RV Q&A by Mark Feb 2008

*NOTE: At Mark's discretion, material might be edited to suit a wide audience. Due to the large volume of material and correspondence we receive, individual replies might not be possible, nor can we acknowledge receipt of submitted material. Selected questions will be answered in future issues of our RV Education 101 newsletter and on our site. Thank-you for your understanding.

Q. Mark, We are looking at the Winnebago Sightseer 35J. The model we are looking at has two roof air conditioners, but only has 30 amp service with an Onan 5.5 KW generator. Will these two air conditioners be able to run at the same time with only 30 amps? Thanks!

Mark Says: Most RV manufacturers use some type of energy management system so both roof A/C's can operate at the same time on a 30 amp system. Our 2006 Bounder 35E is a good example. It will power up one A/C and then the other. Once they are both running it can sense if there is a requirement for more power placed on the system, like somebody making a pot of coffee, and it will shut one A/C down or both depending on the power requirement. When there is no longer a requirement the A/C units automatically start back up.

Something else many manufacturers are doing is to use smaller BTU air conditioners. It was no good to have two 15,000 BTU units if you can only run one, so now they might use a 13,500 and an 11,000 BTU unit which a 30 amp system can run at the same time.

I recommend calling a Winnebago dealer and ask them how Winnebago deals with this issue and to send you some literature on the topic.

Q. I was reading your article on battery maintenance and noticed a short section on "battery equalization". It mentions that you overcharge the voltage to clean the plates of build up. What sort of voltage are you talking about here? 13V; 18V; 24V? Thank you.

Mark Says: Equalizing is basically a controlled overcharge of the battery. All you are really doing is continuing the charge after the battery is fully charged. Equalizing is fine as long as there is not excessive heating or electrolyte boiling over. Keep in mind if equalizing a battery is done correctly the electrolyte should not boil over but it will create a good bit of bubbling, and when the cycle is finished you will normally need to add some distilled water to the cells.

In an equalization cycle, the battery voltage can rise to approximately 16 volts and be kept there for as long as eight hours. This can be done by adjustment of the charging current. Equalizing mixes up the electrolyte, which normally would separate into a layer of water and a layer of battery acid (the acid stays on the bottom). Equalizing also helps remove some of the sulfate build up. I recommend you test the specific gravity every hour during equalizing. Equalization is complete when the specific gravity readings no longer rise during the gassing (bubbling) stage. Some battery chargers have an equalization cycle or charge setting.

Q. Mark, I read your article titled "RV Refrigerator Efficiency 101" and have a question. In the article it states:
"Older RV refrigerators required more precise leveling, but even the newer models need to be close to level for optimum performance. Over time a cooling unit operated out of level will be permanently damaged. "

My question is does the refrigerator need to be level when it is being stored and is not being operated? The manufacturer of my camper recommends parking it at an angle when stored so that moisture runs off the top. Just wondering whether this would damage the refrigerator. Thank you.

Mark Says: The damage occurs when the refrigerator is operating and the cooling unit is out of level (more than 2 degrees or half a bubble) An out of level refrigerator can cause the coolant to pool in one area and block the flow resulting in damage. It's okay when in storage and you're not using the refrigerator but when you decide to use it make sure it is fairly level. The general rule is if you feel comfortable walking in the RV it is level enough for the refrigerator to operate properly.

Copyright 2008 by Mark J. Polk owner of RV Education 101

RV Expert Mark Polk, seen on TV, is the producer & host of America's most highly regarded series of DVD's, videos, books, and e-books. http://www.rveducation101.com/