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Solar Charging Issue


Solar Charging Issue  

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I am new to this stuff......


I wonder if you would be able to offer some advice on an issue that I have related to my solar panel not maintaining my leisure battery when my Bailey 760 motorhome is in storage.


Installed on the standard Bailey 760 is:


* a 90W Solar panel which has a Steca Solsum F(6.6F) Solar charge controller connected to the leisure battery.


* a Stirling Power products Auxiliary Battery Charge/Maintainer 12v - 12v, 3A, Code BM12123 which is connected to both the vehicle battery and the leisure battery.


Problem - since installation from new whenever the vehicle has been stored for a month or more the Leisure battery drains down to zero. Not even enough energy to light the LCDs in the control panel for the motorhome. Whist the Leisure battery is completely flat the vehicle battery has enough power to start the engine with no problem.

In storage the motor home is amongst trees and I do have a Protec cover which has a clear section over the solar panel to allow light through.


Once charged through driving the vehicle or through mains supply the battery seems to function ok. Once on site camping, if I disconnect the mains supply and rely on the battery for an evening, it supplies power enough for TV, lights, pump etc. The last voltage reading at night may show something like 12.4V and next day this will rise to say 12.8V suggesting that the solar panel is charging the battery. Also when looking at the indicators on the Steca controller it shows when the battery is fully charged and being charged through green and yellow leds.


I purchased the solar panel specifically to keep batteries up to scratch whilst in storage and yet it seems to detract from performance.


Could the Solar Charge controller be draining as well as charging the Leisure battery?

Could the Stirling maintainer be causing the drain?


Should there be some kind of diode protecting something here to prevent reverse current flow?


Any advice would be most welcome.


I have taken the vehicle back to the dealer where it was purchased from new in January 13. They have confirmed that the installation of all items is as specified by the manufacturer. I am taking up the issue with them again but if they are missing something it would be good to furnish them with information that may help them resolve.


Thanks all

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Hi and welcome to the nuthouse!


You will need to get some voltage readings.


Output from solar panels before and after the regulator both on a dull day and on a sunny day.


That will tell you whether the panel and the regulator are working.


Battery voltage at the terminals both on and off charge.


That will tell you whether the charge is getting to the battery.


Remove battery and check voltage when charged. Leave it fro a few days and check the battery voltage again.


That will tell you whether the battery is holding it's charge.


Let us know the outcome and somebody better qualified than I might be able to come up with possible answers but as it is there are too many unknown factors to be able to tell very much.


I suspect that both the regulator and the Stirling have built in blockers to prevent reverse current flow and the literature that came with both units might well tell you haw to test them?


A good auto electrician should be able to check the system for you and advise if you have any doubts about the dealer's competence.

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Thanks Tracker.

I also had a response from Clive Mott from MMM. He gave some good tips on the approach to take as well. In fact I took the van to the dealers yesterday for some other warranty work and asked them to look at this issue again. I passed Clives point by point approach to them and three hours later they determined the issue to be the leisure battery. They did a drop test and said that it did not recover as they would expect. They replaced with a new one. During their checks they measured for current flow when all was switched off and it was minimal. Less than 100 millamps. Today I have to say that the Leisure battery seems to be being charged. Last night voltage was 12.8 V, 10:00am this morning it was 13.2V and at 2:00pm it was 13.4v so something seems to be going in the right direction. I guess the real test is storing the van for 1 month and seeing if all is well then.


Thanks again for your response.

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Glad to be of help Richard although Clive is the real expert whereas all I have is a little personal experience and given what crap so called leisure batteries really are I did suspect the battery all along!!


That charging rate, assuming it is taken at the battery terminals, sounds about right, and if you do want to test the battery alone you would need to disconnect it first. You may also need to disconnect the solar panel input to the regulator as I believe that some regulators need to have an output load to prevent damage from an input voltage - but I am unsure - the instructions should tell you - or Clive will!

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