Re: Not sinking, but still not cold

Uncle Marvo wrote:
In 1150728875.337750.138580@xxxxxxxxxxxxxxxxxxxxxxxxxxx , Gibbo wrote this,
allegedly :

Uncle Marvo wrote in another thread which was really about sinking boats
so he started another one (hopefully):

Anyone know where I can get rid of 200 metres of 4mm cable?
100metres black, 100 metres red. Cheap.


How long is the cable run from batteries (or fuseboard or whatever) to
the fridge?

Not that long, maybe 3 fathoms or so, and there's no appreciable voltage
drop. The cable that's already there is fat. There is another problem, that
being that the battery isn't charging properly from the charger.


How do you know? And if this is the case, is it becasue the batteries
are not accepting a charge properly or is it because the charger isn't
charging at a high enough voltage? The charger should be getting the
batteries up to at least 14.2 volts. Anything lower will take forever
to get a decent charge into them.

Oh well, I
was going to get rid of the noisy thing anyway.

I think the big problem is the batteries, they are Varta (spits)


Varta actually make good batteries, but they are not known for making
deep cycle batteries. Mainly engine start batteries, which last about a
week when deep cycled.

and they
have a logo on them which says Pb and has a picture of a dustbin. I assume
that either means you're not supposed to put lead in the dustbin, or they
are fit only for the dustbin. 110Ah, times 3, quite new. Or were bought
quite recently. However, the suspicious thing is that the labels have ALL
been scratched off near the top, probably where the sell by date was, so
some sneaky battery salesman has perhaps pulled a fast one. There are part
numbers and stuff all over them, which I have written down,>

Maybe you should have written them here?

but I think the
word Varta is probably enough to determine that they are not very good. They
are obv lead acid and so might need some lead in, or acid, but that means
undoing the string that the previous incumbent used to tie them to the
engine with.

I measured the voltage at the batteries (12.1) and the fridge (12.1) and the
fridge with the compressor running (12.1)


Now I can hazard a guess here that this means they were at roughly 45%
charge status at that time. Don't ask how, cos it isn't possible, but
I've done it anyway.

then went to the pub.


Good move.

When I came
back several hours later, the batteries/fridge were measuring 10.4,


They are now flat as a pancake. In several hours, with the fridge and
not much else, this implies knackered batteries. Probably a result of
deep cycling engine start batteries.

the
charger was making its usual din,>

The charger should have kept up with the fridge, This implies charger
ast too low a voltage, or cabling problems to the batteries.

and the boat opposite was full of drunken
midlands girls


This sounds promising.

so I started the engine to get rid of them.


Are you insane?

After half an
hour it measured 12.1 volts again,


It should have been higher.

and the pie was cooked. I suspect I
dislodged the charger croc-clip while I was mucking about earlier.

This morning, batteries having been "on charge" all night, the fridge was
flashing its light and the bacon had gone off in the heat, so things are
getting more urgent.


Something amiss with the charger.


I might do some work today.


Me too.

Gibbo

.

Relevant Pages

  • Re: Electrickery on the new boat
    ... subscribe to the vew that cheap batteries replced rather more often is ... domestic batteries to low voltage trip point overnight. ... Firstly, in my experience, fridge bleeping is more often caused by ... If you keep your eye on the voltmeter, you don't need a charge warning ...
    (uk.rec.waterways)
  • Re: More Battery Recharging Questions
    ... >>Golf Cart batteries tend to be fairly high impedance so the bulk phase ... Deep cycle batteries are not built like car batteries and do ... I installed a larger than stock charger. ... The reason for the voltage rise is ...
    (rec.outdoors.rv-travel)
  • nb Virgo
    ... Among the other things I now know is that the fridge is a 12 volt one and keeps going OK overnight when we moor without flattening the batteries. ... Following the previous responses to my questions I am a little confused by the suggestion that one needs a ginormous battery charger. ... Surely this is only the case if there's a heavy drain on the batteries when the engine isn't running and when there's no shoreline mains supply. ...
    (uk.rec.waterways)
  • Re: Is this the right way to charge a battery?
    ... I want to make a charger for them. ... |> Does anyone know of a schematic for these 7.2 AA packs? ... Your circuit offers only current control using the 7805 Voltage regulator, ... unless the batteries are abused. ...
    (sci.electronics.basics)
  • Not sinking, but still not cold
    ... being that the battery isn't charging properly from the charger. ... I measured the voltage at the batteries and the fridge and the ... back several hours later, the batteries/fridge were measuring 10.4, the ...
    (uk.rec.waterways)