TonyReynolds wrote:I would like to order some of these for my eBike lighting, which is currently slated to be a single 25W 12VDC H3 halogen driving light.
I figure if I run 4S3P (12 cells), that will get me 13.2 nominal with 6.9 Ah, about 91 Wh. At 80% DOD, that would get me about 2.9 hours of runtime for the headlamp.
A couple things me stuck, as I'm I'm not a EE and I don't play one on TV:
1. What would I need for a charger and,
2. Would I need a BMS if I'm just running lighting, which is a steady current draw?
I could also do 16S1P (just 4 more cells) with a step-down dc-to-dc convertor to 12-14VDC, but I don't know whether that would get me any more runtime for the light, but it *would* give me extra Ah's as a "reserve" for my 52V 16S5P tringle battery if I used Andersons. I could simply unplug my main pack if I were to hit LVC on a ride and get a little more distance...
My recommendation and I think it might be the cheapest. If you buy these packs you will have to disassemble them and then put together the configuration you want. Each pack is 3S. I don't know why but I have a certain phobia of BMS's its just the way I am I can't trust em so I usually put balance connectors on every battery pack I have/make. Here is my recommended cheapest route to make what you described above.
1- You will need 4 packs total for 72$ shipped
2- For a charger if you don't have one the cheapest one that I can say works pretty good for its value is the imax B6 which you can buy for mid 20's on ebay. For it you will need a power supply it could be a bench or brick one. On ebay the cheapest one I think runs for 10$ shipped. With that combo you can charge up to 6S packs just in case. So a total of ~35$
3- If all you are running is lightning out of it then you don't need a BMS just charge it fully every time and balance once every couple of weeks.
If you would like me to build you such a pack let me know and I can assemble it for you and heatshrink it or put it inside a hard case enclosure with a 4S balance connector and powerpole andersons.
PM me for any more info on that
PS- BTW are you planning on running an HID 25wtt kit? I think this might be even better.