Alternator charging issues

[mjs2011]

First off, I apologize if this question has been asked too many times. I am on my phone away from home, and have tried searching, but the search bar is **** and I didn't come up with much.

So I have been having some hard starts lately due to slooooowww cranking. Well, I was at home and grabbed my dad's load tested to check my batteries. They are only three years old so I thought they should be good. Load tested them individually and each one held good for over 15 seconds, the tester only States 10. So then we hooked it back up and fired the truck up, the alternator sat around 13.5 volts on the charging gauge, which is the border between bad and good on that tester. Shut the truck off and the voltage gauge hardly moved, so my alternator isn't charging. Now, my veggie system requires a lot of power to run, as I have a beefy electric fuel pump for wvo, resistance injector line Heaters, and a filter wrap heater. With these charging issues, I can't run the filter wrap heater at all, and can only run the injector line heaters intermittently, without causing the voltage gauge in the dash to drop down too low.

So, what are the common causes of no charging with these alternators?

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[typ4]

Bad alt or reg, With your loads I would highly advise a 3g conversion, many articles on it, very simple.

 

[riotwarrior]

13.5 volts is absolutely fine for charge rate.

You need to calculate max load on system, and what Alt is rated at and compare to ensure you are not draining more than Alt can return to system.

How is starter is it dragging? Is it weak?

A load test on the Alt should indeed help determine if it's adequate.

JM2CW

 

[icanfixall]

Upgrading the alternator is a good idea but the 13.5 volts is what you want to see for a properly working alternator too. What an alternator does is refills the battery after a start. then it supplies all the voltage and amps to run every electrical component on the truck or car. what they are not supposed to be used for is recharging a dead battery.

 

[mjs2011]

Batteries are fully charged. I have to top them up about every two weeks. Then it starts good for a while and starts to slow down, so I charge again. I don't think the starter is weak, it cranks just fine when I have the batteries topped up, it just seems the alternator isn't keeping up and after some time, the batteries need a charge.

I was under the impression that an alternator should provide between 13.8 and 14.2 volts. Google confirms that notion. 13.5 seems to be borderline low. Possible voltage regulator?

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[ToughOldFord]

I had a set of batteries like that, turned out one had a bad cell.

 

[mjs2011]

When running my veggie system, I have the pump drawing around 10 amps, the injector line heaters drawing 16 amps, and the fuel filter wrap, which would draw 16 amps, but I can't run it at the same time as the other equipment. So I'm drawing just over 25 Amps for my veggie system, and add on that headlights, blower motor, stereo to give an idea of my power draw. That doesn't seem too high to me.

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[typ4]

Check voltage with headlights and heater on, only, fast idle, if voltage drops the more you turn on you have some toasted diodes. and 13.5 is fine on external reg. there is an adjustable reg for them, ill did up the transpo number if you find thats it, before the 3g conversion I had my 1g set to 14.2 and it quit blowing headlights. Low volts are ******* halogens.

 

[riotwarrior]

Google says it's more than 13.5 so it must be eh?

I'm saying 13.5 is about ideal, or you tend to cook cells in my exp....funny how internet is like that ROFL leading info both ways.

I'd not want to go above 13.8 max for normal use.

What is all this veggie stuff about anyway? Why not use a heater in tank from cooling system?

Sounds really complex to me, I ran straight WVO in my tanks with little to no problems, in the past in summer and blended for winter...but that's me.

If possible check specific gravity of battery cells after depleted, mark that down then do same when charged.

The loss of charge is likely more important that what the Alt has to do to keep it charged. I'm suspecting something keeping a draw or bad cell more than alt based on 13.5 volts charge, and really it's more the amperage at that voltage that's the more important #

Again I'd be looking into a load tester that can be utilized to test an alternator to check it's rate of charge at a specific voltage.

JM2CW

 

[mjs2011]

If any sort of reliability is to be expected with a veg oil system, these heaters are required. The viscosity of oil at different temperatures varies greatly, and it's not until nearly 300 degrees Fahrenheit that it's viscosity is similar to diesel. Therefore, injector line heaters are needed to prevent build up. The filter wrap heater is mainly for pre heating in the winter time. It will let me warm the filter before I switch over to oil. Also, running wvo from the factory tanks is a bad deal, especially when the weather gets colder. The IP and other internals need to be flushes with diesel, oil polymerizes on most brass and steal surfaces.

Not only does Google state the 13.8 to 14.2, but that is matched by the load tester I was using when measuring the alternator.

I'll take a look at it tomorrow and see what my voltage is fully loaded.

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[ToughOldFord]

13.5 volts is plenty. My old alternator was tired, put out 12 at idle, 13 max at speed. Never had a charge problem other than that battery with the bad cell.

The obvious question here is, why be Jack Benny about your fuel? Tear out that veggie oil crap and just run #2 diesel, your engine will love you for it.

 

[tbiagent69]

I would run WVO or make biodiesel if I could get any of the restaurants around here to give me some

I did the 3g conversion on my 92 bronco a while back and it was really, really easy. I'd suggest you look in to it.

 

[mjs2011]

Why not run wvo? I can run oil and not have to buy furl and save a substantial amount of money. Number 2 is almost 4 bucks a gallon here.

Wmo, that's a different story. But I'm having no negatives with the wvo.

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[mjs2011]

So I finally got some time to take some readings with different things running. These voltages were read both at the battery and at the line connecting at the top of the alternator. They were taken with an analog multimeter, so maybe not the most accurate, but they should give a pretty good idea of what's going on.

So, with nothing on but the stereo, I had around 13 to maybe 13.5 volts at the battery, no change at the alternator terminal. Revving up, no change. Then I went in the cab and flipped on my electric pump for wvo, my injector heaters, and switched it over. I watched the volt meter in the dash drop immediately. I then had 11.5 to maybe 12 volts at the battery and the same at the alternator terminal. Again, Revving made no change.

Shutting off the oil system does not make an immediate change on the volt meter in the dash, but it does come back up to its normal position after a few minutes.

These values seem quite low to me.

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[laserjock]

Sounds like either the alternator is bad or just not big enough for all that stuff. Without knowing for sure what all that stuff draws no way of knowing but I would wager that to heat a tank of oil in any kind of reasonable time, its a lot of juice, probably commiserate with the GP's draw or close to it. What size fuses have you got on that stuff? How long does it take to recharge after a GP cycle and start up? It just may not be enough alternator for all that if it's still the original but I would have it tested before I tossed it aside.