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Old August 3rd 17, 07:02 PM posted to uk.rec.motorcaravans
Whiskers
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Posts: 17
Default Leisure battery flat

On 2017-08-02, bert wrote:
In article ,
Whiskers writes
On 2017-08-01, bert wrote:
In article ,
Whiskers writes
On 2017-07-29, Roy wrote:
Whiskers wrote on 28/07/2017 18:19:


[...]

You need to check the spec for current (or power rating) and power usage
but the consumption should be fairly low so 75AH should be OK. Does your
fridge have battery monitoring? If so do a "suck it and see" test.


The dealer said the fridge would flatten the battery in 8 hours. It did
) He didn't warn me not to do that. I'll have to dig out the
literature that came with the fridge - I think it's packed into one of
the storage spaces in the van at the moment.

It has no connection to the bottled gas that makes the cooker
work. It doesn't run off the engine-starter battery either.

Maybe not directly but when the vehicle engine is running it will be
charging the battery supplying the fridge which is effectively the same
thing.
6W solar battery chargers are a waste of time IME.


They're sold as 'battery conditioners'; I think the idea is that they
keep a charged battery topped up rather than charge it from flat. A
couple of sunny days did get the charge indicator up from 'flat - red
LED' to 'almost flat - amber LED' but it dropped back to red as soon as
the solar panel was disconnected. There was enough charge to run the
cabin LED strip lights for a short while.

I had a similar one. Didn't produce anything except in bright sunlight.
They should have a diode in the output circuit to prevent the battery
discharging back through the charger when its output falls.


The one I have says it's safe to leave connected overnight. We'll see!

Leisure (deep cycle) batteries are more resilient to discharge than
normal auto batteries so you may get away with it.


That was what I thought.

Charge it up and
leave it disconnected for 24 hours then measure the voltage. Should be
12v. N.B. some modern chargers will not actually work on a totally flat
battery. Alternative is to put it in the campervan and go for a drive.
75ah (same as mine) is adequate unless you are a TV/computer addict.


Any idea how long a drive? 20 miles doesn't seem to have been enough,
but that was in slow moving stop-go urban traffic.

Alternators are capable of charging even when idling. If you don't have
a charger you could take the battery to a dealer and they will test it
for you.


I've got a new 70Ah unit from Halfords (their 115 Ah units are too big
for the compartment in my van) so things are working now. I used a
multimeter to check the old battery and it registered only 2.3 volts,
after going for a drive, so I decided to replace it.

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