Is my battery safe from over discharge?

Batteries, Chargers, and Battery Management Systems.
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Electric Earth   100 W

100 W
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Joined: Nov 11 2018 8:02pm

Is my battery safe from over discharge?

Post by Electric Earth » Dec 22 2018 7:25am

I didn’t find a specific answer to this. I know the BMS is there to make sure the pack charges safely, but does the BMS also mean the battery pack is safe from damage due to being discharged too far? I ran the battery low enough yesterday that the bikes controller, which also has a low voltage cut-off, shut down power if I gave it too much throttle. Is that OK since the pack has the BMS?

john61ct   100 GW

100 GW
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Joined: Dec 18 2018 2:06pm

Re: Is my battery safe from over discharge?

Post by john61ct » Dec 22 2018 10:28am

Don't we need a link to the BMS and battery to answer?

Some are adjustable.

For LFP for example I would not allow below 2.9V, maybe 2.8V for higher C rates.

For House loads, 3V.

Volt_Ampere   10 W

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Re: Is my battery safe from over discharge?

Post by Volt_Ampere » Dec 22 2018 11:27am

You should set your bike's controller to shut down before you overdischarge your battery. Don't rely only on the BMS.

jonyjoe303   100 W

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Joined: Aug 31 2017 9:44pm

Re: Is my battery safe from over discharge?

Post by jonyjoe303 » Dec 22 2018 11:57pm

yes with a bms the battery is safe. The bms usually shuts off when one of the cells reaches its over discharge limit. The bike controller monitors overall voltage and will usually activate before the bms. Your battery will be ok.
But if possible you might want to add a voltage monitor to see the battery voltage in real time. Thats just so you never have to wonder whats going on with the battery.

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