Growatt 5000 ES 240volt off grid - not charging AGM batteries

[DanET1983]

We are off gird with solar and generator. We purchased the Growatt 5000 ES a few months ago, connected to 4 Renogy 200ah 12 volt batteries and it has been working fine until recently. This past week I've noticed that even with decent to good solar input 200-275 volt PV input, the LCD display was showing the system to be in Battery Mode and was not charging. I ran the generator quite a while yesterday and found that the batteries were still only at around 46 volts by nightfall, with a battery low voltage alarm in the middle of the night. I put the system in standby mode to shut things down until morning. Upon daylight at around 6:30am when solar was kicking in I turned the inverter back on and it began charging the batteries. I wasn't paying attention to the display, but several hours later realized that it was not charging the batteries anymore with the batteries only sitting at 45 volts.

I started the generator, yet it still was not charging the batteries (while solar was still in the 200volt or greater range). I went through the settings and adjusted a few items to try and see if I could get the system to start charging. By setting the Charger Source to both solar and utility it did temporarily show that it was charging the batteries but then that dropped off within 2 seconds and displayed only output from the batteries.

I am not getting any fault codes, but this sounds like there is an issue with a hardware component or maybe the software that is not allowing current to charge the battery? I doubt that the batteries would have powered our laptops and cell phones throughout the day so we must have been getting output direct from the solar panels earlier today.

Not sure what troubleshooting options I could try? Maybe just consider a different Inverter/charger unit and replace?

 

[timselectric]

It sounds like your batteries can't receive the charge.
You may need to pull the batteries and charge them separately and verify that they are all working correctly.

 

[Pierre]

Unfortunately I am not a proponent of putting batteries in series to form a battery bank. The series current is limited by the weakest battery in the chain. Most of these batteries are sealed and replacing individual 3.2v cells impossible as in the case with LFP. I think you have a dud battery somewhere. Maybe consider changing to Lithium.

 

[DanET1983]

Thanks for the quick replies!

It does sound like this could be a bad battery or possible bad connection in the series (slowly checking in between work obligations).

As an update, in order to prepare all our devices for the next day I ran the generator to be sure all laptops and cell phones were topped off. Before shutting down Tuesday night I checked the Growatt and found it had been charging the 48volt battery bank and pushed them to approximately 59 volts!

Wednesday I paid closer attention to the display and found it was periodically going into charge mode. Not in the morning when you might expect (low point on the batteries from overnight), but maybe 11:00 am despite having 200 volt solar input from early daylight. Same for this morning. Down at 46 volts in the early am, no input to charge despite 180-200 volt solar input. However it started charging at around 9:30am when solar input is average of 220 volts input.

 

[DanET1983]

Adding, first paragraph typo, Tuesday night batteries were at 49 volts, certainly not 59 vokts!