starter current draw?

Copy of post to alt.autos.studebaker - car in question is a '55 Commander coupe with '63 model 289/automatic. otherwise mostly stock. I did get some good responses there but they all either point to a bad starter or a too-small battery, anything else I should check? Is there any rough guidelines for how much a starter should draw? my shop manual does not specify.

Reply to
N8N
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For you, I am going to do an experiment. I am going to amp the current draw on the starter for my 2003 taurus ( merc sable ).

I'll be back:

230.9 amperes DC U code V6 vulcan 182 cc displacement, 152 hp

Lg

Reply to
Lawrence Glickman

make that 182 cubic inches displacement ;-))))

Reply to
Lawrence Glickman

Hmm, this is making me question the accuracy of the little meter I borrowed (some Japanese thing of unknown age that just sits on the battery cable and has an analog movement.) Perhaps I need to invest in a good Fluke clamp meter. (you'd think with all the money I've spent on tools over the years I'd have everything I needed by now; you'd be wrong.)

Seems like the battery is the prime suspect if your readings are accurate; I can't imagine a 289 would take significantly less current to crank over than a little V6. Granted, it's got (relatively) low compression (8.5:1 or thereabouts) and unknown mileage, but it seems fairly "tight" at least ring-wise, and holds good oil pressure.

I guess that also means that a battery load tester might be a good investment... (that "giant sucking sound" you hear is the sound of my banking account being depleted.)

Or I could just buy one of those portable jump start things and carry it with me wherever I go... (that would be what's known as an inelegant solution)

thanks for the input...

nate

Reply to
N8N

Yes, I am using the Fluke-type clamp meter with the *max hold* turned on. It is new, has never been been dropped ( handled like a baby actually ).

It takes a number of starting cycles to get up to the maximum reading. When the number of amperes doesn't increase anymore, but holds steady in repeated starts, you've got the reading.

Yes, I have one of those also. You're right about the "giant sucking sound" of your wallet being vacuumed dry ! ;-((((

Glad to help.

Lg

Reply to
Lawrence Glickman

I would far prefer the "giant sucking sound" of four hungry venturis taking in a big slug of atmosphere through an open-element air cleaner, but it seems you can't have one without the other :(

I don't think I need to mention that since a) we're talking about a 50 year old car here and b) it's mechanically completely a mutt, although fairly well done (well, it is now after I fixed a few pretty egregious previous-owner errors) that taking it to a mechanic is a completely last-resort kind of proposition...

nate

Reply to
N8N

Back to basics, then. What are the voltage drops, measured at the battery and at the starter terminal, with no load and during the unsatisfactory cranking? And what are the off and vehicle-running voltages at the battery posts?

I suspect that if it cranks fine with the booster but not with the battery alone, that's a hint, but before condemning parts, we need to see whether the battery is kaput or merely not getting a good charge.

His battery might or might not be good. His cables should also be carefully checked all the way from end to end, with attention both to the vicinity of the terminations and to how good a connection they are making. (Don't all the best problems have more than one thing going on at once?)

Starters are a rather specialized sort of motor that can do a huge amount of work, relative to their size, for a short time. (Or a medium time or a lot of short times in quick succession, if one enjoys the financial and mechanical aspects of replacing them.) A lot of work at low voltage means a lot of current.

I think we're usually talking about a couple hundred amps, not three or four hundred, for automotive starters; but first I suggest he make sure the battery is putting out the proper voltage under load, and that said voltage is making it all the way to the starter.

See for instance

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Reply to
Ad absurdum per aspera

To add to the info given, the battery is at about 12.1V measured with my (ancient) Fluke with the key off, and 14.3ish running. So I don't think that the alternator is at fault. However the 12.1 seems a little low, but I don't have a more finely calibrated meter to check with.

Battery cables from the battery to the starter solenoid and from the battery to the engine block are brand new 1 gauge. I did not replace the big cable from the solenoid to the starter but it appears to be in good shape. I suppose in the interest of completeness I ought to check the voltage drop of that particular section of cable however.

The voltage drops to about 9-10V while cranking, again measured at the battery. I did not check voltage drop across the solenoid or overall from the battery to the starter simply because it wasn't convenient to do so. I am thinking that perhaps 9V isn't enough to fire the coil even with the ballast resistor bypass.

Now when the car has been running, it starts lightning quick. But if it doesn't start on the first crank, it's not going to start without the booster battery. With the booster hooked up, again, it starts lightning quick.

I am curious about the state of the battery - it's only 6 mos. old but it does seem to be the most likely culprit. Unfortunately I do not have a battery load tester :/

nate

Reply to
N8N

Charging circuit is doing its job...

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That indicates a *weak* battery. You don't want the battery voltage to drop below 10.4 volts whilst cranking the starter motor.

It could be you just need to charge up your battery with a battery charger. It could be as simple as that. If you are doing a lot of short trips around town, maybe the battery isn't getting fully replenished by the alternator each trip and needs a nice charge in your garage ( which I do to mine periodically, especially during the winter months when I am running headlights, heater fan, window defogger, etc. during short trips ).

See instructions: run hi beams 10 minutes with engine off to dump

*surface charge.* Then watch voltage across battery terminals whilst cranking engine. Should =not= drop below 10.4 volts.

I think all you really need to do is put the battery on a charger periodically as I do, even with my *new* used car, and you will be OK.

In the summertime I might do it once/month.

In the wintertime, if it is _really_ cold, I might just do it every night on trickle, because of the short trips I make to the commuter train to drop off the wife.

Lg

Reply to
Lawrence Glickman

What is the CCA of the battery you are using? You cannot use a battery from a 4 cylinder car in those V8 engines. They just don't deliver enough power. Back in the 70's I had the battery go dead in my Olds. I tried umpiring from a Vega. Wouldn't even turn it over. Get the correct size battery for the car.

Reply to
Woody

The OP must just likes to play aroung with this thing and there's nothing wrong with that. He describes an almost dead battery by his own numbers. You can purchase a high amp battery in a fairly small envelope today so there should be no problem replacing the bad battery this afternoon.

Reply to
Al Bundy

I agree, but is it common to have a bad battery out of the box? This battery is only a couple months old and doesn't have many miles on it at all.

nate

Reply to
N8N

I think it is 650 CCA - it was basically the largest case I could fit in the old Group 1 battery box in a 12V flavor. There is no "right" battery for the car as it originally had a 259 and 6V charging system, and has had a heart transplant from a '63 Lark.

nate

Woody wrote:

Reply to
N8N

Sure if it never got a deep charge to start. A battery that is only used once in a while needs a good deep charge now and then.

A dried out or polished up fan belt will also only half charge the battery. I test them with a cold off engine and see if I can make the alternator pulley slip by hand. If it will hand slip, it will not hold good enough to charge the battery under load and you will always have marginal starting power.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's
Reply to
Mike Romain

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