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Lithium Battery Charging System

CYCLEPATH
Explorer
Explorer
It is time for a new battery in my '04 Lance 921. I am looking at an Interstate battery they sell up the road. But through my research into charging systems/problems, I got to thinking about Lithium batteries. Being a retired cargo pilot, my knowledge about lithium batteries is that if they catch fire, they become quite the spectacle. I was actually surprised they were using them in campers.

My question is, are they worth the price? What do you have to change/do to your charging system to be able to charge one, and is that added expense worth it? I have a PD charger/inverter, and charge wizard now. Is this what you have to change out to be able to charge the lithium battery? And what would take their place? Will the truck alternator charge the Lithium battery? Will the current battery separator need to be changed? It seems a lot easier to just install a new Interstate. I don't do a lot of boondocking, but that could always change in the future. Thank you.
48 REPLIES 48

time2roll
Nomad
Nomad
The existing setup should work perfectly well. Just drop in the battery and have fun. Consider 200 to 400 watts solar if getting off grid much.

theoldwizard1
Explorer
Explorer
CYCLEPATH wrote:
Will the truck alternator charge the Lithium battery? Will the current battery separator need to be changed? It seems a lot easier to just install a new Interstate. I don't do a lot of boondocking, but that could always change in the future. Thank you.

The short answer is, if your current lead acid meets your needs, stick with it. Maybe upgrade to a pair of 6V golf cart batteries.

Your current battery separator would have to be replaced with a DC-DC charger. It prevent discharging the vehicle battery and ensure that you LiFePO4 battery is charged correctly.

covered_wagon
Explorer
Explorer
Nothing wrong with wet cell batteries, especially if you want to keep it simple, not have to worry about anything. The technology to recycle them is there too.

3_tons
Explorer
Explorer
The prior lithium hazard was associated with a ‘hotter’ more power dense chemistry using cobalt… A common ‘drop-in’ type RV battery (straight replacement) is of a friendlier, safer chemistry (LiFePO4, or ‘LFP’ = Lithium, iron, phosphate..) and there’s virtually no record of such mishaps with this chemistry and can be shipped as non-hazardous…Also, the built-in BMS System (Battery maintenance system) works as a redundant secondary catastrophic safeguard that prevents over current, overcharge (etc…), and acts to balance the cells upon a full recharge (although with LFP a ‘full recharge’ that enables cell balancing should be viewed more as a periodic rather than a routine regime)..

Your PD with charge wizard will work fine so long as you kick it into the Absorption or Boost Mode (14.4v), but once fully charged (i.e. post cell-balancing) discontinue charging shortly thereafter since it’s not good to continue charging for extended periods, and for this same reason (unlike wet-cell types) LFP’s should not be equalized (over time can lead to damaging dendrite formation)…

Determining ‘accurate’ LFP State of Charge (SOC) will require a decent LFP compatible meter (or say bluetooth), such as a Victron ‘Smart Shunt’ or BMV-712 (or equiv), this due to LFP’s relatively flat discharge voltage plateau…With either battery type a good shunt based meter (shunt installed in batt neg cable) is truly an invaluable asset!!

Usable wet-cell depth of discharge (DOD) is down to about 50’ish percent, whereas LFP’s can routinely go down much deeper discharge, some even advertised to zero percent, but in the interest of cycle longevity a somewhat lesser DOD would seem more practical…

In summary, LFP’s have a relatively flat, stable voltage plateau, uber deep DOD (Depth of Discharge), a FULL daily charge is not a routine objective (unlike FWC, something best avoided except for occasional re-balancing), single stage charging is ideal (tolerant to a relatively wide breadth of ‘Absorption’ or ‘Boost’ voltages (upper 13’s not to exceed 14.6v), tolerant to extended Float mode (at less than 13.6v,) tolerant towards infrequent charging or ‘less than full’ charging cycles for a near grid-like experience, and efficient harvest receptivity to more rapidly exploit peak harvest hours…

On the downside, LFP’s cannot be charged below 32d/F, but can continue to be discharged to as low as -4d/F…Since they don’t off-gas one option may be to interior mount (or heated basement), while higher-end versions can be had with built-in heaters, or one might insulate battery case with a electric (12 or 120v) battery blanket…Due to LFP’s uber deep DOD ability, charging can often be postponed until the arrival of warmer ambient temps..

3 tons