Converter and Battery Question

[Roam America]

Got a question regarding battery charging and converters.

Let me start by saying, I am fulltime and am always plugged in. We are usually stationary for a few months at a time.

A few weeks ago there was a power failure where we were staying. About 15 minutes after power went out, I check the battery levels on the guage inside. Battery was at 50%. I figured, 6 years old, I guess I need a new battery. So I bought a new battery and installed it. After three weeks we picked up stakes and am now heading south for the winter.

We pulled out, and stayed in a CG for the night (full hookups) so the coach was plugged in all night. The next morning I unhooked everything and went inside to wash my hands. I thought about the battery so I checked the level. Now remember it was plugged in all night. Battery read 75% but while checking dropped to 50%.

I have no problems with 12v when stationary (plugged in to 50A AC).

So now the reason I am posting. It sounds to me like the converter is working, as everything works fine, but maybe not charging properly. How do I check part of the converter that does the charging?

[BryanL]

Get a digital voltmeter -- I've seen HF sell them very cheap. There are also some that plug into a cig lighter plug that are convenient.

If your converter is not one that does multiple stage charging and has a storage maintenance mode (like the ChargeWizard or Iota types) that features a sulfation inhibiting technique (not trickle or float alone), then an upgrade is one of the best things you can do for your batteries.

When the converter is working, battery voltage should be from 13.0 to 14.5 volts. (all voltages based on 12v system - double for 24v) depending upon charging phase.

When the plug is pulled, the battery should settle down to 12.6 to 12.8 volts after a while. When the battery is in use, the voltage should drop slowly down to 12.0 volts. For these 'state of charge' battery measurements, always make sure the battery has had no significant charging or discharging for a half hour or more. Try to measure voltage as close the battery or fuse block as possible.

A resting battery voltage down to 12.4 volts needs a plan for recharging. Down to 12.2v and charging should be a priority. For best battery life, don't let it get below 12.0v

6 years on a battery is about as long as you can expect. An old battery usually just acts like a small battery. Maybe a fifth of battery failures are more catastrophic.

The battery indicators in RV's are usually just voltmeters with very low precision. They can be useful but you need to calibrate them against your experience. They do need appropriate interpretation in terms of battery load, temperature, and other factors, just like other state of charge measures.

[garym114]

The converter output goes to 12v distribution and the batteries. Get a handheld multimeter and check the battery DC voltage while connected to power. Do the same while disconnected. How often do you look at battery water level ??

[Roam America]

I'll double check the water level. I didn't bother checking the old battery due to its' age and I went out and got a new one. I cannot remember if I checked the water in the new one or not. I hate CRS..