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hilux01 asked

2 Systems - 1 reach 100% SOC, 2nd never do

Good day

Looking for some advice please help. I have 2 systems.

1ste system in my Overlanding vehicle consist of:

150w solar panel fixed

MPPT BlueSolar charge regulator 75/15

Smart shunt with BT connected to VictronConnect App

82Ah Lead Acid battery (6months old) that runs mainly a 52l NL fridge and some lights

I often find that SoC in the morning will typically be at around 90% so lets say Cumm AH = -8Ah

I find that the system have the SoC back to 100% before lunch here on a typical autumn day with good sun

2nd system in my Off road caravan consist of:

150w foldable solar panel

MPPT BlueSolar charge regulator 75/15

BMV712 via VictronConnect App

2 x 102Ah Lead Acid Gel batteries (5years old)

Runs 12v water pump, some lights and a NL 80L Firdge Freezer

I typically find on the first morning that the SoC is above 92% and that I have a Cumm Ah used around (-11 to -14Ah (depending on use etc))

However, the same day I will see that the second system will bulk charge for a short period and then drop the current to <1A when there is little or no draw on the battery. This then results on the battery never recovering the full Consumed Ah, as the fridge freezer pulls at around 3.4 - 4A per cycle and never gets back to the 100% SoC. I did see hpowever after 2x days of very little charge due to rain and overcast conditions that the current pushed to 4 to 5A when the SoC was below or around 80%

Help somewhere I am missing a setting on the second system either with bulk / absorption etc settings? Is it the charge current or tail current that is wrong? Can I fix this via the BMV712 on the battery or must I have the dongle to do the changes on the Controller? Is it a case of the age of the batteries?

Regards Henk

MPPT Controllersbattery chargingBMV Battery MonitorAGM Battery
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kevgermany avatar image kevgermany ♦♦ commented ·

What are the charge settings of the problem vehicle?

What are the settings of the BMV?

It sounds as if the charger and 712 do not match. Could also be wrong charger settings as well. Or tired batteries.

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