What battery for high cranking voltage?

[CosmickGold]

I have discovered my Express 3500 van's V8 engine is hard to start because the new (but cheap) battery I put in is pulled down to 10.2 volts during cranking.

What battery can I get that will maintain 12 volts even while cranking my large engine?

 

[abnorm]

Google says you need a Size 78 Battery about 660 ColdCrankingAmps......................What's there now ?

 

[CosmickGold]

Google says you need a Size 78 Battery about 660 ColdCrankingAmps......................What's there now ?

Currently, I have Size 75 with 650 CCA. Ha!! Thanks for giving me the standards I need to have in mind as I pass through the AutoZone door tomorrow! I had no idea what to look or ask for, but now I do.

And actually, I want to go even higher than those standards if I can.

Many thanks!

 

[jonyjoe303]

10.2 volts is within limits, the minumum is 9.7 volts. You would need a very large high performance battery to keep the voltage anywhere near 12 volts during cranking.
One thing to check is what the voltage of the battery is before cranking over. On my astrovan I have a slow cranking problems for years, especially after sitting over a weekend, I replaced at least 4 batteries. At least 3 to 4 times I had no cranking where I needed a jump.
I did find a loose terminal cable that connected to the sidepost and replaced but still had problems. I finally found the problem, while sitting with engine off and everything disconnected I put a ampmeter on the start battery cables and found something somewhere in the van is consuming 290ma of power (max allowable is 30ma) . So just sitting the van consumes several amps every day.
The space in the engine bay doesnt allow for a large battery, the recommended battery's are too small for the drain I have.
I have been using a 3 amp dc to dc trickle charger from the house battery to the start battery. If the start battery voltage drops to 12.3 volts, the trickle charger charges it back to 14.4 volts then stops. Its fully automatic and havent had anymore slow cranking problems. I almost bought another battery.
The only other options is the locate the item draining the battery or disconnect the start battery every day.

 

[CosmickGold]

Google says you need a Size 78 Battery about 660 ColdCrankingAmps......................What's there now ?

10.2 volts is within limits, the minumum is 9.7 volts. You would need a very large high performance battery to keep the voltage anywhere near 12 volts during cranking.
. . . .

I have purchased this 800 CCA battery, an "Optima AGM Red Top Battery 34-78 Group Size 34 800 CCA" for $279.



I thought they'd have to dig through the back store room to find one, so even brought them the above picture printed I had printed out for them. But when I walked in the door, there was the battery on a prominent display rack on the main aisle! They told me it's a great battery, and now it does make my engine turn over a lot faster and start sooner (though still not immediately. Takes about three turns of the key. I can't guess why.) The previous battery was still new, but cheap-cheap-cheap. So only 10.2 volts for cranking, which did work but required about 8 turns of the key to start. This one is turning the engine with 11 volts of thrust and turning it fast requiring only 2 or 3 turns of the key!

WARNING! Previously, I didn't know you can't just hold the key on and keep a steady cranking. Non-stop cranking quickly toasted my starter, requiring me to replace it with a new one. So now I let go of the key after about 5 seconds to let the heat spread out before I crank it again.