Problems with Sunsaver SS-10 PWM controller & vehicle voltage regulator

[WideAngleWandering]

I have 100 watts manas:ged by a Sunsaver SS-10 PWM controller in my vehicle. I have a freshly rebuilt stock alternator and external voltage regulator.

A few weeks after installing the panels & controller my battery warning light started acting wonky. It is flashing at different rates and levels of brightness. I am fairly certain that it is the charge controller pulsing as I can't recreate the problem when it is disconnected but I usually can when it is connected.

Morning star says:

Engine generators and other sources of power may be connected
directly to the battery for charging. It is not necessary
to disconnect the SunSaver from the battery. However, do
not use the SunSaver to regulate these other generators.

My theory is that the SS-10 is hitting it's set-point voltage (14.1v for a sealed battery) while my alternator is usually below that. The voltage regulator is then utterly confused when it senses the battery voltage is inexplicably higher than the alternator's voltage. Or something like that. I can't really explain this electrically.

It's driving me nuts but I don't want to electrical tape my warning lights. I kinda need them.

Can anyone explain what may be happening here? Is something going to be damaged? Any suggested fixes?

[pods8]

So you've got solar connected to your main vehicle battery? If so you don't need the solar charging while the vehicle is running you could consider a relay that disconnects the solar during that time.

[WideAngleWandering]

The sunsaver controller can't be disconnected from the battery unless you first disconnect the panels from the controller. This would require some kind of logic with a timer and multiple relays. It shouldn't be required, at least according to the manual and the experiences of everybody else who uses them. Why should I have to?

[pods8]

I'm not positive that is right, during wiring you're supposed to make the solar panel connection before the battery bank circuit is completed, so to disconnect I'd assume the reverse (once the bank is removed the panel will stop flowing amps). Either way you could put a relay in one of the appropriate wires if you wanted, it would not require multiple relays. You just would have to break the connection in one spot whether before or after the controller. Just was a brainstorm idea off the top of my head, do what suits your fancy.

I mainly only research/follow solar on axillary battery banks in which that battery is going to act as a buffer even when linked up to the vehicle's main battery. If there are other folks running solar on just their main vehicle battery I'll leave it to them to explain whether you'll have issues or not, this is the first time I'm seen mention of it but I haven't been looking or had interest in it. I could see how it would be messing with your alternator though.

Good luck.

[WideAngleWandering]

The manual disagrees - it explicitly states that the charge controller can be placed in parallel with the engine's alternator and it also explicitly states that the controller must be connected to the battery before the panels connect to the controller.

But thanks for the creative idea. I can see where you're going but I don't think it's feasible.

[4x4junkie]

I have a SunSaver MPPT and I found connecting the panels before the battery indeed caused it to error out (or at least the battery status indicator continued to show a discharged battery when it was very near full charge). Upon unplugging everything and reconnecting the batt first, everything was fine.

Maybe you can put a relay on just the solar panel input, and leave the controller always connected to the battery. Without the panels connected it's not going to put out any charge power and shouldn't spook your vehicles regulator.

[WideAngleWandering]

It still flashes even when the panel is disconnected, at least under this circumstance:

I have a quick disconnect on the panel to make it easy to plug and unplug it when I am welding or doing electrical work on the vehicle. When the flashing first started, I pulled over and unplugged the panel (with the engine running). The flashing continued. For a while I was looking at causes other than the charge controller because of this.

That might not be the case if I have a relay tied to the ignition that kills the panel when I start the truck but like I said - this shouldn't be required so I don't want to go this route until I've given up on understanding the issue and how other drivers cope.

[4x4junkie]

I cannot see how the controller without a panel connected would affect anything... Maybe the flashing simply continues until you cycle the ignition off-on again?

What is the vehicle in question here anyway?

[pods8]

I was looking at the Gen 3 sunsaver manual, that one says to put the fuse in the wire between the controller and battery last ie that would be the last connection made. I just looked at the gen 2 manual, it doesn't talk about a fuse in that line so the panel is getting connected last. Regardless it states that is the recommend connection order and doing other ways will not damage the controller. Just an FYI.

I see the manual says you can go parallel with the alternator but all that means is sunsaver is saying it won't damage the controller. That isn't an endorsement that the controller won't throw off your alternator...

Are other folks actually running solar on their primary vehicle battery while the engine is running successfully?

[WideAngleWandering]

It's an early 80s Toyota with an external regulator.