Gel batteries - charge problem due to solar?

Discussion in 'Tech/Mech General' started by maz, May 31, 2012.

  1. maz

    maz Funster

    Joined:
    Jan 26, 2011
    Messages:
    2,516
    Likes Received:
    2,157
    Location:
    Out there somewhere
    Looking for some advice on what might be causing new gel batteries to underperform. Am suspecting solar regulator but this is just a guess. :Blush:

    Van has 3x80a exide gel batteries - new with van about 6 weeks ago. Also has 2x85w solar panels with 20a MPPT regulator.

    With all the glorious sunshine (now disappeared!) we've had over the last few days, the regulator never once indicated that charging had stopped as batteries were full. From time to time the red light flickered indicating that float charging was going on, but most of the time it's steady red indicating batteries need charge. Have been off hook-up for almost a week now.

    Yesterday after a good day's sunshine I went out for the evening. On return, water pump ran while having a quick shower then lights (LEDs) were on for about half an hour. Voltage reading on control panel had dropped to 12.5 after minimal use. :Eeek:

    Not used to gel batteries but expect better performance than this! Am now wondering if the solar regulator has damaged the batteries by overcharging them? It's a Juta 20a MPPT and when I rang a supplier to ask if it was suitable for use with gel batteries he said no as it 'didn't have the correct settings'. Can anyone tell me if the regulator is likely to be the cause of the batteries not holding charge as they should? Before I have a go at the dealer who installed the system. :Angry:
     
  2. Reallyretired

    Reallyretired Funster

    Joined:
    Apr 27, 2008
    Messages:
    5,709
    Likes Received:
    3,214
    Location:
    Eastbourne East Sussex
    Gel batteries do have to be charged at a lower rate than normal batteries, but your solar set up would not produce more than 10A in optimum conditions. This is then shared by 3 batteries which is only 3.3A each.
    To charge your 3 batteries from half charged would take around 25 hours of midday/midsummer sunshine. So it could just be that they are not fully charged yet.

    Try charging from EHU for a day or two.
     
    • Like Like x 1
  3. maz

    maz Funster

    Joined:
    Jan 26, 2011
    Messages:
    2,516
    Likes Received:
    2,157
    Location:
    Out there somewhere
    Thing is, I arrived on site here after weeks of being on hook-up and driving around 50 miles so the batteries would have been pretty much fully charged when I arrived. Since then we've had really bright sunshine almost all day (until today) so they should easily have maintained a full charge. I use very little 12v power.

    The previous van had 2x110 lead/acid batteries with just one 85w solar panel and that would keep topped up for 3 weeks or more with less powerful sunshine than we've been having. So I'm not at all happy with what's going on with the current system. :Sad:
     
  4. Snowbird

    Snowbird Funster Life Member

    Joined:
    Apr 24, 2009
    Messages:
    10,141
    Likes Received:
    16,407
    Location:
    Liverpool.
    Take it back Maz, something is amiss.
     
    • Like Like x 1
  5. Reallyretired

    Reallyretired Funster

    Joined:
    Apr 27, 2008
    Messages:
    5,709
    Likes Received:
    3,214
    Location:
    Eastbourne East Sussex
    Ah, puts a different slant on it.

    Fully charged battery would have an open circuit voltage of 12.6-12.7V.
    If your meter is a bit out, and most of them on control panels/regulators are'nt too accurate then your batteries may in fact be fully charged if it's showing a voltage of 12.5v.
    Have you tried with a multimeter with no charging going on?
     
  6. aba

    aba

    Joined:
    Oct 27, 2009
    Messages:
    2,793
    Likes Received:
    1,119
    Location:
    yorkshire
  7. maz

    maz Funster

    Joined:
    Jan 26, 2011
    Messages:
    2,516
    Likes Received:
    2,157
    Location:
    Out there somewhere
    Haven't got a multimeter but hopefully may bump into someone who has. And who knows what to do with it. :Smile:
     
    • Like Like x 1
  8. maz

    maz Funster

    Joined:
    Jan 26, 2011
    Messages:
    2,516
    Likes Received:
    2,157
    Location:
    Out there somewhere
    That's interesting - says for solar needs 14.2v constant. The info sheet for the regulator on my system says 'full charge cut' = 14v. :RollEyes:

    http://midsummerenergy.co.uk/pdfs/juta_regulator_datasheet.pdf
     
  9. aba

    aba

    Joined:
    Oct 27, 2009
    Messages:
    2,793
    Likes Received:
    1,119
    Location:
    yorkshire
    either you need a regulator that will charge gel batteries or have the system modified so the solar charges the vehicle battery then through a b2b charger to the leisure batteries i think that some like the sterling has a switch system for gel / lead acid so should work but the cheapest option will probably be a different solar regulator.
     
  10. maz

    maz Funster

    Joined:
    Jan 26, 2011
    Messages:
    2,516
    Likes Received:
    2,157
    Location:
    Out there somewhere
    Think I will be having a chat with the dealer who fitted the system tomorrow ................ :wub:
     
  11. Snowbird

    Snowbird Funster Life Member

    Joined:
    Apr 24, 2009
    Messages:
    10,141
    Likes Received:
    16,407
    Location:
    Liverpool.
    As I said earlier Maz.......Take it back, You would be surprised at how many dealers don't understand solar.
     
  12. 1948

    1948 Read Only Funster

    Joined:
    Dec 3, 2009
    Messages:
    444
    Likes Received:
    46
    Location:
    surrey
    Not sure if this helps
    I have recently changed my 2x gel batteries charged by solar panels, and noticed terminal voltage were high, I e-mailed Schaudt who made the regulator and these are the info I received.
    Maximun charge output from regulator should not exceed 14.2V for gel batteries, this is preset in factory and if charge output exceeds measured by 14.2V by digital meter then regulator is faulty anf batteries will not charge correctly and even damage. In summer months, battery should be on main charge once monthly, and once weekly in winter months.
    When connecting regulator , alway connect battery end first and solar input last.
    Also, was advised that if battery in digital meter is old Reading can be up to 1V higher so always check battery in meter before use.
     
  13. maz

    maz Funster

    Joined:
    Jan 26, 2011
    Messages:
    2,516
    Likes Received:
    2,157
    Location:
    Out there somewhere
    So that's different again - with 14.2v being the absolute maximum as opposed to the required constant 14.2v charge by Exide. :Confused:
     
  14. 1948

    1948 Read Only Funster

    Joined:
    Dec 3, 2009
    Messages:
    444
    Likes Received:
    46
    Location:
    surrey
    My old batteries were exide there is a label on it maximun 14.4V
    Regarding the solar charge, maximun the unit will give to battery is 14.2V but it will depend how much is picked up by the panel It may well be not reaching max of 14.2V It is just a safe guard that batteries will not be damaged by excessive voltage. It will depends how big or how strong the sun is. Batteries will still be charging below 14.2V in put Just it will take longer time to charge
     
  15. maz

    maz Funster

    Joined:
    Jan 26, 2011
    Messages:
    2,516
    Likes Received:
    2,157
    Location:
    Out there somewhere
    So do we still reckon I have the wrong regulator ......... or not? :Confused:

    Don't want to look a total pratt if I query it with the dealer ......... :wub:
     
  16. magicsurfbus

    magicsurfbus Funster

    Joined:
    Oct 11, 2010
    Messages:
    3,510
    Likes Received:
    8,266
    Location:
    NW England
    When I had my solar panel fitted, the dealer's technician wired my charge regulator directly to an inverter that wasn't even connected to the leisure battery, thinking he'd created a short cut. Fortunately, I checked the wiring route out of curiosity and found the fault. It was fixed, and we were compensated with money off a future service, but after we cashed that in that was it - we never went back. The dealer shall remain nameless.

    By coincidence I've noticed this evening that whilst my solar charge regulator cuts out at 13.6v (I have a carbon fibre leisure battery), the EHU charger puts 14.2v into the circuit. Should I be looking for a higher-rated charge regulator?

    One thing I've found handy was buying a pair of voltmeters that plug into the lighter sockets. They've helped me prove conclusively that my alternator is not putting current into the leisure battery when the engine's switched on, which may go some way to explaining why my fridge won't work properly on 12v. That's being investigated soon.
     
  17. 1948

    1948 Read Only Funster

    Joined:
    Dec 3, 2009
    Messages:
    444
    Likes Received:
    46
    Location:
    surrey
    Not necessary so, provided that maximun charge voltage set at 14.4V
    If you get a multimeter from place like Maplin (£10ish) You can measure on a sunny day what is going into regulator and what is coming out into battery
     
  18. maz

    maz Funster

    Joined:
    Jan 26, 2011
    Messages:
    2,516
    Likes Received:
    2,157
    Location:
    Out there somewhere
    Update

    Took van back to the dealer yesterday and explained the problem of solar not charging the batteries properly. Initially treated as if I was stupid and told that batteries dropping 0.1 or 0.2v overnight with no load was 'nothing'. According to them I could let the batteries drop to 11v 'with no problem'. :Angry:

    Pointed out the error of their ways and told them the generator would be out at 12.3v. Stood my ground and told them that I'd had solar in my previous van with no problem and knew what to expect from its performance. Informed them that the regulator they had installed was not suitable for charging gel batteries (had spoken again to a supplier who knew what he was talking about and that regulator would never manage to charge gel batteries adequately). So the dealer could either change the regulator or change the batteries. Getting another regulator in would have taken some days and I'm not impressed with gel batteries anyway so went for changing to wet and venting the compartments.

    Good news is that 110Ah wet batteries fitted in the same space as 80Ah gel, so I now have a battery bank of 330Ah rather than 240Ah. Will be off hook-up again from next Wed so will see what happens then but am quietly confident that the system will now work properly. :Smile:
     
    • Like Like x 1
  19. aba

    aba

    Joined:
    Oct 27, 2009
    Messages:
    2,793
    Likes Received:
    1,119
    Location:
    yorkshire
    i hope you got some of your money back as a 110ah wet battery is nearly half the cost of a gel one unless they put trojans on.
     
  20. 1948

    1948 Read Only Funster

    Joined:
    Dec 3, 2009
    Messages:
    444
    Likes Received:
    46
    Location:
    surrey
    Do post a feed back in due course Please
    Happy mhoming
     
Loading...

Share This Page