Motorhome Leisure Battery /ECU Issues

[forrest]

I have a 2005 Swift Kontiki 610 Low Profile and just been doing my usual pre winter check. I should say at the outset we are still amateurs re van electrics despite having driven around Europe and the Middle East over the past decade or so. Anyway ,to my surprise, the leisure battery reading was very low and hardly any power when turning the pump on. I suspected the leisure battery/ batteries having died but just to make sure we gave it a 12 hour charge and the readings rose again to around the usual 13.4 . I say around because the readings were fluctuating - 13.4 to 13.2 and then 14.0 etc
We have a solar panel and 2 leisure batteries . The display showed one of the batteries was completely dead .We disconnected the oldest battery suspecting this to be the culprit. However this made no change to the 13.4 reading we were getting on the ECU.We reconnected said battery and then disconnected the 2nd battery but again the ECU reading remained 13.4 . When we subsequently turned on the taps , there was insufficient power from the pump to provide more than a trickle. 10 mins later, the pump was firing up as normal with a strong flow from the taps.
Finally, we disconnected and reconnected the ECU in case this was the cause of the problem. This was because the readings on the ECU were shifting up and down .
So we are at a loss as to the root of the problem .Could anyone suggest what is happening here or suggest what else we should be trying to diagnose the cause of the problem. Thank you in anticipation

 

[UNG]

Looks like you need to do a proper load and capacity test on the batteries, just looking at the voltage does not really give a true indication of the batteries ability to deliver what you need
You don't state how old the 2 leisure batteries are which may be a factor as to why you are having problems

 

[forrest]

Looks like you need to do a proper load and capacity test on the batteries, just looking at the voltage does not really give a true indication of the batteries ability to deliver what you need
You don't state how old the 2 leisure batteries are which may be a factor as to why you are having problems

hi and thanks for your reply. The 2 batteries (Trojan 27TMX ) were bought at same time as solar panel was fitted - so about 7 years ago. At time of purchase, we were told that the batteries were maintenance free - 7 years on I now learn that they were not lol !!! As I say, I am a numpty when it comes to van electrics so I suppose we have been lucky over the past 7 years lol. We have depended on the accuracy of the Sunsaver Duo Controller and it's associated Morningstar Remote LCD Meter. At present that meter shows 1 good battery reading of 13.4 but battery no 2 reading shows zero and a red light. So my next step was going to test charge battery no 2 using the charger I use for my car starter battery - yes/no ? I had just bought myself a half decent digital multimeter so I will read up re your suggested load and capacity test. Thanks once again.

 

[UNG]

For testing batteries I have something similar to this https://www.amazon.co.uk/dp/B09Y1YV...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

From a battery website I use the Trojan 27TMX has a CCA of 650A @ 32°F so gives you a reference point for a capacity test

Most vehicle chargers will charge leisure batteries be careful not to overcharge if you have one of the intelligent even better as some will give various modes that can do conditioning / recovery charging to recover a battery's capacity

Maintenance free or not all batteries have a finite life which can vary depending on use, the number of charge and discharge cycles, how deep it is discharged and how often, charger type used to recharge, ambient operating temperature, there are so many variables that can affect a battery's longevity it is difficult to predict how long they will last

 

[forrest]

For testing batteries I have something similar to this https://www.amazon.co.uk/dp/B09Y1YV...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

From a battery website I use the Trojan 27TMX has a CCA of 650A @ 32°F so gives you a reference point for a capacity test

Most vehicle chargers will charge leisure batteries be careful not to overcharge if you have one of the intelligent even better as some will give various modes that can do conditioning / recovery charging to recover a battery's capacity

Maintenance free or not all batteries have a finite life which can vary depending on use, the number of charge and discharge cycles, how deep it is discharged and how often, charger type used to recharge, ambient operating temperature, there are so many variables that can affect a battery's longevity it is difficult to predict how long they will last

thanks aqain