I saw a question about air conditioning a camper shell for dogs. The answer was to let the dogs ride in the front.
I am looking for a way to A/C my camper shell as well. I have a heavy duty alternator in my pick up.
Kristi
Kristi,
Several companies make a 12 Volt DC powered air conditioning unit for truck cabs that can be powered from an alternator charged battery. They are not cheap and they usually require adding a heaver dual battery power system, but you can buy these.
I think you will find the cost will be so high that its not worth the trouble, but give it a try.
Any truth to the claims of adding water injection systems to increase my mileage for my gas-guzzling SUV?
Thanks
Joe Rocchio
West Palm Beach, Fl
Joe,
I am no expert on automobile engines, but I do know two things:
1. You can find 1000 different gadgets claiming increased mileage including wrapping magnets around the fuel line, injecting water, all kinds of fuel additives, coils to make a hotter spark, hotter spark plugs, and slicker lubricating oils.
2. If I manufactured low mileage cars in today’s high fuel cost environment causing many buyers to switch away from the “gas guzzlers”, I think I would be adding any gadget I could to make my design more efficient unless I had already tested and found all these gimmicks to either have little or no improvement, or their improvement caused long term engine damage.
Have been reading your articles for years. Especially liked the one about reducing loads that just eat you to death.
I have been pointing out to people for years that their phone chargers use electricity whether the phone is connected or not. They are incredulous. So for years I have been shopping for a power bar, (multiple outlets), that has a separate switch for each outlet. Seems to me like the perfect set up for families with multiple phones, tooth brushes, etc that all need charging. It doesn’t exist, so I intend to make one, one of these days.
At any rate, I have a couple questions to ask.
1) Could styrofoam packing peanuts be scattered in an attic to make insulation? I hate working with fibreglass. Seems like we get them all the time, and out they go in the trash. And what about the wheat paste version?
2) Awhile back, a fellow came to our house to steam clean a couple carpets. His cleaner machine was 240 VAC powered. Instead of waiting for me to open the garage to plug into the Arc welder outlet, he had a simple solution. He had twin extension cords to plug in around the house until he found two that were on the separate sides of the sine wave, and went to work.
So I was wondering, if I took a couple automobile-type inverters and hooked them up to my truck, could I get 220/240 by hooking both neutrals together in an adaptor? Or do the waves have to be coordinated? I was just hoping I could use my arc welder anywhere I could drive.
Thanks
Glenn Willis
Glenn:
Good questions!
1. You are not the first who wanted to insulate with these “peanuts”. The problem is these are not all the same materials and many are polystyrene, which is extremely flammable and will give off very toxic gasses when it burns. Others are made from bio-degradable materials which can break down when damp or with time. Since you are planning to do this over time, this means you will be collecting many different packing materials even if they are all peanuts. Due to the danger of getting the highly flammable materials, I would not recommend this. If you want to check this out, take a few samples outside and light with a match and you will see, but do not breathe the gasses given off so stay upwind!
2. The power from the grid into your house has each “phase” of the 240 VAC power in phase, regardless of which outlets you use, as long as one is wired to each phase. However, when you have 2 different inverters, there is no way for one to know what the other is doing, so taking the output from each separately will have the differences between the phases changing all over the place. Not only will you not hold 240 VAC, but you could actually damage your connected load because the resulting voltage will be changing over 60 times per second. However, many high end inverters now include a communications cable that allows each inverter to time its output with the correct timing and phasing in reference to the other inverter so you can get a true 240 VAC output.
I doubt if your lower cost automobile inverters will have this timing capability.
I have two solar panels 80 watt each on my boat wired in series to make 24 volts 160 watt. I have two sets of two batteries also wired in series 24 volt. Start and house batteries. I also have a Morning star 24 volt 10 amp controller.
When I leave the boat I would like to charge both sets of batteries. When using the boat I would like to charge the house batteries only as they will be running a fridge etc and the start batteries will be charged via engine Alternator unless it fails at sea. So I will need a switch for off, battery 1, battery 2, or both.
Is there anyone that can help me with a circuit diagram required for this project?
Regards,
Simon Brock
Simon:
As noted on the web site, we cannot provide specific wiring diagrams and other detailed design assistance since we do not have all of the information about your specific application, and this is a free site so time is very limited for each reply. However, I can give you some basic guidelines. You have to be careful because if one battery gets really discharged, and the other is fully charged and you close a switch between them, there can be a huge in-rush of current from one to the other that could easily melt any smaller wires between them. There are 2 ways to charge these batteries separately without tying them together and have a potential melt down.
You can buy a battery isolator at the RV store which has a connection for a charger or alternator input, and two separate outputs to connect the 2 batteries. This device has diodes that will allow charging current to flow from the single solar charger or alternator out to 2 separate batteries, but will not allow one battery to flow back to the other. Although intended to connect one alternator to 2 batteries, you can use the solar charge controller as the charging source. Make sure the isolator has a common negative and one in and 2 outs. Just let both batteries stay connected to the solar charger. If one battery starts to get charged separately from the engine, when it raises the voltage of that one battery, the higher voltage will stop the flow in from the solar charger so all of the solar charging will divert to the battery not being charged by the engine because its voltage will be lower. You would not need any switches to do this, but your connection should be on the battery posts so the existing 1-2-both engine switch will not isolate the charger from the batteries.
The alternative is to use two identical solar charge controllers with one to each battery, and both connected to the same solar modules. The battery with the lowest voltage will receive most of the charge until they are close, then the charge controllers will be charging equally and sharing the same solar modules.
Be sure to install a DC rated fuse in each charger output connection to each battery.
I live in Wisconsin, which is prone to ice storms similar to what shut down the power grid in the Northeast and across Indiana this winter.
I am considering a battery backup system using four golf cart batteries wired to 12v and a 1500-2000 watt inverter to power lights, fridge, gas furnace, or wood stove blower [separately, of course].
Since I don’t have the budget yet for solar or wind, I was wondering if using my Honda Odyssey’s alternator with a battery isolator installed to recharge the battery bank would be a good idea. Any thoughts would be appreciated.
Thank you in advance,
Frank Falzon
Frank:
We have many projects with batteries and inverter for emergency power that did not include solar. However, I would not use the car to re-charge the batteries as this will be a major load on the small alternator and will use more gas than you think as you will probably need about 3 hours of charge time per day which is like driving 200 miles each day.
Keep your idea, but buy a generator. Most high quality inverters will include a high capacity battery charger which will allow re-charging for about 1 or 2 gallons per day. The only caution is you need a good quality generator in the 6 kW or larger size range, and having a good voltage regulator. Low cost generators drop their peak to peak voltage as they get loaded up and any battery charger will stop charging altogether when this happens.
I just recently found this website and I want to tell you I am impressed. Very informative !!
I am a expediter. I basically spend hours and hours, sometimes weeks out on the road at a time.
I have a 2500 watt power inverter and I am getting ready to buy 2 6v golf cart battery and am considering buying a 120 watt solar panel from e-bay.
What I am trying to do is power my electric heater which is 1200 watt’s. Gasoline is too expensive to let the van run and propane is no different. I want to wake up alive and this is the safest way to go as far as I know.
Do you have any other suggestion’s or any past articles on safely heating my van?
Thank you,
Bill Weatherford
Bill:
If you check my last thousand replies you will find I keep telling people its not cost effective to power any electric heating device with solar electricity. For example using the numbers you give, your 1200 watt electric heater would run about 1 hour before totally discharging your 2 gold cart batteries, then it would take your single 120 watt solar module about 2 or 3 days to re-charge the batteries before you could again run the heater.
A 6-volt deep cycle battery stores about 1 kWh of power before totally discharged, which damages any battery. Two would gave you the same amount of power by safely discharging only to 50% discharged. You will get about 3 hours of full sun during winter days in most parts of the US due to the low sun angles and shorter days. Also a typical solar module will only put about 70 to 80% of its nameplate rating into the battery charge. 120 watts X 80% / 3 hrs/day = 288 watt-hrs per day, which requires 4 days to produce 1200 watts, and your heater requires this much power every hour it operates, so it will only run 1 hour before it uses up 4 days of solar charge.
I have a motor home that has 3 deep cycle 12 volt batteries.
I want to keep them charged with solar as much as possible.
Will connecting 2 or more 45 watt separate systems charge them better than just one?
As they are all the same watt I am not sure adding 2 or more same watt systems will charge any more than 1.
Help Please.
Thank you
Att: Help Please:
I assume you mean connecting each battery to its own solar module and charger verses connecting one solar charging system to all three batteries. For good battery voltage balance, its better if you connect one solar charger to all batteries wired in parallel. I don’t know how you could do this separately unless each battery can be disconnected from the others, since normally they all are wired to the same 12 volt positive and negative mains. Assuming you could separate them from each other, as soon as you connected a battery that was at a higher charge than the others, current will flow from one to the other until they are equal in voltage.
I would like to put Air conditioning in my pickup truck camper shell to keep my dogs cool in the summer. It would only be in use when I was traveling down the road, not while the truck was turned off. Here was what I was thinking – could you offer an opinion on whether it would work or how to to do it, if it is even possible.
[I want to] put an RV air conditioning unit on the top of my camper shell and run that off an inverter connected to my pickups battery.
I do have a 2500/5000 watt inverter but I wonder if the air conditioning unit would suck so much energy that the alternator could not keep the truck battery charged up going down the road.. My truck has two batteries up front
Mike
Hello, MIke.
The problem is not battery size, it’s your alternator capacity. There is no way an RV air conditioner can run off one or two truck batteries for more than a few minutes without draining them. For example, the smallest, newest, and most efficient truck camper AC unit draws 8 amps at 120 VAC. Assuming a 90% system efficiency, this would be a 1,100 watt “run” load on your inverter, and require an inverter that can handle at least 2 kW “start” load since any compressor load is a dead short on the power source for the first few seconds it is trying to rotate.
You said you had a 2,500 watt inverter which should be able to handle a small RV air conditioner, but that is not your main problem. Your inverter will have a constant draw of 88 amps at 12 volts DC while an 8 amp load air conditioner is running, and could draw up to 150 amps for a few seconds every time the compressor kicks in. This means your truck alternator and all related cables need to be large enough to handle these larger current flows and still have enough excess power to operate your lights and other electrical loads in the truck. Each time you stop at a light, there will not be enough amps coming from your alternator even if it is a larger 150 to 170 amp heavy duty model.
This is why the air conditioning unit in an RV is always wired into the exterior shore power or generator panel, and not powered from the batteries. Any 120 VAC electrical load on an inverter will draw 11 times the AC amps from a 12 volt DC battery.
