Crank how long before batteries die

[soggybottom]

How long should I be able to crank before the batteries won't turn the engine over?

Truck has two 900cca batteries, both one year old. Starter new last winter. All new battery cables. Lately I crank for 10 seconds and after that the engine barely turns over. Usually it's below freezing when I try to start it. -10 today and it cranked for maybe two 10 second bursts before it wouldn't turn the engine. Does that sound normal?

Thanks.

 

[lindstromjd]

Nope. Sounds to me like your batteries are shot.

 

[89greendiesel]

i concur with lindstrom

 

[opusd2]

Not really.
What group batteries are they? What is the reserve capacity on them?

I have a couple of batteries about two years old +, group 31 commercial (don't remember the specifics) but I can can roll the engine quite a while before losing too much to start the engine when/if I lose prime like I am currently and am currently trying to repair.

Now I don't know if you plug in your engine at all in the cold weather, but what I do to help is to permanently install a set of battery trickle charger/maintainers on my batteries. It helps to keep the batteries topped off and warmer than a battery that only discharges in the cold. I've done this on every vehicle I've owned since at least 1990 and to go without would seem backwards to me. It gets plugged in when I plug in the engine warmer, or sometimes I just plug that in on my own. At 12volts and just a couple of amps at most, it barely uses any juice.

 

[89greendiesel]

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[soggybottom]

The batteries are group 31. I had them tested at the parts store and they said they passed. They didn't disconnect the batteries from each other though, and I thought they were supposed to?

Guess I'll take them out of the truck and have them tested individually. Of course they are 1 month past the free replacement period

 

[89greendiesel]

advance auto parts......bought two of these the end of september and the the recent jolt of cold when it was -15F, truck cycled glow plugs, and started after 2 secs of cranking and half throttle and i still have a couple fuel leaks to take care of. can't complain about that for a 1989 truck.


http://www.retailmenot.com/view/advanceautoparts.com

i know we are a cheap lot, but there really isnt a way to get around paying for new batteries. atleast i havent found one

 

[89greendiesel]

The batteries are group 31. I had them tested at the parts store and they said they passed. They didn't disconnect the batteries from each other though, and I thought they were supposed to?

Guess I'll take them out of the truck and have them tested individually. Of course they are 1 month past the free replacement period

i think they are supposed to be disconnected too. i am sure our trucks are ******* batteries. pushing eight cylinders at 22:1 compression has to be rough

 

[lindstromjd]

The batteries are group 31. I had them tested at the parts store and they said they passed. They didn't disconnect the batteries from each other though, and I thought they were supposed to?

Guess I'll take them out of the truck and have them tested individually. Of course they are 1 month past the free replacement period

You can't trust the parts store "testers" because I can almost guarantee that they didn't actually "load" test them. They probably just hooked them up to a volt meter, saw they were close to 12 volts, and said "yup, they're good". Which means absolutely nothing for a battery. You have to test it's ability to maintain it's amps while on a load, like cranking over a 21:1 compression engine.

As far as the free replacement, I would argue it. Batteries that are dead as a doornail after 13 months isn't right. Any decent parts store manager will help you out, even if it's with a 50% pro-rating price. Better than paying 100% of the brand new price.

 

[89greendiesel]

i also have new cables, full disclosure

 

[lotzagoodstuff]

How long should I be able to crank before the batteries won't turn the engine over?

Truck has two 900cca batteries, both one year old. Starter new last winter. All new battery cables. Lately I crank for 10 seconds and after that the engine barely turns over. Usually it's below freezing when I try to start it. -10 today and it cranked for maybe two 10 second bursts before it wouldn't turn the engine. Does that sound normal?

Thanks.

Just wondering: are you plugging your block heater in? Diesel oil is pretty thick at that temperature, and although I strongly encourage having a tip top GP system in an IDI, I think I'd plug in and see how your batteries crank with a warmer engine.

Good luck and stay warm

 

[soggybottom]

Plugged in it pops off in a split second. But I can't always plug it in.

 

[OLDBULL8]

How long should I be able to crank before the batteries won't turn the engine over?

You answered your own question.

When the batteries won't turn the engine over anymore there considered DEAD. The colder it is, the less efficient a battery becomes. Check the battery voltage after cranking, if it's down to 11VDC and doesn't recover back to 12.3VDC in a minute or so, then it could have a shorted cell on one or both batteries. On a very cold start, you can draw as Hi as 600 to 800 amps starting,

Reserve Capacity (RC) is a very important rating. This is the number of minutes a fully charged battery at 80 ° F will discharge 25 amps until the battery drops below 10.5 volts.

 

[icanfixall]

How long is the usual cranking time. If you have to make several cranking periods you may have burned up the starter already no matter how new it is. Have you checked and cleaned the battery terminals yet. They will not stay clean for a year so looking at the outside of the clamp is not telling you whats on the inside. Feel the clamps after an attempted start. If one is warmer than the others thats the bad connection. Corrosion in the clamps makes more heat trying to push the amps thru the mess.

 

[wildman7798]

Most parts stores with a decent load testing system will be able to narrow it down to batteries or starter. When lead acid batteries reach 32 deg. F they lose half of their power. The other thing to consider is that a starter that is failing or one with bad brushes or commutator can draw excessive amounts of current when cranking, masking itself as bad batteries. When it is warm out the starter gets by, but coupled with it's failing self and the drop in temp leads many to believe their batteries are bad.