RV Doctor Column RV Doctor #271 Dear RV Doc, we own a three-year old Jayco, 12-foot popup camper. We have always camped at sites with electricity. But now we want to go to a campground that does not have electric sites. Are generators the only way to provide power in this situation? Running a generator on a week long trip seems like more trouble then it is worth. Are there other alternatives? Mike Peterik, (Plainfield, IL) Dan, a lot depends on what you actually need that power for. If it's just to run the water pump and a couple of 12-volt lamps or a furnace fan occasionally, you might consider adding a solar battery charging system and maybe adding an additional deep cycle battery. Solar kits of various sizes are readily available, affordable and easy to install. If you truly need 120-volt alternating current, a solar panel, an inverter and a healthy battery bank would be another option, but probably not very plausible for a pop-up camper. Lasting a week or so in a pop-up usually only requires a decent battery system, a cylinder full of LP and some good conservation practices. But if you really had your heart set on taking along that deep fryer, the big screen TV and the industrial strength hair dryer, then the generator seems a much better fit I'm afraid. Dear Gary, I have a 1988 Gulfstream Sunsport with only 26,000 miles. Everything is in great shape but I have some electrical problems. It is not charging but I had the alternator checked and it seemed to be fine. I reinstalled it but the output at the alternator is now only what the battery measures. Some people are telling me it's the battery isolator, but no one can tell me how to test that. Larry Tirronen, (Spring Hill, FL) Larry, here's how to check the isolator using a DC voltmeter. First, measure the voltage at all three terminals of the isolator with the engine completely off. You should be able to read each battery voltage independently on each of the outside terminals. If there is voltage on the center terminal, one of the diodes in the isolator is faulty and the complete isolator must be replaced. (Some VOMs do have a diode test circuit to double check the diodes in the isolator). If voltage is only read on one of the two outside terminals, there is an open in one battery system. Next, start the engine and check the voltage at the center terminal of the isolator; it should be at least 13.8 volts and there should be an increase in the voltage measured at the two outside terminals, though it will be less than the center terminal. If you have access to a clamp-around DC ammeter, you will be able to measure the charging current on the alternator output wire. Additionally, be sure to check all the cable connections at each battery very carefully. I just ran across the same symptom as yours and found a corroded ground cable from the engine battery to the frame ground. If you are sure the alternator is functioning as it should and the isolator tests good, you just may have a cable problem. Dear Gary, if I want to increase the number of batteries on my RV from two to four (because of an inverter installation), is it necessary to start with all new batteries? They will all be six-volt batteries hooked together to produce 12-volts. Len Daddona, (Morton, PA) Len, in some cases it is not necessary to start with all new batteries, but it usually is always recommended. In a best case scenario, it is most advantageous when all batteries in the same bank are the same age, the same type and the same amp-hour rating (size). But it really depends on how old the original set is and to what degree the plates have sulfated. Deeply sulfated batteries connected in a series/parallel configuration with brand new batteries may shorten the life and the capacity of the newer ones. Take an extremely close look at the original set. If they are not too old and still in good shape, keep them in series with each other and the new set in series with each other. The two sets can then be wired in parallel to provide double the storage capacity. Dear RV Doc, I would like too know how to test a Shurflo water pump once it has been removed from the RV. When I turn on the main switch the interior lights will pulsate, when it was working that was not a problem. The pump will not function at all now. Will I have to replace the entire pump? Paul Smith Jr., (Midway Park, NC) Paul, since the pump is out of the coach try hooking up a 12-volt source directly to the motor wires, effectively bypassing the pressure switch mounted at the very front. If the motor still does not run with 12-volts applied, it will be necessary to replace at least the motor portion. Before condemning the motor however, remove the pump head and try the motor once again. If the pump portion has frozen, it could bind the motor. SHURflo has packaged replacement parts for their pumps which makes it quite easy for the RVer to repair the pump. While you have it out, the pressure switch can be bench tested using an ohmmeter. The switch is a normally closed switch, which means there should be continuity across the two terminals in a static situation. Pushing in on the micro switch opens the contacts and you should not be able to measure any continuity across the terminals. But my guess is it's the motor with maybe the pump portion running a distant second. If the pump is relatively new, buy just the parts you need. If it is quite old, replace the entire pump. Dear RV Doctor, I am responding to an earlier question in a previous column. It was a question about hydraulic levelers though it was not mentioned what brand of jacks were being used. I had the same problem with my HWH Computerized Auto leveling jacks. They would not be completely vertical before extending. It turned out that I was shutting the jacks off too soon after retraction. This system has an auto shut off feature that takes approximately six minutes to fully cycle to retract and auto shut down. Unless you follow the proper retraction procedures, the next time you extend the jacks, the jacks will start to extend before they reach the full vertical position. It could also be a faulty or a misadjusted mercury switch. HWH told me that to properly retract my jacks to start the engine first, then switch the jacks to retract, then do not shut the engine off until the jacks have gone thorough their full six minute retraction procedure and automatically shut down as programmed. HWH was absolutely outstanding in their Tech Support with my problem. Robert Johnson, (Boise, ID) Thanks Robert, it's nice to hear when companies are doing a good job. Too often we only hear the complaints. Kudos to HWH!
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