Testing your battery
Hi all just got back from our first caravaning weekend and would like to test the battery.
I have a screwfix metre with loads of options and I've no idea what so ever. So could someone talk me through what I do.
Thanks in advance
Andy
Comments
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I'm in a similar situation, had my 110 ah battery 4 years, and it doesn't seem to be lasting/holding charge as long as it did. I can check the voltage, which I know is related to charge level, but how can I tell how many amp hours there are left and if its
failing? Can I test amperage?Thanks for any help.0 -
Hi Andy,
Not sure why you want to check your battery unless you have had problems or it is an old one but you cannot do a proper test with a meter as you need to place it under load and do a drop test on it and that will then tell you if it is OK. The only thing
you can check with your meter is the voltag, if it falls below 12volts quickly after a charge I would say it is knackered and You need a replacement but if you take it along to Halfords or your local caravan service dealer they will check it out for you free
of charge and let you know it's condition. The last thing I would add is to make sure your battery charger in the van is working correctly. Whilst charging the battery the battery voltage should be around 13.2 volts, hope this helps.!0 -
Hi the battery seems absolutely fine I just wanted to know how to test the battery sorted I would know
Take care
Andy
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So if I put the kettle on then the battery would be load bearing ?
Take care
Andy
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That would work only if it is a 12v kettle (unlikely) or you are using a normal 240v kettle from an inverter running on 12v (even more unlikely!). Most of the domestic equipment in your caravan will be supplied with "house" electricity through the EHU cable.
The battery is 12v DC and runs things such as (some) lights, radio, toilet flush. Only something like a motor mover will put enough load on it to find out how good it is, and then the battery might fail with the 'van in an inconvenient spot.Testing is actually dangerous so get someone who knows what they are doing to take the risk. Basicly they connect the battery away from the van to a device that measures the voltage while puting a great big heater element across it as well. Lots of power
goes to the heater and the voltage will drop. How much it drops and how well it recovers tells the condition of the battery. Not surprisingly, a battery can explode when doing this sort of test, so watch from a distance.0 -
Hmm I think I'll take you advise and take the battery to be tested
Take care
Andy
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..... You need a replacement but if you take it along to Halfords or your local caravan service dealer they will check it out for you free of charge and let you know it's condition. ...
I'd imagine you'd get a blank look at Halfords if you asked them to drop test a battery. And years ago when I bought a battery from a local caravan dealer and had problems with it, they had to send it away to be tested.
You need a proper old fashioned auto electrician
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..... You need a replacement but if you take it along to Halfords or your local caravan service dealer they will check it out for you free of charge and let you know it's condition. ...
I'd imagine you'd get a blank look at Halfords if you asked them to drop test a battery. And years ago when I bought a battery from a local caravan dealer and had problems with it, they had to send it away to be tested.
You need a proper old fashioned auto electrician
I agree, MM. Drop testing / heavy discharge seems to have gone out of fashion but is the only test worth doing to prove the state of the battery.
I imagine Halfords would drop test it by dropping it from a great height!
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Thanks for everyone's help
Take care
Andy
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Andy you don't say if you have a battery panel in the van - I came back to caravanning a few years ago from the era when there was almost no onboard 12 v! It took a while to get used to the control panel that showed the voltage etc. Now I find it fascinating
to watch the battery when not on electric hook up and using solar and inverter, but seldom check the battery now when using EHU. My battery was new last year and i have just checked it after an extended period away all on EHU and its in great shape.0 -
It's not just Halfords who have the current loading tool necessary for testing a battery's condition, your nearest tyre and exhaust centre will also have one - assuming that they sell battery's, which most do.
The C&CC have an excellent guide to leisure batteries
Perhaps one of the Mods could make it live. The pamphlet is also downloadable as a .pdf, We keep a copy in our caravan.
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I might have missed the point here but here goes:-
Switch meter on.
Select DC.
Press the 'Range' button 3 or 4 times (It's 4 times on my meter).
Clamp or touch probes on to the battery....observe the + and -.
It should read about 12 volts......if you get a silly reading it's probably the range. Tap the button and keep trying until you get a sensible reading.
12.5 volts plus is OK.
12.4 volts and below requires charging.
After charging it takes many hours to 'settle' and give a correct reading.
If I have not understood your original question....Sorry!
PS. It makes a lot of sense to check your battery on an add hoc basis.......a drop test should be the last resort which is normally not worth the bother!
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I think EJB that you may not fully understand the issues being discussed and which the OP didn't understand well enough to ask the question. What you describe is a simple voltage test which may well give a favourable reading eg 12.5V even though the battery
has lost the ability to support a load for a reasonable period, for example 85Amps for an hour or 85 hours at 1 Amp. In practice the discharge rate isn't linear, but my example will do. The discharge test which people are referring to is used to ascertain
the battery's ability to deliver and sustain a current loading (in Amps, not volts). Anyone planning to go off EHU for a few days, without a means of topping up such as a solar panel, could find themselves with a flat battery, sooner than hoped, despite having
charged it to above 12.5V immediately before departure If the battery's capacity in Ampere hours has diminished.0 -
Thanks for your advice Jenny.
Having made simple voltage checks in caravans and MHs for over 50 years it has never let me down.
I don't want to extend my comments any further as they are quite understandable and concise!
As a retired spark I don't need to make things too complicated!
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Our golf pro was keen to find a way of testing trolley batteries and asked my advice. In theory there are instruments that will do this but batteries are all slightly different and the tests are not reliable. in short, the method other pros use involves
a discharge test over a few hours using a resistance test bank. This is probably the best way as it simulates something like the actual conditions of use.I am not sure that a drop test is ideal for a leisure battery as it is not designed for this. It also needs expertise in interpretation.
A voltage test after charging, repeated over a week or so will tell you if it is holding charge for a short period (look to maintain 12.7 volts) other than that I have tried a 12 volt halogen bulb and plotted the discharge Voltage but it is trial and error.
I think that if you take the battery off the van then charge it with a decent charger like a Ctek, you should get an idea of how long it is lasting off EHU. Most Caravan chargers will not recharge a discharged battery properly when on EHU.
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Hi all
Thank you all for your comments however I am now more confused.
We are totally new to caravaning so please excuse my stupid questions.
We a have 2 berth sprite alpine with motor movers fitted and my main concern is after we have been on rallys will my motor movers still get our caravan on the drive so wanted to be able to test the battery
Take care
Andy
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Perhaps Andy you just go and do what you want to do and find out, but have a (borrowed) spare battery waiting at home just in case.
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If your car & caravan are wired correctly, your caravan will be charging while on your way home.
As jennyc suggests, even a battery showing 12.7 volts on the meter could still be on its last legs, it depends on how long it takes to discharge. Think of a mobile phone, when new, the battery will last longer than it does when it's 12/18 months old. Your
car's & caravan's battery is the same.Getting your caravan onvthe drive when you get home? You've always got your car
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Perhaps Andy you just go and do what you want to do and find out, but have a (borrowed) spare battery waiting at home just in case.
Surely this is the correct answer.
We had a case exactly like JennyC explained a fully charged battery showing a good voltage. Completely flat within an hour of being attached to the caravan. Simply solution buy another battery.
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Getting your caravan onvthe drive when you get home? You've always got your car
Not much cop when you want the van parked hitch inwards!
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If your worried about being able to get the van onto the drive, why not, with a fully charged battery 12.7 / 12.8 volts, run it up and down the drive a few times with the mover. Not onto the road or anything, in case you get problems. Our OK battery shows
12.5 to 12.6 after significant mover use and recovers to 12.6 to 12.7 after a few hours. It would still be good to do the same again. If yours is similar, I would say you will not have any problems if you leave the site with a charged battery.0 -
Hi all just got back from our first caravaning weekend and would like to test the battery.
I have a screwfix metre with loads of options and I've no idea what so ever. So could someone talk me through what I do.
Thanks in advance
Andy
Write your comments here...do what we did , we purchased a very good used second leisure battery off eBay 110amp less than £40 , it's always there fully charged & ready to go.
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Hi all
Thank you all for your comments however I am now more confused.
my main concern is after we have been on rallys will my motor movers still get our caravan on the drive so wanted to be able to test the battery
Andy
Write your comments here...
To try and un-confuse you, if that is a word ! How much power is remaining in your battery when you get home depends on how much you take out of it during the rally, the age and condition of the battery and how much manoeuvering you need to do when you get home.
A digital multitester set on 20 volts DC, (which is a letter V followed by a solid line above 3 dots) will give you a "rough" idea how much is in the battery. 12.7 or above should be full, 12.5v is 75%, 12.4v is 50%, 12.2v is 25% which for a mover is as good as flat.
As others have said, having a spare full battery at home will rescue you, if the vans battery if struggling when you get home.
Have a read about solar panels, there's loads of info on here. I have just come home from a Rally for a long weekend, my panel is a 40watt and with a reasonable amount of sun I came home with a full battery.
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If your car & caravan are wired correctly, your caravan will be charging while on your way home.
As jennyc suggests, even a battery showing 12.7 volts on the meter could still be on its last legs, it depends on how long it takes to discharge. Think of a mobile phone, when new, the battery will last longer than it does when it's 12/18 months old. Your
car's & caravan's battery is the same.Getting your caravan onvthe drive when you get home? You've always got your car
Write your comments here...
My caravan has 13 pin socket dose that mean it will charge the battery.
Take care
Andy
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My caravan has 13 pin socket dose that mean it will charge the battery.
It means "perhaps". The wiring in the car and in the caravan needs to be correct, complete and no blown fuses. I can't tell from here if that is the case.
The earlier 7-pin connectors were also meant to charge the battery but often were let down by someone skimping on the wiring.
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Hi all
Thank you all for your comments however I am now more confused.
my main concern is after we have been on rallys will my motor movers still get our caravan on the drive so wanted to be able to test the battery
Andy
Write your comments here...
To try and un-confuse you, if that is a word ! How much power is remaining in your battery when you get home depends on how much you take out of it during the rally, the age and condition of the battery and how much manoeuvering you need to do when you get
home.A digital multitester set on 20 volts DC, (which is a letter V followed by a solid line above 3 dots) will give you a "rough" idea how much is in the battery. 12.7 or above should be full, 12.5v is 75%, 12.4v is 50%, 12.2v is 25% which for a mover is as
good as flat.As others have said, having a spare full battery at home will rescue you, if the vans battery if struggling when you get home.
Have a read about solar panels, there's loads of info on here. I have just come home from a Rally for a long weekend, my panel is a 40watt and with a reasonable amount of sun I came home with a full battery.
Write your comments here...
Thanks for your help I've set my meter to the Voltage setting with the solid line and the 3 dots. At this point the meter showing 3 naughts
Do I test the battery now
Take care
Andy
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My caravan has 13 pin socket dose that mean it will charge the battery.
Take care
Andy
It will if your car's wired up to charge it
Plug your caravan into your towcar, get your multi meter & set to 12 volts DC as described above, put the probes onto the terminals of the caravan battery (doesn't really matter which way ... you'll get a minus reading if 4rse about face), get your better
half to start your car and the meter should show around 14 volts. If it stays at 12.7, and a rev of the car makes no difference, then your car's not wired to power your fridge or charge your caravan battery.0
