Batteries not charging

Rheumatoid

I had 4x Pylontech US2000c fitted in April. They have worked pretty well. I notice in the last few days that they have not taken any charge. I put it down to grey weather and us being at home using everything that was generated.

However, today is nice and sunny and they are still not charging, even though we aren't using a lot. The monitoring s/w also indicates that I have exported 3kWh to the grid and the batteries haven't moved off 21%.

I've been in the attic to have a look and the only light on each battery is the green 'run' light which is flashing. None of the SoC lights are on.

Any idea what might be going on?

Thanks.

Solarchaser

Hi, it's the inverter that decides to direct the charge to the batteries, not the batteries themselves.

The soc lights will tend to only be on if the batteries are active.
On constant if discharging or one flashing if they are charging.

As the simplest thing to try, id go and switch your batteries off at the switch one at at time, count to ten and switch them all on one by one, when they are all on, press the run button on only the first one and make sure they all cascade on from that one, that will tell you the connection between them is OK. 
Be aware that sometimes doing this makes the pylons decide they are a lower charge than previously and if they are below the level you have chosen they may decide to request charge from the inverter.

I'd be tempted to switch you inverter off when you have the batteries off also, and give the whole lot the old I.T. fix

Rheumatoid

Solarchaser said:

Hi, it's the inverter that decides to direct the charge to the batteries, not the batteries themselves.

The soc lights will tend to only be on if the batteries are active.
On constant if discharging or one flashing if they are charging.

As the simplest thing to try, id go and switch your batteries off at the switch one at at time, count to ten and switch them all on one by one, when they are all on, press the run button on only the first one and make sure they all cascade on from that one, that will tell you the connection between them is OK. 
Be aware that sometimes doing this makes the pylons decide they are a lower charge than previously and if they are below the level you have chosen they may decide to request charge from the inverter.

I'd be tempted to switch you inverter off when you have the batteries off also, and give the whole lot the old I.T. fix

Thanks Solarchaser

If they are flashing and charging as you suggest, why do you think they are not actually taking any of the 4kWh that was exported to the grid yesterday?

How do I determine which is the first battery to push the run button on and what is the best way to turn the inverter off and on?

Have to say I'm a bit disappointed as hoped this system was zero maintenance. If I hadn't been keeping an eye on it I could have been losing out for months. I will get in touch with the fitters tomorrow as well.

Any idea why this sort of thing might happen?

Solarchaser

Sorry Rheumatoid I don't know about solis inverters, I've never had one, so can't answer that.
If they are flashing, they definitely are taking charge, is it possible the source of your information is wrong rather than the batteries not charging?

Switching inverter off at the isolator switch they must have will be fine, or sometimes there is a switch on the inverter itself.

The first battery will be the one without a comms lead in the zero port, the others will have a small lead going into port 1 and port zero, and your last battery will have only a lead going into port zero

Rheumatoid

Solarchaser said:

Sorry Rheumatoid I don't know about solis inverters, I've never had one, so can't answer that.
If they are flashing, they definitely are taking charge, is it possible the source of your information is wrong rather than the batteries not charging?

Switching inverter off at the isolator switch they must have will be fine, or sometimes there is a switch on the inverter itself.

The first battery will be the one without a comms lead in the zero port, the others will have a small lead going into port 1 and port zero, and your last battery will have only a lead going into port zero

Thanks, seems to have done the trick but a bit concerned it happened in the first place. Is this to be expected occasionally or should I be chasing the installers to check it out as the system is only 6 months old?

Solarchaser

To be honest I've never had it happen, perhaps someone with a solis inverter will be able to comment.

I do however, every 3 months or so, power everything off and back on, but thats for me to double check the batteries are not getting too far out of balance from each other.

Rheumatoid

Thanks. That sounds like good practice. Does that force a balance from the BMS in case its not doing its job properly or does it enable you to check the state of balance?

I will call installers tomorrow anyway to discuss and ask why this might happen. They have installed hundreds of these systems so might have encountered it before.

Solarchaser

It seems to help them balance,  but its just as likely that I'm confirming my own bias only.

If they are really far out, say one is on 4 lights and one is on 2, then I disconnect the inverter and the comms cables and power them up purely on DC and leave them an hour which tends to sort them out, though tbh I've only ever needed to do that when adding an extra battery to the stack.

It's certainly worth a call to your installer, if there is some sort if common fault, they would be the one to know