This has become a rather interesting study, zooming into the response of SOC to V-Batt and V-Batt

As the plant list increases so more data becomes avaiable.

We have identified what might just be a firmware upgrade or a problem with a battery.

Looking at the data I have found that all the sites which have Sunsynk batteries have a similar pattern. The V-Batt and V-BMS will be equal, however at some point there will be a difference of around 2 volts, what I have learnt is that so long as the lines are equal, the battery will stay at 100 % SOC.

However if one of the lines taper off, you will notice a drop in SOC.

All expect 1 Sunsynk battery we have installed stay at 100% SOC and the lines are equal.

We have one battery which started off with just a 1 % drop to 99%, it didnt seem like there was an issue, its 1 %, really whats 1 %, however it has been 5 months since the battery was installed and it has slowly got worse (dropping to 95%).

It has been a challenge back and forwards to technical support, firmware upgrades (which seems to be the solution to every problem with inverters and batteries).

We have just installed a different brand of battery, saved the customer almost R10k, but here is the first thing I noticed about this cheaper battery, the same issue, a drop in SOC and the same downward trend.

Lets see if the firmaware upgrade sorts it out. If it does then we will request a firmware upgrade for the cheaper brand.

It is a good idea to let your backup system run for a couple of weeks before you start sing system mode timer and stuff, to see if the SOC charge drops below 100 %.

IF you see a 2V difference on the V-Bms compared to the V-Batt, it is normal. If the V-Bms trend doesnt stay the same and you notice a downward trend, it might be advisable to monitor it.