question

@Elias Kortesalmi from your description of the issue, there must be some correlation between the problem that you're experiencing and the installation of the new battery and the second battery. It could well be that, in the course of installation, one of your connections between the MPPT and the batteries has become loose... if one connection had not been fully tightened, it would allow current to pass but would build up heat as it did so, and heat=resistance, and as the resistance/heat built up, the controller would throttle back its throughput. Then after throttling its throughput, the loose connection would cool off and the controller would start sending current again... and repeat.

I suggest that you carefully go over all of your connections... both the connections between the two batteries as well as the connection of the charge controller and etc. Look for improper crimps (a good crimp can take a minimum of 100lbs of pull without moving) or a loose bolt or nut or cable clamp that wasn't fully tightened back down when the new batteries were being installed. Be careful, however, as a loose connection will likely be hot and may also be carrying live current.

Check all connections and report back to us if that doesn't turn up any results... good luck and happy new year!

Hi @Justin Cook

I went trough all connections previous and new ones. They all was fine and tight. I also have been checking temperature of connections but no heating has happened.

I still have problem. Cutting off is totally random. Two days ago day was foggy and max power from solar was 15w. I got two cut offs during day. One in morning and one at afternoon. Both time it was required to take fuse of and re-install it before charge continued. Yesterday it was sunny, max power from solar was 47w and charging was fine whole day. I got more energy that for any day at last week.

Today at morning when sun rises charging start normally but after hour charge died again and needed to take fuse off.

I have been monitoring problem now about two week but haven't found any couse of connections or my doing by plugging devices on or off from circuit. It still feel like completely random problem.

Any ideas? I'm getting little bit frustrated to check charging many times of day.

Hi @Elias Kortesalmi

Best would be to connect with Victron Connect software to read out the status (and update the firmware), if you have the 'smart solar' version you can do this through a bluetooth connection, if you have the 'blue solar' version you need a ve.direct - USB cable to do this.

https://www.victronenergy.com/support-and-downloads/software#victronconnect-app

if you're sure it's defective, please contact your distributor for warranty services.

I have smart solar charger. So I'm monitoring charing trough app. Firmware and software are on latest version. And I don't get any errors.

When it's not charging software shows that solar voltage is same than battery voltage and watts and charge are at zero. When I measure voltage of panel its normal high like 18-20v. And when I take fuse of and put it back charging start line normal after minute or so.