# 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.

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

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.

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

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.

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

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!

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.