Girly question re battery chargers...

Azari

anotherbaldrick wrote: »

Will it hell , a trickle charger will not work on a totally dead battery. and you can totally drain a battery with an interior light that did not switch off in less than 2 days from full, a weary battery overnight/.

I really don't know where you get that idea from.

True, if you repeatedly deep discharge a non deep cycle battery it will lose capacity and eventually fail completely but it won't fail just because it goes dead once.

I know because, many years ago, I did completely discharge a car battery and it charged perfectly well using a very old trickle charger.

anotherbaldrick

Azari wrote: »

I really don't know where you get that idea from.

True, if you repeatedly deep discharge a non deep cycle battery it will lose capacity and eventually fail completely but it won't fail just because it goes dead once.

I know because, many years ago, I did completely discharge a car battery and it charged perfectly well using a very old trickle charger.

I did not say if the battery goes dead it will fail, what I said is that if it is totally flat you will not start the charge with a trickle battery charger . It needs a few volts of charge in the battery before it will start charging the battery. If it is totally flat a short boost charge at a garage will put some charge in then you can finish it off on the trickle charger. Your old battery must have still had some dregs of charge in it >

Azari

anotherbaldrick wrote: »

I did not say if the battery goes dead it will fail, what I said is that if it is totally flat you will not start the charge with a trickle battery charger . It needs a few volts of charge in the battery before it will start charging the battery. If it is totally flat a short boost charge at a garage will put some charge in then you can finish it off on the trickle charger. Your old battery must have still had some dregs of charge in it >

Unlikely as I stupidly left the lights on dipped beam from Friday afternoon until Monday.

That would have resulted in a battery that was totally without charge. And yet by Tuesday morning it was right as rain.

No doubt you will be able to provide a link that explains your contention but, until you do, I maintain that the battery was completely flat and still took a charge.

anotherbaldrick

Azari wrote: »

Unlikely as I stupidly left the lights on dipped beam from Friday afternoon until Monday.

That would have resulted in a battery that was totally without charge. And yet by Tuesday morning it was right as rain.

No doubt you will be able to provide a link that explains your contention but, until you do, I maintain that the battery was completely flat and still took a charge.

http://www.honestjohn.co.uk/forum/post/index.htm?t=54431

http://www.pistonheads.com/gassing/topic.asp?h=0&f=23&t=882479&mid=0

Gloomendoom

birkee wrote: »

No "Where on earth" about it.
I have a charger which will only work if it recognises a battery is connected. A flat battery is a 'brick'. (I do have two chargers)

Second point is, that it is better to maintain the onboard battery, than to overcome it with a jump starter. Are you going to use the jump starter all day, as you go about your business doing short runs?

Third point, is that short runs are battery killers. Back when dynamos were common, it was reckoned by experts, that the charge removed when starting the car, took 20 miles driving to replace.

Fourth point is, that a lead acid battery that has gone below 10.5 volts, will become irrecoverable fairly quickly. (days) A FLAT battery is a 'deal with it NOW' problem.

My authority on batteries?
Several years working in a battery testing laboratory evaluating all their characteristics.

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.

Kilty_2

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.

I'm pretty sure subsequent starts from the stop/start system are "soft" starts in some way. I don't know how it works though!

Road_Hog

pinkteapot wrote: »

Thanks all - from the sounds of it a jump start kit would be a better option. As I said, we've only had the battery problem once so it's not like we regularly need to charge the battery.

Nope, your best option would be, to not leave the car sat there for two weeks in freezing weather. It's okay to leave the car for two weeks in the summer for a holiday, but not during the freezing cold.

If this happens again, start the car up and run it for 10 minutes each day (but don't turn on all the electrics, just the radio while you're sitting in it). That sort of weather can kill a battery, your charger will do nothing for you. Your jump start kit would get the car going, but if you stalled the car (easier to do with a flat battery and embarrassing in the middle of traffic) you would not be able to start it without using the jump start kit.

Also, as you had no battery power, as soon as you slowed down/came to idle, your lights would dim and all electrics would start to lose some power.

Azari

anotherbaldrick wrote: »

http://www.honestjohn.co.uk/forum/post/index.htm?t=54431

http://www.pistonheads.com/gassing/topic.asp?h=0&f=23&t=882479&mid=0

Both of those links say that some chargers will not charge a flat battery.

I was never disputing that.

I was merely saying that some will and I know that because I've done it.

When I asked for a link I meant one that explains why the laws of chemistry (according to you) fail to operate if the battery is flat.

Kilty_2

Road_Hog wrote: »

Nope, your best option would be, to not leave the car sat there for two weeks in freezing weather. It's okay to leave the car for two weeks in the summer for a holiday, but not during the freezing cold.

If this happens again, start the car up and run it for 10 minutes each day (but don't turn on all the electrics, just the radio while you're sitting in it). That sort of weather can kill a battery, your charger will do nothing for you. Your jump start kit would get the car going, but if you stalled the car (easier to do with a flat battery and embarrassing in the middle of traffic) you would not be able to start it without using the jump start kit.

Also, as you had no battery power, as soon as you slowed down/came to idle, your lights would dim and all electrics would start to lose some power.

I'd still wonder about the condition of the battery - I left my car for 8 weeks last winter over the worst of the freezing temperatures and it started first time when I went back to it. And it was a Renault! :eek:

anotherbaldrick

Azari wrote: »

Both of those links say that some chargers will not charge a flat battery.

I was never disputing that.

I was merely saying that some will and I know that because I've done it.

When I asked for a link I meant one that explains why the laws of chemistry (according to you) fail to operate if the battery is flat.

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