dual batteries

[motorhead446]

I'm considering adding a second battery in the trunk. More often than not I find I have to run my electric fan while in the staging lanes. Between the starts and fan i m usually right at twelve volts and 190-200 deg when I roll up to the line. Any suggestions besides a better battery? The current battery is not old but doesn't seem to hold well. I run the smaller power master alternator so my idle output is not great.

 

[mderoy340]

put a square back alt in with electronic voltage reg. add switch in the field circuit. Switch field off after you stage, turn back on after run.

 

[motorhead446]

What does this accomplish?

 

[mderoy340]

squareback alt will have better output at idle. Switching the field off prior to run cuts output off = no load

 

[pete9857]

Do you have an electric water pump? Also, bring a big friend to push you through the lanes or a golf cart. 180 is my max at staging in a dragster.

 

[motorhead446]

Do you have an electric water pump? Also, bring a big friend to push you through the lanes or a golf cart. 180 is my max at staging in a dragster.

I do not have an electric pump but I am considering one. This season I started charging my battery between rounds to see if it helps. It seems to help. i sometimes will run the fan after returning to my pit to help cool the car faster with the charger attached. I feel a electric water pump would help cool it faster also. I would need a good battery reserve to run the pump during the run if I had the field off. Just weighing my options. Its only on really hot or muggy days that I start having the temp issues. It rarely gets over 200 deg. I really just want to have consistent temp and voltage during my passes.

 

[bOb shingler]

consider a marine trolling battery as a replacement. they hold the voltage and amps up for a longer period of time unlike a automotive battery which starts to drop off the second you use it.

 

[pete9857]

With an electric pump, sometimes you don't need the fan on and you obviously don't run the engine. If the radiator is large enough, the water flowing from the pump will bring the temp down.
Back in the day, I had a quick release top hose on my Duster and would pour gallons of water backwards through engine to cool it off in staging lanes. Yes, a long time ago!
I used a moroso electric motor and cog belt to spin water pump.

 

[Duane]

I would either add a second battery or a single huge one for more capacity.
Depending on you track that you run at, if you have a successful day they may hot lap you.
The electric water pump is great to bring down the engine temp rapidly but you may not have enough time to get a good charge. I lost races years ago because of this scenario when I could not get the car started when in the lanes due to inadequate time to charge. Not the way you want to lose. You could also then more safely turn off the field to the alternator without so much worry about the voltage falling to low especially with a capacitive discharge ( msd etc) ignition
Which does not like low voltage.

Just my opinion.

Duane

 

[tubtar]

Unless you want weight and or balance , two batteries is a bandaid.
A decent alternator should provide enough juice to run all your accessories with amps to spare.
Switching it off to give you more h.p. is cool if you are class racing or need every 100th you can get. I don't see it as necessary for a bracket deal.
We used a Tic-Toc sequential switch to cool down between rounds.......especially late in the day when time between passes got shorter.
Shogun industries made them..........they would cycle between the water pump and fan , and could cool the car down in about four minutes.
Something like 30 seconds of water pump to cycle the coolant out of the radiator , then 45 seconds of fan.
Even using this , starting was never a problem in the late rounds.
I have not tried the trolling motor battery , but I have heard of guys who liked them.
I always get the biggest battery I can and make sure everything is well grounded and works like it should. Electric water pump , fuel pump , fan , MSD ignition and line lock is the extent of amp load and I have a charging system rated at about 40% over the max load.