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westen avatar image
westen asked

Question on BMV and Battery Capacity Setting

Hello everybody, I wish you all well!

I have a question I hope you can help me get answered.


Suppose I have a 100Ah battery and a BMV Battery Monitor.

Suppose I want to keep this 100Ah battery at a minimum charge of 80% (for reasons of well being of the battery).

To make this clear to me, Suppose (again, sorry) I want the BMV's SoC to tell me 0% when it has in fact only reached 80% ...


2 questions:

Would I accomplish this by setting the battery capacity (of my 100Ah battery) to 20Ah?

Would this ("faulty" setting) create havoc in any way (I mean would this stop my batteries from properly charging, cause it to self destruct or cause any other devastating activity?


Thanks for your thoughts, I'm trying to understand how to set up this thing to my personnel liking.

battery charging
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3 Answers
wkirby avatar image
wkirby answered ·

The main problem with doing this is if suppose (sorry, I had to get that in) you discharge below 0%, then you'll not know by how much because the BMV will nt go negative. Alarms would not work below 0% if the battery does actually get into deep discharge territory.
I can totally see what you are trying to do, similar to a mobile telephone, 0 is th point where to stop. Less technical people would rightly ask why 80% means "flat battery". However, the purpose of the battery monitor is to give you an idea of the state of charge over the entire charge / discharge cycle and if you wish your target to be 80% SOC then aim for that.

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westen avatar image
westen answered ·

Hmmm..

I suppose ( ....) you've got a point there.

I'll target for 80% and aim for that.

Thanks (I suppose) for pointing me in the right direction!



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JohnC avatar image
JohnC answered ·

Hi @westen

You can set the BMV to alarm at 80% SOC, and there's also a Discharge Floor you can set to tell you how long (at existing discharge rate) it would take to reach 80%. Seems you're mostly covered, 'personal likings' aside.

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