Electric Motor knowledge needed

[pstephens46]

Gentlemen! Been awhile, hope everyone is healthy and happy!

Yam, it’s an F150TXRD. The electric motor in question is the starter motor. Question- is it possible the starter might pull enough excessive current to greatly shorten battery life? Are there specs on normal expected load range?

[99yam40]

I have no idea if there are spec on starter amp draw,
but with the short duration of the starter running (drawing amperage)
I would not think it would/could hurt the battery.

[boscoe99]

Diagram below shows peak current flow. In practice using an ammeter one will see more or less 150 amps.

I don't see a defective starting motor damaging a battery. If something is amiss with the starter motor the operator should be able to quickly notice it.

[DennisG01]

Agree, I can't see a way how a "normally" acting starter could ever do that. Not even if you had a bigger starter on there (which you wouldn't, obviously).

Does your question boil down to why you have a battery that is failing too soon? There's much more likely sources for that.

[pstephens46]

Thanks for replies. More testing needed. I’ve had an ongoing issue with voltage drop ongoing for 7-8 years. Most everything has been replaced from batteries to engines. Cables, connections etc. You would have to experience it to believe it.

another topic…Anyone heard from Rodbolt? I have another customer trip to Oregon Inlet in a couple weeks. That’s very close to where he worked in Wanchese NC. If the damn trip isn’t canceled for weather, I may drop in for a visit to his employer there. Last trip was canceled the day before. I’ll take my chances. I did speak with him on the phone once. Quite a character. I’m sure that’s not a surprise.

[99yam40]

Thanks for replies. More testing needed. I’ve had an ongoing issue with voltage drop ongoing for 7-8 years. Most everything has been replaced from batteries to engines. Cables, connections etc. You would have to experience it to believe it.

another topic…Anyone heard from Rodbolt? I have another customer trip to Oregon Inlet in a couple weeks. That’s very close to where he worked in Wanchese NC. If the damn trip isn’t canceled for weather, I may drop in for a visit to his employer there. Last trip was canceled the day before. I’ll take my chances. I did speak with him on the phone once. Quite a character. I’m sure that’s not a surprise.

I once called or emailed/messages the place he worked years ago asking if he was still working there.
he was at the time, but I thought he was heading south to where his wife was from.
he has not been on here for quite some years now.

when you say voltage drop, I am not sure what you are meaning.
to the starter?
to the gauges?
to the battery from the motor?
from the battery to the motor?

[DennisG01]

A couple quick things you can do...

-- Turn everything off and remove the negative battery cable. Put your DVM on 10 amps and connect it between the cable end and battery post. You SHOULD see well under an amp.

-- If you do find high parasitic draw, remove one fuse at a time while monitoring your DVM

[FabricGATOR]

Corrosion inside a stranded cable's insulation... if you can imagine stranded copper cabling. New, bright and shiny, they all touch and the all carry the electrons. When corrosion gets into the siliconized rubber and works its way inside the cable, I can imagine each strand becoming its own insulated tube of copper and thus limiting the ability to carry trillions of electrons at the speed of light. We see 12 or 14.3 vdc with a multimeter (low load) but how much of it can carry the flow (current) when required to move a lot.

Then I relate my previous futility in trying to re-terminate an old cable 'to salvage it' 'to repair it'... Even using table salt dissolved in vinegar to clean the copper so as to solder on a new lug VS swaging

As I look up the list, I recognize that you are all old hats at this. I am not teaching anyone of you anything new here BUT, these writing are read by many others less experienced and perhaps they can gain a better understanding of reading the voltage when load is applied (voltage when cranking)

[Keithbaja]

Sounds like you need to do a simple voltage drop test to starter solenoid,, then to starter...

[zenoahphobic]

We all sometimes reach a point when we are stumped and then suspect all sorts of things.
It then requires a clear head and a slow back to basics analyses.
A starter motor is really only designed to run a very short time, they heat up, chew brushes and grind communtators away. They also gain carbon between communtator tracks that draw power and make the motor inefficient, so they do need maintenance. And they can test a battery to the point that the current can pull the internal battery plates together and short them.
I’m saying nothing new here just reminding.

[Keithbaja]

A marine battery is built with sturdier plates, wider spacing between the plates and a much larger space beneath the plates to help with plate chunks accumulation as to not short.

[zenoahphobic]

A marine battery is built with sturdier plates, wider spacing between the plates and a much larger space beneath the plates to help with plate chunks accumulation as to not short.

True,, but I got one here, a reputable marine designated. Did the one cell shorting trick on me. Had this happen very rarely, but it does happen and just recently did, hence my post.