Battery Upgrade to LiFePO4 with External Solar

[Hometechnc]

My first post here. I plan on doing a fair amount of Boondocking in the near future, and I'm trying to come up with a Simple method to expand the 12v capacity of my 2021 Reflection 278BH fifth-wheel. Not sure if this is possible or technically feasible, but my plan was to replace my single lead-acid battery with a 270Ah lithium, then keep them topped off with two, 200watt 12v solar panels which would be mounted on a roof-rack on my Dodge Ram 2500. The power feed from the panels connected via a quick connect, which would be installed in the exterior wall of the front storage compartment, where the existing battery is located. The power being fed into a mppt charge controller, then feed directly to the battery. Essentially, it would be installed in the same manner as a "Battery Tender', but with enhanced charging power. I have a Yamaha 3000ES generator which could be used occasionally when 120v is required. I'm not sure if it would be necessary to upgrade the factory charger/convertor since the battery would be charged or at least topped off via the panels? So, I'm throwing this out there for feedback. Not sure if it's practical, overkill, or just not feasible?

[Country Campers]

It sounds like a good plan to me. The solar installed on the truck means that you can use it for the next RV.

Brian

[Yoda]

My first post here. I plan on doing a fair amount of Boondocking in the near future, and I'm trying to come up with a Simple method to expand the 12v capacity of my 2021 Reflection 278BH fifth-wheel. Not sure if this is possible or technically feasible, but my plan was to replace my single lead-acid battery with a 270Ah lithium, then keep them topped off with two, 200watt 12v solar panels which would be mounted on a roof-rack on my Dodge Ram 2500. The power feed from the panels connected via a quick connect, which would be installed in the exterior wall of the front storage compartment, where the existing battery is located. The power being fed into a mppt charge controller, then feed directly to the battery. Essentially, it would be installed in the same manner as a "Battery Tender', but with enhanced charging power. I have a Yamaha 3000ES generator which could be used occasionally when 120v is required. I'm not sure if it would be necessary to upgrade the factory charger/convertor since the battery would be charged or at least topped off via the panels? So, I'm throwing this out there for feedback. Not sure if it's practical, overkill, or just not feasible?

First welcome here.
Your idea has merit and I have not seen it done here before. If I understand correctly you would use something like an Anderson connectors at you bulkhead mount. With a good lithium programmable MPPT controller (I recommend Victron) mounted in the trailer you could keep them topped off as long as you have sun. I believe your existing converter will work, but only to about 80% charge. Be sure you have a disconnect switch at your panels and a circuit breaker between the controller an the battery. Why? The MPPT controler should be powered first turning on and when turning off the panels are disconnected first. I think I have that correct?

The other thing to look into for you boon docking is a DC-DC charger powered by your truck alternator. Use the search feature here as there are numerous good threads on both topics

There are lots of experts here, so don't be afraid to ask. I am not an expert and ask a lot of questions.

Good luck on your project.

Keith

[Cate&Rob]

Hometechnc

Welcome to our owners technical forum. When you have a chance, have a look at our welcome post. https://gdrvowners.com/forum/main-fo...to-new-members . This will help you set up your signature and navigate the forum.

I had a similar idea . . . buried in some related thread somewhere. My thought was to use the space ahead of the 5th wheel hitch for the solar power system. Put everything here . . . it could be a module built into a removable box. Batteries, solar controller, inverter, with solar panels on top. More panels could fold open back over the hitch when the trailer is disconnected. Thus, the truck could be parked in the sun, even if the trailer is in the shade. The only connection to the trailer would be a normal shore power cable. Ideally everything in the truck would hide under the tonneau cover.

Rob

[Jlawles2]

Cate&Rob Nice idea Rob. wonder if they make panels close enough in size to the folding hard covers such that you could fold the cover on the bed closed and get a 6'X6' (8; with LWB) solar panel.

[jim-SD]

Look like as good as place as any to add this. This is the version of converter in my 2022 31mb. It is a PD926C. I am replacing with a Lithium version model PD9160ALV. This keeps the 12 volt stuff going but would still be missing 120 ac when boondocking without a generator. Since my unit is inverter ready will need to add that, but will do separate. (converter down to 12 volt dc, invert up to 120 volt ac). Inverter Ready has a 2x 15 amp breakers in the ac panel and a orange Romex wire loop in the front compartment. The built in solar might be able to handle the truck solar.

I am also adding which might work for you, but ran into issue for some reason a Renogy 40 amp dc to dc unit, to charge from the truck. You connect two 4 gauge wires to truck battery, run a 3rd wire to alternator (or toggle switch when engine running or to running lights in 5th wheel). Fuse at battery, anderson clip in back or truck for quick connect. Runs to Renogy DC to DC charger in front compartment. Two output wires connect to the lithium batteries then can charge as you drive or even idle in place of a generator. My issue is at 40 amps somehow uses more power then my 240 amp alternator can handle, but works at 20 amps as expected, not sure if smart alternator issue

[Guest]

Look like as good as place as any to add this. This is the version of converter in my 2022 31mb. It is a PD926C. I am replacing with a Lithium version model PD9160ALV. This keeps the 12 volt stuff going but would still be missing 120 ac when boondocking without a generator. Since my unit is inverter ready will need to add that, but will do separate. (converter down to 12 volt dc, invert up to 120 volt ac). Inverter Ready has a 2x 15 amp breakers in the ac panel and a orange Romex wire loop in the front compartment. The built in solar might be able to handle the truck solar.

I am also adding which might work for you, but ran into issue for some reason a Renogy 40 amp dc to dc unit, to charge from the truck. You connect two 4 gauge wires to truck battery, run a 3rd wire to alternator (or toggle switch when engine running or to running lights in 5th wheel). Fuse at battery, anderson clip in back or truck for quick connect. Runs to Renogy DC to DC charger in front compartment. Two output wires connect to the lithium batteries then can charge as you drive or even idle in place of a generator. My issue is at 40 amps somehow uses more power then my 240 amp alternator can handle, but works at 20 amps as expected, not sure if smart alternator issue

Very nice. Great choice in moving away from the standard charger since you may have the smart wizard feature which has an equalization mode. This will result in a lithium bms shutdown and could damage the battery. You may want to not connect the trigger D+ wire to the alternator since the main cable will be hot all the time and you do not want to connect to the field terminal.

There are losses on these DCDC chargers so in order to get 40 amps the DCDC may pull as much as an additional 50% from the TV. Best to not charge at idle since alternator cooling will not be there but 20 amps is light so it may work with the lower setting. I just activate underway to leave no doubt.

Jim