LI batteries have way less internal self discharge compared to AGM / Flooded Lead acid batteries. If the vehicle does not have low current drains for the ECU or TSSM/BCM, the battery could easily go 6 months or longer without recharging.

 

Not sure what you mean by higher capacity.. Maybe the charger on your RV cuts current as it reaches full charge? LI can be charged at max current close to full charge but needs to shut off before over voltage.

As far as I can tell, HD regulators are not smart, they charge at whatever the output of the alternator is until full voltage is reached.

 

But Harleys have had BCMs for 10+ years. So is that to much parasite draw? Plus with BCM. PIA to disconnect battery.

But it is interesting selling point. Especially in off-road vehicles with out the extra loads. But I don't care about 20 lbs on 4 Wheeler but some sleds and dirt bikes, people might believe they care

 

I was looking at a possible switch to Lithium batteries in my RV.

The way I understand it, is that the RV engine regulators will put out what the batteries will take (amps), until the voltage reaches certain levels. Lithium batteries can take the full charge output (amps) until their voltage is at its charged state (14.4v full charge, and up to 14.7v charging). The RV engine alternators put out 14.1v or thereabouts, so to charge a house bank of lithium batteries, it will not get them to full charge. The RV alternators, because of the charge profile of lead acid batteries, are not designed to run at full output for long periods of time. The RV engine alternators, trying to charge a bank of lithium batteries to a level they cannot reach, will run at full output (amps) almost indefinitely. The large house lithium battery banks can/will burn out the RV's engine alternator, if you drive away with discharged house batteries.

For lithiums in RVs, many call for separating the chassis & house batteries. Let a solar charger and the house inverter/charger (when plugged in or on generator) charge the house batteries at a lithium battery profile, and the engine alternator charge the chassis batteries at its lead acid profile. Many of the solar chargers (like on my RV) will have a chassis battery charge circuit, separate from the house bank profile, that will maintain the chassis battery once the house bank is full.

If you don't have solar, they call for a DC to DC charger, that fits in between the RV alternator and the house bank, so charging the house bank when driving won't strain or overtax the RV engine alternator. I forget exactly how that works.

I hope I remembered/explained that correctly. In the end, I just went with high quality AGM batteries in my RV. It was a lot less complicated, cheaper, and fits my needs rather nicely...

 

Thanks for tell me what I already stated and knew. If you know the drain on the system from the BCM/ECM/and other stuff plus the self discharge rate of LI , you can calculate the time between required charges.

I was just tell you what you didn't know about batteries.

 

I would use deep cells for the RV, like marine batteries

 

I guess some of this depends on the RV for sure.. Have a buddy that had one of those diesel pushers. It had a 10kv generator to keep the batteries topped off..

I have a another bud that has an F350 long bed that had an RV / Trailer connection in the bed. He added a very fancy cab over camper. He had trouble keeping the AGM batteries fully charged so I helped him add a DC/DC converter to the system and a charge controller for solar panels. Worked better but I suspect that he'd already killed that batteries from weak recharge rates. He switched to LI and thought it was the Bees knees.. He could pretty much run the system off of solar and driving around without needing to fire up a generator or hookup..

 

Yeah, most house batteries are deep cell.

I use deep cycle 6v AGM, wired in series/parallel to make up a 12v house battery bank...

 

This seems over the top ridiculously priced to me, just nuts.

 

Agreed.... but I suspect in some cases the quality, efficiency and level of control of the BMS (battery management system) could be the reason for the more expensive batteries....