Proper setup BMV712 w/ 2 agm batteries in parallel

Question

question

supergas193 asked May 21, '19

Proper setup BMV712 w/ 2 agm batteries in parallel

Just installed the BMV712 along with 2 west marine group 24 agm batteries rated at 79Ah each. M on a Morris g and want to be sure that I don’t return to the boat with. Dead house batteries. Went online and found this setup but not sure if it is correct.

Battery capacity 158

Charged voltage 14.1 V

Tail current 2%

Peukert exponent 1.12

Charge efficiency factor 97%

After entering these settings I found the BMV712 exporting the following

12.84v

-2w

-,15a

Am I ok with all of this, or is this too much draw since all the main battery switches are off?

And will be greatly appreciated

Thanks,

Judith Ann

monitoring

2 |3000

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

Modifications Space

Node Red Space

Answer 1 · 2019-05-21T05:54:21Z

JohnC answered · May 21, 2019 at 05:54 AM

Hi Judith. As you've found already, the BMV is a highly configurable device. Accurate when configured with accurate parameters.

Your "-2W" is likely just a zero-error, and the manual describes how to deal with it: https://www.emarineinc.com/pdf/VictronEnergy/BMV-700%20Manul-English.pdf See section 4.2.09 The BMV712 standby spec is '<1mA', which is tiny, and if your batts are isolated, likely irrelevant.

Unfortunately a lot of consumer batts don't provide much help setting this stuff up. Just guessing now, but your 'Tail' and 'Peukert' might be a little low, and the 'Efficiency' a little high (variable in itself, as it has to account for batt self-discharge too). From memory now, but Victron for agm suggest 1.25 for Peu and 0.95 Eff as suitable kickoff points.

Victron actually has a 'Peukert Calculator', but relies on at least a couple of the batt maker's C/Ah figures. Most start/general purpose batts don't show those, and I can't see them either on a quick look at yours.

Familiarity with the manual and what these things all mean will help. Don't rely on SOC til then, but if you go aboard and your standing agm's are 12.5V or greater, then they're ok.

Fair winds..

2 |3000

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

question