We have a well. My husband thinks we should be able to run a cord via a power inverter from the car to the electric box in some fashion to get water from the well. Is this realistic? (Yeah, I know the real trick would be storing an adequate supply of gasoline...)

-- Marsha (MSykes@court.co.macon.il.us), June 18, 1999

Answers

Marsha:

Realistic.....No I suggest you come up with an alternate method. The current demands of a well pump will exceed the carrying capacity your vehicles electric supply.

-- kevin (innxxs@yahoo.com), June 18, 1999.

Several problems. Well pumps usually draw a lot of juice. Cheap inverters don't power motors very well. You would need to know the exact power requirements for the well pump, starting amps, locked rotor amps, and running amps. You would then need an inverter that would handle this. Good inverters aren't cheap.

Most cars have marginal alternators in them that are sized strictly for recharging the starting battery and that's about it. Now if you have a large pickup truck with heavy duty alternator and dual isolated batteries, that more in the ball park.

If you are thinking of running the pump "on demand" to pressurize your water system, forget it. IF you are thinking of running the pump to fill a cistern, you can do it. Ie., the alternator in the car most likely would not be enough to power the pump, you would have to draw down the battery. Car batteries are designed for a brief high amp draw, period. They do not like long draw downs. Hooking up a charged up deep cycle battery to the car and running the engine at very fast idle, say 1500 RPM while running the inverter and pump would work and be less stressful on the system. Leave the hood up to disipate all the heat. If you have a small alternator in the car I would keep the pump running time brief, like 5 minutes. You'ld need to run the car engine for another 5-10 minutes at fast idle 1000 RPM or so to bring the batteries back up.

It can be done. However, buying a small genset that you use strictly for running the pump for short fill up duties might be cheaper than buying a large deep cycle battery, a good inverter, etc.

-- Ken Seger (kenseger@earthlink.net), June 18, 1999.

Marsha,

Why not plug your well pump into the car today and find out?

-TECH32-

-- TECH32 (TECH32@NOMAIL.COM), June 18, 1999.

Marsha, I'm no expert, but I suggest you contact Keith Reuben at simplepump.com. We purchased a pump that can go into the well beside the submersible electric pump we have. You can get a gearmotor to run the simple pump if you don't want to do it by hand. I think that's a better idea that the car battery thing. I have no financial relationship with these guys, but know they treated me well. God bless,

-- ben (benalurker@usa.net), June 18, 1999.

Marsha,

Your husband would have a couple of problems:

Many deep well pumps run only off of 230 vac. Most inverters put out 115 vac. They won't drive the pump. Some people get around this by buying two inverters (such as Trace) that can be stacked to put out 230 volts. But, then again, these inverters are expensive.

Second, the batteries used in inverter systems are special deep discharge batteries that can be drawn down and recharged over and over. (Car batteries are kept fully charged. They don't like being discharged.) Not one battery is used, but many (6, 8, 12) in order to be able to supply the current needed.

Third, the inverter needed won't a cheap one. I've known people who have to go to 3KW inverters in order to power the pumps. The cheapest combination I know of would be to stack a pair of Trace 2424 inverters to put out 230 vac. That will set you back $2000 just for the inverters. (you might be able to get by with 1524s or 1512s, for only $1500.) Then you need the batteries, then the cable for hook up, then a transfer switch, then........you get the idea.

-- de (delewis@inetone.net), June 18, 1999.

Marsha: I went around with the same idea as you and your husband. In the end I found the most effective way was a 6.5 kw gen-set. On a schedule of 3 hours in the A.M. and 3 hours in the P.M., we can keep our freezers solid, washing done and water supply topped off. all for 40-45 gals. a month. With our 300 gal. fuel tank we're good to go for better than 6 months. Good Luck.....

-- Capt Dennis (souza@ptialaska.net), June 18, 1999.

Capt,

I imagine you are talking about a diesel gen set, right? Because I have seen the figures on gas powered ones of that size and they will burn at least 1/2 gallon per hour at 1/2 load. So that would be 3 gallons per day and 90-100 gallons per month. Still, that is a very workable system with 300 gallons of fuel stored. I'm planning on sporadic power available from the utility after the first 2-4 week shakedown. Meaning a day on, a day off, rationing, sharing, whatever, and the gen set then would be only for the days you are without power from the utility. Obviously, if the grid went down and stayed down, it would be a whole new ballgame. But your own plan sounds good.

-- Gordon (gpconnolly@aol.com), June 18, 1999.