Battery charges when plugged into shore power?

A three stage smart converter wil not start charging at 14+V. Its target voltage is 14+ V in boost mode but with a low battery bank it cannot get there right away. As the battery SOC (state of charge) rises the indicated voltage will rise to eventually reach the 14+ volts (usually 14.4v to 14.8v - my Magnum is 14.8v) that is the cutoff voltage for boost. At that point its brain will lower the charge rate to restart a ramped charge up to about 13.7v. when it gets there it will again drop the charge rate to about 13.2v. That rate is just below the gassing voltage of a flooded lead acid battery and can be left on indefinately without battery water use.

Jim

If you can't post the make model, hang a HH volt meter on the battery while its charging, and if you never see more than 13,6-8, you most likely have a single stage converter/charger, which does not charge very fast
And if you never see less than 13.6-8 when fully charged and no loads, then you positively have a single stage converter, which in warm weather can suck a battery dry in a month or 3.

A 3 stage will most times start charging at 14+ volts, and end up floating/ maintaining at 13.2-3

If you have the information packets that came with your RV there should be one for the converter. If not look around the area of your power center and breaker box. The converter should be close by. It will have a 120v AC power source going into it and heavy 12v cables coming out that go to either some place on your 12v power center or directly to your house batteries. Find the brand and model and post it here.

Jim

Okay, how do I find out what converter I have? Is there a label telling me one-stage, four-stage, etc? Appreciate the info......

I always recommend to people to check their rig's converter. A three stage is fine. A four-stage, (PowerMax Boondocker, or a Charge Wizard) is best, as it has a desulfate process.

A one-stage, I recommend chucking the thing immediately. Boil two batteries, and that more than pays for a top tier four-stage converter.

X3 RJ

X2 RJ

Todays converters are nothing more than glorified battery chargers. In reality, that's all they do. Some may view them as a power supply, that supplies the 12v power when plugged in to grid, and that is true to a certain extent. But its easier to view them as strictly a battery charger that is replacing any 12v power that you are removing from the batteries. So in reality again, you could say you never removed power from the batteries as long as Grid power is connected.

Unlike yesteryears converters, there is no switching that takes place when using Grid power. The converter is just monitoring the 12v system voltage, and keeps supplying whats needed. And this is why the house batteries will always be charged by the converter.
The chassis battery should also be charged by the converter, but that would have costs the MFG a few $s more, so most would never go for that, altho, some do.

When unplugged your battery is still supplying voltage to things like the 02 and LP sensors, You may also find parasitic draws to a radio or like me sometimes leaving the antenna amplifier on. I have mine down to just a radio's memory and a LCD volt meter. My batteries will stay above 12.6v (full charge) for over two weeks. Right now it shows 12.78v after being unplugged for 5 days and just after unplugging I ran in 2 slides.

here is simplified 30AMP Electrical Flow Chart used in the typical trailer.



Of course your battery will not get charged from your converter/charger unit when connected to shore power if you have your battery disconnect switch opened...

Roy ken