New build help. Is this safe?

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www.recumbents.com   10 kW

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Re: New build help. Is this safe?

Post by www.recumbents.com » Feb 23 2021 4:43pm

With 20s 10p I'd get an 80A continuous BMS and at least a 100A controller. You won't need that much 99% of the time unless you are offroading or racing or a loon but it's good to have the overhead. Hopefully you get a controller that will allow you to set a max current of 80A and a min pack voltage.

Warren

webosplash   1 mW

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Re: New build help. Is this safe?

Post by webosplash » Feb 23 2021 5:23pm

E-HP wrote:
Feb 21 2021 12:10pm
webosplash wrote:
Feb 21 2021 9:47am
I am asking, I have 200 35e cells so a 20s 10p would run at 80a as each cell is rated 8a each continuous but the max output on the datasheet says max 13a so do i get an 80 a bms for my cont. rating or my max......................?
Goes back to your assumptions for your used cells, since only you r can test their condition.

EM3EV seems to be a highly recommended and knowledgeable battery builder on this forum. They have the 35E cells among their selection of quality cells. They are conservative with cell ratings, balancing performance and longevity. For 35E, they use 5A continuous and <7A max/burst for their discharge ratings when configuring their packs and BMS. They are using new cells.

https://em3ev.com/product-category/ebik ... y-in-case/
do you think i can just limit the draw from my controller as i've already bought everything . I am still in the process of testing the cells. The other pack I had, I used less than 15 times and never ran them to hard. They were 13s 8p and had a 20a bms on them.which i thought was a bit low. I pull around 4000-5000 watts for my take off( much less if i take it easy) but it really is for only a split second
the pack ran very good but the acceleration was just to slow and i much prefer to roll with traffic as i feel safer that way. I dont really have an interest in an e bike I'm striving for the moped route. I am an avid cyclist and while I'm on this bike I don't want to pedal. i was on a budget and so this is what I've come up with.

thoughts?

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E-HP   1 MW

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Re: New build help. Is this safe?

Post by E-HP » Feb 23 2021 8:36pm

webosplash wrote:
Feb 23 2021 5:23pm
do you think i can just limit the draw from my controller as i've already bought everything .
Yes, and probably a more reliable way of limiting current.

webosplash   1 mW

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Re: New build help. Is this safe?

Post by webosplash » Feb 25 2021 8:47pm

is there a way to discharge cells just for the sake of discharge need to bring my batteries all down to level and I still have over a hundred left. Im currently pushing out about 12 cells a day. Can I accomplish this task any faster without buying 3 more chargers (pondering doing so)? is it ok to discharge all 4 @1a on the opusBT-C3100

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