I have two newer chargers a Shumacher Smart Charger and a Harbor Freight one. BOTH cannot charge a discharged battery. When I called them they said there needs to be some capacity left in order for the charger to know that a battery is connected. I said "what do people use chargers for? Charging dead batteries? Right?" They said there is usually some charge left....I said no....interior lights were left on for a month. So they tell me I have to connect a dumb old style charger up for a few minutes then switch to the "smart" charger. I said that was dumb not everyone has an old charger. I do...but most don't. He then went on to say you could connect jumper cables and charge from another vehicle. Why is it too much to ask that a battery charger can charge a discharged battery?? Some junior engineers need to be fired for designing this crap......
Well I bought a "dumb" Schumacher at Tractor Supply recently. Not the top model at $289.00 but the next one down at $259.00. They visually look identical. Reading through the description I could see nothing to differentiate the two. Threw it in the trailer just so I'd have something at the track. Hooked it up for the first time the other day and I guess I found out what the difference was. This thing doesn't have a battery tester, only a charge meter when charging. Two of them actually but no tester! I'm not talking about a load tester either. Just a meter that shows the output of the battery. I guess my eyesight is getting to the point that I need to take my cheaters shopping with me... Why is it too much to ask that an expensive battery charger has a battery meter on it??
Too funny (sorry). I’m an electrical engineer. That’s a typical answer from a desk jockey. Plus this newer stuff is sometimes too smart for what needs to be done. And they gotta Cover there Butts. But on a serious note, there does have to be some level of charge in the battery to take. If it’s fully dead (shorted inside), it could be dangerous. If you have a meter, measure the voltage. If it’s not zero, then it may take doing it the old school method and get some type of charge to it before the smart charger recognizes it and takes over.
Sometimes, you can turn on the parking lights with the charger on. It may allow the charger to start charging , at least it does on my 20 year old stupid charger. Some of the AGM batteries, like the Optima, depending on the type of charger, may require a battery connected in parallel with the dead battery to take a charge.
Had this discussion with my Snap on rep the other day, so stupid, it's a jump box its whole purpose in life is to jump off dead batteries,...but only if they are just weak enough to not start the car but strong enough to run everything else,..makes perfect sense,..idiots
Been there; done it just like that on AGM and flooded types. Ran it up a bit on the "dumb" normal type charger (even had to fake this one out a bit); then switched over to a BatteryMinder for about a three week dose of reconditioning.
Yep, I have to use a jump box to start the car, let it run for a bit, then hook up the “smart” charger. I wish I had been smart enough to not have given away my old dumb charger. This also is why I will never buy an Optima battery.
I think the same principle applies to cordless drill batteries. I have a DeWalt that sat under the back seat in my truck for so long that the battery was completely dead. When I put it in the DeWalt charger I got the "Bad Battery" code. Jumped the two terminals in the drill battery with wires from a 12 volt car battery for about 5 minutes. I guess that put enough juice in it and then the DeWalt charger would charge it. Been fine ever since.... Brilliant!!
This is why I will never get rid of my trickle charger 6 or 12 volt. I have brought back from the dead more than a few Optima batteries. Cliff
I have the small Battery Tender Smart Chargers and they always do exactly what they are supposed to do. Keep a charge on the battery and they do it flawlessly. They have even charged discharged batteries for me but it just took a while. I have an old Die Hard Charger to actually charge batteries. Trickle charges overcharge things. No thanks.
Yeah, I check my battery last night...Measured 9V and the battery tender charged it right up. I've used power supplies to bring batteries back to life if their too low for their chargers. Just have to limit the current and wait.
Thinking of Jump Box. Is there any way to bring them back from the dead? Seems for the cost of these things they'd last much longer
I also have a Sumacher smart charger. I have never attempted to attach it to a totally dead battery, but I keep my almost 55 year old dumb, made-in-USA trickle charger for just that eventuality
Many times, a completely dead battery will not come back. Crap shoot. I don't think you can fault the charger. Briz, jump boxes usually have a replacable battery inside them. I have n old booster pack I bought 20 years ago that still works great (99 bucks), but my 300 dollar cornhole one died after 3 years.
I'm not talking about old dead batteries.....just one that lights were left on or slow discharge over winter. You could have a brand new battery die if interior lights were left on over night. Was working on a Saab 9-3 and if you leave the key in the ignition in OFF position it will kill the battery in a couple days.
Even the recondition function on mine wouldn't work if totally discharged. I've got 15 old cars and 5 old boats and a dead battery is not an uncommon occurrence....if battery is not disconnected.
Ran into this awhile back with the scooter battery - here's the trick to using these "smart" chargers with a severely discharged battery... Hook up a second battery in parallel (positive to positive, negative to negative) that you know can be recognized by the charger, with the bad battery, and attach the charger. After the charger has a while to put some current back, disconnect the good battery. It may take a time or two to get the charger to stay running.
Also on the Schumacher digital chargers there is a way to force it into charge mode by holding 2 buttons down at the same time you plug it in. A tech at Schumacher told me about it but I forgot which buttons...duh, Of course they don't put it in the instructions.....
