Lorrie Posted May 3, 2010 Posted May 3, 2010 We have just spent the weekend on a rally with no EHU. We have a solar panel fitted to the roof. However, on Sat night our battery ran down from 12.4 when we went to bed to the warning buzzer waking us in the morning. The only thing running was the fridge on gaz. Why did this happen? it happened once before but then we had the fridge and the heater all night. Surely the gaz fridge should not affect the battery. Please can anyone give us some advice as we want to spend longer off EHU, that's why we had the panel fitted. The battery does not discharge in storage. (?)
weldted Posted May 3, 2010 Posted May 3, 2010 you do not say what is the capacity of your battery or how old it is, 12.8 after one hour off charge is roughly the voltage of a fully charged battery 12.4 is about half or less, and 80 amp battery when new and fully charged will only give you about 40 amps of usable power, less if it is cold. was it reading 12.4 with no load on it?. If your fridge is an auto select ie changes power source automaticaly it will take roughly .25 to .5 of an amp hour to control the temperature, if it is one that you select the energy source manually it will not use any 12 volt power once it is lit. Add up your power requirements when not on hook up watts divided by volts gives you amps used, and you do not say what size your solar panel is.
Guest Tracker Posted May 4, 2010 Posted May 4, 2010 Further to Ted's observations, are you sure the battery was fully charged when you arrived on site? It is not unknown for the fuses on the split charge relay under the bonnet and/or the fuses close to the leisure battery to get dirty or loose and fail to connect properly? The only way to be sure is with a digital multimeter to get voltage readings at the battery terminals with the engine on/off, the mains hook up on/off and the solar panel charging on/off. Following these get the battery fully charged by whatever means works and check the voltage is around the 12.8 area - any less and it is not fully charged. After leaving it to stand overnight - preferably disconnected so that any loss in minimised check the battery voltage again and see if it has fallen. PS! Can I respectfully suggest that EVERYONE treats themselves to a cheap digital multimeter as battery and electric problems seem to be the main reliability and aggravation issues with 'modern' vans?
Mike88 Posted May 4, 2010 Posted May 4, 2010 Buying a multmeter is very good advice.........................if you know how to use one. I maybe in a minority of one but I haven't a clue. Having worked in an office environment for most of my life modern vehicle electrics are anathema to me. So, my brand new shiny multimeter from Maplins, sits in its unopened plastic bubble. Its very confusing and when I asked somone to explain how it works it was akin to when when I asked someone to explain how to load POIs on my Tom Tom when I was confronted by jargon like gif files and other unmentionables which turned my ageing brain into jelly. So, in simplistic terms, if you fully charge the battery and leave it to settle for a couple of hours and the voltage on your panel (if you have one) falls much below 13 volts then you most probably have a problem battery.
AliB Posted May 4, 2010 Posted May 4, 2010 Lorrie, Indeed a digital multimeter is essential to carry out any meaningful fault finding. In addition to Trackers advise on checking voltage you can check the current drain on the battery. You need to connect the multimeter, set to current reading, in series with the main feed from the leisure battery. With everything including the solar panel switched off the reading should be very small. My van reads less than 10milliAmps. Anything higher than that and something is still connected and not switched off. If there is a fuse in-line from the leisure battery this is a convenient place to measure current. Simply remove the fuse and insert each probe of the multimeter. Or you can purchase a dedicated automotive current tester that plugs into the fuse holder. These are not expensive, less than £10. Once the battery has dropped below useable level our fridge will not work, even on gas. Once the fridge has stabilised to temperature the flame turns off. It will not turn back on without a suitable voltage from the battery. You could take the battery out off the vehicle, charge from a trickle charge and then connect a small load like a lightbulb and see how long it takes for the voltage to fall. Or just take an educated guess and buy a new battery. Clive MGTB wrote a useful article in a recent MMM on using a multimeter. Worth reading.
Brambles Posted May 4, 2010 Posted May 4, 2010 There is another way. If the battery is more than a few years old just buy a new one. Chances are its past its best anyway so is not money wasted. 99% of the time when someone has battery problems the battery has failed anyway. Usually if the fault does exist somewhere else the battery has been left half charged for so long it is ruined anyway. So get a new battery, check if it functions as expected and then make sure you always keep it well charged up when Motorhome/caravan is not being used.
Guest Tracker Posted May 4, 2010 Posted May 4, 2010 Having first ensured that the fuses are clean and intact I would tend to go along with Brambles on his battery assumptiuons - but as these fuses are known to be unreliable it is worth checking them first in my humble view. Regarding the use of a multimeter, use on volts is straight forward enough - simply plug the black and red leads in to where it shows on the meter and either switch it on or turn the dial to show 20 volts DC which in some cases switches it on automatically. To measure volts simply prod the black lead probe onto the negative terminal of the battery and the red lead probe onto the positive terminal and you will get a reading. Don't worry if you get the polarity wrong it will not harm the meter but it might either give a negative voltage or no reading at all which will be your way of knowing you got it wrong. Using it for current measurement is more complex and the ways to get it wrong are many and varied - and getting it wrong with amps can do damage to the meter and maybe even to the van electics although that is unlikely - so my advice on that is if you are unsure don't try it as a voltage reading will do just fine for most fault finding!
Basil Posted May 4, 2010 Posted May 4, 2010 AliB - 2010-05-04 2:02 PM .....................If there is a fuse in-line from the leisure battery this is a convenient place to measure current. Simply remove the fuse and insert each probe of the multimeter. Or you can purchase a dedicated automotive current tester that plugs into the fuse holder. These are not expensive, less than £10...................... Indeed Maplin Electronics do a very nice one for £9.99 which I have found invaluble. See http://www.maplin.co.uk/Module.aspx?ModuleNo=217879 Bas
747 Posted May 4, 2010 Posted May 4, 2010 Whichever one you buy, make sure it has a set of instructions with it. :D
Guest Tracker Posted May 4, 2010 Posted May 4, 2010 747 - 2010-05-04 6:36 PM Whichever one you buy, make sure it has a set of instructions with it. :D Why? Who reads instructions anyway? They will probably be written in a gobbledegook Chinese version of 'English as she is writ' and in a type face so small that you need a magnyfying glass to read it! PS I made two adaptor probes that convert the multimeter propes to flat bladed fuse type ends out of copper tube scrap and these work just fine to check for current flow - and best of all they cost nowt!
spartan3956 Posted May 4, 2010 Posted May 4, 2010 Unless the battery has failed there is something causing a current draw on the battery. Charge it fully disconnected and leave it 24 hours the figures as stated around 12.8 volts its ok,if its around 10 volts it has a cell gone and scrap. I have had all sorts of things do it radio yes its off but they sometimes draw current, solar panel regulators allowing current to flow from the battery and worst of all split chargers allowing current to flow if u/s You really need to have it checked if you cannot do it yourself, if you can an ammeter is the way to check if the battery has a draw on it. The fun begins finding which component is causing it. Leaving your blow air heating fan on over night is a good one. Firstly find out if the battery is ok.
Mel B Posted May 4, 2010 Posted May 4, 2010 Lorrie - 2010-05-03 9:41 PM We have just spent the weekend on a rally with no EHU. We have a solar panel fitted to the roof. However, on Sat night our battery ran down from 12.4 when we went to bed to the warning buzzer waking us in the morning. The only thing running was the fridge on gaz. Why did this happen? it happened once before but then we had the fridge and the heater all night. Surely the gaz fridge should not affect the battery. Please can anyone give us some advice as we want to spend longer off EHU, that's why we had the panel fitted. The battery does not discharge in storage. (?) Hi Lorrie - welcome to the mad house! :-D First question ... had you fully charged your battery BEFORE going by plugging it into the mains for a day or so to get it as fully charged as possible, or were you solely relying on the solar panel to keep the battery charged up and hadn't given it a boost from the mains? If the former, then it looks like you have a problem as others have suggested, if the latter, then with the weather as it has been, it would not have kept the battery charged fully, only giving it a bit of a top up.
Guest Tracker Posted May 4, 2010 Posted May 4, 2010 spartan3956 - 2010-05-04 8:49 PM Unless the battery has failed there is something causing a current draw on the battery. Sorry but can't agree here - if the battery has not failed, in my view, the liklihood of it not getting enough charge is greater than the liklihood of something being left on causing it to discharge? As I recall it failed the first night after an unspecified distance driven to a site and, as I see it, the drive there should have recharged the battery even if at only about the 10 amps that the wiring limits it to?
Lorrie Posted May 4, 2010 Author Posted May 4, 2010 Thank you for all the advice. We will have to look into them all. Unfortunately van is in storage and so only able to charge on mains if booked onto site. Solar panel had charged battery and reading was 13.7 earlier in the evening, after the day of sun. fridge is the auto select, so this could be the drain as I thought I'd noticed the gas igniting during the night.
Brambles Posted May 4, 2010 Posted May 4, 2010 Nah! Normal working battery will sit between 12.6 and 12.8 volts. When one of the cells starts to fail it is normal to see voltage after charging and settling sit at 12.4 volts. Self discharging of the cell will soon take the voltage of the cell down to Zero and you will get 10.5 volts. Any current drain at all and the duff cell gets reverse charged and you get below 10.5 volts and any low voltage alarms normally set at 10.5 volts will sound. The standby current for the panel and any other electronic controls could easily be enough to also drain the duff cell. If the voltage the night before had not been 12.4 volts then I would have suspected something else like a fuse preventing charging or some unexpected fault or otherwise load on the battery. Also temperature drop overnight could have an effect. The key to telling me the battery is duff is the 12.4 volts. A good battery even sitting at 12.4 volts through lack of charge would not have drained down to 10.5 overnight with minium loads for standby currents. So it is a duff battery! Edit- typos only.
Mel B Posted May 4, 2010 Posted May 4, 2010 Lorrie - 2010-05-04 9:01 PM Thank you for all the advice. We will have to look into them all. Unfortunately van is in storage and so only able to charge on mains if booked onto site. Solar panel had charged battery and reading was 13.7 earlier in the evening, after the day of sun. fridge is the auto select, so this could be the drain as I thought I'd noticed the gas igniting during the night. Hmmmm ... you didn't run out of gas by any chance did you? When we had a Rimor with an AES fridge freezer, if the gas ran out it would switch to 12v ... most don't but our van did (probably with it being Italian?), we had to be careful if our gas was getting low (that was before we got the Gaslow system). If it switched to 12v it didn't half gobble the power! As for the gas igniting during the night, that's normal for more modern fridges I believe with electronic ignition (either manual changeover or automatic, but excluding pizzo ones) - they only come on when the temperature reaches a certain level so they are a lot more economical on gas than some older type fridges.
Guest Tracker Posted May 5, 2010 Posted May 5, 2010 Yup - have to agree - on the information now available it does indeed sound like a duff battery! BUT - at the risk of getting boring - I would still take the opportunity to check all connections and fuses for cleanliness and security!
Caroline Posted May 5, 2010 Posted May 5, 2010 We have heard of simular problems, and this was caused by dusting the gas fire top where the dials are and knocking it on to blow air, this does not take long to drain the battery.
Guest Tracker Posted May 5, 2010 Posted May 5, 2010 Caroline - 2010-05-05 12:42 PM We have heard of simular problems, and this was caused by dusting the gas fire top where the dials are and knocking it on to blow air, this does not take long to drain the battery. Good thought! Been there - done that meself and not noticed for a week and as you say it does play havoc with the bettery charge level!
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