Battery upgrade?

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Couchy   100 µW

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Battery upgrade?

Post by Couchy » Oct 22 2018 10:56am

Hey guys I bought a 14s7p battery linked bellow but now want an upgrade. Is there any problem adding cells to a battery to make say 18s7p or 18s#p as long as I get a new charger and either a new BMS or add wires to the existing one depending on what it is?

https://pirez.com.au/52v20ah-samsung-triangle/

Regards

Couchy

420b   100 W

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Re: Battery upgrade?

Post by 420b » Oct 22 2018 11:09am

The issue would be that the cells follow a different charge curve based on their lifetime. With a balancing board this is no problem.

Couchy   100 µW

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Re: Battery upgrade?

Post by Couchy » Oct 22 2018 11:10am

Is that a balancing BMS?

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amberwolf   100 GW

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Re: Battery upgrade?

Post by amberwolf » Oct 22 2018 11:14am

You can always parallel more cells, as long as they are the same chemistry, and you add the same number of cells in parallel with each group.

You're simply adding more capacity and more current capability when you do this.




However, if you add series cells, you have to replace the BMS, or add a new BMS for just the new cells, and series the two BMSs. That can add complications to both charge and discharge, if anything unusual occurs (sometimes the FETs can be damaged during those unusual events). But it can also work fine. You have to use the same number and type and capacity (or higher) of cells, and same C-rate or current capability (or higher) for the group, or else the new part of the pack will limit the capability and capacity of the pack to whatever it's limitations are.

You're adding more watt-hours, so more capacity, but not changing the current capability of the pack. You are also increasing the voltage, which means the rest of the system has to be capable of that higher voltage (controller, charger, DC-DC if any, etc).



There is a teensy itsy bitsy chance that the BMS in the pack has unused channels...but that would cost the original builder/seller more and so is very unlikely to be the case.

Couchy   100 µW

100 µW
Posts: 9
Joined: Oct 14 2018 5:31am

Re: Battery upgrade?

Post by Couchy » Oct 22 2018 11:50am

Thanks for letting me know. Have some research to do. Would try and use the same type of cells.

Regards

Couchy

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