Curtisden Posted May 18, 2015 Share Posted May 18, 2015 I have a 2 year old Van conversion which I am very happy with. My question is re fluid levels in my 68 ah vehicle battery which now and again takes huge amounts of top up fluid while other times requires none. 1.5lts this week after being on PWS mains mains charger for the last month while in storage. The Camper set up is 2 batteries a 65ah and a 180ah banner leisure unit. The Banner is never a problem? The 2 are charged by a power interrogator system that takes input from either the Engine while running or a 85 w solar panel on the roof. This maintains both batteries and fools the alternator to maintain full charge to the leisure unit when the vehicle unit if fully charged. Apart from this the there is a normal mains charger that is supposed to maintain a trickle charge when it finds a full battery. Questions are. 1. What may be causing the overcharging of only the vehicle unit? 2. Could it be the Mains Charger that I do tend to leave on throughout the winter to maintain full charge, which it does??? 3. Low battery fluid levels must cause damage but how much as it still seems to hold 12.8/12.4 most of the time? Peter Link to comment Share on other sites More sharing options...
colin Posted May 18, 2015 Share Posted May 18, 2015 I would guess that having two charging systems and no usage has caused the problem. Why leave it on mains? Unless it is in a shed the solar should keep it charged up ok, Link to comment Share on other sites More sharing options...
starvin marvin Posted May 18, 2015 Share Posted May 18, 2015 Boiling starter battery eh? I can tell you about a boiling starter battery, I experienced mine at a peage toll area just north of Tour a few years ago, problem was a defective diode in the alternator. It had caused the safety plug in the battery to be blown out with steam coming out the hole like a boiling kettle! That's what I call a boiling battery. Which resulted in a tow back to Le Mon for the whole of "le weekend" 700 Euros later with a new battery and alternator I was on my way! By the way, if I didn't have bad luck I would have no luck at all! B-) Link to comment Share on other sites More sharing options...
Brambles Posted May 18, 2015 Share Posted May 18, 2015 starvin marvin - 2015-05-18 12:52 PM ...... It had caused the safety plug in the battery to be blown out with steam coming out the hole like a boiling kettle! ..... "Safety plug"? Are you sure it was not the plugs they put in to seal the battery vent ports for shipping and should be removed before fitting/charging. There are usually two, one each end of the lid and you just need to remove one. Link to comment Share on other sites More sharing options...
aandncaravan Posted May 24, 2015 Share Posted May 24, 2015 It is not a good idea to leave a battery on Mains charge when in storage. Most Motorhome 220v mains chargers are designed around the average MH usage of 2 months a year. If you plug them in for 12 months, you are most likely using up 6 years life in one year?. Secondly, not one of the Mh chargers we repair shuts off when the battery is fully charged, they just drop to a lower charge rate. They are still 'Force feeding' the battery, albeit at a low rate. Not good for any battery. A 65Ah Starter battery seems very small, all chargers have a minimum and maximum capacity, generally 70 - 200Ah is typical. Is the Starter battery less than the 220v mains chargers minimum? There have been cases of inappropriate Solar Regulators wrecking batteries as many supposedly 'for Motorhomes' are not. However, I suspect your battery overcharging is related to the way it is wired from the Mains charger? In a sophisticated set up the mains charger is configured to treat the 2 batteries as completely separate entities with a different charge rate to each battery bank. If yours is configured to just connect the two batteries together when the charger activates then you may have a 180Ah and a 65Ah battery connected as one big bank? Imagine that if your two batteries were connected together, and both down at 10v? You plug in the mains charger and it starts throwing out 20amps which goes equally to both batteries. The little battery is going to charge up 3 times quicker than the big battery and then 'ask the charging system to back down the charge'. However the 180Ah battery is still down at 11v and wants lots more amps, which get sent to both batteries, boiling the small one. If the 180ah battery is past its best it may never get fully charged so continually asks for lots of amps which go to both batteries. A very simplistic explanation, which varies dependent on the charging technology, but shows the issue. Strange as it may seem, but the 'bad' battery may well be the 180Ah one which is continually taking power to keep it topped up. The smaller 65Ah boiled battery (which is now almost certainly past it if showing a heavily discharged 12.4v) was damaged as a side effect of the 180ah battery aging. It is also possible that you have different technology batteries, i.e. the Starter is a Wet Acid battery and the 180Ah an AGM battery, with maybe the charging systems set for AGM so too high a voltage for Wet Acid? This is why batteries connected together should always be the same age, technology and size. Suggest you get an Auto Electrician to check out the wiring? Link to comment Share on other sites More sharing options...
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