how to use a battery charger?

freek · Post by **freek** » 03 Feb 2007, 20:05

Hi,
Because I do not use my citroen cx gti turbo2 very frequently I sometimes use a battey charger to charge the battery. Used to classic diesel engines in the beginning I did not know that you have to disconnect the terminals before connecting the charger because of the risk to damage the electronic parts of the injection and ignition. Fortunately this never occured. The - terminal of the battery in a CX however is vey hard to reach. So what I do now to charge the battery is disconnect only the + clamp and connect the + clamp of the charger to the + terminal of the battery and the - clamp to the engine. Although this against 'the rules' I cannot imagine that this method is wrong. Or do I make a mistake?
Kind regards,
Freek

deian · Post by **deian** » 03 Feb 2007, 20:19

Personally i'd charge the battery by taking out, if you mean jump starting, then you must connect the (-) negative to the bodywork somewhere, thats the proper way of doing it.

Can I have your car, i'd a CX GTI like yours. He he, lucky boy you!

AndersDK · Post by **AndersDK** » 03 Feb 2007, 21:08

Going strictly by your description Freek - its certainly allright what you are doing.

Using a battery charger there is really only one rule to remember :
NEVER turn ON, or connect to the mains, the charger, BEFORE connecting to the battery.
Likewise, ALWAYS turn OFF or disconnect the charger, before removing from the battery.

You should NOT leave the charger connected UN-attended for days. Depending on the charger power capability, the battery voltage may reach a damaging level (beyond 14.5volts). This will cause the battery cell water convert into Hydrogen and Oxygen - leaving only the Sulphur acid in the battery. The acid then starts to boil out with very nasty results.

On my workplace, an electric lifter was left over the weekend connected to the charger. Nobody had checked the battery cell water level for weeks. We were all welcomed by a very UN-pleasant sulphuric smell

Recent "electronic" chargers have a simple electronic circuit to lower, even disconnect, the charge current, when the charge voltage reaches some 14volts. Thats all there is to it.

Recent cars are not "more sensitive" to damage from charging, unless insane battery charge levels are reached - i.e. when the battery is insanely overcharged to some 16-18volts or more. This MAY happen when an old style charger is left on for days, or the battery is weak/defective and have too high an internal resistance.

For jumpstarting, you ALWAYS connect the plus terminal first, as then there is no risc of shortcircuiting either battery if you loose grip of the charger cable during the job.
The minus terminal is ALWAYS connected as second cable, and ALWAYS directly on an engine part near the starter - on the car to help. This is to prevent any sparking near the battery if connecting on the battery pole on the helped car - as then any hydrogen from the helped battery may cause a very unpleasant blow up.

or as step by step :
1) connect first cable on helpING car battery PLUSpole.
2) connect this same cable to helpED car battery PLUSpole.
3) connect second cable on helpING car battery MINUSpole.
4) connect this same cable on helpED car engine block.

NOTE : even experienced DIY'ers forget that there is always a risc jumpstarting a car. Unburnt fuel from starting attempts may cause fuel fumes in the engine bay of the dead car. This can result in very severe blow ups when connecting the jump cables. Always take a deep breath and think over again, what you are about to do.

freek · Post by **freek** » 03 Feb 2007, 22:01

Can I conclude from your remarks Anders that when I follows these rules I can even leave the terminals connected to the electrical system of the car when I connect a charger? (I use an itelligent charger which switches to tickle charge)

Mandrake · Post by **Mandrake** » 03 Feb 2007, 22:15

As long as the charger is switched OFF when you connect and disconnect it from the battery terminals, there is no need to disconnect the battery from the car during charging... (IMHO)

The electrical system of a car is a fairly hostile environment which is subject to fluctuations between about 9v (during cold starting) and 14.5v (during alternator charging) so the electronics connected to it are suitably rugged.

Regards,
Simon

slim123 · Post by **slim123** » 03 Feb 2007, 23:14

If you do not use the car very often, why not invest in a battery manager? These things turn themselves off when the battery is fully charged and on again when it drops off, they can be left connected and turned on forever, with no fear of cooking the battery.

Just an idea!

Regards
Slim

alan s · Post by **alan s** » 03 Feb 2007, 23:57

Depending on where the car is kept, a common trick over here for rarely used cars is to connect a solar trickle charger to them, that way the battery is always kept full and I've never heard of one overcharging as they only trickle a very slow charge whenever the sun is out.
Car in garage and charger exposed to sunlight via a window will work well.

Alan S

AndersDK · Post by **AndersDK** » 04 Feb 2007, 00:56

freek wrote:Can I conclude from your remarks Anders that when I follows these rules I can even leave the terminals connected to the electrical system of the car when I connect a charger? (I use an itelligent charger which switches to tickle charge)

Yes.
You can leave this charger of yours connected to the battery.
This charger will not overcharge the battery.

The solar cell chargers AlanS mentions I believe has more or less disappeared from the market hereabouts. A couple of years ago we could find them at some £20, or the same price as a simple charger.
A solar charger would provide some 0.2Amps max, which is perfect as trickle charging. They are self limiting, as when the battery voltage is at some 14Volts, the solar charger can not provide any more charge current. Because the solar charger provides a max voltage of some 14Volts itself ...

alan s · Post by **alan s** » 04 Feb 2007, 02:24

AndersDK wrote:
freek wrote:Can I conclude from your remarks Anders that when I follows these rules I can even leave the terminals connected to the electrical system of the car when I connect a charger? (I use an itelligent charger which switches to tickle charge)
The solar cell chargers AlanS mentions I believe has more or less disappeared from the market hereabouts. A couple of years ago we could find them at some £20, or the same price as a simple charger.
A solar charger would provide some 0.2Amps max, which is perfect as trickle charging. They are self limiting, as when the battery voltage is at some 14Volts, the solar charger can not provide any more charge current. Because the solar charger provides a max voltage of some 14Volts itself ...

Maybe they're waiting for the Sun to come out again?

Alan S

Mandrake · Post by **Mandrake** » 04 Feb 2007, 02:48

AndersDK wrote:
freek wrote:Can I conclude from your remarks Anders that when I follows these rules I can even leave the terminals connected to the electrical system of the car when I connect a charger? (I use an itelligent charger which switches to tickle charge)
Yes.
You can leave this charger of yours connected to the battery.
This charger will not overcharge the battery.

I think you misunderstood the question - he was asking if it was ok to leave the battery connected to the car while charging it, rather than disconnecting the battery leads to the car first...

Regards,
Simon

jeremy · Post by **jeremy** » 04 Feb 2007, 09:19

The solar trickle charger is still available:

http://www.machinemart.co.uk/shop/produ ... terminal)

NiSk · Post by **NiSk** » 04 Feb 2007, 11:16

You will probably get away with charging a CX with the battery leads connected but i wouldn't guarantee that it doesn't do any damage to the electronics somewhere in the cars electrical system.

BUT the more electronic control systems you have in a car, the greater the chance is that one of them may be damaged by the charger if the leads are left connected. And modern cars have loads of electronic junk all over the place.

I do a lot of translation work for a famous Swedish truck/bus/earthmover/marine manufacturer and they emphatically demand the removal of the battery + lead before connecting an external charger. Otherwise no guarantee. The same applies to "help starter" chargers that can supply starting power if your battery is completely flat - DON'T. If you're really stuck, connect a good battery in parallel with your own.

//NiSk