question

lebmaco avatar image
lebmaco asked

Battery Monitor not accurate??

hi all,

i have a victron battery monitor with the Bluetooth that connects to the app etc. have 2 X 100A Lithium Batteries connected in parallel. the fridge is running 24/7 and Trickle charge the front battery which feeds to the Redarc which feeds the Lithium. I would expect that the monitor would show 100% consistently but unfortunately it drops to weird stats like 80%, 60% 20% then it will come back up to 100%. Just wondering if there are settings that need to be changed or is the monitor now faulty? It only started doing this in the last 6 months.

battery chargingBMV Battery MonitorLithium Battery
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klim8skeptic avatar image klim8skeptic ♦ commented ·
You forgot to mention what Redarc product model you have or how it has been set up.?


You have a trickle charger that charges your start battery to what voltage (s)??

You have wired the Redarc to the BMV and battery correctly? Diagram or photos plz.

Details plz.

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lebmaco avatar image lebmaco klim8skeptic ♦ commented ·
Hi there I have added comment below with all the details - Many thanks!
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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Make some screenshots of your current settings.

There are already many questions about that topic here in the community.
Please use the search function.

All settings are described in the manual:
https://www.victronenergy.com/media/pg/BMV-712_Smart/en/all-features-and-settings.html

There are also some videos available:
https://www.youtube.com/watch?v=4ReljfO3k6M
https://www.youtube.com/watch?v=yMJ_vzB2avE
https://www.youtube.com/watch?v=mEN15Z_S4kE

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lebmaco avatar image
lebmaco answered ·

Hello thanks for all the replies have made some points below.img-20230104-111630.jpg

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From the start of the car:

25A charger is connected to the Optima Blue Top at the front of the car

This Feeds the rear of the Vehicle across 100A cable so loss is minimal


connects to Redarc - BCDC1225D

from there the negative connects to the Shunt with all the loads

Have also attached the configuration


img-20230104-111630.jpg (1.3 MiB)
img-20230104-111634.jpg (1.1 MiB)
img-20230104-111638.jpg (1.1 MiB)
img-20230104-111647.jpg (921.9 KiB)
img-20230104-111642.jpg (1.1 MiB)
img-20230104-111651.jpg (263.5 KiB)
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klim8skeptic avatar image klim8skeptic ♦ commented ·

The first thing to check is that all loads and charging sources are on the correct side of the shunt (bottom bolt). There are only 2 cables connected to that bolt. Where are the other negative leads from the loads going to? Follow this wiring diagram for connecting the Redarc, BMV and battery.

redarc-b.png

The next thing to confirm that the voltage at the input of the dc2dc is above the charge OFF voltage of 12.7v. The dc2dc will not start charging again until the input voltage is above 13.2v (standard dc2dc input settings). Your photo of the battery charger shows a battery voltage of 12.4v, the dc2dc will not be charging.

The yellow fuse at the battery feeds the dc2dc?

Your square circuit breaker under the dc2dc is an insurance claim in the making. Those breakers run hot, are prone to trip below their current rating, have excessive voltage drop, and have no value other than as landfill.

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redarc-b.png (185.0 KiB)