Battery Choise HELP

[Momato]

Hi All

Some newbie questions:

I need a battery for a MTB helmet light (three XR-E leds on a bFlex driver). I need approximately 3h runtime (at 750 or 1000 mA I guess?).

Is Li-Ion the way to go?

Is there any good EU sellers?

Should I get a finished pack with PCB or just buy cells/PCB and solder myself?

What kind of charger will I need to charge the finished 14.8 V package?

Thanks alot for a very nice forum

BR Morten

 

[Momato]

Re: Battery Choise HELP - Tenergy on eBay???

Bump - AND I found this Tenergy one http://cgi.ebay.co.uk/Lithium-Li-Io...hZ014QQcategoryZ34063QQtcZphotoQQcmdZViewItem

Even with import taxes it is still cheap, or?

BR Morten in Denmark

 

[SilverFox]

Re: Battery Choise HELP - Tenergy on eBay???

Hello BR Morten,

Welcome to CPF.

Li-Ion cells will give you a smaller package, less weight, and you won't have to factor in self discharge rates. The pack you listed seems like it should work.

A potential problem is that there is no provision to balance the cells in the pack. If they get out of balance, you will end up with sub standard performance. I believe each cell is protected, so you won't blow things up, but you may end up with one cell being charged to a higher level and other cells being not fully charged.

A charger capable of charging Li-Ion cells would be required for this pack.

Another option would be to get a pack made up of NiMh Sub C cells. These may be available from your local RC hobby store.

Tom

 

[Momato]

Hi tom

Thank you for the info - I have read about balancing, but I have not seen battery packs with a balancer wire connected (at e.g. batteryspace). Do you have a link to a nice package? Or should I just make a pack myself (i.e. order a PCB, some 18650's and a balancer/charger)? Are there any significant pitfalls I should be aware of? What about the initial "conditioning" (??).

Best regards, MOrten

 

[SilverFox]

Hello MOrten,

You will have to check out the hobby sites. The RC people use packs that allow for balancing in their airplanes. You might also ask LuxLuthor if he could put together a pack for you.

Tom