question

fesolar avatar image

soc wrong around 50% ?

hy

i have a probleme with a bmv 700

one off my customer make a discharge test on a systeme with 24 V (2 bat agm 125Ah) .

he had fully charged individualy the batery before start the test.

the test start with a soc at 100 (on bmv and in real because the 2 battery was fully charged)

you can see below the test:


the probleme is he had just loking the soc and suddenly, all system broke done.

the theorical consumption is minimum 0.4A, the real cunsomption see by the bmv is 0.4 A

so if we calcul the Ah used, we arrived around 120Ah so it's look corect with the 125Ah off the battery, but the soc calculed by the bmv (around 50%)when shut down) is not good.

i had checked the bmv parameters, but it'look ok:

during the test there is only bmv, venus and the load conected and nothink conected between the batteri - and the shunt .

i don't anderstand why the soc is aproximatively 50% faults.

do you have an idee ?

best regards


BMV Battery Monitor
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2 Answers
fesolar avatar image

at first, i was thinking about this, but there's no multiplus an quatro in the system during the test only bmv and mppt.

i had just chek and the curve of the bmv soc is the same off the gateway so the information is comming from the bmv !

it's the first time a see this.

for information it's bmv firmwar is the v3.10, normaly it's the last one !

br


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John Hagtharp avatar image

My first suspicion is that your Venus device (ccgx etc) and therefore vrm might be using a different battery monitor, possibly the built-in monitor in a Multiplus or Quattro, which is configured with a different capacity. Have you confirmed during discharge that the SOC displayed on the BMV itself matches what you're seeing in vrm and on the Venus device?

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