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RV conversion to lithium

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Confusedbutwilling

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Joined
Apr 10, 2024
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Greentown,Pa.
I have a 2019 Winnebago Sunstar 29ve. My lead acid batteries are dying and I want to convert to lithium with a possibility of adding solar in the future. Basically all I know is that I have to change the batteries and the battery charger to one that won’t hurt my new batteries and can be used for solar panels in the future. I’m leaning towards the Renogy batteries. I guess I should get the highest Ah battery that will fit in the same area my old batteries are. I live in NE Pa. So I will need heated batteries. Bluetooth would also help. I understand the systems are not plug and play but I would prefer the easiest set up possible. I’m handy but electricity is definitely not my strong suit. Can anyone recommend an easy and reliable system with model numbers and/or videos that will work for my specific RV ?
 
If your inverter can be set to LFP or custom all you really need is a DC to DC charger for the alternator charging. Without that you will burn up your alternator. Do you know what model your Inverter is?
 
Confusedbutwilling said:
I have a 2019 Winnebago Sunstar 29ve. My lead acid batteries are dying and I want to convert to lithium with a possibility of adding solar in the future. Basically all I know is that I have to change the batteries and the battery charger to one that won’t hurt my new batteries and can be used for solar panels in the future.
Click to expand...

You have fallen victim to marketing. The converter manufacturers have developed converters that have a poor implementation for LFP but have been very effective in spreading FUD to encourage sales.

First, LFP battery BMSs protect the batteries, so the charger can't damage them; however, a charger that continuously engages BMS protection isn't desirable.

Dig up the specs on your converter. Link or list them here.

The biggest issue with ANY RV coach battery is the length and gauge of cable between the converter and battery.

Confusedbutwilling said:
I’m leaning towards the Renogy batteries. I guess I should get the highest Ah battery that will fit in the same area my old batteries are. I live in NE Pa. So I will need heated batteries. Bluetooth would also help. I understand the systems are not plug and play but I would prefer the easiest set up possible. I’m handy but electricity is definitely not my strong suit. Can anyone recommend an easy and reliable system with model numbers and/or videos that will work for my specific RV ?
Click to expand...

Renogy is not known for their product quality or follow-on support. I do not have a recommendation for a heated battery solution. I suggest you mine Will's videos for options.
 
Last edited:

lithium-battery-power-centers - Progressive Dynamics

The Mighty Mini Compact All-In-One System offers an AC/DC Power Distribution Panel and Inteli-Power Converter with Charge Wizard battery charging technology.
www.progressivedyn.com www.progressivedyn.com
That would be the easiest way to go. When I did my first conversion in a 5th wheel I got rid of that and replaced it with a Inverter charger. On our motorhome I went with heated Battle Born batteries and Victron. My Motorhome would charge the AGM batteries from the Alternator but with lithium they pull too much current and will shorten the life of the alternator. I added a Victron DC-DC charger. If I do it again it will be with an off-grid inverter and server rack batteries.
 
How hard is it to do? Is it pretty much just undoing the connections I have now and reconnecting the wires on the model in the Linc you sent? Or are there other things that I need? From what I’ve seen and read I’m leaning toward the Renogy batteries
 
Yes plug and play with that one. I do recommend looking at other options for batteries. Like I said I went with heated BB batteries and I do not think I needed the heated ones. My bays are heated and I used foam boar around the batteries so the heat option was a waste of money. With the RV whisperer system I never saw temps less than 35f even when not hooked up.
 
Confusedbutwilling said:
Intel-Power model PD9245C
Click to expand...
This converter will serve you well with lithium. As good or better than the converters marketed as "lithium" compatible.
Plug and play.

Lithium does charge faster and may have a significant load increase on the alternator. Best to measure the effect or at least make sure there is a fuse in the circuit and not the common self resetting breaker.
 
I’m in NE Pa. I need heated batteries. Winter is f’n cold. I was looking at battleborn but a lot of people say renogy is just as good but cheaper. I think I need heated batteries and Bluetooth to keep an eye on them. I’m basically plugged in to 30 amps at home (rv is 50 amps with a 50 amp Generator ) and mostly have electric at the campgrounds we go to but we want to start boondocking for short periods to start and eventually longer stays. That’s why I want solar capability now. I figured I’d be looking for panels in a year or two. I’m thinking I should get the biggest batteries that will fit where my old ones are now (under my step and exposed to the weather from underneath).
 
time2roll said:
This converter will serve you well with lithium. As good or better than the converters marketed as "lithium" compatible.
Plug and play.

Lithium does charge faster and may have a significant load increase on the alternator. Best to measure the effect or at least make sure there is a fuse in the circuit and not the common self resetting breaker.
Click to expand...
Etrailer said it’s not compatible with lithium
 
Confusedbutwilling said:
Can anyone recommend an easy and reliable system with model numbers and/or videos that will work for my specific RV ?
Click to expand...
I changed the RV converter out to this AIMS 120 VAC to 12/24 VDC charger:

www.aimscorp.net

AC Converter / Battery Charger 12/24 VDC Smart Charger 75 Amps - Listed to UL 458/CSA

Get versatility, fast charging and a warranty with the AIMS 12V and 24V AC 75-Amp Converter/Battery Charger from AIMS Power.
www.aimscorp.net www.aimscorp.net

The original RV converter would charge at 10 amps 13.6 VDC constant, and I wanted faster charging and my batteries could handle the full power this throws at it. I use the lowest charge settings on it to gel, 14.0 volts bulk and 13.7 float. This was a swap beteen the old converter and new converter. Because I went up in amperage, I did need to upgrade to new thicker wires.

If you do get a bigger converter, the one I recommended has a fan that can be heard. The bigger AC to DC converters will put out more heat and will needs that fan to remove the heat. I imagine any larger amperage ac to dc charger/converter will make themselves heard.
 
Do you RV in cold or is the cold just for storage?

You can discharge colder than 32F - but DO NOT charge when the battery is colder than 32F.

If you RV when temps are below 35F a battery that has heat would be good.
If you just store your rig in the winter - just disconnect the battery - it will be fine over the winter.

You can buy a “heated” battery or add a way to heat the area. If you add the heat from your furnace to the area you are good.

Make sure the battery has cold temp protection. That way the bms will not allow charging when the cells are too cold.
 
Confusedbutwilling said:
Etrailer said it’s not compatible with lithium
Click to expand...
OK so there is no metric or lithium electricity. Just volts and amps. The existing PD92xx converter meets the specifications for lithium batteries. In some ways better than the lithium labeled converters.

What did Etrailer recommend?
 
I looked up my converter PD9170 70amp output.
Charge voltage 13.6 or 3.400 per cell. Acceptable for Lifepo4.
Boost voltage 14.4 or 3.600 per cell. Still Acceptable for Lifepo4 an below the maximum 3.650 per cell.
You can run into some issues at the upper voltage with HVD if the pack is not balanced but with the Charge voltage being 13.6 it will likely balance after a bit of time.
 

9200 - The full rated load is available for load, battery charging
or both. When charging the battery, the converter has a
nominal voltage output of 13.6 VDC for 12 volt models and
27.2 VDC for 24 volt models. The system will sense voltage
on the battery and automatically select one of three operating
modes (normal, boost and storage) to provide the correct
charge level to the batteries.

BOOST MODE: If the voltage drops below a preset level the
output voltage is increased to approximately 14.4 VDC (28.8
VDC for 24 volt models) to rapidly recharge the battery.

NORMAL MODE: Output voltage set at approximately 13.6
VDC (27.2 VDC for 24 volt models).

STORAGE MODE: If there is no significant battery usage
for 30 hours the output voltage reduces to 13.2 VDC (26.4
VDC for 24 volt models) for minimal water usage. In storage
mode, the output voltage increases to 14.4 VDC (28.8 DC for
24 volt models) for approximately 15 minutes every 21 hours
to help prevent sulfation of the battery plates.

This converter will not damage your battery and charges at voltage very appropriate for LFP.

The biggest issue is likely how to trigger BOOST charge. It may not do this when you want it to. You may be able to simply power cycle the converter to trigger BOOST.

13.6V can easily fully charge a 12V LFP battery, but it may take longer than desired. On shore power, it will fully charge the battery via "normal" mode and then enter storage mode. Generator charging may be a little disappointing.

This is definitely a "try it before you replace it" situation.
 
Rocketman said:
Do you RV in cold or is the cold just for storage?

You can discharge colder than 32F - but DO NOT charge when the battery is colder than 32F.

If you RV when temps are below 35F a battery that has heat would be good.
If you just store your rig in the winter - just disconnect the battery - it will be fine over the winter.

You can buy a “heated” battery or add a way to heat the area. If you add the heat from your furnace to the area you are good.

Make sure the battery has cold temp protection. That way the bms will not allow charging when the cells are too cold.
Click to expand...
This is my thought as well. Low-temp charging protection is the most important piece. Many will tell you not to bother with self-heating batteries, unless you REALLY need that feature. LiFePO4 can be safely discharged in cold temperatures, it's just if the internal cell temperatures drop too low, you do not want to charge them.

Someone more knowledgeable in the RV battery space can correct me on this, but don't they make batteries with internal BMS disconnections/shutdowns? Basically so you can discharge the battery to 20% or whatever, then the BMS can literally turn off and not do any parasitic draining. My understanding is you need to provide power to the batteries (a charger) to wake the BMS up.

I would think if I had batteries sitting for 6-9 months of the year, I might want something like that. Keep them at a low state of charge and then have them completely off.
 
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