2 dead car batteries, not charging

Status
Not open for further replies.
C

cutchemist42

Joined
Mar 28, 2011
Messages
127
Location
Winnipeg, Canada
So I have two cars I don't always drive but keep around. I always unplug their negative wires when not in use. Usually when I do need to start them up again, they are fine and charge up easily. This time though, the one car did not charge up at all. No sparkage or anything. Went to go try it on the other car and that one as well did not charge up either.

So what should I do to test if its the batteries or charger? I have a multimeter.

Thanks!
 
how long have these batteries been sitting unused? And what does your meter say the voltage of the batteries are now? What kind of charger do you have, as in how many amps does it put out?
 
You need a trickle charger or a proper battery charger. Letting the batteries go dead can kill them.
Also car alternators are not made to charge dead batteries.I put mine on a 2 amp charge every two weeks while sitting.
 
removing the negative cable stops the current draw to the car computer & radio, but does not stop sulfation from occurring.

the only thing you can do is put a trickle charger on the battery and keep the current flowing.
 
Originally Posted By: EricF
removing the negative cable stops the current draw to the car computer & radio, but does not stop sulfation from occurring.

the only thing you can do is put a trickle charger on the battery and keep the current flowing.



I agree with the above statement.
 
Originally Posted By: cutchemist42
So I have two cars I don't always drive but keep around. I always unplug their negative wires when not in use. Usually when I do need to start them up again, they are fine and charge up easily. This time though, the one car did not charge up at all. No sparkage or anything. Went to go try it on the other car and that one as well did not charge up either.

So what should I do to test if its the batteries or charger? I have a multimeter.

Thanks!


Charge up both batteries with a plug in charger. If possible do a load or conductive test if you can get hold of the meters. To test charging, measure voltage across battery with engine off. Should be around 12.5 V. Measure with engine running, should be about 1 V higher. That's a basic test of your charging system.
 
If the battery is really dead the alternator can't start charging. The alternator needs a little current from the battery to get going. Follow the advice here. Get a trickle charger because evidently you park your cars a bit longer than the batteries can hold a charge. Also keep the batteries very clean. I use Pledge Furniture Polish and my 4Runner OEM battery lasted 11 years. My Honda battery lasted 10 years. Both batteries looked exactly like brand new off the shelf batteries when I turned them in. People laugh at the idea but it really works, every time. The local guy here that rebuilds golf cart and boat batteries uses it every time he rebuilds or services a battery. In fact he wraps the cans in tape because people tell him that Pledge does nothing but that stuff in the taped can works miracles.
 
First of all, I have not used a multimeter across the dead batteries yet. I will try later when I get home. They sat for probably 2.5 months since last start.

Secondly, this is my harger, is this considered a trickle charger?

https://www.gcsurplus.ca/ic-ci/images/FS330847-231847.jpg



So my first step should be to test the voltage of the batteries? The dead battery will still produce a reading? (Sorry but I dont really know much about the science of how these work)
 
Last edited:
Batteries do not like to sit in discharged state. It damages them. If you have allowed the batteries to discharge almost completely, then you may have ruined them for good. They may hold a charge for a short time but not for long. You really need a battery tender[trickle charger] if you are going to keep letting them sit for more than two weeks.
 
If either of the cars are sitting out far from an outlet, you could try a small solar charger (2-10W), that should be enough to beat the self discharge. (of course, this is after you get it charged back up with your big charger)
 
I've had problems getting those automatic chargers going on a completely dead battery. Get a little charge on it 1st with some jumper cables to another car that's running - then immediately hook to the auto charger. The auto chargers are great for not overcharging a battery, the auto trickle chargers also.
 
Noco G7200 or G26000 chargers have a supply mode made just for this where they can supply a constant 13.6V @ 5 amps to bring the battery up above 7v where most chargers won't recognize it as a real battery. You can leave it on there as long as you like since it is only 5 amps and a lower voltage it won't hurt them if you leave them overnight.

Also once you use the supply mode to bring the battery up, and then use the charger to fully charge it, you can use the desulfation mode to apply a constant 16.5 volts @ 1.5 amps to soften/dissolve the sulfate on the plates.

I would agree if you don't have the proper charger, the next best thing is to jump it and let it run for a minute then immediately charge it.
 
The old stupid "Buzz box" chargers available at every yard sale for a buck or three are great for bringing zero volt batteries back. The 6 amp charge is a great overnight charge too.
 
So I have two batteries that seem to be dead at the same time, and a charger that wont charge them.

What troubleshooting proves its the batters or the charger? There is no sparking like I usually expect there to be.
 
That is the best use for a manual charger is for bringing up batteries below 7 volts, but i wouldn't feel comfortable leaving one on the charger overnight at 6 amps unless i knew the amp hour rating and exactly how flat it was. I kind of wish i had a

When i see my batteries getting low from short tripping, to the point where they won't recover to at least 12.40v after sitting for 6 hours, i bring them in and only takes about 3-5 hours at 2 amps to bring them to full.
 
Originally Posted By: 901Memphis
That is the best use for a manual charger is for bringing up batteries below 7 volts, but i wouldn't feel comfortable leaving one on the charger overnight at 6 amps unless i knew the amp hour rating and exactly how flat it was. I kind of wish i had a

When i see my batteries getting low from short tripping, to the point where they won't recover to at least 12.40v after sitting for 6 hours, i bring them in and only takes about 3-5 hours at 2 amps to bring them to full.


Manual chargers taper off as the battery fills up, so they aren't pumping 6 amps at the end. Your typical car battery is around 80 amp-hours, but will start a car when "half full". A nice 12 hour overnight 6 amp charge has never given me any battery boiling out the vent caps or any trouble whatsoever.
 
I prefer an automatic charge with an actual processor, which will never over charge or under charge the battery.

My car specificies a group size 75 which is only 44 amp hour, and the over sized 78 or 34/78 is only 50 amp hour on average.

Check this link.

http://www.batterystuff.com/kb/tools/bci-battery-group-sizes.html

Also just for fun this link is cool.

http://www.batteryplex.com/sheets/BCI_21170_Combined_with_Cover.pdf

But most of the batteries i know of are in the 40-50 amp hour size, unless you drive nothing but German SUV's
 
So are there any tests I can do to the dead battery to make sure the battery is bad?

What about the charger?

If Im only looking to move the cars around in my driveway, can I jumpstart them?

Does it mean anything if there's no sparking when Im putting the charger on the battery? Or if the charger's ends connect?
 
Last edited:
Status
Not open for further replies.

Similar threads

W
Defective Battery or did my vehicle fry it?
Replies
12
Views
509
wormwood1978
T
how do you charge a 24v system?
2 3
Replies
56
Views
3K
The motor guy
tiger862
Impala lights dimming on acceleration
Replies
4
Views
433
tiger862
S
Toad Ai606 Alarm siren issue
Replies
9
Views
361
slybunda
M
02 Accord sputter once in a blue moon at start up
Replies
9
Views
297
dumkid
Back
Top