Drag Racing Tech - What kind of battery setups are you guys running in back?

I have been having some charging system issues recently after adding an electric water pump (street) and a bigger fuel pump. The alternator just cant keep up at all. At 2000 rpm I can just sit and watch the voltage drop when the fan, water pump and trans brake were on, engine running. Had the alternator checked and its fine, I have 1ga welding cable for battery cable and 2ga for the alternator to the cutoff switch. Iw was better before the EWP and big fuel pump, that probably added another 20 amp draw.

Went and checked the current draw with the car running, fan on, parking lights and trans brake on.

92 amps, wtf lol.

I have a red top in the car now and even throwing a 20 amp charger on the car between rounds its just not keeping up. I was going to switch to a yellow top optima but before I drop 200.00 on a battery I was wondering if anyone else went through the same. I also had the alternator rebuilt to 140 and put out more at idle but when you are sucking 90 amps continious thats a LOT.

We had exactly the same issues as you with the same battery. It got so bad that I had to run to the parts store and pick up the biggest battery they had. :( Everyone has told us to "upgrade" to a yellow top. I looked into adapting the Escalade 145 AMP alternator (not too hard), but we selected to elliminate the alternator completely and charge between rounds. I am going to install another battery, vs. going with a 16V system.

what alt, are you running?
and i would rec. a bigger batt. rec the oddessy pc1200 dry cell. they have a larger one i believe a 1600 and even an 1800 but there is a big price jump and wieght gain.

i think jegs has the 1200 the cheapest. thats where i got mine.

I have a Yellow top and I have to say its the best battery I have ever had. When my Formula was down to the 10 bolt braking the car sat for roughly 6 months. I got in one day and it fired right up. The 3 month old Ac Delco battery in my Camaro took a shit so I pulled it out and threw in the Yellow top. I have put in 2 other cars, its in my Jeep right now untill I get the car back from the Fabricator.

We had exactly the same issues as you with the same battery. It got so bad that I had to run to the parts store and pick up the biggest battery they had. :( Everyone has told us to "upgrade" to a yellow top. I looked into adapting the Escalade 145 AMP alternator (not too hard), but we selected to elliminate the alternator completely and charge between rounds. I am going to install another battery, vs. going with a 16V system.

I used to run a pair of batteries without an alternator ina lot of cars and I dont think they will take an 80 amp constant draw for long. The fan/water pump draw nearly 40 amps, let them run for 10 minutes in the pits and even putting 30 amps in the battery is still discharging then its time to go again.

I just picked up the new alternator and I'm curious to see what it does, I may go to a smaller CFM radiator fan as well, this 3000 cfm fan draws over 25 anps itself and the smaller 1300cfm draws like eight. But there goes the street driving..

I guess I need a bigger battery charger in the pits too ;)

speedracerz,

Stock alternator right now (102 amp).

The yellow top 35 series comes in at the same weight as the odyssey 1200mjt and is cheaper as well. Plus has a higher reserve and higher amp/hour. The 122 has a higher short term crank amperage but they dont give at what temps and thats not really a huge concern for me.

are you running factory wiring or an aftermarket ecu?
more importantly how is the voltage output controled on your setup

as far as the optima, that is preferance. I have not had the best of luck with any optima i have run. they seem to have a short life. my tahoe is on its 3rd
one in the past 3.5 years, yes i get a prorated price each time, but id rather pay more and not have to deal with it.

when the yellow top in my f-body would no longer hold a charge i replaced with the odessey.

We're fighting an overheating problem with my car and the builder suggested the battery (one of those little Odyssey's, 680 I think) is causing some issues. I have the Magnafuel pump (same as KP's), big fan that came with my procharger, EWP, and whatever else is on (lights, stock stereo, ecm, etc). I always thought the alternator would run stuff so as long as the car started the battery was fine. Am I wrong?

Sorry for the thread jack BTW.....

Must be that water pump? Even after sitting for months my car starts right up. I have a redtop, and heavy gauge wire running to the front.

In our top sportsman car, we run two 16v turbo start batteries w/o an alt. and with charging between rounds we never had a problem. Turbo start is no longer around however.

In the nova, I run 2 red top optimas and a shogun alt. I race this car pretty much every weekend and when it gets down to the end, sometimes they round robin us and I've never had a problem in the 4 years we've raced the car. Again this car gets charged between rounds.

Im building a turbo 98 camaro 25.2 car now and im going to run 2 16v powermaster batteries and a powermaster alt.

The weight of the extra battery to me is worth it. The last thing you want is to get to the finals and your car wont start.

are you running factory wiring or an aftermarket ecu?
more importantly how is the voltage output controled on your setup

as far as the optima, that is preferance. I have not had the best of luck with any optima i have run. they seem to have a short life. my tahoe is on its 3rd
one in the past 3.5 years, yes i get a prorated price each time, but id rather pay more and not have to deal with it.

when the yellow top in my f-body would no longer hold a charge i replaced with the odessey.

Honestly I have a couple optimas here that are 3 years old and still working fine, lot depends on how you charge them but people are hot and cold on them and i can understand that. Car still has the stock wiring/PCM, the regulator is in charge of the system output.

TS6 if you are drawing 90 amps, a 100 amp alternator will on a good day maybe sustain 80 amps, way less at idle, so you are pretty much just draining the battery as you drive. Now put the battery in the back and you have even more voltage drop. I ran a PC680 all last year in front and it was fine, the bigger fuel pump and electric water pump seemed to have pushed me over the edge charging system wise. Plus letting the water pump and fan run after a pass to cool the car down takes a good 40 amps. Do that 10 times in a day with a 10amp charger and the battery just had it..

I think I just need like a 50 amp charger in the pits, the one I have will do 50 amps but its not regulated and thats rough on gel/AGM batteries. I just put the new 140a alternatore on there and I'm curious to see what kind of voltage it can sustain with everything on..

I always ran two 16v batteries and no alt in out TS/quick q16 car but that car didnt have the current draw this one did. I never had to go back to back rounds with that car though and had a big charger so it really wasnt an issue.

I think the problem is running the fan/water pump between rounds, these things are way bigger then a normal 'race car' fan/water pump. Plus if I leave the door open you have dome lights and if I'm messing with the PCM the ignition key is on along with a pair of widebands.. Only 30amps going in and using 50 is not that great lol. A pair of batteries would be a lot better of course but I dont have the excess horsepower power to be throwing another 45lbs in the back :(


In our top sportsman car, we run two 16v turbo start batteries w/o an alt. and with charging between rounds we never had a problem. Turbo start is no longer around however.

In the nova, I run 2 red top optimas and a shogun alt. I race this car pretty much every weekend and when it gets down to the end, sometimes they round robin us and I've never had a problem in the 4 years we've raced the car. Again this car gets charged between rounds.

Im building a turbo 98 camaro 25.2 car now and im going to run 2 16v powermaster batteries and a powermaster alt.

The weight of the extra battery to me is worth it. The last thing you want is to get to the finals and your car wont start.

I agree I think running the pump/fans between rounds with the car off is what is killing you. I've yet to have any problems (knock on wood) but I'm running stock alternator, optima red top, mechanical water pump and only a few small fans (<10 amps and <5amps). Weldon 2025 pump is prolly the biggest constant draw.

i had 2 red tops go bad with in 2 years so i went with the yellow and still cant hold a charge I think there a draw some were

I never ran my fans without the car on because I would see folks kill their batteries that way.

I always have the fans and water pump on after the run in the pits but I always have the charger on it. You for sure have more draw then what I do though with the bigger fans and all. Hope you figure out something. Ill think about this and see if i cant come up with a solution.

The new alternator really bumped up the voltage at lower engine speeds, now it holds 13.5v with everyting going including the rear window defogger.

I replaced the 3300cfm fan (26amp draw) with a 1600cfm fan (16 amp draw), killed the daytime running lights, took out one wideband and some bulbs and now with the parking lights amnd trans brake engaged I'm at like 75 amps draw. Now the cooling fan and water pump are drawing 30 amps instead of 40 so at least my 30 amp charger will be a wash when the they are on instead of drawing off the battery. Every little bit helps I guess, with the alternator putting out more at low speeds I should be able to get whole day at the track with just the 30 amp charger. We'll see..

jesus you're scaring me, I just put a pc680 in my car trying to shed some weight, left it mounted in teh stock location. I was gonna get a large single fan too to replace the heavy stockers.. and the elec. water pump was on my list. All taht, plus teh underdrive pulley, I think I might be cutting my own throat. Guess I can skip the water pump though, the hp that gives isn't a big enough amount to really worry about, still like to change the fans out to a large single, but now that's seeming like a slight risk. Definately no opening windows, radio use, or any fans on when the car's not running, that is for sure.

I went all last year with the single big fan and a PC680 up front and did fine. Part of the problem is moving the battery to the rear. To do the cutoff switch right you have to run the alternator wire to the back of the car, so now you have to go through 24' of cable to get to where the accessories are hooked up.

With the battery up front you will have no issues at all, I used to let my fan run for 5 minutes on the PCM when the car shut off and it still worked fine as long as I didnt have to start the car 20 times in the staging lanes.

Plus my alternator was original and even though it tested OK it never really seemed to do very well, this new one seems to be doing a lot better so far. I didnt do the electric pump for HP, I just wanted to be able to cool the car off quicker betwen rounds on warmer days. Its nice to get the car back down to 160 degrees on a 90 degree day in 5-10 minutes..

That's why I wanted to do teh pump myself, to cool the car off faster. The only racing I really can do is bracket racing around here (or street racing, nto that I'd ever do that) so consistency is important, moreso then the # the car runs really. Good to hear about the batt in the front and the fans, I wont' scratch that off my list now. You said you had a big one that you had on there, what model/size was it and what did it weigh compared to stock, and is it really needed for a bigger ci alum n/a setup, or could somethign slightly smaller be used?

Oh, I'm still on the original alt. too, but it's an 01 and only has about 19K on it, so it's not really that old if ya look at it like that.

I had the biggest spal they had on this car, like 3300cfm or something.

My N/A 414 I just ran the smallest 16" spal they had, drew like 8 amps and it was just fine. Never street drove it much though..

My alt only has 34K on it but a lot of dragstrip passes, these newer little alternators dont last a real long time from what I gather.

I still street drive my car a good bit.. so maybe something in the middle would be good.

How much weight do you think you shaved off with that fan, and how did you wire it, the one ground, and both positive feeds to teh single fan, ro did you only use one of them and program the other one to never come on, etc.etc.

one of the fans like the 2nd or 3rd oen down from the top of here ya think would work?

http://www.slickcar.com/pdfs/16Fans.pdf

Sure, they are all the same size pretty much just pick how much current you want it to draw, none of them will work as well as the stock fans but even the smallest should be fine for a drag race car.

FWIW new alternator really helped out, the thing puts out 100 amps at idle so with my reduced current draw with the new fan and some other little things disconnected I was able to make four passes using the water pump/fan between rounds and it was still at 13.8v at idle without even using the charger. Plus the voltblaster kicked it up a full 2v at WOT instead of half a volt like last time.

Probably costing me 20hp to drive the alternator now though but at least the battery is happier I think..

Maybe I missed it, but what alternator did you end up going with, brand?

J:D

Maybe I missed it, but what alternator did you end up going with, brand?

J:D

Local rebuilder rebuilt mine to a 140A for 120.00.

Cool thanks:D

My 98 TA
http://i5.photobucket.com/albums/y190/76ls1bird/100_0586.jpg

Could there be any chance my little battery is causing an overheat issue? I use an ewp, 2 fans, big fuel pump, etc. Car seems to cool down at sustained speeds, but stop and go and low speeds it just gets hotter and hotter. I'm even running the heater. I'm seeing voltage of 12.7 or so at idle now. Car starts right up every time.