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?

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.

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.

Re: 1 battery or 2, 12V
 

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

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.

Re: 1 battery or 2, 12V
 

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.

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.

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.

https://i.imgur.com/PhDyUCP.jpg

https://i.imgur.com/aDxV95Q.jpg?1

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.

https://www.youtube.com/watch?v=rrDlXn-RYcM

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

Re: 1 battery or 2, 12V
 

The battery cables are about 3 years old. The connectors are copper plated and the wire is 100% copper. The connections were crimped first, then soldered.

The issue isn't that the engine spins over slow (at least, at first). It's that it takes about 30 seconds of spinning before it starts to cough and start firing. About that time is when the starter slows down and it gets into a low voltage situation where the fuel injectors won't fire with the starter spinning. If I'm lucky, i can keep it spinning fast enough that when i release the starter, the injectors will start to fire while it's spinning down and it will start running on it's own. Usually that isn't the case. (Also, the whole starter/injector conflict is common on all the 97-05 dodge trucks. The low voltage cutout for fuel is somewhere around 11.25, spark cuts out around 10.5).

Even though it's on pump gas, it's starting ability is up there with a low compression N/A alcohol engine. It just doesn't like being cold.

I'm considering adding a 120VAC block heater over winter to help get the engine warmed up a bit, but I'm also considering adding the second battery so that I can keep spinning it over until it catches at full speed. With a group 75 battery one would think there would be enough reserve to last longer than that, but it's also a 4 year old battery.

Re: 1 battery or 2, 12V
 

whose starter?

Re: 1 battery or 2, 12V
 

Your issue is not uncommon amongst EFI cars .
I have a lot of EFI stockers come thru the shop and it is something I've seen happen on several older built cars .
I am defiantly a proponent of dual batteries , the reserve they offer comes in handy when going rounds with minimal time to charge the batteries . ... . Running an alternator is a must with any EFI car to keep the voltage above 12.5 v.
Two areas that are overlooked are grounding and master disconnect switch .
I see many cars with no ground wire between the frame and engine or battery grounds bolted to the sheetmetal floor.
I have seen 2 cars this year with problems due to disconnect switches with high resistance /voltage drop issues. ….look at the amp rating of the most common disconnect switches with 3/8" studs ,most are only rated for 125-150 amps intermittent {starting} current . while the heavy duty ones from Moroso or Flaming river are rated for 1000 amps or higher intermittent current.
One last thought regards the wiring of the ECU itself . Holley in particular is adamant about having the ECU connected directly to the battery with no interruptions.

Re: 1 battery or 2, 12V
 

Always remember that heat is the enemy to EVERYTHING......... When your starter is cranking over for 30-45 seconds, it is building a lot of heat inside the starter itself. More heat equals more friction. As someone mentioned, as the voltage drops the amperage goes up. It can be a snowball effect. I run the same size (as the positive) ground wire from the battery directly to the block. Chromemoly is not a good electrical conductor. Soldering your connections is good IF done properly. Not everyone knows how. A fully charged 12V battery should read 12.6V after the surface charge is dissipated. If your battery is reading 12.1V. It will take approx. 10 hours to charge the battery using a 10A charger. I'm going from memory, I used to have a chart from AC Delco but not anymore. The point is that it takes longer than you think to charge a battery. Charging for 20-30 minutes between rounds is NOT adequate. Buy a good battery charger that is made for your type of battery and keep it on your car anytime the car isn't running. I've never seen anyone lose a race because their car started but a lot because it didn't.
Dan

Re: 1 battery or 2, 12V
 

Thank you, Tom. This agrees with what the Dragpak owner told me at the Noble divisional.

The master switch is a Longacre 2-terminal (not sure what that would be rebranded from) and the EFI is as Mopar installed it at the factory. Not sure if the disconnect is 52-45760 or 52-45754, but i'm thinking the former.

Both cylinder heads are grounded to studs on the firewall by factory mopar braid, and I added a #10 ground wire between studs and from one stud to the frame. I am not sure if there is a ground strap off the block or not. Battery is grounded to the frame with a #2 wire 18" long, again connectors are crimped and soldered. Battery itself has marine connectors on it.

I plan to completely re-ground the engine bay over winter to follow the procedure we normally have on our cars, with daisy chained #10 ground wires all the way around and back to the battery, redundant to the chassis.

I guess I'll also plan on adding a second battery.

1320, it's the factory late model Denso-style gear reduction starter for all Mopar platforms (not the earlier style that was the size of a watermelon).