Understanding Power

[rodwha]

I've been reading up on power needs and uses, but things aren't quite clear.

For starters I'm looking at the Keystone Passport 2920 BH.

From what I read not all A/Cs run on DC power. How does one figure this out?

To be able to run the A/C during a hot summer I read one would need to have a 3000-4000 watt inverter, but that most trailers have a 1000-2000 watt inverter. I don't see anything on their site or in their brochure that gives specs on this either.

It seems there's some sort of inverter that works off of your propane? Maybe I've just had an overload of info reading from several sites.

I read lithium batteries are the better choice. Again a lack of info. Is this the typical battery on RV's? The Passport seems to be a bit more than a mediocre trailer.

30 amp service seems to be standard unless one has a 2 A/C trailer. I'm guessing there's no issues with upgrading to 50. This would mostly fix issues with running the A/C along with plenty of typical appliances, right?

I'm a bit fuzzy on the load divider. It ensures there's never an issue where the amp draw is too high?

It seems most trailers come with two batteries. This shows two banks of two. No desire to add any?

If 600 watts of solar panel can be set up well enough and the days are partly cloudy how long could this extend a boondock adventure in the summer running the A/C? What of a winter with the lows around 20* F? I'm guessing with neither the A/C or heat working this amount might keep everything else running indefinitely?

Do the trailer batteries do fine when constantly hooked to AC power? I know many batteries don't do well over time like that as batteries are meant to be well used and then charged. I ruined an iPhone keeping it charged.

[pianotuna]

Hi,

There are a few (read expensive) 48 volt DC air conditioners.

The best batteries are those that meet your particular needs.

Carbon Foam batteries are top of the line for lead acid. The command a top dollar price. LI are excellent except in cold weather--which is just when I need power the most.

[time2roll]

You got it 🙂

[rodwha]

Seeing what it takes, both in weight and expense, I'm not interested in solar enough for the A/C. I just figured there would be enough battery power to run it a couple of times a day.

What I am interested in is being able to keep my batteries charged by solar (eventually). I'll assume the two batteries (the picture confused me and I thought there were two banks of 2 batteries) are the lower tier (Group 24) and has a max capacity of about 170 AH. From what I understand is I'd be in good shape with about 400 watts of solar as long as it was mostly sunny.

Anything more (the A/C) and it's time for a hookup or the generator.

[Sam_Spade]

rodwha wrote:

I was wondering, if with the proper sized inverter, running an A/C could be done using a generator to recharge during the day.

You are making this MUCH too difficult.

A/C runs off of 110 VAC from a pole or from a generator.

Trying to run it from batteries using an inverter is an unnecessary, difficult and expensive proposition.

Run the generator during the day and turn it off sometime between 10 and midnight so as not to disturb your neighbors. By then the interior should be cool enough for the night.

[2oldman]

MNGeeks61 wrote:
This link?

yes, thank you.

[2oldman]

rodwha wrote:
eith the proper sized inverter, running an A/C could be done using a generator to recharge during the day. It seems a bank of 4 (unknown output batteries) aren't up to the task for long enough.

No, 4 batteries won't be enough.

I am one of the few on here who runs a/c on batteries - but only occasionally. I have 8- 80a AGMs, a 4kw inverter, 835w solar. It's a 48v system. Why 48v? Because when I tried running air at 12 or even 24v, things started heating up. Cables, connections, batteries. Yes, everything was sized properly, but the high amperage draw eventually made heat. 48v seems to work fine.

I can run my air for about an hour before the batteries start to sag, even at full solar.

[rodwha]

I am mistaken on the batteries. It has two batteries but the picture was misleading in that by appreance each container held two.

[rodwha]

MNGeeks61 wrote:
This link?

12v side of life

Holy smokes Batman that's some great info!

[valhalla360]

I don't mean to be harsh but there is so much wrong with just about everything you said.

rodwha wrote:
I've been reading up on power needs and uses, but things aren't quite clear.

For starters I'm looking at the Keystone Passport 2920 BH.

From what I read not all A/Cs run on DC power. How does one figure this out? Almost all Air/Con units run on 120v AC power.

To be able to run the A/C during a hot summer I read one would need to have a 3000-4000 watt inverter, but that most trailers have a 1000-2000 watt inverter. I don't see anything on their site or in their brochure that gives specs on this either.The bigger issue is you need to supply power to that inverter and most trailers don't even come with an inverter.

It seems there's some sort of inverter that works off of your propane? Maybe I've just had an overload of info reading from several sites. The only way you are getting electricity out of propane is if you get a propane powered generator to create the electricity.

I read lithium batteries are the better choice. Again a lack of info. Is this the typical battery on RV's? The Passport seems to be a bit more than a mediocre trailer.Lithium batteries are rare on RV's. They are much more expensive than traditional lead-acid batteries. They are lighter for the same amount of power stored.

30 amp service seems to be standard unless one has a 2 A/C trailer. I'm guessing there's no issues with upgrading to 50. This would mostly fix issues with running the A/C along with plenty of typical appliances, right?Upgrading to 50amp power can be done but it's not simple (and given your questions it's NOT a DIY project)

I'm a bit fuzzy on the load divider. It ensures there's never an issue where the amp draw is too high?

It seems most trailers come with two batteries. This shows two banks of two. No desire to add any? Most trailers come with 1 battery. If you upgrade to multiple batteries, they can be in one or more banks. Assuming they don't double for starting the main engine (obviously not on a trailer), it doesn't make a lot of sense to put them in separate banks. If you do upgrade and add more batteries, have someone hook them up for you because if you do it wrong, you may wind up with 24 or 48 volts supplied to your 12v devices.

If 600 watts of solar panel can be set up well enough and the days are partly cloudy how long could this extend a boondock adventure in the summer running the A/C? 20-40 minutes (seriously, 600w is only about half of what a typical air/con unit draws so in a very short time your battery bank will be dead...assuming you have a large enough inverter.) 1200-1500w would keep up if it's a clear day and the sun is overhead. Early morning/Late afternoon and output will be far less than the rated amount.)What of a winter with the lows around 20* F? I'm guessing with neither the A/C or heat working this amount might keep everything else running indefinitely?Finally something, that is essentially correct. As long as you are using the propane furnace, 600w and a decent battery bank can be kept up with 600w...of course in the winter solar output is typically much less.

Do the trailer batteries do fine when constantly hooked to AC power?As long as the charger is working properly, it's actually best to keep it plugged in and the batteries fully charged. I know many batteries don't do well over time like that as batteries are meant to be well used and then charged. I ruined an iPhone keeping it charged.

Please find a friend who understands electricity before making any modifications (or pay an electrician to spend an hour or two going over things with you).

[jsteih]

https://www.youtube.com/watch?v=B0rZY5uotKI

[donn0128]

Look at it this way. A typical 13.5BTU AC will draw around 15 amps @120VAC running. That translates to around 150 amps DC. Typical battery you find in an RV is capable of storing approx 100 amps. At a recomended 50% discharge means you will get maybe three minutes run time per battery.
Im simpler terms, it is totally not practical!

[rodwha]

Oh, and the RV has heat ducting to the tanks in a covered basement. R 11 in the floor and ceiling and 7 in the walls.

[rodwha]

I was vague when I asked about an A/C system running on DC power. I meant with an inverter as I know these run strictly on 120 v AC. It was this inverter coming installed in an RV I was questioning as it stated they typically come with about half of that. Keystone doesn't mention this.

I was wondering, if with the proper sized inverter, running an A/C could be done using a generator to recharge during the day. It seems a bank of 4 (unknown output batteries) aren't up to the task for long enough. And with quiet time at parks you couldn't run it at night.

I don't think I'd want to install solar panels on the RV, though being 32' 10" I'd think there'd be plenty of room as the 315 watt panels I looked at briefly were 65 x 40" each. I'd prefer o park under shade and use a stand to support the panels. Each weigh 40 lbs which isn't too ridiculous individually.

We would typically set up at a place with power and water but don't want to be confined to such. And it is for that that we'd like some solar and a generator. But I was curious how well just solar would do in helping extend the stay not knowing the A/C would drain the batteries that quickly. As such it might run for a few minutes?

[MNGeeks61]

This link?

12v side of life

[2oldman]

Someone please post the 12v side of life..I can't now.