So, that flooded battery sucks

[Jerry Burks]

I have installed 380W panels on my 5th wheel, with PPMT controller and 2kW inverter. So far so good. On a nice day I can pump 20 amps into the battery.
The camper came with 2 flooded lead acid batteries with 65 Ah each and I tried how far I can go with it without shore power. Turns out not that far.

I am not asking much (I think). Run the lights (dimmed) and the TV and laptop for a few hours and the furnace through cool nights. The only high power users are the microwave and the espresso maker but only for a few minutes. I am not even trying to run the fridge on inverter but use propane instead.

Unfortunately, through a chilly (not cold) night the furnace fan sucks about 65% of the battery capacity and while the remaining capacity is technically enough to heat the milk in the microwave and run the espresso maker, the voltage drop is so bad that the inverter stops. And a morning without coffee makes me mad. I am even wondering if the batteries could sustain the furnace when temperatures drop well below freezing.

FWIW, the battery drain through inverter for the microwave is 170 amps and the espresso machine is 130 amps, but again for only 2-3 minutes. It does work fine when the battery is fully charged. I understand that is asking a lot from 2 small cheap batteries.

So, the question is what should I get. Would 200 Ah AGM be better than what I have now or still not enough and should I rather get 200-300 Ah Lithium?

The open question I still need to ask the maker of the 5th wheel (Alliance RV) is what kind of 120V battery charger/converter they installed, if it can do Lithium and where the heck this thing is mounted.

[R.Wold]

AGMs give you a lot more mounting options, so you could stick with the same charging system, get creative with mounting two additional batteries, and double your battery bank. Or triple it for that matter. It would be the least expensive, and most simple solution, and you’d have the advantages of AGM batteries. I did this in a small class C and put two additional AGM batteries under the bed, since there is no chance of leakage or off gassing. On a 5th wheel, you have lots of options for locating more batteries.

Then think about maybe another couple panels..

[Nwcid]

Your issue is not with FLA batteries, it is with their capacity. Your other issue is the amount of charging.

If you have 200 AH of FLA or AGM you will have the same amount of useable AH. Right now you have 130 AH. With FLA and AGM for best life it is not recommend to drop below 50% so you have 65 useable AH right now. This sounds like it barely adequate to meet your needs in a 24 hour period. You need to size your battery bank to fit how long you want to be able to run without charging.

So in theory if you have 20 amps of charging and you have used 65AH of reserve you need a little over 3 hours to charge back to full. Of course it is not quit that straight forward it gives you an idea. Also it would depend on what draw you have during the day while your solar is making 20 amps, you have to subtract that amount from charging. In my system I am typically making 40 amps, however I am using about 60% of that to run my "desk" for teleworking leaving about 15 amps for charging.

You can go to lithium if that makes sense for your situation. With lithium it is common to draw down to 80% of rated and you will not see the voltage sag like you do with FLA or AGM. Lithium is a fraction of the weight but costs a lot more than FLA or AGM.

[kcmusa]

I have 400 watts of solar, just spent a week in the mountains( shade issue) Could not keep up my 400 amp hour set of 4 GC2 battery’s with solar alone.
Like you a run the micro a little, coffee in the morning and I have a residential fridge, Some TV and device charging.
I see you have 2 issues, not enough battery and not enough solar.
Ran my generator about 3 hours a day to keep battery’s charged. Lowest I went was 45% charge.
Lead battery’s are cheap ($100 at sams club for a 6 volt 220 amp hour battery) lithium are still pretty high.

[JHinman]

I am starting to explore those same issues. I have one 170 watt Zamp solar panel, two 100 Ah Battleborn lithium batteries, and a 3kw hybrid inverter.

The trailer came with the solar panel as standard equipment, and I am trying it out before I buy more panels. It seems that solar in the mountains is hit-or-miss, as sometimes I get decent production and other times I get so little that covering my roof with solar panels would not produce enough to do any good. After another couple of trips I should make a decision.

I just returned from three nights at one of my favorite Forest Service campgrounds. Night-time temps were 30 to 32 F, with clouds and rain for most of the time. I used 10% to 15% of my battery bank capacity overnight each night, and the single solar panel replenished daytime use of my microwave and toaster (mostly the toaster), heat, lights, etc. It was pretty encouraging.

Last October, though, temps were down to 11 F and solar was negligible. I used half my battery capacity overnight each night just to run the heater.

Fortunately my inverter will supply 80 amps to my batteries from a 2kw generator. The original converter maxed out at 25 or 30 amps, possibly due to a long run of thin wire to the batteries. With that kind of charging capacity I can get by without solar.

I really should have another battery, for a total of 300 Ah. I cannot run my toaster and my microwave at the same time, as the draw shuts off the battery management system temporarily. Unfortunately another battery would require a step up in carpentry to make room for it.

The hybrid inverter is really overkill. We camp for a few days at a time, and do not really “need” a toaster or microwave. However, it is satisfying to have a high-tech system and that makes camping more fun for me. I will never go back to lead-acid batteries, though. I used them for over 25 years, and they are simply too much of a nuisance. Yes they are cheaper, but that is not the point. For me lithium is worth the money.

[Bruceea]

I can run my 32' MH for 2 - 3 days (Depending on Sun exposure) with 420 Watts for panels and two Battle Born 100 Amp Lithium batteries. Remember, lithium can be run down almost 100% so having 200 amps of lithium is like 400 amp of wet cell batteries.

I run the Micro about 5 minutes a day, and typically make four cups of K Cup coffee a day. We limit the TV to about an hour and a half a day. I don't use my heater very much probably because of our location but you might want to think about a vent-less propane heater. I had one in my last trailer and it worked great.

[Mark_K5LXP]

Originally Posted by Bruceea

Remember, lithium can be run down almost 100% so having 200 amps of lithium is like 400 amp of wet cell batteries.

There's no denying the performance of lithiums, but Ah are Ah and lead acid has all the Ah they're rated for. Lifetime delivered Ah between 40% DOD and 80% DOD is nearly the same, so universally applying the "50% Rule" is patently false. Despite the performance of lithium there are still millions and millions of lead acid batteries in use today, maybe not because they're "best" but "good enough". Not every application requires optimum performance and for many, lead acid can be a cost effective and adequate solution.

Mark B.
Albuquerque, NM

[PS56]

Originally Posted by Jerry Burks

I have installed 380W panels on my 5th wheel, with PPMT controller and 2kW inverter. So far so good. On a nice day I can pump 20 amps into the battery.
The camper came with 2 flooded lead acid batteries with 65 Ah each and I tried how far I can go with it without shore power. Turns out not that far.

I am not asking much (I think). Run the lights (dimmed) and the TV and laptop for a few hours and the furnace through cool nights. The only high power users are the microwave and the espresso maker but only for a few minutes. I am not even trying to run the fridge on inverter but use propane instead.

Unfortunately, through a chilly (not cold) night the furnace fan sucks about 65% of the battery capacity and while the remaining capacity is technically enough to heat the milk in the microwave and run the espresso maker, the voltage drop is so bad that the inverter stops. And a morning without coffee makes me mad. I am even wondering if the batteries could sustain the furnace when temperatures drop well below freezing.

FWIW, the battery drain through inverter for the microwave is 170 amps and the espresso machine is 130 amps, but again for only 2-3 minutes. It does work fine when the battery is fully charged. I understand that is asking a lot from 2 small cheap batteries.

So, the question is what should I get. Would 200 Ah AGM be better than what I have now or still not enough and should I rather get 200-300 Ah Lithium?

The open question I still need to ask the maker of the 5th wheel (Alliance RV) is what kind of 120V battery charger/converter they installed, if it can do Lithium and where the heck this thing is mounted.

It may not be the batteries. There are many other factors.

Where were you? Determines length of daylight and angle of sun.

Did you raise and point the panels towards the sun?

Parked orientation e/w or n/s.

How far is the inverter from the batteries.

For you should consider 4 golf cart batteries, upping the # of panels and consider a tilting mechanism.

[Jerry Burks]

Originally Posted by PS56

It may not be the batteries. There are many other factors....

Where were you? Determines length of daylight and angle of sun.
At 9000 feet in the Rocky Mountains, on a sunny day in May, no shade.

Did you raise and point the panels towards the sun?
Panels are bolted to the roof and almost horizontal.

Parked orientation e/w or n/s.
Should not matter with horizontal panels?

How far is the inverter from the batteries.
Right next to the batteries, maybe 2ft 6-gage wire.
Still on the fence about 2 more panels

For you should consider 4 golf cart batteries, upping the # of panels and consider a tilting mechanism.
Tilting mechanism is out of the question but I decided to bite the bullet and ordered a 300Ah lithium battery. Still on the fence about adding 2 more panels.

[Itinerant1]

6 guage wire seems small for pulling 170a load even for minutes.

https://invertersrus.com/battery-cables/

[PS56]

Originally Posted by Jerry Burks

Where were you? Determines length of daylight and angle of sun.
At 9000 feet in the Rocky Mountains, on a sunny day in May, no shade.

Latitude affects sunlight hours.

Did you raise and point the panels towards the sun?
Panels are bolted to the roof and almost horizontal.

Parked orientation e/w or n/s.
Should not matter with horizontal panels?

Assuming you have 1 panel on driver & passenger side; you should park your RV facing South to get the most sunlight into both panels.
https://www.cedgreentech.com/article...-energy-output

If you face e/w the northern side is getting less due to the bow in the roof.

How far is the inverter from the batteries.
Right next to the batteries, maybe 2ft 6-gage wire.
Still on the fence about 2 more panels

Good inverter location. Check wire size when installing your new batteries.

For you should consider 4 golf cart batteries, upping the # of panels and consider a tilting mechanism.
Tilting mechanism is out of the question but I decided to bite the bullet and ordered a 300Ah lithium battery. Still on the fence about adding 2 more panels.

In the future, I think you will want to up that to 2 batteries and more panels.
Where you were in the Rockies in May you had 14+(not all got to your batteries due to the angle of the sun) hours of daylight. That is a lot. If you camp in the same spot in Sept/Oct you will have less daylight to power your daylight needs and recharge the batteries.
Also, you will be using your heating more in Sept/Oct.

You also might consider a generator.
https://www.homedepot.com/p/Westingh...2500/304312161

I have the above. I use it for my a/c (with a soft start installed) and when I use a ceramic heater.