New Skoolie Electrical Issues

[TheDoghouseSkooly]

Hello everybody!

We have a 1991 International 3800 (DT360) 21ft long short bus that we are about 90% done with. The electrical system has been up and “running” for a few months. We are finally out on our first week long excursion to get the kinks worked out for longer trips. Our solar system is receiving ample sun (30-50 amps per hour for several hours here in MN). We are also driving a couple hours a day and have an alternator charger for the battery bank. Despite all of the energy input, our Multiplus SOC continues to drop about 2% each 24 hours, all we are running off of it is a Maxair fan and a 12 volt fridge that draws 7 amps at startup and 1 amp to run. It is currently reading 13.2 volts/6% SOC. The Renogy charge controller states we are at 13.5 volts with 100% charge (I’m told this is the least accurate indicator). It seems to me that the solar and smart charger should be more than enough, so what’s the issue? My electrical knowledge was competent enough to set up the below system but still quite limited as far as settings go. Both Multiplus and Rover are using Lithium battery settings. Any assistance would be greatly appreciated. Thank you!

Components include
8- Renogy 100 watt solar panels
Renogy Rover 60 MPPT Charge Controller
Victron MultiPlus 12/3000/120-50 Inverter
Victron Orion TR 12/12/30
2- 200Ah lithium batteries

[PhilipE]

Is your inverter on all the time or switched?

[TheDoghouseSkooly]

Inverter has been on for the duration of trip. Can switch on and off when needed if you think that will help!

[Albatross]

Big inverters have big idle consumptions.

The inverter should not be powered when there isn't an active load on it. Even a cell phone charger can cause them to kick on, and then your inverter is draining more power keeping itself alive than it's using to charge the phone.

[TheDoghouseSkooly]

Thank you Philip and Albatross! Will definitely shut off and turn on when needed! Even with that on though does that still make sense as to why we are still at an energy deficit? The math just doesn’t seem to add up to me but I could very well be wrong.

[Albatross]

There's a few reasons that could be, honestly.

Latitude could be one, as how far north you are affects the quality of sun you're getting, but more than likely I expect there's probably a ghost load somewhere that you're not fully aware of somehow. It could be anything from an improper ground to some kind of inductive loading, or something not switching off properly.

Go back and recheck all of your connections, and look for things connected that don't need to be.

[TheDoghouseSkooly]

We will be better about the inverter usage like the two of you mentioned. I will go back and retrace like you recommended and see if there is some obvious issue that I can find. Is there a device that one can use to determine load on the 12 volt side of the battery bank? The Multiplus tells me load and input of the 120v but that doesn’t help me track down whether there is a ghost load or ground issue on the battery bank. Thank you guys for your input so far, I truly appreciate it. We have been lurking on skoolie.net for the duration of the build, seems like an excellent community!

[Rucker]

Originally Posted by TheDoghouseSkooly

Hello everybody!

We have a 1991 International 3800 (DT360) 21ft long short bus that we are about 90% done with. The electrical system has been up and “running” for a few months. We are finally out on our first week long excursion to get the kinks worked out for longer trips. Our solar system is receiving ample sun (30-50 amps per hour for several hours here in MN). We are also driving a couple hours a day and have an alternator charger for the battery bank. Despite all of the energy input, our Multiplus SOC continues to drop about 2% each 24 hours, all we are running off of it is a Maxair fan and a 12 volt fridge that draws 7 amps at startup and 1 amp to run. It is currently reading 13.2 volts/6% SOC. The Renogy charge controller states we are at 13.5 volts with 100% charge (I’m told this is the least accurate indicator). It seems to me that the solar and smart charger should be more than enough, so what’s the issue? My electrical knowledge was competent enough to set up the below system but still quite limited as far as settings go. Both Multiplus and Rover are using Lithium battery settings. Any assistance would be greatly appreciated. Thank you!

Components include
8- Renogy 100 watt solar panels
Renogy Rover 60 MPPT Charge Controller
Victron MultiPlus 12/3000/120-50 Inverter
Victron Orion TR 12/12/30
2- 200Ah lithium batteries

My Renogy charge controller is always over-reporting voltage by .2 volts. I recommend you get a multimeter and check actual battery voltage at the charge controller and at the battery itself.

I keep my battery at 13.1 when I'm not on the road, then crank up the charge controller to 14.4 when I want to ensure a full charge.

At 13.3 on the Renogy display, your battery could be as low as 13.1, already 'on the shoulder', and although the SOC is not linearly correlated, it could be quite low.

[Albatross]

I have also noticed some circuits not reporting LiFePO4 batteries accurately, as most of the circuits the cheaper units come from still seem to be stuck in monitoring PbSO4 battery types.

[TheDoghouseSkooly]

Hey just wanted to reach out and say thank you to everyone who commented and helped out. The fridge was improperly grounded (fixed). We shut off the inverter while not in use and we paid for an RV site with electric for a night to charge the batteries to 100% SOC. Boondocking the last two days the battery bank has maintained 100% with solar charging. I think it’s safe to say we fixed it, glad it was an easy couple fixes. Thank you again!

[Leowoodbus]

Heya,

I just wondered if you had any pictures of this bus before you converted it?

Thanks
Leo