Upgrade of Imagine AIM Solar Power System

[Crbright61]

In April of 2024 I purchased a new 2023 Imagine AIM 18BH after having a used Jayco hybrid previously. The new GD came with a Norcold N2175 DC fridge (7.0A std mode, 5.0A nite), a Valterra 200 Watt solar panel, a GO Power 30A solar charge controller (GP-PWM-30-SQ) which per Dometic is able to handle up to 600 Watts, a WFCO 55 Amp converter model WF-9855 (no lithium profile), a standard 12V lead acid battery, and came prepped for a WFCO Model WF-5220 2000 watt inverter. I don’t have and am currently not looking to buy a generator.

I set out to upgrade the solar system to increase the rooftop solar capacity and switch the battery over to Lifepo4 to better ensure that the fridge would stay powered, to support some limited boondocking of 2 or maybe 3 days, and as a lesser goal, to provide a better foundation for possibly expanding the solar setup down the road for additional boondocking with maybe the addition of an inverter.

First, I had my local dealer add another 200 watt panel (a Go Power Overlander Expansion Kit). Wanting to do the rest myself, after considerable research I have come up with the following additional items, most of which I have purchased but have not yet installed:

--Replace the stock WF-9855 converter with a Progressive Dynamics PD9360 60 AMP converter. This PD model is the specific replacement for the WF-9855 called out on PD’s website. It has the ability to manually select the battery type or to select constant voltage, which I understand can be good if problems arise in interacting with the solar setup.
--Replace the Go Power 30A PWM charge controller with a Victron 50 amp MPPT 100/50 Smart Solar charge controller. MPPT superior efficiency to PWM, Victron controller is adjustable whereas Go Power is not, and 50 AMP provides a capacity cushion and better supports addition of one or possibly two more panels in the future.
--Add a Victron SmartShunt IP65 on the negative cable between the DC electrical system and the battery to track battery state of charge via the Victron Connect App.
--Replace the stock 12V lead acid battery with an Epoch 12V 300AH lifepo4 battery with BMS, heat and Bluetooth. Although my 400 watts of solar may not easily be able to fully recharge this battery in a day, the 300AH capacity will help me get through a couple of days off the grid even if it’s not sunny. I am looking into what size battery box will be needed for this upgrade.

Any and all thoughts on any of the above would be appreciated. In addition, I have the following specific questions:

--Is the existing wiring and other infrastructure sufficient to support each of these new items? I’m hoping that, as a new DIYer in the solar arena, most of these changes will involve a fairly simple hookup of the new in place of the old without major rewiring, new fuses, new ground wires, etc. I called GD customer service to ask about the wiring gauge used in the existing solar system, and they could not tell me much, although they did provide a diagram of where each electrical component in the TT was located.

--I’m especially concerned about whether going from a 30 AMP to a 50 AMP solar controller will cause any issues in this setup. I believe there is a 30 AMP fuse (if I can find it) on the positive cable between the Go Power controller and the battery that will need to be replaced, per the Victron manual, with a 55A min to 70A max fuse on the 100/50. As an alternative, I could go with a Victron 100/30 (35A min to 40A max) – less capacity but still get the other benefits of Victron and MPPT, etc. I would only like to keep the GO Power controller as a last resort given its limitations.

Thanks in advance for your input on the above. Craig

 

[Soundsailor]

Hey Craig, your plan sounds fine. It looks like you'll need a 6-gauge cable for your controller to battery connection (see this chart). It would also be a good idea to install a cutoff switch on the cable coming from the panels, if you use a breaker you'll also be protecting the circuit.

 

[Crbright61]

Hey Craig, your plan sounds fine. It looks like you'll need a 6-gauge cable for your controller to battery connection (see this chart). It would also be a good idea to install a cutoff switch on the cable coming from the panels, if you use a breaker you'll also be protecting the circuit.

Thanks so much for your input. A couple of follow-up items:

--I have now decided to go with the Victron MPPT 100/30 controller instead of the 100/50. Does this mean I can now just do a simple swap out of the
go Power 30A charge controller that came with the camper with the Victron 100/30, with no wiring upgrade to 6-gauge like you suggested? And can I just keep the 30A fuse between the Controller and battery that came with the camper? The 100/30 has a maximum short circuit current of 35A.

--Per your suggestion to install a DC breaker between the panels and Controller, how many amps would that breaker need to be, and do you suggest a specific item (I read that quality on these can be poor) Note I have since learned that my two 200 watt panels are wired in parallel, with each at 9.63 amps and 20.8 volts. I am planning to stay at the 400 watt, 2 panel configuration for the near term.

Thanks in advance for your help.

Craig

 

[Second Chance]

@SolarPoweredRV may have some valuable input on this.

Rob

 

[Soundsailor]

Yes, I think you'd be OK using the stock cables with the Victron 110/30 controller and two 200-watt panels. Just be sure you're not boxing yourself out from future expansion. If additional capacity is ever a possibility, you may be better off with a small increase in investment now for expansion capacity in the future. The same goes with a fuse/breaker for the panel to controller. The 30 Amp version of this switch (Amazon.com) and the 40 Amp version cost the same. GD generally uses 10-gauge cables for the solar leads, so the 30 Amp switch would work fine for the stock cables. But if you ever decide to upgrade to more panels, you may need to upgrade the switch and cables.

 

[Crbright61]

Yes, I think you'd be OK using the stock cables with the Victron 110/30 controller and two 200-watt panels. Just be sure you're not boxing yourself out from future expansion. If additional capacity is ever a possibility, you may be better off with a small increase in investment now for expansion capacity in the future. The same goes with a fuse/breaker for the panel to controller. The 30 Amp version of this switch (Amazon.com) and the 40 Amp version cost the same. GD generally uses 10-gauge cables for the solar leads, so the 30 Amp switch would work fine for the stock cables. But if you ever decide to upgrade to more panels, you may need to upgrade the switch and cables.

Very helpful. Is there anything I need to do from a safety standpoint to account for the higher short circuit current in going from a standard lead acid battery to a 12v 300AH LifePO4 battery, such as upgrading or adding fuses somewhere?

 

[Soundsailor]

Ideally, you'd like to protect your cables. So the breaker switch I recommended above protects the cables coming from the solar panels. Another good feature of that switch is that it effectively shuts down charging from the solar controller. That could be useful if you're camping in cold weather and your battery doesn't have built-in protection from charging in freezing weather. You might also want a battery cutoff switch right at the battery for storage purposes. If you decide to add an inverter, of course, you'd want protection for that.

 

[SolarPoweredRV]

Very helpful. Is there anything I need to do from a safety standpoint to account for the higher short circuit current in going from a standard lead acid battery to a 12v 300AH LifePO4 battery, such as upgrading or adding fuses somewhere?

While you are upgrading the system, it is a good idea to install a "Master Fuse" close to the batteries (within the first 6 inches if possible), this fuse should be sized for the maximum expected load from your system. Generally speaking, this fuse is usually sized to handle the max current draw from your Inverter, plus several amps added to accommodate any DC load you might expect. Because Lithium batteries can discharge a lot of current in a very short time this "Master Fuse" becomes critically important.

Based on your current non-Inverter installation, I would recommend a 100 to 150 amp "Master Fuse". If you install an Inverter you would need to increase that fuse to a 300 or 400 amp fuse, based on the current draw from your new Inverter.