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I have 2 secondary batteries both 110 amps , when charged through the normal channels ie on board charger ,the charge is retained ,two days of very frugal use the batteries can go as low as 7.7 volts (both new batteries) , and even after 300 mls of travel this voltage as not increased.

I have checked the charger with a meter and a voltage of 13 .4 is being outputted , probably 12.75 volt reading at the batteries ,the cab battery is fine and recieving a charge from the alternator when checked with a meter.With the engine running at any given time the secondary batteries are not showing a charge from the alternator.

should such a set up give power for more than 2 days of very frugal use ,

and should the alternator be providing a charge albeit small to these batteries also is it possible that the batteries could be being drained by such as a radio , the reason being that Brownhills rewired the radio through the leisure batteries because when wired through the ignition it use to go off after 20 mins.

As I have already stated on previous threads my vehicle is a swift sundance 2.3 600 s 2006 model 15000 mls. :D

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If the batteries are going as low as 7.7volts they are goosed and will not charge up.:-(

There should be a charge from the alternator when the engine is running if you do not have this either the relay or the fuse supplying the charge is faulty. The fuse or relay may have been disconnected when Brownhills were rewiring the radio to enable them to work safely this would be my first port of call. The charge should not be minimal and over a 300 mile trip the batteries should be well charged.

I have one 110 amp battery and find this can last me 3/4 days normal use.


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Something is badly amiss!


With the engine running the batteries should be aiming for about 14 volts from the alternator derrived split charging. This system is quite simple. There is a standard automotive type relay somewhere in your van that energises only when the vehicle alternator is charging. When this relay is energised its contacts join the positive of your leisure battery to the same positive output of the alternator that connects to the starter battery.


More here. http://www.motts.org/SPLIT%20CHARGING%20SYSTEM.htm



This would be the first thing I would sort out.


Then I would look at your charger as it should also settle around 14 volts after a couple of days on charge. Depending on the technology of the charger the voltage may go as high as 14.4 volts but should then fall back to about 13.8 volts.


None of the voltages you mention are adequate to put any meaningfull charge into the batteries.




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As Docted said if they are down at 7.7 volts the only place for them is the tip. A fully discharged battery should still read at least 10 volts.


13.4 volts is not enough to fully charge a battery as Clive says they should be charging at about 14.4 volts a fully charged battery off load after being left to rest for an hour after charging should read 13.2 volts.


You may have one battery with a couple of short circuit cells as they are in parallel this would pull the voltage down and overload the charger. I suggest you check each battery individually if possible on a different charger, also if they are the non sealed type check the specific gravity of the cells.

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