Knocking a battery pack together on the cheap

Batteries, Chargers, and Battery Management Systems.
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tjgaryiv60
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Knocking a battery pack together on the cheap

Post by tjgaryiv60 » Jan 08, 2018 11:52 pm

Dogman

You have helped me before thank you. I need a new battery for my fat tire off road bike.
I wanted to know if LIFEPO4 is a good option. I got a Mxus V3 DD motor and a power velocity
18 mosfet programmable controller. Battery current up to 70a and phase up to 200a. My current
battery is 72v 20ah with 40a bms. It is not powerful enough. Here are two pre-built pack options.

72v 40ah 60a bms LIFEPO4

https://www.aliexpress.com/store/produc ... 30b7as7wmA

72v 20ah 60a bms LITHIUM ION

https://www.aliexpress.com/store/produc ... f36avO1GhB

Jack

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amberwolf
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Re: Knocking a battery pack together on the cheap

Post by amberwolf » Jan 09, 2018 12:08 am

If you need
tjgaryiv60 wrote:
Jan 08, 2018 11:52 pm
Battery current up to 70a
for more than momentary bursts, then anything less than that (like these)
72v 40ah 60a bms LIFEPO4
72v 20ah 60a bms LITHIUM ION
is insufficient.

If you only need momentary bursts of current that high, and the BMS (and cells) can do that, then as long as the cells are really made for whatever the sustained current you'll need is, then they might work.

Otherwise you're (at best) pushing things to their edge too much, and that reduces the lifespan of batteries, and can overheat the power electronics inside the BMS (which is usually contained inside the pack where it can't shed heat).

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