Troubleshooting Solar Panel Charging Issue with Leisure Batteries

[Charl259]

Hi, newbie here. I’ve searched high & low for answers but I’m struggling so hopefully someone can help.

I have 2x AMG 130Amh leisure batteries connected to a 180W solar panel via a Sterling BBS1230 Battery to Battery charger and MPPT solar charge controller.

My batteries charge when the engine is running and I can get them up to 90 odd %. The problem comes with my solar, when the sun is shining, I'm getting good voltage going into the controller and 14/15V coming out. The batteries are then showing 14/15V reaching them, yet there are not charging. I’ve let them run down to 60% and the solar still hasn’t kicked in to recharge them, I have to turn my engine on to charge instead.

My question is, does anyone have any idea why this is happening? I presume the solar and controller are ok considering they’re bringing in voltage, converting it and sending a decent amount out. The voltage is then hitting the batteries so no issues with the connection. I presume the batteries are ok because they charge when the engine is running, so why not charge from the 14/15V that is reaching them from the solar?

The whole set up was already done when I brought the van but it’s been done very well and checked by an electrician. The batteries, charger and solar are all around 2 years old (I have invoices).

Any help would be very very much appreciated because I feel like I’m at a dead end with it

 

[Lenny HB]

What solar controller do you have?
If the batteries are at 90% the controller will have gone into absorption mode where the current will be limited to about an amp and will take 1 to 4 hours to bring them upto a fuul charge.

Also how are you measuring the state of charge?

 

[68c]

How do you know they are not charging? Is it possible they are charging but that the charge is not being detected by whatever you are using to read the state of charge?

 

[Charl259]

What solar controller do you have?
If the batteries are at 90% the controller will have gone into absorption mode where the current will be limited to about an amp and will take 1 to 4 hours to bring them upto a fuul charge.

Also how are you measuring the state of charge?

I have the

What solar controller do you have?
If the batteries are at 90% the controller will have gone into absorption mode where the current will be limited to about an amp and will take 1 to 4 hours to bring them upto a fuul charge.

Also how are you measuring the state of charge?

I’ve got the Sterling BBS1230 Battery to Battery charger and MPPT solar charge controller, it’s both in one. The batteries are depleating to 60% and not recharging from the solar panel, only from the engine

 

[Charl259]

How do you know they are not charging? Is it possible they are charging but that the charge is not being detected by whatever you are using to read the state of charge?

The indicator that I have shows when they’re charging from the engine but when the engine is off the power only goes down as I use it and doesn’t recharge until I turn the engine on again. I went away for a week last week and they went down to 60% but didn’t recharge even though it was sunny and the controller was showing power being pulled through from the panel. I just can’t get my head around how the power is coming through the controller, reaching the batteries but not recharging them. If the engine wasn’t charging the batteries I’d say it was a fault there but they charge absolutley fine with the engine. I’m using a volt meter to check.

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[Bolti]

Try pulling the fuse to the solar panels, allowing the controller to see the correct voltage of the battery then re installing the fuse.

 

[daveandsan]

How are you measuring the voltage from the solar panels going into the battery?

 

[68c]

If the solar supply from the controller has been wrongly connected directly to the leisure battery it will not be read by your capacity display. The battery is probably being charged but the capacity display only sees what is coming from the alternator or EHU. They are rather sophisticated devices that read how much energy is going into the battery and how much is coming out. Due to inevitable losses you never get back all you put in. When first fitting it needs to know the size of the battery, how much you want to use (50%?) Finally the battery needs to be fully charged. Then it can read what is taken out and what has been put back in to calculate the charge percentage. Over time you may have to reset things as the batteries age. But, it can only do this if ALL the charge goes through it, EHU, Alternator and Solar.

 

[autorouter]

What voltage are the solar panels? The maximum voltage for solar input on the BBS1230 is 31V. Have you ever seen the setup working properly?

On the BBS1230, top left are three LEDs labelled
Ignition feed live (green)
Solar power live (yellow)
Solar High V trip live (red)

When the engine is running, the green Ignition feed live LED should illuminate.
When engine is stopped, and sun is shining, the yellow Solar power live LED should illuminate.
If the solar panel voltage is too high (32V or more) the red Solar High V live LED will illuminate.

Can you see these LEDs, and if so do they illuminate appropriately?

 

[Charl259]

What voltage are the solar panels? The maximum voltage for solar input on the BBS1230 is 31V. Have you ever seen the setup working properly?

On the BBS1230, top left are three LEDs labelled
Ignition feed live (green)
Solar power live (yellow)
Solar High V trip live (red)

When the engine is running, the green Ignition feed live LED should illuminate.
When engine is stopped, and sun is shining, the yellow Solar power live LED should illuminate.
If the solar panel voltage is too high (32V or more) the red Solar High V live LED will illuminate.

Can you see these LEDs, and if so do they illuminate appropriately?

Thank you for your reply. Not sure on the voltage, I know it’s 180W. Yes I have those 3 lights, the green is always shown when the alternator is on and the amber when it’s off. I’ve never seen the red lit up and I check it regularly, it’s only ever the amber.

I can’t remember ever seeing it working, I brought it back in February and never paid much attention to the solar until I noticed this happening around May time

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[monzer]

Is there an app for the sterling unit? Could it be something as simple as charging has been disabled in the app?

 

[Charl259]

If the solar supply from the controller has been wrongly connected directly to the leisure battery it will not be read by your capacity display. The battery is probably being charged but the capacity display only sees what is coming from the alternator or EHU. They are rather sophisticated devices that read how much energy is going into the battery and how much is coming out. Due to inevitable losses you never get back all you put in. When first fitting it needs to know the size of the battery, how much you want to use (50%?) Finally the battery needs to be fully charged. Then it can read what is taken out and what has been put back in to calculate the charge percentage. Over time you may have to reset things as the batteries age. But, it can only do this if ALL the charge goes through it, EHU, Alternator and Solar.

This would make complete sense! I’ll have a look at the wiring again from the controller to the batteries and I’ll do some digging on the capacity indicator and see if there’s a way to reset it. Thank you

 

[autorouter]

This would make complete sense! I’ll have a look at the wiring again from the controller to the batteries and I’ll do some digging on the capacity indicator and see if there’s a way to reset it. Thank you

I don't think that's the problem in this case, because the solar and B2B output go to the battery along the same wire, they are switched inside the BBS1230. This could potentially be a problem if the B2B and MPPT were separate, and wired separately, but not in this case.

Yes I have those 3 lights, the green is always shown when the alternator is on and the amber when it’s off. I’ve never seen the red lit up and I check it regularly, it’s only ever the amber.

Does the amber go off when the sun goes down?
The left-hand column of LEDs shows the solar panel input voltage, in 2V steps, reading from the yellow scale. If two LEDs are on, the voltage is between the two. For example if the 20V and 22V LEDs are on, the voltage is 21V.