How to charge Sanyo battery 10s2p on my Backfire G2 to 75% only?

I am struggling with finding a way how to charge my Sanyo battery only up to 75%. It’s only because I want to increase lifespan, and because I am riding mostly short distances.

Is there a specific charger I can use to charge my 10s2p Sanyo Battery which I have in my old Backfire G2 to a preset percentage? Is there some charger from hobbyking or somewhere? I’ve tried those cheap charging control modules which you plug between the charger and battery from Aliexpress, but it seems they don’t work with my charger.

by not charging it all the way you do more damage


Yeah not exactly. The pack sustains damage from being unbalanced because cells discharge unevenly. The best option is to charge it to 90% with a slow charger and discharge it to 10% normally but bring it to 100% every 5 to 10 cycles to balance fully…and store it at 50%

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I also live on a hill and I am having this feeling I am hurting the battery charging it to 100% and going downhill

Not sure if this is what you’re looking for but I use an amazon smart plug to turn off the plug after a certain amount of time. Should work for your case too.

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That’s brilliant, however, I need ti know the exact time when to turn it off…

Buy a brick charger, use a volt meter, open the charger, change the potentiometer with a screw driver; then set desire voltage. It is good for your cells to fully charge them some times…And riding downhill fully charged, is not about damage to your battery, but sudden cut off for excessive voltage from BMS and loosing breaks…That it is a really dangerous situation…stay safe…

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Option B would be to buy a Battery indicator and unplug it ones it reaches 75%. I usually use a multimeter and measure the voltage. I usually stop it at 40v but charge it fully once in a while.

Not sure if something exists like that. A Device “powered” by your battery that sends a singla to a receiver (smart wall plug for example) that shuts off one a certain voltage is reached.

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I just estimate the time - my battery takes 6hr to charge from empty to full so I just charge around 4-5 hours.

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Thanks a lot for your answers. I just received 3rd charging control module from Ali and it seems to be finally working. I will test it more. It shows current Voltage and you can adjust it to stop charging at some Voltage.

If my Backfire is fully charged at 42V I set the module to 41.6V - that should be roughly 80 %, right? (because it doesn’t charge linearly…?)


41.6V is pretty much full, it’d probably be closer to 40.6

Is that a 20700b pack?

yes it is…

yesterday I found out the battery capacity decreased by 30%. I’ve tried to charge it fully, but it seemed somehow damaged by that Chinese module. I found out that actually my charger is faulty. I don’t know if it was because of the module or it was malfunctioning before that, but I stoped my experiments with this, and will charge it to full every time from now or I’ll buy the grin cycle satiator.

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Does it double the range? I have a backfire galaxy g2. My battery died after only 3 months of use from the indiegogo campaign. I think they used 4aH cheap cells. I wish made 20700b packs, they use genuine batteries, precision automated machine spot welding, 1 year warranty, individual cell level fusing, a pack fuse & PPTC thermal fuses on all signal wires, pack bms balance at 50%, 90% & not just 100%:bangbang::drooling_face::surfing_man:t4::battery::zap::electric_plug: Any interest for a 10s2p Sanyo 20700b pack, if we can get a group buy?

Sanyo 10s2p added some 30 % - 40 % more range so not 100 %, but the battery is rock solid stable. It’s well worth the money. Also the acceleration is better, battery sag smaller. The cells in Backfire boards were very low lifespan too

I wonder how 40T vs 20700b compare in range & if 40T 10s2p pack would fit 2017 Backfire G2. I asked backfire, but they didn’t respond.

I told them my board has been sitting dead for a year, wonder how many others from indiegogo g2 are stuck w/ dead battery packs.

by a timed charger