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Daveg

Charging battery from garage wall socket

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Hi all 

 

My battery in situ was reading 11.9v  so I plugged it in to garage 2 days ago and its only reading 12.1 v now !! .This seems very  slow and I need to go away on Saturday .Is a charge always this slow from socket and would I do better by taking it off and connecting a battery charger direct ?

 

Thanks 

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You haven't said how you checked the battery voltage. Did you use a multi meter/ Did you let the battery rest for several hours after disconnecting it  so that you avoid reading the residual charge voltage)? It sound as though your battery may be pooped but, what voltage do you get from the battery terminals while its charging? If its not 14V (ish) then the charger is probably pooped.

Edited by Ern

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There are a few possibilities, but to track it down for certain requires time and/or money.

It is likely that either the battery, charger (or both) are duff.

To get away on Saturday I would buy a new battery now, make sure it is fully charged and continue checking (while away if necessary).

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Guys , Brand new battery > Checked voltage on the caravan display 

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If it was that low in situ I would take it out of the caravan and charge it separately on a battery charger

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1 hour ago, Daveg said:

Guys , Brand new battery > Checked voltage on the caravan display 

The caravan display is not suitable for a proper check as they are quite inaccurate. You need to use a multimeter and you must wait several hours after switching off the charger so that you measure battery charge state and not residual voltage. Also, If the battery is fully charged the charger will settle back to float charge at 13.4V.   if your battery is flat and the charger is working properly it will deliver over 14V. 

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May be a silly question , but do you need the main trip RCD switch on at the caravan fuse box to charge the battery ?

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YES

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4 hours ago, Daveg said:

Hi all 

 

My battery in situ was reading 11.9v  so I plugged it in to garage 2 days ago and its only reading 12.1 v now !! .This seems very  slow and I need to go away on Saturday 

 

Thanks 

 

Sounds as though you only have a trickle charger - NOT a battery charger.

 

More info for you HERE and look under BATTERY

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Our caravan display is useless and shows just over 12 volts when the battery is fully charged at 12.7 volts or so when checked with a multimeter. I treat it as an ornament.....

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13 hours ago, Ern said:

The caravan display is not suitable for a proper check as they are quite inaccurate. 

Speak for your own.  MY current Bailey caravan analogue meter is pretty well spot on.  As was the Swift Nordelectronica digital one that preceded it.  (However checking with a decent digital multimeter is always advisable before accepting the on-board meters.)

 

Voltages that low on a brand new battery means it's been pretty badly abused:  11.9V is almost certainly been completely discharged according to the table in 4.4.2 of www.batteryfaq.org  at our current daytime temperatures.

 

As decent enough digital multimeters are inexpensive nowadays, I'd recommend the OP consider buying one.   I'm keeping fingers crossed that the RCD (and caravan charger MCB) getting switched on will work and that the battery suffers no significant long term damage.

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Many batteries today use calcium and should be charged to 14.8v with a proper, modern charger

 

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Obviously people have different experiences of the on-board meters. I think it's inevitable it'll show a low reading as it's some distance from the battery and caravan wiring is not known for its over-engineering.....

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In order to measure battery voltage the power supply from charger and/or solar panel must be switched off. I do it by simply taking one lead off the battery for about 6 hours and using a multi meter directly to the battery. 

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