Battery Meter reads 6.6% on brand new battery bank

[Ambolorian]

I'm trying to troubleshoot why my battery meter reads 6.6% on a bank of three brand new Renogy 100ah AGM batteries.
I hooked up the shunt per the meter's directions but something must not be right.

I get 13.5 when I test the batteries with a voltmeter and all accessories hooked up run strong.
Is there a reset you're supposed to perform on the meter?

I drove the van to work and it charged up to 3.5%. Then I hooked up shore power and used the Inverter/Charger thinking it would charge faster than using my alternators but after an hour its only went up to 6.6%

Here's my rough setup:




What am I missing?

Thanks!

Mat Z

[Scalf77]

What battery monitor do you have?

Can you manually sync?

Have you plugged in and gone thru a full cycle. Bulk, Absorption, and Float.

They usually need a couple of cycles to get in sync.

[Ambolorian]

This model:







I didn't see a sync method..
I'll try a few cycles.

[1der]

What is the name and model of the
battery monitor? It does not, at least readily, show in the pics.

[1der]

Okay, looks like this one.

Here is a link to the instructions. Likely you need to calibrate the %SOC to 100%. Over night charge the batteries completely and make sure the settings are for the correct battery type.

https://www.rvhabit.com/post/install...itor-from-aili

You are essentially telling the meter that the batteries are 100% SOC so it has a starting reference point. As the batteries are drawn down the SOC should be closer to accurate.

As Scalf77 said, you should run the batteries through a full cycle a few times -100% to 10% and then recharge.

[Scalf77]

I expect they call it "capacity initialization"

[jonyjoe101]

I use the same coulombmeter. Once you set the high(14.4 volts / 100 percent) and the low (11.5 volts / 10 percent), also input your battery bank capacity. The coulombmeter won't go to 100 percent until the battery voltage reaches 14.4 during charging, then it will calibrate itself to 100 percent. No need to cycle the batteries.
If the voltage isn't getting up to 14.4 volts, you will be getting the readings you are seeing. You mention the voltmeter only reads 13.5 volts, next time your charging check the voltage as it is charging to see how high its getting.
For AGM you need to reach 14.4 volts everyday, otherwise they won't last long. They will lose capacity if they are undercharged everyday.

[doublevan2]

Well - I'm confused ! I've got a Renogy AGM 200 amp house batt on shore power - right at 2 years old. It's stored/covered off site and I check it every 3-5 days. The digital volt read out (cheap 12V read out from Amzn) shows 13.2 - 13.5 pretty much like clock work when I do this van check. Are you now telling me "jonyjoe101" that my batt is gonna die soon !? I was under the "understanding" from other forum input that this is a "float" status and "all is well." What do I believe now ??

From past posts and pm's - Scalf77 are you out there ?

[doublevan2]

I'm only mentioning Scalf77 for clarification as he seems to be posting replies on most questions regarding battery topics, etc. His name comes to mind before other qualified forum members -

[Scalf77]

Russ,
You are in plugged in and the charger is in float. This is fine and OK. I believe Jonyjoe101 is a full-timer, and thus using his battery everyday. This means he discharges it everyday, and thus his goal is to bring it back up to 100% everyday. It is true that AGM batteries should be charged back to 100% as soon as possible.

This is considered charging to a Partial State of Charge, this can be one of damaging aspects of AGM battery care.

My general recommendation is to always put your battery on a shore power charger and bring back to 100% as soon as possible. In your case your plugged in and you leave it on float. If you couldn't leave it on float, you can turn of and disconnect the battery until your next trip.

If you have a large enough solar system to fully charge your battery and get through absorption and charge in one day of solar great. This of course could be possible if you had a pretty good drive home and reasonably charged the battery, chances are you will be in absorption early enough.

I hope that kind of clarifies the statements