Battery voltage at starter

February 01, 2023, 08:48 PM

M802138

there are a lot of variables

how are your cable ends attached to the cables?

How much resistance does your cable have?

then all connections?

Went through this and learned a voltage drop test to find things, and things I did find. Lots of them. Shutoff switch, cable, solenoid, starter cable connection, and quite a bit more. It was easier and a little less expensive in my case, to re-wire the entire car.

I switched to 16v many years ago and it's been fine but now that the wiring is all in good condition, it can and very well might go back to 12v. 12v battery is a little less expensive and a 12v charger is considerably less expensive. And everyone's got them. Cant say I have seen a 16v battery charger in a parts store, wal-mart, or really anywhere else other than order it online-but admittedly, "speed shops" do not exist much here, and the few that do, they do not do anything 16v.

February 02, 2023, 08:59 AM

sr4440

quote:
Originally posted by Eman:
The most misunderstood use of a DVOM is a voltage drop test.

^^^^this^^^^ If people would learn how to do a voltage drop test, they would stop "guessing" at what is wrong.

Joe

February 02, 2023, 09:42 AM

TOP38

quote:
Originally posted by sr4440:
quote:
Originally posted by Eman:
The most misunderstood use of a DVOM is a voltage drop test.

^^^^this^^^^ If people would learn how to do a voltage drop test, they would stop "guessing" at what is wrong.

Joe

Your both wrong, the issue is wiring the car correctly in the first place.

February 02, 2023, 10:30 AM

1320racer

This^^^

February 04, 2023, 07:52 AM

adv ET 266

I may of missed if you said if this is causing a starting problem.
Options
16v battery
Relocate battery. My M&M was just in front of foot fire wall
Run a larger or better cable. Perhaps double up on the 0 gauge.
Did you actually use long meter leads and measure from battery pos terminal to starter power terminal? Or just read at starter and assume battery terminal stayed at the no load voltage?
Did you check the grounds? Does engine have an actual copper ground to chassis or reliant on mechanical at mid plate bolts? I’m assuming a dedicated ground from battery to engine was not used and the chassis is the ground.

This message has been edited. Last edited by: adv ET 266,

February 04, 2023, 09:47 AM

Eman

quote:
Originally posted by TOP38:
quote:
Originally posted by sr4440:
quote:
Originally posted by Eman:
The most misunderstood use of a DVOM is a voltage drop test.

^^^^this^^^^ If people would learn how to do a voltage drop test, they would stop "guessing" at what is wrong.
You can wire the car correctly but things wear out and deteriorate over time. If you don't know how to diagnose you might as well rewire the car and replace all of the parts anytime you have a problem.

Joe

Your both wrong, the issue is wiring the car correctly in the first place.

February 04, 2023, 01:58 PM

Nitrous1

Not having issues. Was just wondering if others with dragsters with a single 12v battery in the nose are seeing similar readings at the starter. Anyone actually seeing 9.5+ volts?

February 25, 2023, 06:36 AM

Hammertime

Correct cable to the starter is only part of the equation here. Absolutely the correct size battery cable matters, but so does the starter choice, grounding, relay choice based off starter, battery choice, on/off switch… the list goes on and on.

I’ve fixed dozens of these issues for racers. 90% of the time you’ll find a bad grounding setup, bad crimp or inappropriate starter/relay/battery combination. Does matter if it’s 12v or 16v all this matters.

February 25, 2023, 05:34 PM

Ron Gusack

quote:
Originally posted by Hammertime:
Correct cable to the starter is only part of the equation here. Absolutely the correct size battery cable matters, but so does the starter choice, grounding, relay choice based off starter, battery choice, on/off switch… the list goes on and on.

I’ve fixed dozens of these issues for racers. 90% of the time you’ll find a bad grounding setup, bad crimp or inappropriate starter/relay/battery combination. Does matter if it’s 12v or 16v all this matters.

Do you solder, crimp or both on cables?

February 27, 2023, 10:15 AM

TOP38

quote:
Originally posted by Ron Gusack:
quote:
Originally posted by Hammertime:
Correct cable to the starter is only part of the equation here. Absolutely the correct size battery cable matters, but so does the starter choice, grounding, relay choice based off starter, battery choice, on/off switch… the list goes on and on.

I’ve fixed dozens of these issues for racers. 90% of the time you’ll find a bad grounding setup, bad crimp or inappropriate starter/relay/battery combination. Does matter if it’s 12v or 16v all this matters.

Do you solder, crimp or both on cables?

A good crimp with NOx or any copper corrosion inhibitor will work but I solder mine to seal that connection. The shrink wrap it.

February 27, 2023, 08:11 PM

rusty

a crimp only,can vibrate and crack and loose connection.crimp and solder.yes this has happened to me

February 28, 2023, 01:44 PM

rusty

quote:
Originally posted by rusty:
a crimp only,can vibrate and crack and loose connection.crimp and solder.yes this has happened to me

i got words mixed up solder only and it can crack

February 28, 2023, 02:41 PM

BG7X77

Pros and cons to each. To eliminate crimp resistance we soldered the crimps, yes electrically that is the best you can get, however solder can cause a potential for cracking behind the joint. Soldered and secured and isolated from vibration is the optimum configuration, however that is not always possible depending on the location.