I have a 2011 Airstream and I would like to get rid of the two 80 AH Lead Acid Batteries mostly for weight savings. My plan is to replace with a single 100Ah Lithium Battery. I do not do full time living, just short 4 day trips or maybe a week long trip. In my research they recommend updating the power converter. I really don't want to do that. Is it possible to just use the lithium for short trips and when I get home put the batteries on a Lithium specific charger so they get balanced? Also what provisions should I make to account for charge coming from the car alternator during travel? Thank you!
Adding Lithium to RV Advice
- Thread starter arktec1
- Start date
sunshine_eggo
Happy Breffast!
Depends on your converter. Many work just fine. Link the manual.
A lithium specific charger has no impact on balance. It's the battery's BMS that takes care of that.
For LFP charging while driving, a DC-DC converter is typically recommended. LFP takes on almost all of its charge below 13.8V, so it can run an alternator at max.
A lithium specific charger has no impact on balance. It's the battery's BMS that takes care of that.
For LFP charging while driving, a DC-DC converter is typically recommended. LFP takes on almost all of its charge below 13.8V, so it can run an alternator at max.
42OhmsPA
What's in a title?
Welcome to the forum.
Agreed with @sunshine_eggo.
Current Connected sells some really nice SOK batteries and Victron equipment... That's what and where I'd most likey buy for a mobile setup.
Agreed with @sunshine_eggo.
Current Connected sells some really nice SOK batteries and Victron equipment... That's what and where I'd most likey buy for a mobile setup.
Partimewages
Solar Addict
Would you mount the DC-DC converter in the RV?
sunshine_eggo
Happy Breffast!
Probably. That would allow for charging with different tow vehicles.
If you buy something that is a described as a 12v 100ah LiFePo4 battery it will almost certainly have a BMS. If not then it's a good sign to skip that product.
I was watching a video on adding a lithium battery and it was mentioned that since the power converter is not made for lithium that it will not charged your battery fully and may leave it unbalanced. If I get a battery with an integrated BMS all I really have to worry about is it being fully charged.
I saw this on Will's website. Is this an acceptable battery for my situaltion? LiTime 12V 100Ah LiFePO4 Lithium Battery, Built-In 100A BMS, 1280Wh Energy
I saw this on Will's website. Is this an acceptable battery for my situaltion? LiTime 12V 100Ah LiFePO4 Lithium Battery, Built-In 100A BMS, 1280Wh Energy
chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,208
I would also ensure the battery has some sort of shut off below freezing for charging, unless it has a built in heater. Freezing and charging can damage a battery. More extreme cold even discharge would harm it.
If it has a heater, the next concern is idle draw when stored for long periods of time.
I had a constant voltage 10 amp 13.6 volt charger converter for my lead acid battery. That would be acceptable. Most cheaper RVs probably have this charger. Mine was hidden behind the circuit breaker panel.
If it has a heater, the next concern is idle draw when stored for long periods of time.
I had a constant voltage 10 amp 13.6 volt charger converter for my lead acid battery. That would be acceptable. Most cheaper RVs probably have this charger. Mine was hidden behind the circuit breaker panel.
sunshine_eggo
Happy Breffast!
Lots of misinformation - mostly from converter manufacturers who want to sell new chargers.
Looks like a constant voltage 13.8V converter. This will charge your battery fine.
Upsides:
13.8V will get to 98%+ SoC.
13.8V is a great voltage to encourage BMS balancing.
Downsides:
You can't leave it floating. After the battery TERMINALS have reached 13.8V for two hours, you'll need to disconnect.
It will charge very slowly from generator.
Otherwise perfectly acceptable.
Looks like a constant voltage 13.8V converter. This will charge your battery fine.
Upsides:
13.8V will get to 98%+ SoC.
13.8V is a great voltage to encourage BMS balancing.
Downsides:
You can't leave it floating. After the battery TERMINALS have reached 13.8V for two hours, you'll need to disconnect.
It will charge very slowly from generator.
Otherwise perfectly acceptable.
sunshine_eggo
Happy Breffast!
3.45V/cell is too high to leave it at float. 3.40V is marginal and 3.375V is preferred.
Easy to cut power to the converter to avoid a high float.
https://www.amazon.com/Battery-Charging-Controller-Protection-Automatic/dp/B075NLYJ8S
I would get two of those 100 Ah batteries.
https://www.amazon.com/Battery-Charging-Controller-Protection-Automatic/dp/B075NLYJ8S
I would get two of those 100 Ah batteries.
0truck0
New Member
Back to your original question, which was, can I do it... Yes you can. You did not provide the loads you will be running while camping, but if you get by with two 80 amp/hr LA batteries, then one 100 amp/hour lithium battery will be enough.
With lithium you will have more available/useable amp/hours than with a lead acid, is almost a 2 to 1 ratio where 200 amp/hours of LA equals 100 amp/hrs of lithium. This is all based on USEABLE am/hrs, not total. You cannot use the last half of the LA battery basically.
Get a monitor
something like this works, or you can get a nicer one.
Is cheap and will tell you how much battery is left while u are camping.
The DC to DC charger is a must if you want to drive and charge.
If you dont want to upgrade your charger then you prob dont want to mess with solar, but 200 watts of solar go a long way to extend the battery on the trip. Indefinitely if you have sun, and importantly will end the need to recharge the battery , ever. With solar the battery/solar will recharge itself. You just park trailer and let it do the work. The idea of taking a battery out after a 4 day trip, lugging it in, hooking to a charger, then reinstalling it right before your next trip.... no. That kind of activity is better suited to the overly-expensive all-in-one battery "generators" that are made like luggage to be toted around..
Also, if you do not upgrade the converter, then if you ever camp with hookups, then you will have to still "boondock" power-wise as you cannot plug in and have the converter power the DC items because that includes charging the battery (putting current on the battery), unless you somehow separate the converter from the battery and at the same time separate the battery from all the DC devices so the converter powers DC yet is not connected to devices that are not connected to the battery. Way easier to just upgrade the converter or do something safe so you can have converter giving battery power. So, if you boondock at full hookups and want to run the air cond, then how you going to do that without pluggin in and without having converter power the lithium battery incorrectly?
Lithium is so much better than LA. Just jump in and do everything the right way from the start.
With lithium you will have more available/useable amp/hours than with a lead acid, is almost a 2 to 1 ratio where 200 amp/hours of LA equals 100 amp/hrs of lithium. This is all based on USEABLE am/hrs, not total. You cannot use the last half of the LA battery basically.
Get a monitor
Battery Monitor 50A 100A 350A Caravan RV Motorhome lithium iron lead-acid 999 AH | eBay
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Is cheap and will tell you how much battery is left while u are camping.
The DC to DC charger is a must if you want to drive and charge.
If you dont want to upgrade your charger then you prob dont want to mess with solar, but 200 watts of solar go a long way to extend the battery on the trip. Indefinitely if you have sun, and importantly will end the need to recharge the battery , ever. With solar the battery/solar will recharge itself. You just park trailer and let it do the work. The idea of taking a battery out after a 4 day trip, lugging it in, hooking to a charger, then reinstalling it right before your next trip.... no. That kind of activity is better suited to the overly-expensive all-in-one battery "generators" that are made like luggage to be toted around..
Also, if you do not upgrade the converter, then if you ever camp with hookups, then you will have to still "boondock" power-wise as you cannot plug in and have the converter power the DC items because that includes charging the battery (putting current on the battery), unless you somehow separate the converter from the battery and at the same time separate the battery from all the DC devices so the converter powers DC yet is not connected to devices that are not connected to the battery. Way easier to just upgrade the converter or do something safe so you can have converter giving battery power. So, if you boondock at full hookups and want to run the air cond, then how you going to do that without pluggin in and without having converter power the lithium battery incorrectly?
Lithium is so much better than LA. Just jump in and do everything the right way from the start.
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For short trips, don't aggravate yourself with DC-DC chargers. The cost to do it right is not worth it for a 100Ah battery.
Buy a separate 15-20 amp LFE charger and make sure the battery is charged before the trip.
The batteries have an internal balancer in the BMS themselves not from the charger.
When you're plugged at a campground, the converter is providing 12v power and charging. You'll hardly be using the battery.
A lot of LFE batteries have Bluetooth and an app to show state of charge.
For one battery, I wouldn't even bother with a separate battery monitor.
Checkthisout
Solar Wizard
- Joined
- Nov 14, 2021
- Messages
- 4,819
The issue with most converters is they will not go into boost mode unless battery voltage falls below 12.0 volts so all you get is absorption charging voltage of 13.8 and reduced amps so you never get the full output of the charger.
I would recommend swapping to something like an inverter/charger with power assist.
This will allow you take full advantage of your fancy new lithium batteries.
I would recommend swapping to something like an inverter/charger with power assist.
This will allow you take full advantage of your fancy new lithium batteries.
Partimewages
Solar Addict
Some chargers have a desulfate mode which is bad for Lifepo4.
sunshine_eggo
Happy Breffast!
$20 DC-DC charger:
Only if the BMS fails.
Only if the BMS fails.
