question

20871pault avatar image

Batteries apparently losing charge on light load

This is a new installation set up using default settings on smartsolar and multiplus II.

When first connected, Colour Control GX showed battery charge at 85% if memory serves. Over the course of three weeks, battery SOC indication has dropped to 30%. Apart from two very brief higher load scenarios (vacuum cleaner for 5 minutes and fridge freezer for 2 hours) the only load has been the base load of about 5-7W (according to colour control).

Colour control is recording voltage of 55+ Volts on the 48V AGM 230Ah battery bank (confirmed by meter on the battery terminals), so the smartsolar will not do an absorption charge for very long (1 hour on default) before reverting to float.

As I write this, it is 11:32am, bright sunshine, and VRM is recording a 9W AC load, batteries idle 11W, SOC 29%, 55.4V and current 0.2A, and PV charging at 50W.

What am I missing?

MPPT - Solar Charge ControllerMultiplus-IICCGX Color ControlSOC
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3 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

You wrote you use the default settings so I would recommend to first make all settings according to your system components.

Also please make a list of all the components in your system.
Is everything connected to the CCGX?
Do you have a BMV or SmartShunt?
Is there maybe any other charging source that is not monitored by the CCGX or is connected directly to the battery?

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tozz avatar image
tozz answered ·

is 50W PV expected? Could be if you have a single small panel or something, but it sounds very low.

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20871pault avatar image
20871pault answered ·

Tozz, I have 6 x 315W panels, so yes 50W is low. I had assumed this was because there was no load so the MPPT was only outputting 50W from solar to charge the batteries.

Matthias, my system comprises of the following:

6 x 315W solar panels

150/35 MPPT smart solar (connected by VEdirect to CCGX)

Multiplus II 48/3000W inverter (connected to CCGX over ethernet cable)

CCGX

4 x 12V 230AH AGM batteries in series

I have attached a circuit diagram of how they are connected for reference. solar wiring diagram.pdf No other charging source is connected to the batteries.

Since posting I have downloaded the configuration file from the Multiplus and modified the absorption voltage down by 0.2V to see if it was a problem with the Multiplus not registering that the charger had switched from bulk charge. This does not appear to have made any difference, however the charger was on float at the time. The batteries are currently recording an SOC of 19% and a voltage of 52.2V. As you can see from the graph over the last 7 days, Voltage min and max are more or less unchanged, suggesting this is not a charging problem. Voltage and Current last 7 days.JPG


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