Battery changed

[Billggski]

I realised this should be in hints and tips

 

I've just changed my battery from the original 80ah to a 90ah one and adjusted the Schaudt DT220 controller on my 2009 Dethleffs A5881.

It used to read 64ah when fully charged, it now reads 72ah, both are 80% of the nominal capacity, is this right as both figures sometimes have a question Mark after them?

 

[lennyhb]

If you email Udo Lang at Schaudt he will give you all the info you need.

 

Udo.Lang@schaudt-gmbh.de

[Tracker]

I know nothing of these units but I'm guessing that the meter reads the battery voltage as a means of determining it's state of charge?

 

Not only does there seem to be a wide variation in the voltage that a battery shows when fully charged there is also a variation as to what voltage does constitute fully charged .

 

It is often the case that built in onboard chargers of any sort don't ever fully charge the leisure battery because of the alleged risk of hydrogen escape when the battery gasses when being charged at a high enough voltage to fully charge it.

 

So there may well be nothing wrong with your system or battery - it's just the way it is?

 

To be sure take the battery off and bench charge it with a multi stage charger like Ring or Ctek sell and check the voltage when fully charged according to the charger lights and again after it has sat at rest on the bench for a couple of days. If the voltage has hardly changed the battery is fine and you might expect a figure of well over the theoretical fully charged voltage of 12.75 / 12.80 volts and possibly as high as just over 13.00 volts.

[Retread24800]

I've read somewhere or it might have been one of the tutorials on 'The Motor home Channel' that on board chargers will not fully charge a battery because to do that needs an input voltage of (from memory) 15V which if produced by the on board would tend to cook your appliances, I think C-Tec offer an off line charger that goes to 15V.

[lennyhb]

That was true of the older charges, the modern multi stage chargers will fully charge the battery then drop to a maintenance level to maintain the charge without gassing, they also have different charge regimes for different types of battery.

[Billggski]

That makes sense as I had to change the setting from gel to lead/ acid when I changed batteries, what confuses me is that the 72ah translates to 100% on the display! even though it's a new 90ah battery.

[lennyhb]

I have read about this before but I thought it only did that is the total battery capacity was over 180A/H.

I would email Udo as I suggested earlier if he is in the office you will get a quick answer.