How to charge a car battery?!

cyclonebri1

I think Strider mentioned an "optimiser"?

The answer is the Optimax charger, all bikers ande kitcar blokes use the for stuff that is only used for the summer months, It's a clever charger that cannot over or undercharge the batt. Invest if thats your usage, well worth the £60 ish.

cyclonebri1

[QUOTE=Strider590;35003669 the voltage can be 12v but as soon as you try to start the car it's incapable of supplying the cracking current to turn the engine over.



QUOTE]

Plus the voltage of a healthy 12v battery will read something like 13.5 at rest, at 12 it is under charged or rapidly losing charge.

Sorry, should have combined those 2 posts

cyclonebri1

Strider590 wrote: »

Happened to me..... Charged my battery over night, reconnected it in the morning, tried to start it 5 min later and it was like a bomb going off..... It sprayed acid all over the front wings, the garage door and the windows at the side of the house. The engine bay had to be hosed out to prevent acid corrosion and the paintwork was ruined.

Looked something like this...

Mate of mine was a plant fitter, no not a gardener but the bloke that fixes JCB's, Euclid's etc.

Their start up batteries are massive and still utilise the glass ball bearings that seal the cells in the event of an overturn.

This day he had a machine in the shop. They had been doing welding work in the engine bay and he was laid over the batteries. He got up to go get a spanner and as he turned his back the whole battery assembly exploded and sent these 3/4" glass balls like musket balls through the corrugated tin roof :eek::eek::eek:

New under keks required at least.

Lulu58

cyclonebri1 wrote: »

The answer is the Optimax charger

Thanks for this and your other post cyclonebri1. The CTEK charger I have does something similar to the Optimax I think, ie it charges the battery then switches off and monitors the voltage. As and when it drops, it switches back on. It does not keep charging or giving the battery a continuous trickle charge.

Re your other post, my battery shows around 13.5 when resting so I'm hoping that means it's quite healthy despite the problems I've had over the past few weeks.

Lulu

sassy_one

Just a little bit of extra advice to anyone else considering changing there battery, specially as winter is coming.

Most modern cars now use the ECU to set the best operating and running of the engine, when you disconnect the battery power to the car (ECU) it will lose it's memory.

It will auto re set it's self, after between 10-20 miles of driving

benham3160

Strider590 wrote: »

, this ignites the hydrogen gas and BOOM your cars covered in battery acid.... 30 minutes later and your paintwork is soft to the touch down to bare metal.

As somebody who's had a "facefull" of battery acid it is not a pleasant experience. Lots of time spent in hospital.....

Regards,
Andy

sassy_one

benham3160 wrote: »

As somebody who's had a "facefull" of battery acid it is not a pleasant experience. Lots of time spent in hospital.....

Regards,
Andy

Hope you made a full recovery

skiddlydiddly

I have this image of ECU's with alzheimers.So what does this big lump under the bonnet do again?

bigjl

I got a good charger from Halfords years ago, has saved many batteries after they have run flat through leaving lights on.


Sassy one said "

Just a little bit of extra advice to anyone else considering changing there battery, specially as winter is coming.

Most modern cars now use the ECU to set the best operating and running of the engine, when you disconnect the battery power to the car (ECU) it will lose it's memory.

It will auto re set it's self, after between 10-20 miles of driving "

Sassy one is correct on that, loads of cars have ECUs that adapt to driving styles. They can sometimes be optimised for performance by carrying out a procedure called, I think, revalidation, this was done to my Subaru Legacy Auto after I took it to a mate that is an autogearbox specialist as it was always sluggish to pull away from a standing start, the ECU had been changed and reprogrammed by Subaru UK several time before. He test drove it, did his little trick to fool the ECU into thinking it was being driven more agressively than I would usually drive it, and it became noticably better.

The procedure involved starting the engine then turning the engine off, putting it into, from memory, neutral, pressing the throttle to the floor for 20 or 30 seconds, then switching off the ignition whilst keeping the throttle down on the floor. Then taking your foot off the throttle, restaring the car and drivng as normal. Whenever the car got hesitent in the futre I did this same procedure.

I have to admit I was a little bit dubious, but it worked so who am I to say otherwise. Not all cars will be the same though I would suspect. I am no engineer or specialist in this field, but many ECus used in highend cars also have this learning function, and I have known some minor running faults after sensor problems to be sorted out by disconnecting the battery and in so doing resetting the ECUs memory to factory settings.

cyclonebri1

Which why we always slave a 12 volt fire or burglar alarm batt accross the battery leads before the main battery is removed. This provides a background voltage for the ecu, radio etc stopping coded loss, ;)