Lithium battery

Not in a 195, but in our 179, you can read about my conversion in my mods (see link in signature).

The keys with a lithium conversion are:

place the battery in a heated location, never charge a Lithium battery below freezing temps.

the battery must have a battery management system (BMS) that equalizes cell charge voltage and protects the battery from overcharging. The BMS should come with the battery and is typically internal.

Convert and/or reconfigure all charging sources for Lithium battery use. Those include the on board Ac/DC charger, alternator charging from the tow vehicle, and solar charging if you have that.

The on board lead acid battery charger can be swapped out, and most modern solar charge controllers have a Li setting.

Generally the alternator charging is the most complex to convert. You do not need to run a separate charge circuit, the +12V pin on your 7 way connector will work. You need to run that into a DC/DC converter located in the trailer, before that wire connects to anything else in the trailer. The DC/DC converter should be sized based on the ampacity of your 12V trailer supply. That will typically have a 3O amp breaker so a 20 amp converter would be a good choice.

You will either need to disconnect your 7 way whenever you stop for more than an hour or so or set up that circuit with a relay so it's switched off when the ignition is off (some already are), otherwise the converter will happily continue to charge the Li battery if it is low,discharging your tow vehicle starting battery in the process.

As you can see, much of the cost and most of the work is involved with the charging sources and wiring, not with the Li battery itself, which is getting pretty inexpensive now.

Thanks for all the info and advice.  Think I am going to pass for now.  What about the “AGM” type batteries?  Anything special to add one of those or is just a straight swap?

+1. The AGMs (absorbed glass matt) batteries are quite a bit more expensive but perform no better than flooded deep cycle batteries. They are also more sensitive to overcharging (because you can't just take off the caps and add distilled water) so you have a bit lower peak charging voltage. They do have one advantage which is lower maintenance so if you can't bring yourself to check the water level every month or so by all means spend the extra $$$ for the AGM's.

ummm.

Battle Born recommends using a high quality ac charger specifically configured for Li batteries. The key concern is not undercharging, which won't hurt a Li battery, (just limits useful capacity) but overcharging during bulk or equalization mode. That is dangerous.

My WFCO failed and took my flooded golf cart batteries up to 16V plus volts. No harm done to those batts, just excessive water consumption, because I caught it before the plates were exposed. But that would be very harmful and dangerous for a Li battery. Battle Born's BMS is designed to prevent that level of overcharging but after my experience I wouldn't want to count on it as the sole line of defense against overcharge.

Battle Born also recommends using a DC/DC converter for alternator charging. They are master distributors for both Progressive Dynamics (ac chargers) and Victron (solar charge controllers and DC/DC converters) so you can get all your hardware from them if you want. PD and Victron both make good products for this application.

I'm not recommending Battle Born as a source though, they are overpriced for my budget. I'd personally go with StephenH's lower cost approach. Either way will work fine, but you do need to take some care in a Li conversion. I wouldn't recommend just dropping a Li battery into an rpod without other modifications.