Charging batterys

Shouldn't be necessary, but ideally we'd need a bit more info please. What sort of dual battery switching system do you have (if any)?

If you have a smart solenoid or even a manual solenoid, then when you're charging (I'm assuming you're talking about using a 240v charger or a Christies charger etc), then the solenoid/smart system etc, will automatically have the starter battery isolated, so the charge will only be going into the 2nd battery.

If you have the 2 batteries permanently connected (eg: the 100 series cruiser's standard arrangement as I understand it.....or some blokes do the same thing if they have a Reefer fridge), then if you're charging one, you're gunna be charging the other one at the same time.

Hope this helps

Roachie

That completely depends on your setup, charger and vehicle, but in general terms if you have ANY electronics or computers on board to run or control the vehicle and unless you have a charger which is voltage limited to below 14.8v and spike suppressed then you should ensure that the battery you are cahging is isolated from the rest of the vehicle.
If your auxillary battery is isolated from the vehicles electrics at rest and there is no way that charging the auxillary will cause it to reconnect then its ok to charge it with any charger whilst connected.
It is far safer however to spend the bucks on a voltage limited, spike suppressed charger.

GaZZZaa

Hi there reelchippy, I would presume that you would have to so that you dont spike any of the electrical's (eg computer) You would have to do this to the main too if it happened to go flat. May depend on what the vehicle is, I have charged the hilux with the batt still connected but I dont have any computerised stuff to spike. have heard of people blowing up computers by doing this.Maybe I should be doing the same thing dissconect but worse case cenario is I could possibly blow up alternator of voltage regulator or possibly a fuse. All up I wouldn't run the risk. Dissconnect just to be sure. Regards Vitara

Sand Man,

your a leg end. Ive learnt more about car elcetrics reading your posts here than 1000 12v zaps under my bonnet !

Just though that needed to be said.

keep up the helpful posts and havagood xmas.

cheers
Rich

Some SOLENOID systems DON'T disconnect when you turn off the engine, the two batteries actually stay connected till the system reaches a 'low seperation voltage' then they seperate, so if you connected the 240v charger to the Aux battery, it may still be connected via the SOLENOID system and as you charge the Aux battery ... you may also be charging the Start battery, just a thought and is worth asking your solenoid supplier how the system works.
My Rotronics system works inderpendantly and you don't have this delema, the Aux can be charged independantly with the ignition off or the two batteries can be charged together by bridging the isolator bolts.

I wont debate the finer points with you Mate because that wont help readers that don't have electrical qualifications.

What I believe is important to point out is that basic solenoid systems may only link two batteries together. (in parallel) Nothing more.
They will charge at the same time and discharge at the same time.
When things are all kosher, this has the effect of providing one big battery that will last longer between charges than a single battery on its own. Now some people are happy with this cheap solution. (until something goes wrong)

But, when one battery kacks itself, it will drain the good battery until both are stuffed.

A "smart" Dual Battery controller will keep both batteries electrically ISOLATED from one another. They will both be charged by the vehicle alternator, the Primary (starting battery) first. To all other intents, they will operate independently of each other when supplying electrical power to devices connected to each battery's circuit. Other functions, such as switching of the secondary battery to start the vehicle if the primary battery fails, (by bridging as you call it) is not even in the least important. One can perform the same result by swapping the batteries over in an emergency, or using jumper leads to provide the bridging.

Now I know you actually know all this Mainey, but consider those with less electrical knowledge and how we can best explain the basics to them, to assist them in making the correct decision to suit their specific purpose.

Have a good one.

Thanks for the help guys the system is one i got put in by ARB Battery separator Model 1314 by Sure Power Industries.I got told that the car can only take the battery to about 80% so would like to get it to 100% before tgo on a trip.Thanks

Chippy,

YES! If you wish to provide a boost charge to the second battery, then you need to connect the charger to that battery, thus bypassing the Controller, the primary battery and anything that is connected to it.