Battery draining/short?

[rockdogz]

Well I went out this morning and found both my batteries dead. I'm not sure, but I might have left the switch on to connect them together while the ignition is off. I have the painless switch that lets you combine the two either when the ignition is on or off.

Anyhow, I charged the main battery back up and was able to drive, and everything seemed ok. When I got back home, I went to investigate, and put a voltmeter on the auxillary battery. I could see the voltage drop... 10.75...10.74....10.73.... I thought maybe something was shorting, so I pulled off the cables. Well, the battery kept dropping voltage, with nothing else connected. It's an Optima Yellow Top. This doesn't sound right, does it? Could the battery have a problem?

[68sixspeed]

Well, the meter shouldn't be drawing enough to cause that fast of a drop. Probably a defective battery; I've had 'issues' with Optima's not holding a charge, they were good about giving me a replacement though.

[rolltide]

Make sure the electrolyte covers every cell. If the charged voltage is below 12v with no load... din we gots a problem wit da battry.

[rockdogz]

Make sure the electrolyte covers every cell. If the charged voltage is below 12v with no load... din we gots a problem wit da battry.
It's an Optima so it's sealed. It will take a charge over 12v, but it is quickly depleted...

[rolltide]

If there's no load and it drops below 12v., it's discharging internally. Unfortunately, there's nothing you can do but replace it.

[MonzaRacer]

One thing is that you have to have proper charger to charge dead batteries.
Most think a car battery needs a long slow charge but that isnt how they operate. They have to dump a large amount of amperage fast to start a car so charging a battery hard and fast for approximatley an hour (wet batteries need the electrolyte above the top of the plates) till it finish charges. Most high amp chargers will start low on the guage then raise up then fall back as the charge get up in the battery(charging a battery raises the resistance to charger voltage, similar to the way the battery light works on a car or if you have a barrel with a hose hooked up and no vent, when preasures are equal, nothing flows.
Most people dont understand that voltage is a state of charge not a state of electrical potential.
NOW if your battery has been discharged slowly and let sit for several days or months you should try to start slow to bring a slight charge into it then crank it up on high (not the start setting on some chargers).
Also an alternator is not a battery charger, it is a battery maintainer.
You have a battery lower than 12 to 12.25 volts then you need a good heavy charger not a trickle charger.
If you smell the nasty smell charging a battery but it goes away after a short time of charging then it is "burning" the sulfation(in wet batteries) off the plates.
Sulfation is the chemical act of after discharge the sulfuric acid is aborbed into the plates(a discharged state) a low sometime isotonic sulfate solution(read this as very small amounts of the residual sulfuric acid) can create a sulfate crystal (similar to making the old sugar candy on string made from sugar water)surface on the plates. This in turn restricts the electron flow from the charger in pushing out the sufuric acid of the plates.
And then you need a battery. A battery is an electrochemical electric potential sorage device. This means that by means of a chemical reaction it causes elecrons to flow (or be stored for use later) when the circuit is connected.
Optima batteries are a very different set up as they work similar to nicad batteries.
BUT hey still need a steady ,medium heavy charge to charge back up. Also the reason they work better is that they will release or "dump " electrons faster and in a higher/larger dump say to start a high compression engine.
I know Autozone used to have heavy duty chargers that charge hard and fast but are "smart "chargers and if the battery is bad it will kick it out.
If I ever buy a battery charger for my home use it will be a big one with wheels and a handle.
OH and those little 100 amp toaster testers you see everyone use (has a wire that gets hot in small hande help box)they will test your lawn mower battery but not your car battery.
The proper way to test a battery is to either use an capacitance tester OR a carbon pile tester. I have the latter and it will test batteries up to 1200 CCA.
Most batteries should (unless specified by manufacturer) be load teste with these at half the rates CCA (ignore CA for testing but the closer this is to the CCA and the higher the CCA rating then the better battery you have)if you have a battery rated at 500 CCA and 800 CA it will not start your big block in 0 deg weather.
Now the battery has a minimum voltage at the end of a 15 second test at a specific battery temp.
Most testers like mine say to hit the battery after charge with a 100 amp draw for 3 seconds to loose the surface charge(excess voltage that will disipate over a few minute).
Then you hit it with a load and see how fast it drops. If it settles in well above the rating (9.6 at 60 drgrees I believe, but this goes down with lower) battery temps and holds out till the 15 seconds arre done its good but if it slows then start dropping fast below that then its bad..
I hope you getyou problem figured out and make sure you get the full charging system checked out in the car (as a bad diode will allow AC current from the alternator "spike " or discharge the battery) as battery only wants to see the DC side of a power sinewave. Make a up down loop line then slpit it with a line in the middle the top part is waht your battery/car uses.
Hope i havent confused anyone and if you need any help give me a shout.
Lee Abel
AFTERMARKET PERFORMANCE

[rockdogz]

Ok, thanks for all the info...

I checked it again today after removing the cables, and it kept dropping until it hit 10.73 volts. It seemed to like that, and has stayed at that voltage for some time. The red top stays at 12.15v. I don't have one of those big chargers with wheels and handle, so I will see what Costco can do for me...

[HzEmall]

www.ctek.de

get the US800 and hardwire it into your car and have the electrical outlet easy to get to, just plug it in at night or when your not driving the car, it's awesome for storing cars.............

[rockdogz]

Got a new yellow top, so we'll see how it goes now... it was over 12v as soon as I bought it, so I feel better about this now...

[whytry]

What was the outcome of your battery issues? I think I am having the same problem. My Optima Redtop slowly drops to 10.80ish, over the span of about 2 days with the battery disconnected.

[MonzaRacer]

If a batttery drops to 10.8 sounds like a dead cell, especially if its unhooked.
Another thing is that matching dissimilar batterys limits the larger battery.
I had e fella trying this in his truck with a large cmaper that used the battery for power. He tried to use one regualr battery and one Deep cycle with an isolator and we had big problems till we matched batteries.
We also found a started circuit online that would start his truck when battery voltage got low nad since it was electronic fuel injection it woked ok after we wired it into the P-brake light so it "knew" it was safe to start.
Batteries should not loose big voltage in only a 1 or 2 days or even a week .
My Optima blem battery sat in the weather for 9 months, on ground throught out the winter in snow and ice then I decided to install it in my truck and have used it since (much to my luck as it covered up my bad starter too!.
Imagine what my battery cable lookedl ike when I tried to start the truck when the starter was opulling over 600 amps! It didnt melt the cables but hey sure got hot.
Good Luck
Lee

[rockdogz]

Everything is great with the new optima yellow top. I was cleaning up the car today and played the stereo for over an hour and it went from like 12.5 to 12.1... no probs. You may have a dead cell.