Larry D. asked a question about charging voltage that has been asked a lot. His question:
Brad, a battery charger question please. I have a Magnetek 7200 Charger/Converter in our 1993 Winnebago. Have you ever heard of the charging voltage increasing to 16.8 volts as the battery approaches full charge? I am not sure if this is normal or not or if the regulator is the problem? I have just replaced two size 27 old batteries that gassed and boiled out (which almost overcame me with H2S as I slept). I replaced it with one group 29 battery that also gassed and boiled on the first cycle.
Brad: OK Larry, there is more to your question that I will address in a minute but lets take this part first. The problem is not the battery. The problem is in your charging device. All chargers are supposed to have a voltage high end limiting device in them to control the battery charge. In a 12 volt system that limit is usually around the 14.4 volt range. However my solar system will charge to 15.3 volts and then top off there. 16.8 volts is way too high and the charger needs service or replacement. Now to the second part of your question.
Larry D.
With no battery connected and the Converter/Charger on I turned on my radio. It commenced to crackle and then smoke came out of it. Would you believe that when I measured the voltage it was 43 volts?
Brad: First of all a unit should never be run with the battery disconnected. The battery acts as an absorber for the current that the unit will put out. The unit should havecaught the increase in voltage and throttled back the output voltage, just another indication that the unit is defective. Since Magnetek is no longer available a search for another brand is in order. With the voltage regulator out to lunch and no battery in the circuit to absorb the energy the voltage will spike to the maximum that the unit will put out. Then when you turned on the radio you were lucky that it was only smoke that you got. The battery will offer more resistance to the flow of current, amps, as the level of charge of the battery increases. When the voltage regulator in the charging unit is working properly it will limit the voltage flow as the battery voltage opposes the charging units voltage flow controlling the charge rate.
Big T sent in the following comment and question: I have an Alfa SeYa 2004 and have a lot of corrosion around my batteries while in storage. I thought my solar panels were over-producing so I disconnected them but the problem persists. I clean them regularly with baking soda and water but it continues to build up. I’ve now had to replace the wiring harness as the corrosion has made them brittle and destroyed the wiring links to the battery terminals. The corrosion is also eating into the steel mounting cages. Do you have a remedy or suggestion as to what i can do to fix this situation?
Brad: It kinda sounds like your batteries might be getting a little old and tired. If the coach is a 2004 and the batteries are the original ones, they could be actually 2003 production. Most times the chassis is close to a year old when they start building the coach on it. I would suggest load testing the batteries with a commercial load tester. If they are close to the lower acceptable level then they will gas more than a battery that wil accept a charge better. Secondly, cleaning is good but it has been my experience that unless you coat and seal the metal it will continue to corroded. There is a paint on the market called POR-15, Google it, that will seal the metal and stop the corrosion. When I built the battery box for my big battery pack I made it out of wood because I did not want the corrosion problem. But I would check the voltage output of the solar system, the converter/charger, and alternator. None of the units should show more than 15.3 volts at the battery.
Remember I like to answer comments on the chassis, engine and power train, and electrical systems. So, more next time stay tuned.
Brad