Help! Battery problem.

iampatman

iampatman

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A week ago we came off the ferry from Greece and drove 20miles to Jesi in Italy. When we arrived I checked the BM1 monitor and the LB was showing 84% charged which I thought strange as it should have shown 100%. Thirty minutes later it was down to 22% and ten minutes later 2%! I checked the battery connections, fuses and everything seemed ok. I ran the engine for 20 minutes and got the LB back to 62% but it soon dropped down again. Eventually everything went off - lights, water pump, fridge. We had a fridge fan fitted before we left England last September and when we arrived in Jesi I noticed that it wasn’t working and when I checked the connections they had come apart, presumably bouncing down the ferry ramp and Italian roads had caused this. I taped up the bare leads from the 12v fridge supply. The sosta at Jesi is provided by the local motorhome club which has a club room above the parking area and I noticed a light on there so went up, knocked on the door and a guy who spoke perfect English listened to my problem. I said I either needed a new battery or an auto electrician who knew his way around 12v systems and he offered to take me to the nearby Bosch service centre the next morning. The next day the solar panel had brought the LB back to 60% and we drove to the Bosch centre. The guy there had a cursory check of the battery and declared it ok. I asked if he could check out my system but he was too busy or didn’t have the inclination and so it was agreed I would spend another night at Jesi and if I had the same problem the next day he would sell me a new battery. During the day the solar brought the battery up to full so although the fault hadn’t been identified everything was working normally, everything has been fine since then.
This morning we were woken by the distribution unit frantically clicking on and off. Jumped out of bed, checked BM1 monitor and LB at 0%! and nothing working. No lights, fridge or water pump. Nothing had been charging off the LB overnight. Sun came up, and after a couple of hours LB showing 13.6v and 45% charged and everything working.
The battery is a 110ah Varta silver, three and a half years old and the charging/distribution unit is a refurbished Calira EVS 38/20, also three and a half years since fitted.
Any ideas as to what the problem may be?
Any advice or suggestions greatly appreciated,

Pat
 
are you sure its the battery?

I had very similar problems last month and I had a brand new battery (2 months old) turned out it was the battery monitor, on my M/h once the battery monitor says 10v the habitation electrics shut down - what ever the true voltage of the battery is.

So before you do anything rash like buying a new battery put a volt meter across the leisure battery terminals and check what the true voltage is

My battery was fine and I have now adjusted the battery monitor even though doing so results in the vehicle battery now reading 26v!!!!
 
Find a local auto electrician to find out what the real fault is.

:wave:
 
getting a proper electrician to look at it is obviously the best solution but its not always a practical one - if I wanted to see either of my local autosparks I would need to wait a week or more

"84% charged which I thought strange as it should have shown 100%. Thirty minutes later it was down to 22% and ten minutes later 2%! "

that is exactly the sort of readings I was getting, after a 150 mile drive I expected to see 13v I got less than 12v a few milesdown the road it was reading 7v after struggling through a month of this - booking into campsites just to charge the battery I arrived home after driving well over 100miles to be greeted with a reading of 0v (and everything shut down) I put a meter across the battery and it was reading 12.8v - just as it should have done.

Im wondering if Iampatman recently disconnected his leisure battery as I think that is what caused my issue (I think!)
 
The LB hasn’t been disconnected since fitting three and a half years ago. Just driven 50 miles or so and monitor shows 13.5v and 104% charged (it’s always shown 104% when fully charged). I don’t think it’s a battery problem as such but that something (?) is intermittently draining the battery at a fast rate. I don’t think an auto electrician in France is the solution unless I can find one with better English than my schoolboy French. We’re on our way to our daughters place in France so tomorrow I’ll see if son in law has a multi meter (and knows how to use it).
In the meantime any other suggestions would be gratefully received.

Pat
 
If the battery charges up on solar but goes down overnight it could be the diode on the solar panel has failed allowing the current to go back to the panel at night, I would disconnect the panel when the sun goes down and see if your batteries stay charged.

If you had a problem with a large current draw from something else I doubt the solar panel would charge it up that quickly in daylight
 
Tezza33 said:
If the battery charges up on solar but goes down overnight it could be the diode on the solar panel has failed allowing the current to go back to the panel at night, I would disconnect the panel when the sun goes down and see if your batteries stay charged.

If you had a problem with a large current draw from something else I doubt the solar panel would charge it up that quickly in daylight
Click to expand...

Thanks for that Tezza, it seems to make sense in so far as I’ve not had any problems during the day. How can I check if the diode has failed?

Pat
 
iampatman said:
Thanks for that Tezza, it seems to make sense in so far as I’ve not had any problems during the day. How can I check if the diode has failed?

Pat
Click to expand...
It is on the back of the panel in the box where the two wires come out so you would have to remove the panel, I wouldn't worry about testing it until you have tried disconnecting the panel at night, I fitted my own panels and I have a fuse in the positive cable so I can just pull the fuse out to disconnect mine


Sorry about the delay posting a reply, I had a slight problem yesterday
 
Hard to diagnose this type of problem from a distance, as several folks have stated, it needs an auto sparky to take a look.

Have you added any circuits or loads to the batteries since the BM1 was originally fitted ?
If yes, are you confident that the negative(s) are connected to the correct terminal on the BM1 shunt,if you simply strap new connections directly onto the battery terminals, you are by-passing the shunt and that will give you crazy readings on the BM1.

james
 
FringeDweller said:
Hard to diagnose this type of problem from a distance, as several folks have stated, it needs an auto sparky to take a look.

Have you added any circuits or loads to the batteries since the BM1 was originally fitted ?
If yes, are you confident that the negative(s) are connected to the correct terminal on the BM1 shunt,if you simply strap new connections directly onto the battery terminals, you are by-passing the shunt and that will give you crazy readings on the BM1.

james
Click to expand...

Thanks for the suggestion but all negatives are connected to the BM1 shunt.

Pat
 
The BM1 is reporting massive drops and could be suspected as being faulty EXCEPT what is it reporting is being bourne out by what is happening .... Electrics died, clicking, etc, so as the BM1 is purely a monitor and does not influence the electrics USE, I would take that as good and reporting correctly.
How big is your solar array? Going from a dead battery to full so quickly indicates a massive mismatch of battery capacity and solar panels. I doubt that is really the case when you specified the setup so I would agree with the comments about the battery being FUBARed. It has lost most of its capacity, hence why it apparently charges up so fast and also discharges so fast.

During the day you will be running everything off the solar harvesting and the broken battery is not noticeable.
As Tezza33 suggests, disconnect the solar and put a known load on and see what the BM1 is saying over say 30 minutes. Is is as you would expect or is the SOC and/or Voltage dropping faster then it should?
 
I would suspect you have been camping on board a Greek boat and the electric supply to your camper was faulty and this as either damaged your battery or
charging circuit. i hope it is the battery
 
Sorry i thought you said you had just returned from Greece to Venice even if i have not been camping on board they have connected me to their electric to run the fridge
 
wildebus said:
The BM1 is reporting massive drops and could be suspected as being faulty EXCEPT what is it reporting is being bourne out by what is happening .... Electrics died, clicking, etc, so as the BM1 is purely a monitor and does not influence the electrics USE, I would take that as good and reporting correctly.
How big is your solar array? Going from a dead battery to full so quickly indicates a massive mismatch of battery capacity and solar panels. I doubt that is really the case when you specified the setup so I would agree with the comments about the battery being FUBARed. It has lost most of its capacity, hence why it apparently charges up so fast and also discharges so fast.

During the day you will be running everything off the solar harvesting and the broken battery is not noticeable.
As Tezza33 suggests, disconnect the solar and put a known load on and see what the BM1 is saying over say 30 minutes. Is is as you would expect or is the SOC and/or Voltage dropping faster then it should?
Click to expand...

I have a 100w solar panel and a 110ah battery. I’m tending to go with Tezza33’s theory regarding the solar panel diode. For the last few evenings I have removed the fuse from the panel to the regulator and put it back in the morning and everything is behaving as it should. I’ll continue to do this until I return to England in a fortnight or so and then get on the roof, remove panel, check diode and replace if it looks knackered. (Or get someone with a bit more knowledge and skills than me to do the job!) I appreciate that flattening the battery which has happened twice now isn’t doing it any good however the guy at the Bosch service centre suggested that as it had only been flattened for a short period it shouldn’t have done any serious damage. Should the battery not be at its best then I’ll obviously buy a new one but I don’t think the problem I’ve described is caused by the battery failing.


Pat
 
Solar panels come with long warranties so it might be worth talking to whoever you bought it from, but the diodes are not expensive and doesn't take long to change if you can solder


solar panel diode.jpg
 
Glad it looks like you have isolated the cause and got a workaround in place :)

Is it safe to ask a silly question now without taking thread offline too far? If the diode has failed and is allowing reverse feed why did the solar controller not stop it? If not all controllers have that feature inbuilt then I understand but otherwise I am a bit confused again
 
Nabsim said:
Glad it looks like you have isolated the cause and got a workaround in place :)

Is it safe to ask a silly question now without taking thread offline too far? If the diode has failed and is allowing reverse feed why did the solar controller not stop it? If not all controllers have that feature inbuilt then I understand but otherwise I am a bit confused again
Click to expand...

That thought has occurred to me too. I bought the panel and a PWM controller as a kit from Photoelectronic and at the time there was some debate as to whether an MPPT controller was really more efficient. When I get home I’ll have a look at the diode first, replace if necessary and then replace the controller with a 10a MPPT one. If the diode is ok then I’ll be thinking that the PWM controller has failed or didn’t have a feature to prevent reverse feed in the first place. Whichever the case is I’ll be fitting an MPPT controller anyway.

Pat
 
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