Batteries

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Illahe

Mopower
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Hello Gentlemen,

In need of a recommendation for a pair of batteries. The car has two Interstate 700 CA in the back with some serious battery cable, but they are straining. I though that there was a 14v set up, but the car has a 7al with the grid and a delay box. That being said, wiring is not a strong point of mine. Any advice would be helpful.
 
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Straining to do what, crank the engine? Unless the batteries are down in charge, or old, or defective, I can't believe the batteries themselves are the problem.

You have a thermometer gun? Crank the engine with no ignition for about 20 sec and then quickly run around to every heavy battery cable terminal/ connection you can find and see if one is abnormally hot
 
First let’s start with the model of batteries you currently have.
Typically it will be called a “group”
Like group 31 or 24 or 27.
Also, if two batteries cannot turn your engine over there is another issue.
Have the batteries tested outside the car. Walmart or Advanced auto type place will test for free.
One may be bad or both are weak.
You may have a bad starter or bad wiring.
 
67Dart273 said:
Straining to do what, crank the engine? Unless the batteries are down in charge, or old, or defective, I can't believe the batteries themselves are the problem.

You have a thermometer gun? Crank the engine with no ignition for about 20 sec and then quickly run around to every heavy battery cable terminal/ connection you can find and see if one is abnormally hot
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Straining to crank the engine over with authority. The cables and points of connection are spotless. Thanks for the heat gun tip!
 
I've run a Group 65 AGM battery for many years. Die-Hard (When made by Odyssey), Odyssey & even Walmart 65 AGM But even with a small 50 amp alternator, I charged the battery as much as possible between rounds while running the water pump, onboard fan, exterior box fan & a garden sprayer to cool as quickly as possible. The idea was to keep the charge as high and consistent as possible. The more electrical stuff you have, the more battery you need. Voltage variance can affect consistency.

How old are your batteries?
 
Locomotion said:
I've run a Group 65 AGM battery for many years. Die-Hard (When made by Odyssey), Odyssey & even Walmart 65 AGM But even with a small 50 amp alternator, I charged the battery as much as possible between rounds while running the water pump, onboard fan, exterior box fan & a garden sprayer to cool as quickly as possible. The idea was to keep the charge as high and consistent as possible. The more electrical stuff you have, the more battery you need. Voltage variance can affect consistency.

How old are your batteries?
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Thanks for the response. Bought the pair last July, but they went through a -0 winter storage cycle. The car has a interior fan, dual radiator fans, electric fuel pump and all the ignition hoo-ha. With start and restart in the staging lane they drop a couple .1V in no time. They charged to 12.5V this time, but I though they were right at 13.1 last season wen they were new.
 

Syleng1 said:
First let’s start with the model of batteries you currently have.
Typically it will be called a “group”
Like group 31 or 24 or 27.
Also, if two batteries cannot turn your engine over there is another issue.
Have the batteries tested outside the car. Walmart or Advanced auto type place will test for free.
One may be bad or both are weak.
You may have a bad starter or bad wiring.
Click to expand...
Group 24. New mini starter that worked well last season. The batteries read 12.5v independently, yet drop down into the high 11V range when cranking. Sounds like they need to be load tested.
 
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Syleng1 said:
First let’s start with the model of batteries you currently have.
Typically it will be called a “group”
Like group 31 or 24 or 27.
Also, if two batteries cannot turn your engine over there is another issue.
Have the batteries tested outside the car. Walmart or Advanced auto type place will test for free.
One may be bad or both are weak.
You may have a bad starter or bad wiring.
Click to expand...
Newbomb Turk said:
Buy a series/parallel switch and start the engine on 24 volts.

Your engine and your starter will thank you.
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Thank you, Sir. I will look into the series/parallel.
 
If you check everything else out and it checks ok, especially when doing a voltage-drop test. XS does make a 14 volt battery and it will work with everything that you already have. You'll need to purchase a 14 volt charger. I eventually went to a 16 volt battery and a 16 volt alternator. I've been very happy with that set up.
 
9secRR said:
i switched to XS 16 volt 4 years ago. best thing i ever did
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This right here is what I was going to suggest. I have been running 16v XS power batteries for 10 years. I would never go back to 12v. I also run an MSD Grid and a powermaster 150amp alternator that puts out 18.5 volts at idle. I have gone whole race days without charging the battery. Over 14:1 compression, 800+ valve spring pressures.
 
71Demon540 said:
This right here is what I was going to suggest. I have been running 16v XS power batteries for 10 years. I would never go back to 12v. I also run an MSD Grid and a powermaster 150amp alternator that puts out 18.5 volts at idle. I have gone whole race days without charging the battery. Over 14:1 compression, 800+ valve spring pressures.
Click to expand...
Thank you for the advice. Just purchased a pair of sealed 935's CA for the weekend. And will look at the XS 16V set up on Monday. Who makes the alternator?
 
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