Power-Battery Questions

[Vantastic]

Hello...
I have an opportunity to boondock on a friend's property.  If he does not provide a electrical opportunity
I go either solar or find some way to charge batteries.  I do not need much power and have not crunched
numbers. RV w/LCD lighting, small A/C, hot plate, small fridge. It is in the desert area of So Cal so it does get hot.

Can anyone suggest some type of system that charges batteries from an A/C power outlet?
Open to any and all suggestions outside of solar.  I am not opposed to solar but if he offers
electrical connection why not use it.  The issue is distance which is why charging batteries 
makes sense to me. We have not worked out the exact cost but the electrical will be added.
I have no clue about the battery charging cost if this is a good option.

Thank you...

 

[wmyers4u]

if its too long for a heavy duty extension cord then the batteries would have to be brought to the electric source daily assuming you are using the AC at all.

So from what I see you either have to get a generator or pull the batteries daily to bring to electricity to charge with a battery charger.

 

[Rabbit]

The first thing you need to do, I'd say, is to figure out how many batteries would be required, and how much space and money you have for them. In turn, this will depend on how long you wish to go between recharges. Then figure out how fast the batteries _can_ charge, and how much money you're willing to spend on a charger or generator that can achieve a charging rate that's practical for you. Also, the amount of power available at the charge-point, if limited, may come into play. In other words, you can't take even baby steps until you've "crunched the numbers". Establishing how many watts of power you're going to want to use for how many hours is a good first step, then figure out from that what size your battery bank has to be in order to support this usage. (In other words, you'll have to figure out what appliances will use how many watts for how long and how often. Then a good rule is to add 25-50% because you _will_ forget to include stuff, and there will be higher-than-normal-usage days. Don't forget, if you use lead-acid batteries of any kind, that discharging them more than 50% does serious damage to them in the long term and shortens their life drastically.) That will in turn give you the basis for beginning to establish what sort of recharging strategy is appropriate under the given circumstances.

So, it's a lot more complicated of a question than you probably realized.

 

[John61CT]

Aircon and hotplate are very expensive and difficult to power off solar.

Get a little genny for those and park far enough away so the noise doesn't bother him.

If you can get a meter and pay him for mains, even triple his cost will save you lots of capital investment.

 

[highdesertranger]

for running on batteries an AC and hot plate are huge draws. the refrigerator could be too depending on type. first thing you need to do is a power audit and see how much power you need and go from there. highdesertranger

 

[Vantastic]

Thank You...from what i am hearing, batteries not the best option.
I was thinking that a solar system charges batteries that are used
to power appliances, so instead of a solar system, I would charge
with electricity.  BUT...air con and hot plate draw a lot of power.
I need A/C in the desert...but can seek other options to cook with.

Solar would allow for continued charging over a single charge and
I understand you do not want to draw a charge too low with batteries.
One person said they can get 2 hours on a battery for A/C which is not 
feasible. That would mean an investment of too many batteries and a 
daily charge which would become a full time job.

This helped: A/C 24 hrs a day
The mathematical formula looks like this: 550 x 24 ÷ 1,000 x $0.12. 
The cost to run a 5-amp, 5,000-Btu air conditioner over a 24-hour 
period is about $1.60.

If I can use my friends outlet, I can tell him this formula to get a general
idea of cost.  This formula is $48 a month, but I would use half of this
so it is very reasonable.  A small fridge, latop and LCD lights are not too much.

 

[John61CT]

Yes solar creates electricity that charges batteries.

Just that if your budget is less tgan many thousands, the **amount** of energy is a tiny fraction of what mains house appliances consume.

> small fridge, latop and LCD lights are not too much

Correct, if it is a portable 12V compressor fridge, expensive.

A mains fridge that efficient is very rare in the US marker.

 

[wmyers4u]

I'm putting $3000+- into my solar/battery setup and the plan is to be able to run AC in the evenings for a couple hours(maybe a little more when the sun plays nice) to cool down before bed.

Hope this may give you an idea of what the costs could be to set up solar to power AC.

 

[Vantastic]

"I'm putting $3000+- into my solar/battery setup and the plan is to be able to run AC in the evenings for a couple hours"

WOW...ok...i need to make every effort to tap the power on site!!! Solar is out for now
if the cost factor is that high. i will pass this to my buddy who thinks a few small panels
will run his 5k btu unit

 

[highdesertranger]

you need a lot more than a few small panels to run an AC. if you want to run it after the sun goes down you need a huge battery bank. highdesertranger

 

[John61CT]

WOW...ok...i need to make every effort to tap the power on site!!! Solar is out for now
if the cost factor is that high. i will pass this to my buddy who thinks a few small panels
will run his 5k btu unit

So aren't you glad you asked?

Having a small solar setup, say around a grand, is very worthwhile for when you're off the grid.

You just can't expect all the mod cons, and aircon is one of the greediest.