Need some advice

windog1

I have a 1988 Ford Econoline van that i will use for camping. When not at a place that has hookups I would need to run really 2 things. I have a 12v endless breeze fan that at the highest setting says it uses less than 3 amps and I have an electric blanket that I believe is 100 or 150 watts. In the cooler weather I would probably like to run both at night as I have gotten used to a fan on me year round. In the summer just the fan.
What is the minimum setup I could get to power my nneeds as well as charging the battery/batteries

Thanks for any help you can give me.

BB.

Re: Need some advice

Conservation and measuring your power needs are the first two steps.

Get a Kill-a-Watt type meter to measure your AC load usage or one of these for your DC power usage. Once we know how much power you use in a day (Watt*Hours; kWH; Amp*Hours at what voltage), then we can figure out how large of battery and how many watts of solar panels you will need (also need to know where you will camp and what seasons desert south west, rain forests of Washington state, etc.).

-Bill

Cariboocoot

Re: Need some advice

Welcome to the forum.

Let's see, first advice; get rid of that carburetted Econoline and go for the newer fuel injected version. Although I have that one ('92) and it drinks gas at a rate that can only be described as "scary". It's really bad on the highway, but in town it's much worse! Probably something to do with all that weight in it being lugged up and down the mountains.

But seriously, here's a thread on efficient fans: http://forum.solar-electric.com/showthread.php?t=12177 I believe your "endless breeze" model is well thought-of. Good choice.

This electric blanket: 120 VAC model? Or 12 Volt? (For those wondering: http://www.roadtrucker.com/12-volt-heaters-blankets-sheets-1.htm) You said 100-150 Watts so I assume 120 VAC, which would mean an inverter and its associated overhead.

So what you have to look at is the Watt hours: the Watts drawn over the time used. A 100 Watt blanket on for 10 hours will cycle on and off, so it won't be a steady 100W * 10H = 1 kW hour, but you can see how it adds up fast. What's worse is that this will vary with ambient temperature; the colder the night the more it will be 'on'.

You can either plug it in to a Kill-A-Watt meter and get some estimate of real power used or plan for the worst. It isn't difficult to come up with 1kW hour on 12 VDC, but it requires around 200 Amp hours of battery (don't forget the inverter's consumption which could be another 20 Watts, depending on how big you go for).

Thus you're looking at a couple of golf cart batteries: 6 Volt @ 220 Amp hours each. You can sometimes get these really cheap from the big warehouse stores. As for an inverter, if all you're going to run is the resistive load of the blanket (for some reason I'm assuming the fan is 12 VDC - that could be wrong) it won't take much to supply that. You don't even need a pure sine wave inverter. But be careful! Electricity is addictive! Once you can run one thing you want to run another, and another, and another ... So think very carefully about what all you want to run.

Then you have to recharge those batteries. Here's some good info on battery use and charging: http://www.windsun.com/Batteries/Battery_FAQ.htm If you use the batteries I mentioned above you'll want at least 172 Watts of panel, and more is better (especially as the addictive loads begin to grow). You don't get perfect insolation with panels mounted on the roof of an RV, so it never hurts to have a bit more than minimum. A good choice here might be a couple of 135 Watt Kyoceras, as they are relatively small but a good value and ought to supply a good medium charge rate.

And of course you need a charge controller for that. One that can handle the peak potential current. Fortunately you should not need the fancy MPPT type for this application. You'll also want some sort of back-up charging system, such as a way to tap the vehicle's electric should that become necessary. Depending on what you're comfortable with using, that can be anything from jumper cables to a dual battery isolator.

And wait for it; others will have more ideas as well. It's not an unusual request, and poking around on the forum you should find other threads with RV type applications similar to yours.

windog1

Re: Need some advice

I will have to get one of those. I live in West Point, Ga. about 70 or so miles from Atlanta and would most likely stay in the southeast.

windog1

Re: Need some advice

Cariboocoot wrote: »

Welcome to the forum.

Let's see, first advice; get rid of that carburetted Econoline and go for the newer fuel injected version. Although I have that one ('92) and it drinks gas at a rate that can only be described as "scary". It's really bad on the highway, but in town it's much worse! Probably something to do with all that weight in it being lugged up and down the mountains.

But seriously, here's a thread on efficient fans: http://forum.solar-electric.com/showthread.php?t=12177 I believe your "endless breeze" model is well thought-of. Good choice.

This electric blanket: 120 VAC model? Or 12 Volt? (For those wondering: http://www.roadtrucker.com/12-volt-heaters-blankets-sheets-1.htm) You said 100-150 Watts so I assume 120 VAC, which would mean an inverter and its associated overhead.

So what you have to look at is the Watt hours: the Watts drawn over the time used. A 100 Watt blanket on for 10 hours will cycle on and off, so it won't be a steady 100W * 10H = 1 kW hour, but you can see how it adds up fast. What's worse is that this will vary with ambient temperature; the colder the night the more it will be 'on'.

You can either plug it in to a Kill-A-Watt meter and get some estimate of real power used or plan for the worst. It isn't difficult to come up with 1kW hour on 12 VDC, but it requires around 200 Amp hours of battery (don't forget the inverter's consumption which could be another 20 Watts, depending on how big you go for).

Thus you're looking at a couple of golf cart batteries: 6 Volt @ 220 Amp hours each. You can sometimes get these really cheap from the big warehouse stores. As for an inverter, if all you're going to run is the resistive load of the blanket (for some reason I'm assuming the fan is 12 VDC - that could be wrong) it won't take much to supply that. You don't even need a pure sine wave inverter. But be careful! Electricity is addictive! Once you can run one thing you want to run another, and another, and another ... So think very carefully about what all you want to run.

Then you have to recharge those batteries. Here's some good info on battery use and charging: http://www.windsun.com/Batteries/Battery_FAQ.htm If you use the batteries I mentioned above you'll want at least 172 Watts of panel, and more is better (especially as the addictive loads begin to grow). You don't get perfect insolation with panels mounted on the roof of an RV, so it never hurts to have a bit more than minimum. A good choice here might be a couple of 135 Watt Kyoceras, as they are relatively small but a good value and ought to supply a good medium charge rate.

And of course you need a charge controller for that. One that can handle the peak potential current. Fortunately you should not need the fancy MPPT type for this application. You'll also want some sort of back-up charging system, such as a way to tap the vehicle's electric should that become necessary. Depending on what you're comfortable with using, that can be anything from jumper cables to a dual battery isolator.

And wait for it; others will have more ideas as well. It's not an unusual request, and poking around on the forum you should find other threads with RV type applications similar to yours.

The good news is the 88 is fuel injected.

Yes, the fan is 12 VDC and I've never seen a 12 VDC electric blanket but if it would save some power I'll start searching. Since it will only be me camping in the van, my wife has no interest in it, I dont see running too much more than what I've mentioned. I have an old Honda 300 Watt generator but depending on where I am it might bother some.

windog1

Re: Need some advice

also got the endless breeze at the local pawn shop for $15.00 so I'm happy.

techntrek

Re: Need some advice

windog1 wrote: »

Yes, the fan is 12 VDC and I've never seen a 12 VDC electric blanket but if it would save some power I'll start searching.

Cariboocoot listed a link above that shows two 12 volt blankets.

windog1

Re: Need some advice

techntrek wrote: »

Cariboocoot listed a link above that shows two 12 volt blankets.

Thanks, I missed that the first time. I think I'll invest in that to take an inverter out of the equation for now.