Disaster alert. Battery explosion!!

Discussion in 'How To' started by lawts0908, Dec 4, 2019.

  1. A couple of months ago, I’d tucked up the bus for winter. She has an inbuilt charger system connected via a standard 240v hook up. She’s all nice and clean, secured away in the car port with the garage door down.
    A couple of days ago my wife and I decide to take the bus out on a beautiful cold day. Strange, it only cranks about half a turn.....? Oh well thought I, I’ll just jump start off of my spare battery. So I grope around in the dark of the engine bay trying to connect the jump lead to the battery. I find the +tive terminal but think it odd that it seems to just be floating around and loose... To my horror, I discover that the chuffing battery has violently exploded all over the place and the terminal I’ve connected to is just sticking out of the separated top of the old battery.

    Now, thinking about it, I can’t honestly remember checking my battery cell levels since I rebuilt my bus some 5 years ago. As a result, I’m obviously concluding that it’s run dry which has caused the disaster. (Although the end cell at the +tive side has really a misshapen bulge to it, so it may have been a faulty battery.)

    Anyway, here am I, trying to neutralise the H2SO4 acid with the wife’s ironing sprayer filled with either bicarbonate of soda (have tried white vinegar too) the paint’s gone in the battery try and the acid has soaked into the battery tray joins with the outer panels.

    So my reasons for writing are to warn owners. (And confess to my muppetry) If you have a lead acid battery, DON’T neglect it!! It was too easy to forget - out of sight, out of mind. I’d completely forgotten to check the levels.
    And I’m looking for advice too. I’m never fitting a lead acid battery again. Instead i think I’m going for an AGM type, sealed for life etc.

    Can anyone recommend a brand and size? I’m guessing 40- 63Ah? My bus has the 2.0l CJ engine.

    Cheers in advance! I’ll get back to my buggered battery tray :(

    Sent from my iPad using Tapatalk
  2. Sounds nasty. Are you sure the charger was behaving and not overcharging?
    Iain McAvoy, mgbman and IZZYBAY like this.
  3. I would go for a bigger battery say 075 with a higher CCA of around 600, to help on those cold days (063 CCA is around 350) I had a issue years ago before I bought a sealed battery, was rain water ingress coming via rain from air intakes and seeping into the cells through the filler plugs on two cells nearest the back. This caused the cells to over fill and when I switched off the engine and the hot box got hotter in there the water expanded and flowed out of the overflow tube onto the tray and smell of acid. Did all you have done to rid the acid and all ok. Nb I thought a quick fix of flow from overflow was to drill a small hole in the tray and poke the overflow tube through it BUT drilled too close to battery and put a hole in the battery so it was buy a new battery ASAP.
    When you fit the new battery I would check your charger is not overcharging, this could make the battery hot if it is.
    Last edited: Dec 4, 2019
  4. PIE


    you did take the transit plug out didn't you?
  5. Shocking! ;)
  6. You don’t need an AGM battery to have a sealed battery. I’ve ran AGM,s for years as my main battery and my leasure battery but just because I got them for free. They cost a lot more normally and are supposed to have a more complicated charging process.
    theBusmonkey likes this.
  7. Thanks guys,
    Yes, I had thought about my inbuilt trickle charger being faulty. It’s as though it may possibly be pumping a full charge and has just boiled it dry. When I get everything up and running with my new battery, I’ll definitely be checking this.
    Good point about the vent plug, but yes it was removed.
    Thanks for the advice re CCAs etc. I’d like to say what battery it was that exploded (and the Ahs etc) but there’s so little left, I can’t retrieve any of the info from it!
    I’ve been researching AGM batteries. They seem to be the best bet, but I wasn’t aware of any charging complications..... I figured that they just charge normally.
    Normal lead acid batteries are a pain to check the cell levels on bays as they have to be removed to do it. Sealed units have to be the way forward!

    Sent from my iPad using Tapatalk
    PIE likes this.
  8. I had a leisure battery explode a couple of years back. I put it down to being lazy and not isolating it from the main fully and connecting just one intelligent charger across both in parallel (I used to use one charger on each).

    I figured the leisure was older and must have deteriorated through a faulty voltage regulator not making enough voltage to switch on the split relay.
    Charging in parallel means the intelligent charger just sees one virtual battery with the combined characteristics of both which with one healthy-ish main and a knackered leisure looks like a permanently low battery and the charger output is high enough to switch the split charge relay on, so it keeps charging. The leisure can’t recover so then fizzes away boiling itself.

    Cell plugs flew out, top blew half off, acid everywhere. Nightmare to remove with acid proof gloves!
    Charger burnt out too.

    Like you I used baking soda in a spray to wash the inner rear arch and surrounding area.

    A new regulator and two new batteries fitted, closely matched in size and characteristics, another charger and now I charge separately when laid up for a week or more.

    Sent from my iPhone using Tapatalk
    IZZYBAY likes this.
  9. Some of the so called smart chargers are not that smart & if left on can boil a battery dry over time. A friend of mine left one on his bike in Spain. When he returned a few months later the battery had disintegrated :eek:
    Keep your eye on it :thumbsup:
    lawts0908, art b and Gingerbus like this.
  10. The more I think about it , the more I think it will have been a problem with my charging set up. Like Gingerbus, I have a smart charger connected to both batteries in parallel. My leisure battery is a seal unit somewhat bigger in size and power than the car battery. All seemed ok with the setup up to now.... but I’ll not be charging using it in future!

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  11. Does sound very much like overcharging.
  12. As mentioned smart chargers calculate the required charge by monitoring battery voltage and internal resistance of the battery. Wiring two batteries in parallel will confuse its control.
    Gingerbus likes this.
  13. I think with mine the main root cause was a combination of things, the regulator not kicking out enough voltage to switch the volt sensing split charge relay on meaning the older leisure battery wasn’t getting charged much at all when running. Then overcharging when dead as explained.

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  14. What brand and capacity charger were you using?
  15. It is (was?) a Banner Accugard-car 1800. Supposed to be ideal for trickle charging during the winter months.....


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    IZZYBAY, F_Pantos, scrooge95 and 3 others like this.
  16. Yikes!!!

    I think mine was mostly just gas by the time it went pop.

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    Last edited: Dec 5, 2019
  17. AGM batteries are still lead acid batteries they still gas when being overcharged and I'll say it again never charge two batteries from the same source if that source can reach the gasing voltage of the battery.

    And don't use an angle grinder near a battery on charge.
    Valveandy, IZZYBAY, Gingerbus and 2 others like this.
  18. or drill a drain hole without making sure it is not going to go through the battery....like I did.....doughnut!
  19. Dubs

    Dubs Sponsor

    Or charge the battery In situ on a classic mini, then make a spark when disconnecting the charger...
  20. Now you have scared me I have turned my charger off .

    I had the Aldi battery charger connected to my starter battery with a durite split charge relay going to my leisure battery.

    Following this video I assumed it would be safe enough to leave on.

    I might just put mine in charge a day or so before setting off camping from now on.

    Sent from my Pixel 3 XL using Tapatalk
    lawts0908 and IZZYBAY like this.

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