Battery disconnect

January 10, 2022, 07:06 AM

183N

Battery disconnect

More like, it does happen as SL mentioned and so did tas. Just because it hasn’t happened to you yet doesn’t mean it doesn’t happen. But it is going to be funny when you roll a car out of the trailer one day and the battery is dead because the diode stuck on your hot wired alternator.

Like 67TSCHEVY, I want no power past the disconnect switch when the switch is off. Much safer not having a 10’ hot wire to risk shorting out. A good way to accomplish this is with the aforementioned 4 post switch.

January 10, 2022, 07:45 AM

Undertaker II

In a typical dragster situation with the fuel cell behind the driver and the alternator wire less then two feet away from the fill neck, I'm wanting that alternator wire to be dead with the master disconnect off in the event of an accident. Just because some people do things a certain way and have forever doesn't mean it's the only or best way. Why Ed still talks about Undercover and how they do/did things in this day and age still baffles my mind. Good luck with whatever way you choose> Kevin

January 10, 2022, 07:52 AM

1320racer

I ain’t skeered neither are the thousands of racers who’s cars are wired the same l neither are the builders who are wiring cars exactly the same right now.

Further, I’ve got 2 of the best battery chargers, 2 spare alternators, 1 spare battery and my cars are on the charger overnight at every event. Again, a non issue and no concern to me.

January 10, 2022, 07:52 AM

DragRaceResults

lol... Ed your stuff's a dinosaur just like I told you a few weeks ago. Step up, move on, sell that tank. Things change, actually for the better. Besides it's worth a fortune now since your blessed by crook Kurt chassis is a dinosaur.

If you have a 50lb dinosaur battery like you use, the diode can probably stick and it be ok for a month. If you have a latest state of the art LI battery there isn't enough reserve capacity.

Come on man...

January 10, 2022, 07:57 AM

1320racer

My dinosaur still turns on a lot of win lights and collects big checks.

Again over 3 decades and not only haven’t I had this issue, I don’t personally know 1 racer that has.

January 10, 2022, 08:02 AM

DragRaceResults

lol now you know 2

January 10, 2022, 11:02 AM

329L

SL,
What is your opinion on the master switch that Danny Nelson cars usually have that is an electric cut off? I have re wired several of these cars, and it seems to work just fine. I really prefer mechanical switches for this, but one time i had a friend that was in a bad wreck in his dragster, and it had a mechanical switch in it, and because the chassis was twisted up and the cables were in a bind and wouldnt move the switch, "luckily" the car was on its side, and i was able to punch the switch and get the car to shut down. In that situation, an electric cut would have been better, because worse case, i could have ripped the wires off the switch. NHRA doesnt seem to care one way or another, as long as it has a working disconnect switch.

January 10, 2022, 11:20 AM

1320racer

I know Elite Chassis has used this switch in their cars.

January 10, 2022, 01:44 PM

SP 124X

quote:
Originally posted by 329L:
SL,
What is your opinion on the master switch that Danny Nelson cars usually have that is an electric cut off? I have re wired several of these cars, and it seems to work just fine. I really prefer mechanical switches for this, but one time i had a friend that was in a bad wreck in his dragster, and it had a mechanical switch in it, and because the chassis was twisted up and the cables were in a bind and wouldnt move the switch, "luckily" the car was on its side, and i was able to punch the switch and get the car to shut down. In that situation, an electric cut would have been better, because worse case, i could have ripped the wires off the switch. NHRA doesnt seem to care one way or another, as long as it has a working disconnect switch.

When I rewire my dragster this winter I'll be using a solid state battery disconnect with switches.

January 10, 2022, 02:13 PM

Goob

Leaving a single circuit live when "disconnected" from power is just ignorant.
Especially one that carries a 100 Amp + load.

Carry on with your arguing if you want.

January 10, 2022, 03:14 PM

Mike Frizie

anyone got a pn for the solenoid being used for the shut off?

January 10, 2022, 03:27 PM

SP 124X

quote:
Originally posted by DRB Motorsports:
anyone got a pn for the solenoid being used for the shut off?

Cole hersee 24213 is what I've used

January 10, 2022, 03:43 PM

183N

quote:
Originally posted by Goob:
Leaving a single circuit live when "disconnected" from power is just ignorant.
Especially one that carries a 100 Amp + load.

Carry on with your arguing if you want.

My thoughts exactly. Easy enough to wire it this way, not sure why anyone would want a large high current wire always hot in 2022 when 4 post disconnects such as the Cole Hersee 75912 are easily available.

January 10, 2022, 04:04 PM

Toad1

I got my master disconnect solenoid from Fastronix. Joe Schmall has a great line of products.
I do one thing I didn't mention. I have a manual Moroso Master Disconnect on the Alternator cable. When I tow longer distances I kill the power to the alternator, just in case. Other than that the alternator wire is always live but in 12 years, on three different cars, no issues. Simple wiring for On-Off Master Switches. As long as the car shuts off when one of them is pushed in, all is good.

January 10, 2022, 05:41 PM

TOP38

quote:
Originally posted by 183N:
quote:
Originally posted by Goob:
Leaving a single circuit live when "disconnected" from power is just ignorant.
Especially one that carries a 100 Amp + load.

Carry on with your arguing if you want.

My thoughts exactly. Easy enough to wire it this way, not sure why anyone would want a large high current wire always hot in 2022 when 4 post disconnects such as the Cole Hersee 75912 are easily available.

First I agree the 4 pole switch is a good idea but if you think not using this deal is a major issue then I guess you better move all your cars out of the garage attached to your houses cuz they may burn the house down! There are more potential issues with fire caused by "Rat Nest" wiring hack jobs then having one small wire run from the bat to the alt!

Just saying.

January 10, 2022, 06:46 PM

183N

Agreed!

January 11, 2022, 02:52 PM

CURTIS REED

For you guys wanting good relays to carry over 100 amps look here. They give good info on some of them about how much inrush amperage they will handle along with the continuous amperage and voltage. If you can't find what you need on here they probably don't make it.

https://www.texasindustrialele...c.com/relays.asp#top

January 12, 2022, 05:18 PM

Goob

quote:
Originally posted by TOP38:
quote:
Originally posted by 183N:
quote:
Originally posted by Goob:
Leaving a single circuit live when "disconnected" from power is just ignorant.
Especially one that carries a 100 Amp + load.

Carry on with your arguing if you want.

My thoughts exactly. Easy enough to wire it this way, not sure why anyone would want a large high current wire always hot in 2022 when 4 post disconnects such as the Cole Hersee 75912 are easily available.

First I agree the 4 pole switch is a good idea but if you think not using this deal is a major issue then I guess you better move all your cars out of the garage attached to your houses cuz they may burn the house down! There are more potential issues with fire caused by "Rat Nest" wiring hack jobs then having one small wire run from the bat to the alt!

Just saying.

I agree to the hazards of the wire nut and scotch lock electricians, but O.E. vehicles do have those live circuits fused or fusible link protected.
Just saying.