Overcharging leisure battery

[Chajoma]

I have a fairly newly converted 2010 Alphard. On a recent trip (NC500 since you're asking :)), we plugged into the EHU and headed for bed. Just as I was dropping off, I noticed the CO sensor was giving a reading. We definitely didn't have anything burning so I had no idea where this was coming from.

 

However, my wife had mentioned that she had heard a hissing noise which was outside my hearing range, and it seemed to be coming from the leisure battery which is mounted under the R&R seat. I switched on the battery monitor and could see that it was reading over 15V which seemed excessively high. A quick google revealed that overcharging a car-type battery can release, among other things, hydrogen, and CO monitors can detect hydrogen. I disconnected the EHU and the CO monitor returned to a happy state.

 

Now I am home, I plugged in the the mains and watched the reading on the charger itself rise to 15.3V (see picture). I found a manual for the unit online and apparently it shouldn't go above 13.8V. I have tried setting the mode to 'wet' but the unit doesn't seem to do anything then - the fan in the unit shuts down.

 

So, before I take it back to the convertors to complain, I wondered if anyone on here had any experience with these chargers and could share that with me.

 

Thanks
Paul

[OldWellhouse]

That's scary if your partner hadn't noticed either. I have no idea about leisure batteries still and need to learn so will watch this thread with interest.

[Rojie]

18 hours ago, Chajoma said:

I have a fairly newly converted 2010 Alphard. On a recent trip (NC500 since you're asking :)), we plugged into the EHU and headed for bed. Just as I was dropping off, I noticed the CO sensor was giving a reading. We definitely didn't have anything burning so I had no idea where this was coming from.

 

However, my wife had mentioned that she had heard a hissing noise which was outside my hearing range, and it seemed to be coming from the leisure battery which is mounted under the R&R seat. I switched on the battery monitor and could see that it was reading over 15V which seemed excessively high. A quick google revealed that overcharging a car-type battery can release, among other things, hydrogen, and CO monitors can detect hydrogen. I disconnected the EHU and the CO monitor returned to a happy state.

 

Now I am home, I plugged in the the mains and watched the reading on the charger itself rise to 15.3V (see picture). I found a manual for the unit online and apparently it shouldn't go above 13.8V. I have tried setting the mode to 'wet' but the unit doesn't seem to do anything then - the fan in the unit shuts down.

 

So, before I take it back to the convertors to complain, I wondered if anyone on here had any experience with these chargers and could share that with me.

 

Thanks
Paul

 

Is your battery charger set to Lead Calcium ?

Lead Calcium batteries require a higher output voltage to fully charge that type of battery.

That could explain the high voltage on the charger; but not while being charged by your alternator.

 

I have a charger in my van, so as soon as I go EHU the leisure battery gets charged.

My leisure battery is not Lead Calcium, and I doubt yours is either; but its worth checking the battery type.

 

Do you have an independent voltmeter. Always worth it.

[Chajoma]

4 hours ago, Rojie said:

 

Is your battery charger set to Lead Calcium ?

Lead Calcium batteries require a higher output voltage to fully charge that type of battery.

That could explain the high voltage on the charger; but not while being charged by your alternator.

 

I have a charger in my van, so as soon as I go EHU the leisure battery gets charged.

My leisure battery is not Lead Calcium, and I doubt yours is either; but its worth checking the battery type.

 

Do you have an independent voltmeter. Always worth it.

Almost certain it's a standard lead acid battery. Yes I do have a meter but I am already measuring it twice - once on the charger and once on the control panel inside the van. The battery is pretty tucked away so it would not be easy to put a meter across it.