Upgrade to LFP batteries and inverter-charger

[ridingabout55]

We purchased our Reflection 226RK back in February, 2023. It came with the standard electrical set-up: Furrion 165W solar panel, Furrion MPPT 50A solar charge controller, Inteli-Power Charge Wizard converter (not LFP compatible), and an Interstate 12V 88AH lead-acid battery. With this set-up and the 12V refrigerator, we have been frustrated with our inability to boondock without running our portable Yamaha inverter-generator every night to prevent the battery from dropping below 12V.

We have recently purchased two Renogy 12V 100AH LiFePh batteries and a Renogy 2000W inverter-charger; the owners manual is not very helpful. I have watched about 20 YouTube videos, but none really gave me a clear idea on how to 1) replace the existing converter with the inverter-charger, and 2) maintain the solar charging system with this new set-up. Also, I have not found a decent wiring diagram showing all of the proper connections.

I am hoping other Reflection owners have been through this process and can offer me advice and perhaps a good wiring diagram.

Thanks for any assistance!

 

[SolarPoweredRV]

We have recently purchased two Renogy 12V 100AH LiFePh batteries and a Renogy 2000W inverter-charger; the owners manual is not very helpful. I have watched about 20 YouTube videos, but none really gave me a clear idea on how to 1) replace the existing converter with the inverter-charger, and 2) maintain the solar charging system with this new set-up. Also, I have not found a decent wiring diagram showing all of the proper connections.

Thanks for any assistance!

First, let's get your batteries installed...

When you are switching from Lead Acid batteries to Lithium, you need to be concerned about charging your batteries when the battery temperature is at, or below, 32 degrees. Your Renogy batteries should have a low temperature cut-off to protect the batteries from being charged, however, you should be aware of this limitation and plan for it during the installation of your batteries, especially, since you have Solar that will charge your batteries anytime the Sun shines.

To accommodate this limitation on Lithium batteries, your camping style needs to be considered...

Do you camp in Winter when the Temps could drop below 32, or, do you store your coach all Winter? If you store your coach, then all you need to do is install a battery cut-off switch on the positive cable coming from the batteries (actually the Buss Bar [more about that later]) and make sure it, and the Solar system are both disconnected when you store the coach. Note: do not rely on the battery cut-off switch installed by the OEM because this switch leaves some devices on all the time, additionally, your Solar charging probably bypasses that switch and is wired directly to the battery.

If you camp in cold Temps, then you might consider installing the batteries inside a heated hold, or inside of the coach (under the dinette, or inside a closet). Another option is to install the batteries inside an insulated box and add a heater to keep the battery temperature above freezing.

To be clear, you can use the batteries when they are cold (32° or below), you just can't charge them until they are above 32° (internal battery temperature).

When it comes to wiring the batteries, I strongly recommend wiring each battery to a Buss Bar and then wiring the coach and Inverter to the Buss Bar. I will include an explanation as to why wiring your batteries to a Buss Bar is better at the end of this post.

Because you are adding an Inverter to your coach, you are going to need to increase the size of the cables connected to your batteries as well as installing a couple of fuses between your batteries and the Buss Bar. Your fuse size should be equal to the max current output of your batteries, including any "surge" current they are rated for. The size of your cable will depend on how far away the batteries are from the Inverter, however, you should mount your Inverter as close to your batteries as possible to minimize energy loss along the length of the cable (most 12 volt systems use 4/0 [four ought] cabling.

Your Inverter/Charger will charge your batteries whenever you are on "Shore Power" so you will need to disconnect both the 12v and 120v lines from your Converter (or simply remove it).

Because I am not familiar with your Inverter's specifications, I am going to leave the 120v side for somebody else to explain installing that part.

Battery wiring diagram And sample of Buss Bar:

 

[Scott'n'Wendy]

Your fuse size should be equal to the max current output of your batteries, including any "surge" current they are rated for.

As long as your cables are up to it.

 

[ridingabout55]

Thanks so much for the thorough explanation of proper parallel battery wiring. I've typically seen battery banks wired as Method 1 shows (and that's how I was going to do it). I like the idea of using buss bars for all the connections, and plan to wire as Method 3 demonstrates.

I do plan on installing the batteries and inverter under the dinette seat, as they will be right next to the fuse/breaker box.

Thanks again!

 

[TsnTexas]

First, let's get your batteries installed...

When you are switching from Lead Acid batteries to Lithium, you need to be concerned about charging your batteries when the battery temperature is at, or below, 32 degrees. Your Renogy batteries should have a low temperature cut-off to protect the batteries from being charged, however, you should be aware of this limitation and plan for it during the installation of your batteries, especially, since you have Solar that will charge your batteries anytime the Sun shines.

To accommodate this limitation on Lithium batteries, your camping style needs to be considered...

Do you camp in Winter when the Temps could drop below 32, or, do you store your coach all Winter? If you store your coach, then all you need to do is install a battery cut-off switch on the positive cable coming from the batteries (actually the Buss Bar [more about that later]) and make sure it, and the Solar system are both disconnected when you store the coach. Note: do not rely on the battery cut-off switch installed by the OEM because this switch leaves some devices on all the time, additionally, your Solar charging probably bypasses that switch and is wired directly to the battery.

If you camp in cold Temps, then you might consider installing the batteries inside a heated hold, or inside of the coach (under the dinette, or inside a closet). Another option is to install the batteries inside an insulated box and add a heater to keep the battery temperature above freezing.

To be clear, you can use the batteries when they are cold (32° or below), you just can't charge them until they are above 32° (internal battery temperature).

When it comes to wiring the batteries, I strongly recommend wiring each battery to a Buss Bar and then wiring the coach and Inverter to the Buss Bar. I will include an explanation as to why wiring your batteries to a Buss Bar is better at the end of this post.

Because you are adding an Inverter to your coach, you are going to need to increase the size of the cables connected to your batteries as well as installing a couple of fuses between your batteries and the Buss Bar. Your fuse size should be equal to the max current output of your batteries, including any "surge" current they are rated for. The size of your cable will depend on how far away the batteries are from the Inverter, however, you should mount your Inverter as close to your batteries as possible to minimize energy loss along the length of the cable (most 12 volt systems use 4/0 [four ought] cabling.

Your Inverter/Charger will charge your batteries whenever you are on "Shore Power" so you will need to disconnect both the 12v and 120v lines from your Converter (or simply remove it).

Because I am not familiar with your Inverter's specifications, I am going to leave the 120v side for somebody else to explain installing that part.

Battery wiring diagram And sample of Buss Bar:

This is a great thread, thanks!