Solar System for 25' motorhome

I am wanting to install a system modeled after the “400 Watt Solar Package w/ Alternator Charging” described on the web page. The recommended components include the following.

• 400 watts of solar panels
• 50-amp DC to DC charger with MPPT
• 300-amp hour lead acid deep cycle battery bank (or 200-amp hour lithium battery)
• 1100 to 2000-watt inverter

My equipment choices are as follows.

• (4) Renogy 100-watt 12-volt Monocrystalline solar panels (400 watts)
• (1) Renogy DCC50S 12V 50A DC-DC On-Board Battery Charger with MPPT
• (4) 100-amp Battle Born lithium batteries (400 amp hours)
• (1) Victron Multiplus 2000 watt 12 volt Inverter/Charger

My differences are as follows.

• First, I have 400 amps of lithium batteries instead of 200 amps
• Second, I have an inverter/charger instead of just an inverter.

Will my proposed system work? Will the doubling of the size of the lithium battery bank and replacing the inverter with an inverter/charger cause any difficulties? Any other advice would be greatly appreciated. Thanks.

Your two differences are significant enhancements to the system.

The inverter/charger permits charging your system through shore power or generator.

With Victron, you have the potential for an awesome ecosystem of products, but they are spendy. I would recommend the Victron 100/50 charge controller and a BMV-702 as well as a Color Control GX or other GX device for system integration, control, monitoring and logging. I figure you're made of money with those 4X BB batteries...

The Victron charge controller also has a low temperature cut-off protecting LFP batteries from charging at low temperatures.

Here's an example of the Victron ecosystem:


I can remotely monitor and control my installation via the internet. Should the internet go down, the unit will log data internally and then upload when it becomes available again.

Definitely not made of money. The system as described on the web page did not list an AC source for charging the batteries. I want to charge the batteries while at a campground. And, I wanted to size my system for adding batteries at a later date. I will start with two BB batteries. Is their a cheaper way to get what I want?

There are other inverter/chargers, but they're not cheap. Will also lists the Samlex, but for the price difference, I'd go for the Victron, and I bet the Victron charge controller isn't much more than the Renogy. Add a BMV, and you have a system! You can always add the GX later.

I’m sure that the Victron inverter charger is very good but I have had good luck with a considerably less expensive Kisae Abso 2000w inverter/charger I bought about four years ago. Doesn’t have the Victron ecosystem but it does have a nifty control panel that can be remotely mounted in your RV. The main difference in specs I see is the shore power charger on the Kisae Abso is 55 amps vs 80 on the Victron. I’m not sure that’s a big issue because when you are plugged in you tend to be plugged in for a while. The biggest selling point of the KA for me was the compact size as space is at a premium in my Sprinter conversion RV. BTW the model I got seems to be on sale for less than I paid because Kisae is coming out with a newer model

It's cheap because it's a high frequency inverter with no real surge capability.

snoobler said:

It's cheap because it's a high frequency inverter with no real surge capability.

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That’s true, but it all depends on the OP’s requirements. I use my inverter mostly to run a 900w coffee maker every day while traveling and a 1500w microwave occasionally. I really don’t need surge capability and wanted to save space and money. The OP’s priorities might be different though.

What is bad about a high frequency inverter? And, will the Kisae Abso 2000 work with lithium batteries?

HF inverters have negligible surge capacity. Motors have a very large surge 3-10X their initial draw. HF inverters can't handle them. The Multiplus is a low frequency inverter with a very large beefy transformer that can handle substantial surge loads for many seconds.

The Kisea Abso will work with Lithium batteries but it doesn’t have a lithium-specific charge setting . The main consequence is that it has a float stage that’s needed for AGM and other lead acid batteries to maintain their charges when idle but is not needed or desirable for Lithium. I am replacing my AGMs with a DIY lithium battery bank and plan to use the Kisae Abso for shore charging. The float is not an issue for me because I never leave the RV plugged in for extended periods - it only gets plugged in occasionally when we are camping. When it’s parked at home the solar MPPT charger does its thing and it fortunately does have a lithium charge setting.