Solar panels query,

[Mr B]

I have just come across a statement that if you dont have the battery connected to the controller and the panels are connected,
It will fry the Controller,

My 500 Watt solar panels are connected to the controller and then fused with a 30 amp fuse, then connected to the battery,

My question is, If the fuse blows, Will the solar panels fry the controller if the battery is not connected now by the blown fuse,

My two Solar panels with inbuilt diodes are set up in parrellel , joined into one wire under the panels and then a long run to the controller next to the battery and then the fuse next to the battery,

I have a 40 amp controller, Supposed to be MPPT, but I dont think it is, It may just be PWM,

Thanks Brian,

[sailorboy1]

I don't know. But my controller manual also says to connect the battery side before connecting the solar side. The fuse on the battery side should be sized to protect the wiring and not related to the controller output at all and rated way more than what the fuse should ever see expect for a grounding short. In which case not catching the boat on fire I would guess is worth more than the controller.

[motion30]

I have to Outback controllers, I have opened the breakers to the batteries multiple times with no ill effects

[Hesti]

Having read a few manuals recently before deciding on a regulator: Yes, some manuals do raise this issue. And some don't. So, it is probably depending on the innards of each regulator. You will have to check your manual to find out if it can be an issue with your regulator.

[Achab65]

Originally Posted by sailorboy1

I don't know. But my controller manual also says to connect the battery side before connecting the solar side. The fuse on the battery side should be sized to protect the wiring and not related to the controller output at all and rated way more than what the fuse should ever see expect for a grounding short. In which case not catching the boat on fire I would guess is worth more than the controller.

The manual of my controller says to connect batteries as last and disconnect as first, therefore i think it depends on the controller.

[GRIT]

I just set up our boat with Victron MPPT solar controllers, and lithium batteries. I asked Victron about cutting the MPPT out of the system, if the BMS decides the voltage is too high. My concern was that the manual says the controller could be damaged if the solar were connected first.

It turns out, for Victron, that the batteries are connected first, "out of the box", when the controller is new, to set the voltage. In my case, the controller set itself to 12 volts, forever, unless I manually change the settings. Then, according to Victron, it's fine to disconnect/connect the batteries from the controller, while solar is connected.

So my BMS disconnects the solar, on overvoltage, and I sincerely hope the tech was right.

Cheers.
Paul.

[nebster]

Yep this is design-specific. Check with your manufacturer.

[Mr B]

My system is up and running and works fine,
The cost of the controller is not an issue, I do have spare controllers,

But for some reason, The fuse blows, Will it fry the controller if its all up and running,

The solar panels are still pumping power into the controller but its not going any where,

Does the controller have some sort of overload, cut off switch or some thing in it,
Just to protect itself from having a melt down,

I dont particularly want a molten blazing controller hanging on the wall,

[GRIT]

If the batteries are not connected, there shouldn't be any flow of electrons, unless the controller is using solar energy for something.

It's something like having the solar panels in the sun, but not attached to anything. It's an open circuit, and no electrons will flow.

I'd contact the makers of the controller, but there shouldn't be an issue.


Cheers.
Paul.

[dutch-barge]

yes it is design specific....the Victron units have to be connected to the battery first, so they can sense the voltage and initial themselves one time. ( to 12 or 24V). after that you can disconnect at will.