General How to charge battery

[greylag]

Years ago I was always taught to disconnect the battery, loosen the filler caps and connect the charger.

On my motorhome the battery it is almost impossible to disconnect both terminals, short of asking the local garage to fit a new battery.

My brother said he never disconnects the battery to charge it, he just clamps on the charger and leaves it.

I will attempt to jump my van today and leave it running, but I know it will need a good charge.

Any info appreciated.

 

[CDK]

Your brother is right!
The alternator can produce charging currents up to 50 Amps without damage to the battery or connected circuits. And batteries with removable filler caps are a rarity.

 

[greylag]

CDK

Thank you so much!

Regards.

 

[corcai]

Years ago I was always taught to disconnect the battery, loosen the filler caps and connect the charger.

Years ago chargers were mostly unregulated sometimes even unregulated AC. As the current dropped the voltage rose to battery boiling levels. Even more modern chargers often had a fast charge switch that would switch the charging voltage to 16.5+V which will also boil a charged battery and cause a valve regulated battery to vent.

Modern chargers are typically microprocessor controlled and won't overchare a batttery many digital ones won't even attempt to charge a flat battery if the voltage is below 8v. Modern dumb chargers are typically very conservative with the charge voltages so nothing to worry about.

Be aware that if you've left your battery flat for the winter then you will have sulfation of the plates which will reduce the capacity of your battery and if you've left it flat for several months it is likely scrap.

 

[greylag]

Many thanks for your reply.....I fully expect to replace the battery. I will return to the van to check how the charging is going in a couple of hours.

Kind regards.

 

[Ocwobio]

Hi,, I just replaced the battery in my Burstner a class, looked like (and was seen mention on the net as) a real pig of a job, needing dash panel top off and accessing it from inside. In the end, did it from the front in about an hour- way less than expected. I tried charging it twice, it appears it died in storage, was healthy in October, but died by end of Jan. Looked like the original battery from 2005. I always just connect the charger to the battery in any vehicle, and have no problems. That said, after the new battery was fitted, I am left with the abs and handbrake wrning light on, so maybe there is something to be said for disconnecting a battery whilst charging- but I doubt it. This fault is likely cuased by the drastically low voltage on the dud battery. They may go out after driving it but it is sorn and in storage. It might be there is a socket inside your vehicle for charging, there is one under the drivers seat in mine (05 Burstner i821) and IIRC it connects to the engine battery, and can be used to connect a charger, but it needs a special plug. If you can get the leads on the terminals, just go for it, and make sure they are well connected and can't short out, the key to battery health is voltage readings, monitor it when taking off charge, see if or how fast it drops. it doesn't need to drop much below about 13v to cuase problems. Mine went to 10.7 in 2 mins. with 2 attempted starts (waste of time of course, just clicks and buzzing from relays, when abs possibly thought there was a fault during self test i.e. low volts). What model is yours?