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platypus asked

Victron Battery Monitor doesn't seem to be discharging

My battery monitor seems to be stuck at 100%, even with several loads connected to it.


- I'm confident it's wired in the correct oritentation

- All loads are connected to one side, and it's the only thing connected to the NEG terminal of the battery


I wonder if it has something to do with my settings?


I have this battery: https://www.batteriesandsolar.co.uk/wp-content/uploads/2020/06/TN-Power-TN100-Data-Sheet-CLICK-HERE.pdf


And the settings I currently have are here:

screenshot-20220525-082419.png


I've messed around with the settings a bit:


- I moved the charge voltage from 12.8V to 13.8V.

- I've also moved the charge efficiency factor from 95 to 99

- I've moved the Peukert exponent from 1.25 to 1.05

- I turned off the "Battery starts synchronized" - this one I think could've been a problem, as I don't think it should assume the battery is chargd at the start


No idea if these are correct, and the data sheet i linked above doesn't really have those values. -- What should the settings be set to?

-- EDIT --

I took another read of the documentation and re-set:


- Voltage to 13.2V

- Moved the discharge floor to 15%


I wonder if the best bet is to remove the battery, fully charge it via mains, then "synchronize" the state of charge to 100%.


With a couple more loads, it's now down to 99% - but I still feel it's off. A fridge had been running at 1-5amps for three days now. It should be max in the low 90s.

BMV Battery Monitor
screenshot-20220525-082419.png (248.3 KiB)
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2 Answers
JohnC avatar image
JohnC answered ·

Hi @platypus

With Li the charge V curve is very flat, so it's important not to set the Charged V too low. Your link suggests charging at 14.6V, so you could try 14.4V. It also suggests a '0.02' Tail when fully charged. That's 2%, so 3% might be suitable.

What you could also do is set the SOC manually to (say) 50%, and watch it on the VictronConnect Trends graph while it's charging. It will sync to 100% when it's ready. With a low Charged V setting, sync can happen prematurely, and be useless.

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platypus avatar image platypus commented ·

Interesting - so if I manually set it to 50% and apply the settings you mention above it should right itself?

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JohnC avatar image JohnC ♦ platypus commented ·
@platypus

It should. But note that I used the words 'try' and 'might', and tweaking may be necessary for that perfect setting. It helps to understand why you're doing this, the manual (over 'n over if necessary) is a good start point. And pondering the graphs while it's happening I find quite informative, even entertaining.. :)

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mkuiken avatar image
mkuiken answered ·

Have Hi @platypus

Regarding you remark "All loads are connected to one side, and it's the only thing connected to the NEG terminal of the battery":

Can you confirm that only the shunt is connected to the NEG terminal of the battery?

Can you share a wiring diagram of your setup, and a photo of your shunt installed?

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