Down a rabbit hole at Mosport last weekend.....

[billtebbutt]

Well,

Before race #2 on Sunday, I hit the starter button to run the motor a bit. "Click". So I check the voltage at the battery and the starter - 12.5v. It is the solenoid then, right? Whip out the old one, fire in the new one - "Click". Same reading at the starter and battery, but the wire to the solenoid when engaged is now <9v. WTF???

Has to be the starter, right? Whip out the starter, fire in a new one. "Click". ARGH! Now we are looking for a wire shorting out in the solenoid circuit, a duff switch, etc. Whip in another starter, car starts multiple times and runs fine. Whatever.....

A couple laps into the race (under yellow) the ignition system fails and comes back a few times, and, deciding that discretion is the better part of valor and should we go green again (turns out we didn't) I didn't want to be *that guy* that again puts us under yellow by having to retire the car somewhere on track, I pull into the paddock and retire from the race.

I put the 4amp charger on the battery, and wait. For a couple of hours. It will not take a full charge, so the problem is clearly the battery. Replace the Odyssey dry cell with a new one, and the car runs great all weekend. Problem solved

My question for you folks is simply, "Where did my critical thinking fail?" As in, without a load tester at the track, how could I have easily diagnosed the problem earlier and saved myself a lot of effort and swearing?

best
bt

[Lastminuteracin]

So you had voltage but no amps? I too would be interested in how to diag that at the track.

[TimH]

Whip out the old one, fire in the new one - "Click". Same reading at the starter and battery, but the wire to the solenoid when engaged is now <9v. WTF???t

There was your load test?

[E1pix]

Voltage means very little compared to cold cranking amps.

I use something like this...
EDIT, this is exact model I have:
https://www.napaonline.com/en/p/SORBA9

[billtebbutt]

There was your load test?

Yeah I guess so Tim. But I was pretty flustered, and maybe not thinking all that clearly...
bt

[E1pix]

If it takes anger to not think clearly, I wanna be mad more often.

[FVRacer21]

Well,

My question for you folks is simply, "Where did my critical thinking fail?" As in, without a load tester at the track, how could I have easily diagnosed the problem earlier and saved myself a lot of effort and swearing?

best
bt

If you had a bad connection in the battery that was intermittent - you basically did nothing wrong.

Even with a broken connection you will usually read full voltage until you put any load on it. (Not familiar with some of the high tech batteries so someone can chime in on the voltage readings while failing).

Since you have a new solenoid, starter and battery in right now, I would disable the ignition and note the voltage when cranking with a fully charged battery. Maybe check during a weekend to see how the voltage drops when the battery is not 100%.

In the future - use a jumper to start the car to test the solenoid and starter. Takes the battery out of the system.

But sometimes you cannot find what fails until it totally fails however. If this was a championship race I would change everything and then look for the problem, but rarely can we afford to do that.

And then is when you find the bad wire...

ChrisZ

[FVRacer21]

Voltage means very little compared to cold cranking amps.

I use something like this...
EDIT, this is exact model I have:
https://www.napaonline.com/en/p/SORBA9

I have been holding off buying one of these, but it seems to be the type of tester everyone is using.

I have been old school using something like this:

I am not sure I would use the old school on any of the new hi-tech batteries....

https://www.harborfreight.com/1000-a...ter-58933.html

They still have the classic

https://www.harborfreight.com/100-am...ter-61747.html

NAPA seems to have more quality, but if you are cheap there is this:

https://www.harborfreight.com/12v-di...ter-58759.html


ChrisZ

[Offcamber1]

My question for you folks is simply, "Where did my critical thinking fail?" As in, without a load tester at the track, how could I have easily diagnosed the problem earlier and saved myself a lot of effort and swearing?

bt

I don't think your critical thinking failed at all. Logical progression to isolate the problem was followed. Unless you had the proper tester or were an electrical engineer by trade it sounds like you now have a spare good starter, solenoid, and know to always carry a good spare battery to the track.

[TimH]

And then is when you find the bad wire...

Connecter crimp last weekend. But then the solenoid failed the next day, and the starter itself the day after. It was just their time...

[scott fairchild]

If you don't have a load tester, use a Halogen headlamp bulb as a substitute for your solenoid then starter motor. It will provide enough load to check for broken wire strands or poor connections. Remember that ONE strand of wire can carry voltage, but can't handle much amperage. Visually check the brightness for 10 seconds or so. A voltage drop test, while cranking, can also be helpful.

I've been known to bring a lab-scope and amp clamp to the track before, but know I'm probably the only one who does.

Cheers,
Scott

[Hawke]

If you don't have a load tester, use a Halogen headlamp bulb as a substitute for your solenoid then starter motor. It will provide enough load to check for broken wire strands or poor connections. Remember that ONE strand of wire can carry voltage, but can't handle much amperage. Visually check the brightness for 10 seconds or so. A voltage drop test, while cranking, can also be helpful.

I've been known to bring a lab-scope and amp clamp to the track before, but know I'm probably the only one who does.

Cheers,
Scott

Scott, you are not the one one. I take my two Channel PicoScope to the track, and it’s invaluable in finding problems. There is no other way to measure secondary voltage.

[E1pix]

I have been holding off buying one of these, but it seems to be the type of tester everyone is using.

I have been old school using something like this:

I am not sure I would use the old school on any of the new hi-tech batteries....

https://www.harborfreight.com/1000-a...ter-58933.html

They still have the classic

https://www.harborfreight.com/100-am...ter-61747.html

NAPA seems to have more quality, but if you are cheap there is this:

https://www.harborfreight.com/12v-di...ter-58759.html


ChrisZ

Hi, Chris:

I should clarify I’ve only used our tester for street and house (van) batteries, so don’t know if racing batteries are different, or requiring a tester with inputs for other battery types.

Ours are lead acid gels, aka, AGMs.

[Pi_guy]

Buy the one from NAPA

I have carried one of the toaster type testers since the 70's. It is the one go to tool for confirming you have a proper voltage source.
It has settled more bad battery questions than I care to remember.
The testing of a master switch becomes much easier with one of these, testing of other components is very achievable often with a little care in the process. The trick is watching the swing of the meter. The downside used improperly you will make equipment permanently fail.

I have a few other load testers also but this one has paid for itself many time over.

[Lotus7]

[QUOTE=Pi_guy;656203]Buy the one from NAPA

/QUOTE]

So I looked it up, and it says this:

"... and is optimized to test six distinct battery types. These include conventional flooded acid, AGM flat plate, AGM spiral wound gel cell, start-stop AGM and start-stop enhanced flooded batteries."

There I was thinking I sorta understood acid vs AGM vs Lithium, but now there's 3 kinds of AGM?
How does one know what one's testing?

Any education gratefully appreciated.....

[E1pix]

In my experience, the model number should be enough to research it and identify the type.

If we ever get our budget set, and our Vee out, I will load-test the battery throughout the weekend. I rely heavily on “real” charge to be able to work on the road, so have built some protocols and this is one.

We once had a house AGM test at normal voltage, but the CCA showed 9 instead of the spec 1100 aH. It was junk, despite the voltage.