So the other night when it was -30*C out here, my truck was out in the cold unplugged for 3 hours. Was only supposed to be 25 minutes, but turned into 3 hours, I know very bad!!

However, here's my problem. When I went out to start the truck, she only turned over a few times and then the batteries were dead. (they're still the 770CCA AC Delcos) I got her boosted and let her idle for about an hour, took her home and shut her down for the night and plugged her in. All in all about an hour and 15 minute run time.

The next morning I go out to start her again in -30*C and same thing, she cranks over a few times and the batteries are dead again. Once again I boost her and leave her idle for an hour and then hop in and run around town for an hour and a half doing errands, leaving her run the whole time. Two hours later I go to work for the night and she starts fine. I leave her plugged in at work for the full 12 hours and when I go to start her up at 06:00 hrs she's dead as a door nail again. Once again, boost and then straight to the dealership to find out what's going on.

6 hours later after I've had a nap from working all night, I go pick her up from the dealer and they tell me that load test on both batteries is fine but I had a 890 miliamp draw on my radio circut because of the way my OEM deck was mounted under the back seat. (I have aftermarket stereo and had to mount OEM deck someplace else). So they "fix" the problem by removing the power button from the deck as it was being constantly pushed in by the seat causing the draw on the system. System now has 12milliamps of draw, within GM specs.

So I took her home and let her run for another hour to recharge the batteries. I should mention that I've got dual altenators, one at 105amps and the other at 145amps. I would think this should charge my batteries in an hour quite easily right? PLEASE correct me if I'm wrong. That night I went to work again and in the morning, the same thing happened, hardly any volts and a few cranks and she's dead again. Another boost and home I go. She runs at high idle (1500rpm) for a full hour and then I shut down for 7 hours to sleep. Once again plugged in the entire time.

When I get up, same story all over again, no voltage, but great starting when boosted. She turns over 4 or 5 times and the fires right up and the gauge reads 14.4v almost immediately.

My questions are these....

1. Would 890milliamps for 12 hours draw my batteries down far enough to kill batteries?

2. I though our trucks had protection agains draw for long periods of time to cut all power untill the key was re-inserted into ignition.... Should this not have kicked in?

3. Is an hour long enough to charge batteries with 250amps of charge or should I be going longer?

4. Is there something I or GM is missing? I've already given them 3 hours worth of money so far, I can't afford this right now.......

I don't think an hour would be enough to charge the batteries. Also you put a lot of strain on your alternator by letting it do the charging. You should leave it on a trickle charger overnight.

Not that I'm doubting you knowledge, but shouldn't 250Amp charging do better than that?

I will however put her on a trickle charger this morning when I go home....

I'm not 100% sure about our trucks but, I know on the rigs we run that if you let the altenator charge dead batteries, it will usually kill it.

Interesting, well I won't be taking that chance ever again, thanks Ozzy!

I will stick it out and say you probably need new batteries, being run dead so many times really takes the step out of the wet cell. You might try optima if you replace them. They aren't damaged when run dead like your delcos.

I Have dual alts also, a nice feature, but charge rate can be another problem, if your batteries charged with 200 amps they would fry very quickly (and the math would be 15 minutes). With dual alts, you won't do damage to the alts, but you also are not fully charging the batteries, an hour is nothing to a dead battery, as it can only accomodate a slow charge anyway. The best thing to do when the battery is dead is to charge it continuously til charged A slow 2-5 amp charger is the only right way to charge a wet cell, and it takes a whole 24 hours. If it shows fully charged in 2 hours that means the capacity is gone from the lead. The vehicle charging system is not designed to properly charge from a drained condition. With optimas, these are concerns of the past. Also, they are like a faithful horse, they will crank hard faithfully until they just lay over fully discharged, less resistance or something, better for cold weather starting.

Sounds like you may have a bad battery. Disconnect the grounds on each battery, charge them seperately, reconnect grounds,burn off surface charge by leaving headlights on for about a minute.. Disconnect grounds eack battery and measure voltage each barrery using a digital voltmeter, record readings. Leave everything for an hour and make measurements again. Battery voltage should be at least 12.5 volts after burning surface charge off.Reppeat measurements in another hour. If batteries are discharging without a ground connection you may have problems. If one battery is bad, it will take the other down when they are both connected.Wish you luck, battery problems can be a real headache and expensive.

You guys are making me think. with 2 batts, can you double the charge rate using a charger?

One battery is weak and drawing down the other, I would replace both if I had that problem and not look back. You should follow Bill Gisse advise for testing if you want to find out which one is the problem.

Aren't they under warranty?
Richard

These batteries create electricity from a chemical reaction. little goobers moving from one plate to another when discharging or suppling energy. When recharging those same little goobers move back to their original plate, they take their time and sometimes loose their way. I am sure someone will yell at me if I have explained this improperly. ):h

Even if you decide to buy new batteries you still need a modern battery charger. I don't mean the old tech 10 amp charger. I have one of the new smart chargers from Vector. It has three fully automatic rates of 2/10/20 amp plus it will desulfate/recondition the battery also. Everyone should at least check the Vector web site. Later! Frank

Zorganov,

Just to try & understand exactly what is happeneing, when you do boost the vehicle, exactly where do you make the positive & negative jump start connection attachments on your vehicle, just trying to help, poss. connection related issues, I've seen alot at work recently (gm tech)?

Todd.

I agree with DIESELHOLIC. Make sure you don't have ground problems

Well, after dealer told me it was my stereo's fault I went back to him after recharging both batteries seperately at a 15amp charge rate (yes I have a modern fully automatic charger) and the truck still didn't want to start. It would have also helped if mechanic remembered to attach the ground on the passenger side battery again as well. Service rep is an arogant pig that is "never wrong" and wouldn't listen to reason, so I had to tear a strip off him in front of 4 other customers, refusing to leave untill problem was solved. Mechanic was working on another vehicle so I said I'd wait. 10 minutes later my truck was in the bay and batteries "retested" which I found out actually had NOT beed done on my first visit like the service rep told me they'd done. Found both batteries were totally fried due to so much charge and recharge so both were replaced on "warranty" due to dealers incompetence on the first visit. All systems checked out 100% again with a 12 milliamp draw at shut down state. I politely and graciously thanked the mechanic and service rep for fixing it and I'm happily on the road again.

So all in all, the original problem came from the installation of my aftermarket stereo, which I paid $186 in the first visit to fix, however the problems that followed were soley the responsibility of the dealer and was properly covered by my warranty by them. Not too happy about the $186, but fair is fair, I did take it to them to fix it so I pay shop rate if not GM's fault.

I do think a set of yellow tops are in store within the next year or so, so that I can have a bit of a draw for running the stereo and so on while the truck is not idling.

Thanks for the reply's guys, your advice is always bang on and appreciated!!!

It gets pretty cold here too. At -35* my truck started not being plugged in. I know that it took all the juice the battery had though, cause I lost all the memory in my radio. Just replaced with Optima Red Tops for the helluvit. Just my .02$. Nick

You must have one of the early wiring harnesses for your stereo. The later ones like what I have come with a little box that does everything the stock stereo did so you don't need to retain the stocker in the truck. The box has a dinger in it and keeps the retained accessory power and other functions. Although I tore the wires off the dinger speaker before I installed it. Hate dingers. So other than no dinger it works the same as it did stock.

Zorganov, you are being a little hard on yourself. A one amp draw should not pull a pair of good batteries down in a week. Later! Frank

Zorgonov, another thing to consider is the capacity of a battery at -30 could be as low as 20-30 % of rated capacity. It's already been said but a few hours of idling with a cold, dead battery just doesn't cut it. Bring them inside and trickle charge em for a day. I lived in High Level for 3 years, loved the place, hated the bugs. The roads around Zama and Rainbow are still well cared for? ):h

I think a 1 amp draw will do it.
In perfect conditions that would 60-70 hours worth, per battery. Used batteries, in 0 degree, that have been discharged many many times eventually are just damaged, and without capacity.


In the cold weather, I'll bet after one day and a cold start, they are at 10-20%. Doing this over and over...

You must have one of the early wiring harnesses for your stereo. The later ones like what I have come with a little box that does everything the stock stereo did so you don't need to retain the stocker in the truck.
Actually I don't think it's a prebuilt harness at all. I put the stereo in the truck a week after I got it. I'm thinking the guy who installed it just made his own.

Zorganov, you are being a little hard on yourself. A one amp draw should not pull a pair of good batteries down in a week. Later! Frank.
This is what I was told by a few electrician friends of mine as well. But I think it's more like what Masterp2 said.

In perfect conditions that would 60-70 hours worth, per battery. Used batteries, in 0 degree, that have been discharged many many times eventually are just damaged, and without capacity.


In the cold weather, I'll bet after one day and a cold start, they are at 10-20%. Doing this over and over....
I lived in High Level for 3 years, loved the place, hated the bugs. The roads around Zama and Rainbow are still well cared for?
Yeah, right! I know what you're talking about!! The roads are in mint condition!! I'm assuming you're probably familiar with the service rep here then as well?