiMH charger........."Nickel- and lithium-based batteries require different charge algorithms. Unless provisions are made, these two chemistries cannot share the same charger."
From
http://batteryuniversity.com/learn/arti ... t_chargers

Lots of cool battery stuff on this site.

:D
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Re: Choice of battery.

Postby kaptain_zero » Mon Aug 20, 2012 9:46 pm

You need to use the proper charger that understands the cell chemistry you are attempting to charge. A typical NiMH/NiCD charger is not equipped to handle Lithium based cells... Be they Lithium Ion, Lithium Fe or any other Lithium based cells as their voltage peaks and minimums are different.

As mentioned above, a basic hobby charger such as the Accucell 6 (around $23 from Hobby King) can handle Lipo's and A123 type LiFE cells, NiCD and NiMH packs as well as lead acid cells. They are not exactly expensive and will make your investment in battery packs last that much longer + make it safer for you. But, you do need to remember to set a hobby charger such as this for the correct battery chemistry, capacity etc.. Lithium Polymer, LiFE and LiIon are the 3 basic lithium cell types handled by most hobby chargers.... There are more types, but you don't often run into them in a model hobby situation.

Regards

Christian
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Re: Choice of battery.

Postby talisman » Tue Aug 21, 2012 12:39 am

Thankyou gentlemen. Seems my cheap option is not a good idea. So its off to HK backorder queue.
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Re: Choice of battery.

Postby Shotglass » Tue Aug 21, 2012 6:34 pm

trustfire a123? doesnt sound very legit
if you have genuine a123 cells you can charge them off pretty much any dc source with the correct voltage
for about a year or so the lifepo4 charger we used for out a123 packs (only works for 4 cell) was a cardboard box with an amp and a voltmeter (no real need for either but it does make look things at least vaguely professional) that we connected bewteen the a123 4s packs and a car with the engine running (the alternator puts out more or less exactly 14.4v)
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Re: Choice of battery.

Postby kaptain_zero » Tue Aug 21, 2012 7:57 pm

Shotglass wrote:trustfire a123? doesnt sound very legit


Good call, I neglected to check DX... they have nothing listed under a123, nor did a quick search for Trustfire LiFE bring up anything there.... Too many pages to dig through so I can't say for sure one way or the other unless the OP gives us a link to the cell he wanted to use, but if it was a Trustfire cell, it was most likely a Lithium Ion cell which must charged with with the proper charger for safety's sake.

While it is possible to charge a cell/battery using a variety of energy sources, it is best to stick to proper chargers, even if you know what you are doing. When you cobble something together... unless you sit there and monitor the charging, it's only all to easy to over charge and cause unnecessary wear and tear (or, depending on the actual chemistry involved, cause a possible catastrophic failure) on a cell/pack, all for the want of saving a paltry $25.00 on the proper charger.


Regards

Christian
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Re: Choice of battery.

Postby Shotglass » Tue Aug 21, 2012 9:40 pm

kaptain_zero wrote:While it is possible to charge a cell/battery using a variety of energy sources, it is best to stick to proper chargers, even if you know what you are doing. When you cobble something together... unless you sit there and monitor the charging, it's only all to easy to over charge and cause unnecessary wear and tear (or, depending on the actual chemistry involved, cause a possible catastrophic failure) on a cell/pack, all for the want of saving a paltry $25.00 on the proper charger.


i fully agree
that said however a123s are the most bullettproof things ive ever seen
we never balanced ours and like i said charged them off the alternator countless times and they still work just fine
in fact after a year of doing that the pack still was able to deliver enough amps for it to melt the insulation on one of the wires comming off it when we finally overdid it with the motor combo in the cars

for a while a friend of mine would take the too hot to hold in your hands for very long a123s out of his plane connect them directly to his car battery (with the engine running of course) and charge it back up right away
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