More batteries rather than more solar panels?

[CountryFit]

Originally Posted by Blackhat6mik

I have 6 x 100w panels and 5,000w inverter that will run my AC for several hours...

i am learning new things and correcting my outdated concept... what kind of a/c unit(s) are you using?

[Tony Lee]

Originally Posted by PeaceOwl

Yikes! I am hoping there is a warranty on the batteries., six months old. The rv never shows signs of battery problems otherwise. I was kind of wondering if the solar set up has disguised abnormal battery discharge. And maybe the long trips have charged it well enough to not show a problem....hmm...it's been sitting around for the last few weeks...no battery problems to note. Thnx guys!

Ok, read that often, now I know to get the MPPT controller. Always money!

Batterycide shouldn't be covered by warranty.
Running a residential fridge plus all the usual stuff on that amount of solar and with those batteries is pushing things way too far, especially if you have been relying on a battery monitor that isn't really telling you anything about the state of the batteries. Probably all that has been saving you is your need to run the generator for a while morning and night.

BTW Under some conditions, it is true that an MPPT controller will result in a few percent extra charge over a PWM system, but in most situations may not be worth rushing out and spending a lot of money on a new controller. If an extra 10% is really the difference between life and death, it means your system is way underdesigned anyway.

i am learning new things and correcting my outdated concept... what kind of a/c unit(s) are you using?

I imagine there are more than a couple of readers who will be hanging on every word of the reply

[twinboat]

I have a 8000 btu portable, AC that draws about 8 amps running. I have run it for 1/2 hour, on my 2500 watt psw inverter. I have a 800 ah battery bank.
According to calculations, I should get a bit over 4 hours before I am at 50% charge.

There comes the problem, putting 400 ah back in. I would need the whole next day and twice my 675 watt solar input, to get there.

I don't have that kind of room upstairs and I still need to run the fridge and TV.

Obviously, I was just doing it to see it happen.

[Tony Lee]

There comes the problem, putting 400 ah back in. I would need the whole next day and twice my 675 watt solar input, to get there.

Yes, but at least you are aware of that 'little' problem. Many choose to ignore it.

[Possum]

I find it mind boggling that people want to run 110volt a/c fridges while boondocking. What's wrong with the 50 or so years of propane design and work? In all my years of RVing I have only had one Dometic Fridge die on me and that was almost preventable. When at a FHU site I switch to a/c and run but while underway or boondocking I just leave her on propane. Current unit is a Norcold. The only time it acts up is when the batteries get low.

[twinboat]

If I have boggled your mind with my 120 volt fridge, let me clear it.

I split my time between a boat and MH. My insurance won't cover unattended gas appliances on my boat and 12 volt fridges are not frost free and expensive. The example I gave, was on my boat.

I have a gas fridge, in my MH , until it gives me problems. Then 120 is the way to go.

[Blackhat6mike]

Originally Posted by CountryFit

i am learning new things and correcting my outdated concept... what kind of a/c unit(s) are you using?

Two Dometic units, one 15,000 BTU and one 13,000 BTU unit. The 15,000 unit runs on 13 amps and the 13,000 unit takes about 12 amps. Never have needed to run both as the Aviator is super insulated with tinted windows and block laid styrofoam in the ceiling and walls. The smaller unit is in the BR, but is enough to cool the entire TT if I leave the door open.

[mlhusmann]

I have moved away from the old standard lights and moved to LED lighting. Saves lots of voltage and gives more light. I have 500 watts solar and three 4-D batteries and that is NOT enough battery power.

[CountryFit]

Originally Posted by Blackhat6mike

Two Dometic units, one 15,000 BTU and one 13,000 BTU unit. The 15,000 unit runs on 13 amps and the 13,000 unit takes about 12 amps. Never have needed to run both as the Aviator is super insulated with tinted windows and block laid styrofoam in the ceiling and walls. The smaller unit is in the BR, but is enough to cool the entire TT if I leave the door open.

let's see how many batteries do you have...

a typical 13000 btu ac will draw 12 amps running on 120 vac. that is 2160 - 2400 watts starting, and 1440 watts running. assuming no more than 85% efficiency (have to consider inverter loss and msw incompatibility), so you would be drawing about 1700 watts whenever the ac is on, or 142 amps at nominal 12 volts!! assume no more than 50% state of draw-down on your batteries, you said you use it several hours per day, let's take 5 hours for a simplicity, it would require 1440 amp hours of battery capacity. that' about 7 typical rated 8d batteries. wow, you have a BIG system!!

[twinboat]

With a 600 watt solar setup, it would take 4 sunny days, to recharge 7, 8 D batteries, from 50%

[Tony Lee]

Yes, the devil is in the detail, except of course for those owners who managed to find one of those magic solar systems that always have the batteries up to full charge by morning coffee time. They had sold out when I asked about them.

One minor - well, not so minor - point about running AC from the batteries (as I have done a few times) is that if the ac is on, it is probably because the sun is shining so the solar panels will likely be delivering full output so this will be supplying say 30% of the power and that will reduce the level of discharge of the batteries somewhat.

The other thing I have been looking for for a long time is an airconditioner that will cool the next room just by having the door open between the rooms. They were sold out too.

[Reed Cundiff]

It does take around 1700 W to run our Dometic ac considering losses. We do have 1420 W of solar with max ever noted of 1300 W input so we are running at a rate of 400 W or so from the batteries: 9.6 kW of LFP. We have done so in excess of four hours. Prefer to just go north or much higher in elevation. We do have space for another 470 to 700 W on roof but see no reason. We run the Dometic grudge on 110 during day and propane in the dark. Currently finishing a twelve week tour of Ecuador and Peru. Left rig at daughter's place in NM. Planning to do Trans Labrador and then. Month or so on Newfoundland this summer

[Imurphy907]

1400 watts? Holy cow. I thought I was crazy with the 1 kw system I'm putting together.

[twinboat]

They are also using expensive, LIFPO 4 batteries. Top of the line system.