Battery readout

[Bessy765]

2019 Burstner Iexo, Fiat 2.3 (150) fitted with 2, 95 amp AGM batteries. If I let the batteries run down to 80% when back on hook up the follow readings are showing on the display. Voltage 13.7, charge rate 0.0, 88% state of charge. This is after being on charge for three days. If after turning everything off I remove the main and small fuse next to the batteries. Wait a couple of minutes replace the fuses the percentage of charge will read 100%. This has been happening for sometime, the van has a Schultz EBL 630 with an 18 amp. Charger. Voltage at the batteries with two different voltmeters with everything disconnected after 2 hours is 13.6 volts. If I turn the lights on the amps will show a charge for a few seconds then drop back to zero. Cant understand why the percentage will read 100% if I remove and replace the fuse. If I keep the batteries above 95% this doesn’t happen.

 

[pappajohn]

Is the charger set to AGM perameters?
A 'wet' charger won't have a high enough voltage.

 

[Stealaway]

Is it that there is a load on the battery when you fit the fuse. Pulling the voltage and reading down.
It seems ok to me-- what's the problem

 

[Lenny HB]

Batteries may have had it that's a long life for rubbish AGM's.
Thry doing a controlled discharge test on the batteries to how they are performing.

First charge the batteries fully and leave it to settle for an hour then:-
Worth splitting the batteries and testing each seperatly as one may be dragging the other down.

For example if it's a 100a/h battery load it with a 5 amp load and run for 5 hours, this will represent a 25% discharge. (adjust load/time to suit the size of the battery)
Disconnect the load and leave to stand for at least 30 min then measure the voltage.
Repeat the test and you will have discharged the battery to 50%.
You can repeat again then it will be 75% discharged.

 

[Bessy765]

The problem is the batteries will not go above 80% state of charge even after three days on hook up. But if you remove both fuses by the batteries the put them back in the percentage of charge reads 100% I have a freezer box the two batteries off charge will run it for two days at the -22 coldest setting fine. Get the same results when only one or the other batteries are connected. They are both Exide premium and have never been allowed to drop below 80% van is garaged and on hook up