Switching from lead acid to lithium batteries

[ranger1001]

Winnebago 2022 Micro Minnie model 2225RL.

Getting ready to probably make the switch from lead acid to lithium batteries. Spend 99% of my time in campgrounds with shore power so not really making the switch for serious boondocking. Had battery/power issues all last season in particular with operating the slide. After spending entirely too much to solve the issues over the year thinking that switching to lithium will go a long way towards eliminating the issues in the future. No plans to change or increase the factory installed 200 watt solar panel but pretty sure I'll be going with a new Victron solar controller - although still not sure which model I need. Visited Victron site but scracthing my head over too many options. Don't want to buy more than I need but also don't want to buy less than I should have for my current setup. Also not sure what my current converter situation is and want to make sure I have the right equipment there as well. Pretty well settled on either Battle Born or Dakota batteries as I plan on running two 12V 100AH batteries.

So would welcome any input on what I'm going to need to make the conversion? Talked to a local shop but these types of conversions are pretty rare here in Maine and knowledge of systems isn't the best.

Thanks for any help and suggestions.

Richard Perry
Orrington, ME

[powercat_ras]

You can't go wrong with the Victron 100/30 for $ 129. Great product at great value for a smart SCC that has smart phone Bluetooth functionality. It can handle about 400 watts of solar maximum so you'd have some potential to add solar down the road.

The OEM onboard converter charger that works when you are 120 VAC powered will not fast charge Lithium Iron all the way to 100%, it can be upgraded to one that will if you decide you want to.

The charge line from your towing vehicle will not charge Lithium Iron all the way to 100% unless you add a DC-DC charger right at the TT battery. This will step up the DC voltage being fed from the towing vehicle to the TT to the 14.4 volts right at the battery so it can fast charge to 100% from the towing vehicle. Renogy 20 A DC-DC is a good option it will limit the power drawn from your towed vehicle to 20 amps which is good.

There are also some combined products that combine some or all of the above things into a single unit but they can be expensive compared to the separate units I have mentioned above.

[ranger1001]

Appreciate all the great suggestions. Will do some follow-up studying on your advice.

Thanks again,
Richard Perry
Orrington, Maine

[Marine359]

Hi Richard,
Are you adding an inverter/charger or inverter? Or upgrading your charger? I went the route of running SP sized cable from pass-thru down and under the floor, then up back through the floor near the distribution panel. Also mounted two charge controllers in pass thru with a fuse block between them and battery. Also installed a second disconnect dedicated to inverter/charger. Found out by nearly getting stranded that the battery needed a heating mat, so, I wired that in later. You can now get LFP with self heating and Bluetooth. More expensive than using a mat, but simpler. Since you’re in Maine, you need a battery heating strategy if you plan to mount battery in pass-thru. Take a look at photos in my upgrades and mods album. You can PM me if you have questions.

[Riverbend]

I'll second the recommendation for the Victron 100/30 MPPT controller. The boost in solar gain over a PWM controller is significant. I used BB batteries in my previous conversion but am going with an Epoch 300Ah in my new rig. You might want to consider their 105Ah for a drop in replacement. Great price for a Bluetooth/heated LiFePo. Check out Will Prowse on YouTube, he does a great review of that battery.

[Jokaj]

Hi Richard,
I have the same rig as you. I had the dealer swap out my lead acid with Lithium. They installed it in the front bay further away from the tongue.

Joe

joe

[Rcook]

I have made the switch already. It’s an awesome upgrade if you plan to boondock. With only staying in campgrounds I would save your money and just go to a good quality AGM battery. Minimal maintenance, high draw down capable and half the cost and no charger upgrades needed.

[Marine359]

Originally Posted by Rcook

I have made the switch already. It’s an awesome upgrade if you plan to boondock. With only staying in campgrounds I would save your money and just go to a good quality AGM battery. Minimal maintenance, high draw down capable and half the cost and no charger upgrades needed.

You wouldn’t be saving much by buying AGM. Maybe 50 bucks. And, you don’t have to change the charger with LFP. Not perfect or fast charging, but will still get you more useable amp hours than the same amphr rated AGM. No maintenance at all. And less weight.

[Rcook]

Your existing chargers will only bring lithium up to 80%. Not sure about USA but a heated lithium in Canada is 700 bucks on Renogy. A good AGM is 350. So you need two to match the lithium ah and being that they fully charge you will have a full 100 ah not 80 like a single lithium at 80%. DC to DC charger is about 200 and new converter is at least 200. Your AGM can be charged at any temperature. Lithium need to be above 4 C degrees. Again with AGM being fully sealed they require no maintenance. Having used both, only go lithium if you need to have lots of power without shore or generators. Ie boondocking.

[MDJDCarter]

Hi,
This topic has been in other threads on this forum. Do a search on "lithium" and they should come up. I know the tech changes and improves, so I am always interested in hearing the latest stuff; but, there might be some nugget of information in a prior post that could be important to your situation.

[Marine359]

Originally Posted by Rcook

Your existing chargers will only bring lithium up to 80%. Not sure about USA but a heated lithium in Canada is 700 bucks on Renogy. A good AGM is 350. So you need two to match the lithium ah and being that they fully charge you will have a full 100 ah not 80 like a single lithium at 80%. DC to DC charger is about 200 and new converter is at least 200. Your AGM can be charged at any temperature. Lithium need to be above 4 C degrees. Again with AGM being fully sealed they require no maintenance. Having used both, only go lithium if you need to have lots of power without shore or generators. Ie boondocking.

Not exactly true. A 30amp LA charger will eventually bring LFP close to 100%, but the last 20% will take a long time, maybe as much time as absorption mode for AGM, and will not top balance. And there’s no harm in just charging to 80%. If OP doesn’t buy heated LFP, a 12v thermostatic tank heating mat works great in cold weather. I paid $35 for one. I think OP has already made the decision to go with 2x 100ah LiFePo4. If he’s not going to change his charger in order to charge faster and top balance, that job can be done by solar, dc/dc, or the inexpensive little NOCO Genius 10 for $80. We used one before we got a 80amp charging system, and it works great overnight from any 15amp ac source. 2x 100ah LFP weigh a total of 50#. 2x 100ah AGM weigh 120#. The comparison comes up in many threads, but you have to acknowledge that it’s not just a $/ah argument. There are many other factors like cost/year over a given number of years.

[Bill F]

We have a 2022 Micro 2306BHS. I put in a Renogy 100 AH and found the charger and the solar controller were both compatible with LFP batteries. I had to manually set the solar controller, but the 120V system has auto-detect (I had to look up the manufacturer info to learn that!).


I am changing the solar controller to a Renogy dual input MPPT that will also boost the voltage from the tow vehicle to properly charge the LFP.



BTW, I recently got the wiring diagrams from Winnebago, and learned that the outside connectors for solar panels are wired in parallel with the rooftop solar, unlike what most manufacturers do.