Lithium battery - will I get a longer usage

[Paperthreads]

We have the residential fridge, the most we boondock is for just overnights while traveling from location to location. Though we would like to do more - or longer stays.

Our problem is the batteries just don't make it through the night. If we park sometime around 8pm, run nothing but fridge, lights, maybe a fan, and a CPAP machine, then by 2am, the Carbon Monoxide detecter is beeping that we have low battery and when we check, the batteries are showing about 11.2 on the monitor. We would then need to kick on our generator.

We are thinking of changing out our batteries from the lead acid to Lithium - in the hopes that we can get through a full night using fridge, lights, fan and CPAP - from at least 7pm through 8am, so we can get through a night without needing the generator.

Eventually, we would like to get some solar panels put in, so going to the lithium in preparation for that eventual add-on makes sense to us.

Thoughts from others though on if we will reap some benefits right away by changing over to 2 -100amp lithium?

[Daryles]

With lithium batteries you can safely use them down to 10% and not shorten their life.
With FLA battery if you take it below 50% frequently, you will shorten their life.
Look for a white sticker on your circuit breaker panel. It will tell you your model # of your converter.
Go on Progressive Dynamics webpage and look it up to see it it is lithium ready. If so all you have to do is swap batteries and flip the switch.

IF not, not the end of the world. Mine is not Lithium ready but the FLA converter gets them to about 90%. I've been running this way for 3 years. Then added solar. The solar MPPT is set to lithium so it tops the batteries up to 100%.

[Paperthreads]

Thank you - this is exactly what I need to know.

[mhs4771]

Sounds like your batteries aren't in very good shape. When we first got our current unit I did a test of the two OEM crap batteries and they ran the fridge for 36 hours and were still at 12.6. I now have four 6 Volt Golf Cart AGMs and run both the fridge and portable freezer easily over night, plus putting jacks up & down and slides in and out and voltage never drops below 12.6.

[Carl n Susan]

The first question you should answer is: "how many amps do I need?". Whether it is just overnight or for a day or two, that is the amount of power you need to have on hand.

Once you know the "magic" number, then you can decide on the storage medium. FLA and AGMs can only be depleted to 50% so they require more capacity than a Lithium which can be safely drawn down to 10%. There is still a significant difference in cost between FLA/AGM and Lithium batteries although it is shrinking.

[Paperthreads]

Originally Posted by mhs4771

Sounds like your batteries aren't in very good shape. When we first got our current unit I did a test of the two OEM crap batteries and they ran the fridge for 36 hours and were still at 12.6. I now have four 6 Volt Golf Cart AGMs and run both the fridge and portable freezer easily over night, plus putting jacks up & down and slides in and out and voltage never drops below 12.6.

Yes, unfortunately, we were in the storm of the century in Texas, and with 28 degree weather and no electricity, our batteries took a beating - and then our transfer switch went out - about 2 days later, and we went another 4 days with charging up the batteries with our truck to keep running. It did a number on our batteries.

Prior to that, we had boondocked a couple of times and went the full night with no problems. Just can't anymore.

[Daryles]

If you survived that record breaking cold in Texas, yes your batteries took a beating.
To be sure you can take them into any auto parts store and have them tested.
I also installed a DC-DC charger. My write up here.

https://www.montanaowners.com/forums...hlight=charger

In March we spent 10 days dry camping on Ocracoke Island OBX NC Campground.
The solar panels worked great again as they had previously, however, the last three days we had nothing but rain. We used the DC-DC charger in the morning and again in the evening to recharge the batteries to get us through those three rainy days.
Next year we plan on going west and doing a lot of boondocking on BLM Land. We will be taking our generator with us on that trip.

[Todd & Mary]

Yes, because you can draw a lithium battery down farther than a lead acid battery, so you will get more capacity from them. I have 6 100ah lithium batteries and 4 350watt panels and we can run our fridge almost indefinitely. We just completed our install so still testing it out. We used 2% battery with fridge and CAPAP and watching TV for hours last night and woke up still at 96% while boondocking.

[DougVelting]

We have the residential fridge in ours and had the same issue with the battery alarm. We now have 4 lead acids, only because you cant buy the lithiums in a store anywhere.
I would DEFINITELY go with a 200 amp hour single lithium over the 4 batteries we have now i we were able to have waited to get them.
Everything ive read says you will get twice the useable hours out of them, and theres no power drop off.

[Foldbak]

Originally Posted by DougVelting

We have the residential fridge in ours and had the same issue with the battery alarm. We now have 4 lead acids, only because you cant buy the lithiums in a store anywhere.
I would DEFINITELY go with a 200 amp hour single lithium over the 4 batteries we have now i we were able to have waited to get them.
Everything ive read says you will get twice the useable hours out of them, and theres no power drop off.

Amazon delivers...

[DougVelting]

Not when you're dispersed camping

[Ram Montana High Country]

The point most glossed over on the OP was the CPAP & fans. That’s why the 2A wake up call. But the answers were all still right on. I added solar/ lithium along with wire size increase , real breakers and it cured my leveling issues in our Montana High Country.

[Foldbak]

Originally Posted by Ram Montana High Country

The point most glossed over on the OP was the CPAP & fans. That’s why the 2A wake up call. But the answers were all still right on. I added solar/ lithium along with wire size increase , real breakers and it cured my leveling issues in our Montana High Country.

You're right, running just a CPAP on the inverter will drain my batteries to 11.5 in 8 hours. Add a frig and 2 am sounds about right. A bigger battery bank is needed. More lead acid or 2 lithium's. The nice thing is with solar by the time I get up the batteries are charged. (as long as there is sun)

[twindman]

CPAPs don't really use much power IF they aren't doing the 'humidity' thing. Mine has a tank you add water to and turn on the humidifier. However, without this it uses practically no power.

[Foldbak]

Originally Posted by twindman

CPAPs don't really use much power IF they aren't doing the 'humidity' thing. Mine has a tank you add water to and turn on the humidifier. However, without this it uses practically no power.

Mine is 24 volt and I use the humidifier. And since the inverter is on there is a parasitic drain from 2 TV's, the stereo, 2 charging phones and a sound bar.