Don't want to overcharge the battery

[margeleept]

We are heading out on Sunday for a 1 week trip in the Casita. We have a 2004 LD. I trickle charged the battery to a full charge, then turned the battery cutoff switch to "off," only to discover that the battery is still very much "on." I need to plug her in to shore power so I can get the fridge cooling. We have an older converter. I know we either need to replace the old switch or upgrade the converter, but I'd like to wait until after our trip to do it. It would be nice to not have to manually lug the battery out and disconnect it every time we want to use shore power.

My questions: How long can I leave the rig plugged in to shore power before the fully charged battery overcharges? Do you think I should just use propane to get the fridge going?

[gordon2]

Even with a old single stage converter it will take some time to damage the battery. Keep and eye on the electrolyte level, and plug into shore power 24 hours before you leave to pre-cool the fridge. No worries.

[J Ron]

Converters in travel trailers do not raise the battery voltage high enough to overcharge a battery. More likely the battery will suffer from under charge. A lead acid battery must be raised to 14.2 volts to be fully charged. If kept at that voltage for an extended period damage can be done. All RV Converters i've seen, I'm 77 and camped all my adult life, only go to 13.2, which should not harm your battery. Keep an eye on the electrolyte level anyway that's just normal maintenance. As stated by the name converter, it is not a proper charger or the name would be charger.

[Byron Kinnaman]

Originally Posted by J Ron

Converters in travel trailers do not raise the battery voltage high enough to overcharge a battery. More likely the battery will suffer from under charge. A lead acid battery must be raised to 14.2 volts to be fully charged. If kept at that voltage for an extended period damage can be done. All RV Converters i've seen, I'm 77 and camped all my adult life, only go to 13.2, which should not harm your battery. Keep an eye on the electrolyte level anyway that's just normal maintenance. As stated by the name converter, it is not a proper charger or the name would be charger.

Unfortunately there are many different converters made my many different manufacturers. To make a blanket statement about converters is usually wrong. A person needs to read and understand the specifications of their converter. NOT rely on blanket statements.

[ehoepner]

The problem of over charging occurs when you have the trailer plugged in to AC power over an extended period of time when the trailer is not in use. For example over the winter time when the trailer is in storage. As the battery voltage goes up the converter pushes the battery voltage higher. The ideal sustainment voltage for a fully charged battery is 13.2. Above that the battery begins to evaporate the water from the cells. So checking the water level in the cells becomes critical for battery life.

There are replacement converters out there that do drop the charge voltage back to 13.2V when the battery is charged.

When you are camping and using the lights, fan, and other DC applications there will be no problem of over charging.