1 battery or 2, 12V

DailyDriverSst · 11-27-2018, 11:05 PM

Who runs 1 battery and who runs two? I'm not having any issues per se with one, but I am considering adding a second as an insurance policy of sorts. I have 2 gauge ran from the battery (right front corner of the truck bed) to the master switch and 2 gauge from master switch to the front distribution block, then 4 gauge to the starter. It takes it's sweet time to spin over when cold, and if it's a bit low on voltage after spinning over, the injectors stop firing due to Vdrop with the starter spinning.

I talked to a fellow at the OKC Divisional in a dragpak, he said he had to go to 2 batteries for essentially the same reason, fuel injectors and starter simultaneously doesn't add up after a couple starts and nudging forward in the lanes.

Once it's warm I don't have any issues. It's just the initial cold start. I keep it on a battery tender, so it's not a low battery issue initially. It just takes 30-45 seconds of spinning before it catches.

Worth adding a second battery?

Lenny5160 · 11-28-2018, 10:49 AM

I run 2 batteries with an alternator on my door car. I can and have run the entire season without hooking up a battery charger. I also put relatively few demands on the electrical system, with a belt-driven fuel pump and almost no fan usage when the car is not running.

I've not run 16 volts, but I'm considering it for my dragster which has always had 1 battery and alternator. I do put the charger on that after a few runs.

I'm not sure if 16 volts is a reasonable consideration with the "daily driver" thing. It sounds like voltage is your primary concern rather than reserve capacity. I understand that more reserve should lessen or slow the voltage drop when demand is high.

Ken MacNicol · 11-28-2018, 12:35 PM

I just changed from the 2 gauge I had on the car for almost 30 years to 1/0 gauge this past week and it was night and day difference in starting this past weekend in Bowling Green.

Jeff Stout · 11-28-2018, 12:40 PM

Quote:

Originally Posted by Ken MacNicol

I just changed from the 2 gauge I had on the car for almost 30 years to 1/0 gauge this past week and it was night and day difference in starting this past weekend in Bowling Green.

^This I had the same experience. Worked much better.

jmcarter · 11-28-2018, 05:47 PM

All it will take is hot-lapping in final rounds, minimum charging time and getting shut-off just before staging and then an “apparent” good battery failing and you will have another battery in no time. Haven’t thought about going heavier than 2 guage...sounds like good insurance.

DailyDriverSst · 11-28-2018, 08:12 PM

Quote:

Originally Posted by Lenny5160

I run 2 batteries with an alternator on my door car. I can and have run the entire season without hooking up a battery charger. I also put relatively few demands on the electrical system, with a belt-driven fuel pump and almost no fan usage when the car is not running.

I've not run 16 volts, but I'm considering it for my dragster which has always had 1 battery and alternator. I do put the charger on that after a few runs.

I'm not sure if 16 volts is a reasonable consideration with the "daily driver" thing. It sounds like voltage is your primary concern rather than reserve capacity. I understand that more reserve should lessen or slow the voltage drop when demand is high.

I would have to step-down most of the factory electrical to 12, and I wouldn't (easily) have a way to run a 16 volt alternator.

The PCM on my platform controls the 3 wire alternator, so charging once running at temperature isn't an issue. Just the initial start when the engine is cold.

I thought about using 1/0 wire when i wired the truck, but I thought 2 gauge would be "good enough". It sure beats the 6 gauge it came from the factory with, despite being about 25 feet longer, with the battery being relocated and master switch installed.

gnicholson · 11-29-2018, 09:09 AM

2 guage has an amperage capacity of about 150 amps at 10 feet with a voltage drop of 2 percent. a typical gear reduction starter will draw 150 amps 250 to 300 for a direct drive unit. remember this is for a fully charged battery. as the battery discharges amperage goes up.

1320racer · 11-29-2018, 11:01 AM

You don't need 16v but without question you should change out the cable to 1/0. If it's still hard to start, the next culprit is your starter. Whose starter and model are you currently using?

That said, I run two 12v batteries in my dragster and my door and always have because they were built for 2 batteries.

1legjerry · 11-29-2018, 06:38 PM

Battery cables should also be changed out every 5-10 years also. It is getting hard to find good wire and it will go bad. You should also check the terminals on the cables too make sure they are tight. I would suggest doing a voltage drop test on your starter/battery circuits a couple of times a year. It should also be the first thing you do when you are having a starting issue.

FED 387 · 11-29-2018, 07:17 PM

If you use 2 12 volt batteries you can wire the car so that the starter gets hit with 24 volts and the rest of the electrical system is ONLY 12 volts------Ever listen to Greg Andersons Pro car when he hits the starter ??? Cranks probably at 500 RPM(LOL)- It starts RIGHT NOW !!!!Most pick up truck diesels use 24 Volts to start while the rest of the electrical system remains 12 volts ---- You don't need the weight of 2 big 16 volt batteries or even 2 "large" 12 volt batteries to accomplish this if you do it this way---FED 387

11-27-2018, 11:05 PM	#1
DailyDriverSst Junior Member Join Date: Dec 2017 Posts: 56 Likes: 0 Liked 7 Times in 6 Posts	1 battery or 2, 12V Who runs 1 battery and who runs two? I'm not having any issues per se with one, but I am considering adding a second as an insurance policy of sorts. I have 2 gauge ran from the battery (right front corner of the truck bed) to the master switch and 2 gauge from master switch to the front distribution block, then 4 gauge to the starter. It takes it's sweet time to spin over when cold, and if it's a bit low on voltage after spinning over, the injectors stop firing due to Vdrop with the starter spinning. I talked to a fellow at the OKC Divisional in a dragpak, he said he had to go to 2 batteries for essentially the same reason, fuel injectors and starter simultaneously doesn't add up after a couple starts and nudging forward in the lanes. Once it's warm I don't have any issues. It's just the initial cold start. I keep it on a battery tender, so it's not a low battery issue initially. It just takes 30-45 seconds of spinning before it catches. Worth adding a second battery?

11-28-2018, 10:49 AM	#2
Lenny5160 Senior Member Join Date: Nov 2015 Location: Inver Grove Heights, MN Posts: 898 Likes: 604 Liked 431 Times in 224 Posts	Re: 1 battery or 2, 12V I run 2 batteries with an alternator on my door car. I can and have run the entire season without hooking up a battery charger. I also put relatively few demands on the electrical system, with a belt-driven fuel pump and almost no fan usage when the car is not running. I've not run 16 volts, but I'm considering it for my dragster which has always had 1 battery and alternator. I do put the charger on that after a few runs. I'm not sure if 16 volts is a reasonable consideration with the "daily driver" thing. It sounds like voltage is your primary concern rather than reserve capacity. I understand that more reserve should lessen or slow the voltage drop when demand is high. __________________ S/ST 51 S/C 53

11-28-2018, 12:35 PM	#3
Ken MacNicol Junior Member Join Date: Apr 2010 Location: Hendersonville, Tn. Posts: 82 Likes: 903 Liked 26 Times in 12 Posts	Re: 1 battery or 2, 12V I just changed from the 2 gauge I had on the car for almost 30 years to 1/0 gauge this past week and it was night and day difference in starting this past weekend in Bowling Green.

11-28-2018, 05:47 PM	#5
jmcarter VIP Member Join Date: Dec 2008 Location: Richmond Hill GA (and Port Ludlow WA) Posts: 4,273 Likes: 2,308 Liked 3,099 Times in 954 Posts	Re: 1 battery or 2, 12V All it will take is hot-lapping in final rounds, minimum charging time and getting shut-off just before staging and then an “apparent” good battery failing and you will have another battery in no time. Haven’t thought about going heavier than 2 guage...sounds like good insurance. __________________ Jim Carter 2340 Super Stock 2340 SST/2340 Stock Set another place at the table

11-29-2018, 09:09 AM	#7
gnicholson Member Join Date: Sep 2011 Posts: 103 Likes: 15 Liked 4 Times in 3 Posts	Re: 1 battery or 2, 12V 2 guage has an amperage capacity of about 150 amps at 10 feet with a voltage drop of 2 percent. a typical gear reduction starter will draw 150 amps 250 to 300 for a direct drive unit. remember this is for a fully charged battery. as the battery discharges amperage goes up. Last edited by gnicholson; 11-29-2018 at 09:17 AM.

11-29-2018, 11:01 AM	#8
1320racer VIP Member Join Date: Nov 2007 Location: New Jersey Posts: 2,628 Likes: 160 Liked 758 Times in 379 Posts	Re: 1 battery or 2, 12V You don't need 16v but without question you should change out the cable to 1/0. If it's still hard to start, the next culprit is your starter. Whose starter and model are you currently using? That said, I run two 12v batteries in my dragster and my door and always have because they were built for 2 batteries.

11-29-2018, 06:38 PM	#9
1legjerry Junior Member Join Date: Jul 2011 Posts: 85 Likes: 4 Liked 72 Times in 15 Posts	Re: 1 battery or 2, 12V Battery cables should also be changed out every 5-10 years also. It is getting hard to find good wire and it will go bad. You should also check the terminals on the cables too make sure they are tight. I would suggest doing a voltage drop test on your starter/battery circuits a couple of times a year. It should also be the first thing you do when you are having a starting issue.

11-29-2018, 07:17 PM	#10
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,400 Likes: 482 Liked 320 Times in 172 Posts	Re: 1 battery or 2, 12V If you use 2 12 volt batteries you can wire the car so that the starter gets hit with 24 volts and the rest of the electrical system is ONLY 12 volts------Ever listen to Greg Andersons Pro car when he hits the starter ??? Cranks probably at 500 RPM(LOL)- It starts RIGHT NOW !!!!Most pick up truck diesels use 24 Volts to start while the rest of the electrical system remains 12 volts ---- You don't need the weight of 2 big 16 volt batteries or even 2 "large" 12 volt batteries to accomplish this if you do it this way---FED 387