Charging a car battey

[dazza]

How hard can it be?

The car has a varta battery which is about 15 months old.

Not moved the car for months as its stuck in garage have been turning it over now and then and letting it run.

Tried to start it the other day and it was as flat as a pancake.

Got the charger out (one of these auto ones) Charger shows the battery as full and went into recondition mode.

Left charge for a while and the battery was showing 1.5v.

Tried charging another battery and it showed the battery as full and switched off. Took charger back to shop did not tell them i had used it on the electrolysis tank for 3 days and got a new charger (this was a result as did not have the receipt and bought it about 3 years ago). They showed me the new charger working but when i connect it to the varta battery is shows full and switches off.

Connected it to another battery and it charges it fine. For now i have piggybacked the varta battery off the other battery which is charging.

Whats going on with this could the battery be nackerd? Or did the charger i broke mess it up. Or voltage too low?

 

[dazza]

After charging via the other battery for 30 minutes its now showing 11.6v. I've connected the charger to it and its charging properly.

 

[Robotstar5]

Some auto chargers don't like too low battery voltage and decide it's knacked so switch off, as you found out, piggy backing a decent one across it can get it started.

 

[dazza]

Some auto chargers don't like too low battery voltage and decide it's knacked so switch off, as you found out, piggy backing a decent one across it can get it started.

They also don't like being used for an electrolysis tank by the looks of it, won't use it again will have to find something else to use.

 

[slim_boy_fat]

Some auto chargers don't like too low battery voltage and decide it's knacked so switch off, as you found out, piggy backing a decent one across it can get it started.

A mate has a Kia Cee'd and occasionally [read 'often'] leaves things on, flattening his battery completely. If he connects his charger it won't accept a charge; what he has to do is piggie-back a former battery of mine [ex my BMW] which keeps good charge on its own - then his own will start to take the charge as normal. I think this is particularly the case with the new AGM type of battery, more than the wet-cell type we grew up with.

The battery I gave him must have been 7-8 years old.....

 

[DAPPH]

After charging via the other battery for 30 minutes its now showing 11.6v. I've connected the charger to it and its charging properly.

That was lucky ... a totally discharged battery with a voltage of less than 2 volts rarely ever can be recharged .
I lost two 110 amp 12 volt caravan batteries due to mains problems that unbeknown to us had tripped out the caravan on board mains breaker but not the house or garage electrics & over time the battery became totally discharged
Now I've set up an LED corn bulb in a plastic jar plugged in a mains socket inside the caravan to act as a mains on witness light that can be seen from out lounge window .

You're best giving a little use equipment a full top up charge at least once every four months just to keep the battery in good condition & de sulphated on the plates .
Better still if it is possible , is to disconnect the earth lead so the battery has no form of equipment drain upon it , but with modern electronically controlled cars this option is not normally available .

Thanks for this post too you've also reminded me to look in the diary . I see my small Honda 2.2 kva pure sine wave genny is due for a battery recharge & ots five monthly test run .

 

[Robotstar5]

They also don't like being used for an electrolysis tank by the looks of it, won't use it again will have to find something else to use.

Have you tried leaving a battery in circuit as a "buffer" for electrolysis?.

 

[dazza]

Im surprised it got that low as it started it a couple of weeks ago. Does the recondition mode drain the battery then recharge?

 

[dazza]

Have you tried leaving a battery in circuit as a "buffer" for electrolysis?.

I piggy backed it off the battery it worked for 3 days then it started saying battery full and switching off. Think i cooked the voltage sensor as it was tested on 6 batteries in the place i bought it from and said all were full, the new charger worked on all but one of them.

 

[Robotstar5]

That was lucky ... a totally discharged battery with a voltage of less than 2 volts rarely ever can be recharged .
I lost two 110 amp 12 volt caravan batteries due to mains problems that unbeknown to us had tripped out the caravan on board mains breaker but not the house or garage electrics & over time the battery became totally discharged
Now I've set up an LED corn bulb in a plastic jar plugged in a mains socket inside the caravan to act as a mains on witness light that can be seen from out lounge window .

You're best giving a little use equipment a full top up charge at least once every four months just to keep the battery in good condition & de sulphated on the plates .
Better still if it is possible , is to disconnect the earth lead so the battery has no form of equipment drain upon it , but with modern electronically controlled cars this option is not normally available .

Thanks for this post too you've also reminded me to look in the diary . I see my small Honda 2.2 kva pure sine wave genny is due for a battery recharge & ots five monthly test run .

What about a low voltage alarm?, first ebay hit or build you own here

 

[dazza]

What about a low voltage alarm?, first ebay hit or build you own here

I have a low voltage cut off for all the extra bits i added in the boot and dash cams. I have a feeling that the battery was not dead (noticed the - lead was very loose and removed it without a spanner). Connected the battery charger which showed battery as full then went into recondition mode (dont know if this drained the battery).

 

[Robotstar5]

I once saw a "clever" trick at a used car lot (the type with cars for a couple of hundred quid with a bit of MOT on them) one car had a flat battery so the guy brings another battery out, turns it upside down and jams it on the car battery so the terminals touched to get it started

 

[johnik]

i have a charger that is prob as old as me ,it charges even dodo dead batteries,the new "smart" ones dont like dodo,s so go and have a sulk.
might be worth seeing if an "old boy" in your area has an old low tech one you can borrow.

 

[Robotstar5]

i have a charger that is prob as old as me ,it charges even dodo dead batteries,the new "smart" ones dont like dodo,s so go and have a sulk.
might be worth seeing if an "old boy" in your area has an old low tech one you can borrow.

I've got an old metal cased one inherited from my dad that will charge anything, it even has little shorting plugs you move round to select 6/12V and low-med-high charge rates

 

[Cobbler]

I once saw a "clever" trick at a used car lot (the type with cars for a couple of hundred quid with a bit of MOT on them) one car had a flat battery so the guy brings another battery out, turns it upside down and jams it on the car battery so the terminals touched to get it started

Sometimes if you've got a knackered battery, if you turn it upside down & shake it, it will hold charge again. You redistribute the sediment that shorts the bottom of the plates out.

 

[gavcarter]

Apparently ( I've never tried and don't recommend you do) hitting it with an arc welder for a few seconds puts enough current into it to dissolve some of the scale on the plates inside the battery and helps the battery hold a charge again.....

 

[pedrobedro]

Round at the bike shop there is a start and charge and if you boost a knackered battery with 24v till it starts to fizz then drop it back to 14v it sometimes resurrects them. I salvaged one for my Honda and got another 14 months out of it. It fizzes the sulphate off between the plates and as long as they are not buckled and touching it will go again.

 

[gavcarter]

Possibly the same principle as hitting it with an arc welder, as cheap buzz boxes are A.C. I assume this would clean the lead plates a bit better? Or corrode them to nothing if you did it wrong?

It's not something I would fancy trying to be honest, easier to get a new battery lol

 

[johnik]

I've got an old metal cased one inherited from my dad that will charge anything, it even has little shorting plugs you move round to select 6/12V and low-med-high charge rates


blue hamerite with an ammeter in the middle ?

 

[gavcarter]

I've got an old metal cased one inherited from my dad that will charge anything, it even has little shorting plugs you move round to select 6/12V and low-med-high charge rates


blue hamerite with an ammeter in the middle ?

The ones where if you forget the battery is on charge you walk back into the kitchen to a horrid smell of eggs and a very hot bubbling battery containing about 19.volts.....