Solar panels and the CTEK system

[FlyingTexan]

Don’t quite get this CTEK system. It seems to be running on BMW software that keeps it from charging normally. If I leave my overhead switch on to power my fridge/cooler and it drains the battery down overnight. Normally not a big deal except the battery doesn’t charge very well the next day. Does a quick charge to 65% or so then goes low amperage so it just trickle charges and doesn’t actually top itself back off. Drive for an hour and it may be at 70% or something. Meaning day two of using the batteries isn’t an option.

-Has anyone found a way to make it charge normally until the battery is full? This doesn’t really help with being off grid for a few days.
-Is there a way to reverse charge through the Dutch plugs? Wondering if I flush mount solar panels to my Leitner rack if they could leave the battery topped off when it sits so I’m not starting the day at 65%. Right now I’m running a charger to the battery through an extension cord I wedge in my door and not thrilled about that.
-If I connect a battery maintainer under the hood to the jump points on the engine block and the positive on the frame will that charge the batteries even with the system off or is that only for jumping with the power on so the electrical system can regulate the current?

 

[Logsplitter]

Don’t quite get this CTEK system. It seems to be running on BMW software that keeps it from charging normally. If I leave my overhead switch on to power my fridge/cooler and it drains the battery down overnight. Normally not a big deal except the battery doesn’t charge very well the next day. Does a quick charge to 65% or so then goes low amperage so it just trickle charges and doesn’t actually top itself back off. Drive for an hour and it may be at 70% or something. Meaning day two of using the batteries isn’t an option.

-Has anyone found a way to make it charge normally until the battery is full? This doesn’t really help with being off grid for a few days.
-Is there a way to reverse charge through the Dutch plugs? Wondering if I flush mount solar panels to my Leitner rack if they could leave the battery topped off when it sits so I’m not starting the day at 65%. Right now I’m running a charger to the battery through an extension cord I wedge in my door and not thrilled about that.
-If I connect a battery maintainer under the hood to the jump points on the engine block and the positive on the frame will that charge the batteries even with the system off or is that only for jumping with the power on so the electrical system can regulate the current?

Yes a smart battery charger will work when attached to the jump start posts under the bonnet. In the past I regularly charged my batteries using both a mains smart charger and portable solar panels, connected to the jump start post under the bonnet.
I now have 270 watts of solar connected permanently to my Alucab roof and controlled via a Victron mppt controller in the battery compartment. I can confirm that solar keeps both batteries fully topped up even during the U.K. winter.
Hope that helps.

 

[Tom109]

The smart alternator is pretty bad and backs off at an unreasonably low state of charge. My guess is this is for fuel economy reporting, but it’s not practical for the Grenadier’s intended use.

I put 200W of solar on my roof and an MPPT controller connected to the main battery. When I’m not parked in the garage my SoC is always 91%+. The screen grabs below show the modest top-up provided by solar. If my fridge was running you’d see a significantly larger drop overnight, as well as solar + alternator recharge.

 

[FlyingTexan]

The smart alternator is pretty bad and backs off at an unreasonably low state of charge. My guess is this is for fuel economy reporting, but it’s not practical for the Grenadier’s intended use.

I put 200W of solar on my roof and an MPPT controller connected to the main battery. When I’m not parked in the garage my SoC is always 91%+. The screen grabs below show the modest top-up provided by solar. If my fridge was running you’d see a significantly larger drop overnight, as well as solar + alternator recharge.

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If doing the MPPT controller does it replace teh ctek? Is it the CTEK causing the issues or the alternator?

 

[OkGo]

You will want to look into what a CTek Smart pass does v/s what the real CTek charger like a D250se would do.

I have never had two charge circuits connected to my battery ( either house side or engine side ) - prefer to use something like the D250SE that can handle the solar input and the alternator inputs and do a really good job of keeping the circuits from affecting each other, yet topped up as needed. The d250se includes a mppt controller.

 

[Tom109]

If doing the MPPT controller does it replace teh ctek? Is it the CTEK causing the issues or the alternator?

No, I left the CTEK 120S in place so both it and the factory dual battery system work as normal. The MPPT just adds solar input to the battery in addition to alternator input.

The CTEK D250SE has a 23v solar input limit so I chose a Victron MPPT.

 

[OkGo]

I am guessing those are still 12v panels, but you have them in series rather than in parallel ?

 

[Tom109]

I am guessing those are still 12v panels, but you have them in series rather than in parallel ?

Yes, 12V24V. I used one 200W panel.

Rooftop Solar on Factory Rack