Girly question re battery chargers...

Azari

anotherbaldrick wrote: »

Yes TRICKLE CHARGERS will not start a charge from absolute flat!
You can buy home chargers that are man enough to get charge going but not TRICKLE CHARGERS which is what the average owner has bought to keep his battery topped up ! Do your own research if you dispute it

You can keep saying that until you are blue in the face but unless you can link to some article that explains why the laws of physics and chemistry do not apply I'm calling BS.

It may be that you have encountered one or more trickle chargers that have some circuitry that stops them charging a flat battery but that does not mean they all do. Certainly the one I used didn't.

Strider590

^^ In completely flat battery (if left for some time) the plate's will be irreversibly damaged/sulphated, the reason you can't get an ordinary charger to bring these back to life, is that they need a damn good kick to get those plates cleaned up, usually a high voltage, high current pulse charge (to prevent overheating/explosion).

Even if a charger does this, the damage is usually too extensive and the battery may only be capable of half it's design capacity, ie a 60AH battery might only be 30AH.

It's like throwing a tonne of rocks into a swimming pool...... The water may be upto your "full" marker, but actually water capacity is drastically reduced.

It's false economy trying to bring old dead batteries to life.

Azari

Strider590 wrote: »

^^ In completely flat battery (if left for some time) the plate's will be irreversibly damaged/sulphated

I think the underlined section is salient here.

I wasn't talking about one which had been left some time.

shaun_from_Africa

Yes TRICKLE CHARGERS will not start a charge from absolute flat!

Some trickle chargers will not start a charge from absolute flat.

As far a a charger is concerned, a totally flat battery is seen as a dead short circuit and so the initial charging current will often far exceed the maximum that can be supplied by the charger hence the charger will either trip a manual safety cut out or an electronic sensor will detect that the current required will be too high and will not allow the charger to start its charging cycle.

One of the chargers that I use at work (on aviation batteries) is a trickle charger that can safely be used on totally discharged batteries.
This works by sensing the battery voltage (which will be zero) and then switching to a constant current charging rate of 1A until the battery voltage has recovered slightly.
Once this has occurred the charger will revert to its nominal charging current of 5A.

Moglex

shaun_from_Africa wrote: »

Some trickle chargers will not start a charge from absolute flat.

As far a a charger is concerned, a totally flat battery is seen as a dead short circuit and so the initial charging current will often far exceed the maximum that can be supplied by the charger hence the charger will either trip a manual safety cut out or an electronic sensor will detect that the current required will be too high and will not allow the charger to start its charging cycle.

One of the chargers that I use at work (on aviation batteries) is a trickle charger that can safely be used on totally discharged batteries.
This works by sensing the battery voltage (which will be zero) and then switching to a constant current charging rate of 1A until the battery voltage has recovered slightly.
Once this has occurred the charger will revert to its nominal charging current of 5A.

Trickle chargers used to avoid this problem by having a nice, chunky, low value, resistor in series with the transformer/rectifier that limited the current flow to something the unit could handle.

It's probably more sophisticated now and hence the problem some chargers have with completely dead batteries

cubegame

Regardless of the ongoing argument about battery chargers, the OP would be better spending her money on a new battery.

colino

Getting back to the point, the OP already has breakdown cover, had one isolated non-start a year ago and this is a money saving forum. The answer is don't go to any additional expenditure, make sure you don't run unnecessary electrics if your journey isn't long enough to recharge the battery and look forward to a mild winter!

MX5huggy

How about a simple set of jump leads? the OP has another car so can use them at home and on the street, if you stand by your dead car with a set of jump leads it does not take long to get some one to stop.

shaun_from_Africa

Gloomendoom wrote: »

Interesting, and I agree with all you say. Although, my wife's car has one of those stop start doo dahs. On a busy traffic day the engine (diesel) gets started twenty times or so on a twenty mile journey.

Some of the cars with "stop/start" have 2 batteries, one for normal starting and one for the stop/start mode. (My partner has a Volvo V50 like this and the 2nd battery is hidden dehind the front bumper and is almost impossible to get to).

Flyboy152

Azari wrote: »

It's almost instantaneous.

It's like jump starting with a small, very high power, battery.

But, if it isn't kept charged (which has the potential to shorten it life), it could take up to a half an hour to charge it enough to jump start the car.