Charging and using batteries at the same time

[fullthrottle]

Hi All

If I have 2 x 6volt deep cycle batteries connected in series, I can charge them with a 12 volt charger no issues.

Now can someone tell me, could I leave the charger connected to them continuously, while I am also drawing from the batteries to power various devices? Like when you plug your cellphone in and can still use it.

The aim is that while off-grid, all devices are powered by the 12volt supply. Then when I roll up to a campsite and plug the mains in, the charger will start to charge the batteries, but I can still use the 12 volt devices.

I don't expect the charger to keep up with the discharge rate in some cases where power hungry devices maybe in use. But while I'm sleeping, or the devices are off, the charger will do its job.

I have read that the chargers produce a DC ripple and can stuff some more sensitive devices. So maybe a filter in-line from the battery to the devices is required??

Cheers

[kbjj]

Two 6v leadacid batteries the same, and in the same condition in series, with a 12v charger is fine. They are made up of seperate cells in series anyway.

I use a 12vdc leadacid on a 230vac style charger when charging the kids 7.2vdc nicads, and temporary outdoor led lighting with no probs to date.

I havn't heard of the 'dc ripple' being a problem on some devices before (while charger is connected to a battery), and am a wee bit surprised as the battery is acting as a bloody big capacitor to smooth said ripple. Most cheap 230vac style chargers have pretty crude rectifier set ups and will have bad 'dc ripple'

Hope this helps
Jeremy

[ChurchurDan]

The problem is in the way the charger works. Assuming it is a smart electronic charger the answer is no you cant. A smart charger will detect the load applied to the batteries and think they are discharged so it will switch back to a high charge rate. If you are constantly turning loads on and off the charger will stay in a high charge rate and over charge your batteries as it will never get into its float or maintenance modes.
If you want to charge them while in use you will need a specific charger designed for caravans and motor homes, these normally are hard wired to the battery and have the load attached to them instead of being connected to the battery so they can monitor battery condition and load applied.