Voltage regulators

[THuebner]

Hi,

Can someone please tell me what the proper gauge reading is for charging the electrical system. If I am reading the gauge correctly, it goes from 8-18 in increments of 2 for each line. I consistently read 9-10 with the indicator occasionally jumping to 11 or so. That seems a little low to keep the battery charged, but I am not sure what is normal.

I'll say thank you ahead of time for the help.

Tom

 

[DPellegrin]

I would not depend on the dash gauge for accuracy. Get yourself a good quality voltmeter like a Fluke or Simpson and take the voltage reading accross the battery posts the voltage should be 13. 9 to 14. 2 at 60F. If you are in a colder climate the voltage will be slightly higher. For example at an ambient temp of 25F my voltage is 14. 4.

Regards,

 

[JFaughn]

If the voltage was that low , the eng would turn over slow & may not start .
Is there more to this story ?

 

[THuebner]

Hi Guys,

Thank you for taking the time to reply. Sorry about the delay, I have not been able to make the time to get back here till now.

DPellegrin, thanks for the tip. Yeah the thought didn't cross my mind that the dash gauge was not accurately reading what is actually going on. A quality volt meter sounds like a good idea. At least I'll know what the gauge is actually doing.

JFaughn, as to more to the story, a few things may be pertinent. First, the battery is still good, but it is four years old. The truck sometimes does crank slowly, but has not stuck me yet. As a rule, I do not drive it long distance regularly, but it is driven around town almost every day. I live only ten minutes and two traffic lights from work. Having said that, the block heater is plugged in every night.

On new thing: last night on my way home I noticed the headlights and dash lights dimmed and brightened at about half second intervals for the first ten minutes or so of driving after the truck sat in a parking lot for about two hours.

Thanks again guys for taking the time to reply.

Tom

 

[SMcDougald]

Sounds like your battery might be going south

I had the same "dimming" of the lights. My problem was my battery going south. I replaced the cables and the battery (remember 1100 CCA) and it starts fine.

 

[JLEONARD]

First, the battery is still good, but it is four years old. The truck sometimes does crank slowly,

Those are mutually exclusive comments. If the batterry is four years old and the started cranks slowly, the battery is no longer suitable for service in a diesel truck. I just went thru the same thing... replaced the 4 year old battery and she cranks fast now. . HUGE difference.

I have tested batteries in the past and the standard testers say they are good but they crank the engine too slowly.

Now you are putting extra strain on everything electrical in your truck. That will take it's toll long term. Been there done that, won't do that again.

Do yourself a favor and break down and buy a new battery.

Jay

 

[THuebner]

Hi Guys,

I appreciate you taking the time to help me.

OK I can take a hint, new battery it is. :{

Jay, in what way does the run down battery put a strain the electrical components of the vehicle? In what way does that take a toll on those components?

Thanks again.

Tom

 

[JDancoe]

TH- Short version is: Ohm's Law. Watts are what does the work. Watts roughly, is Volts x Amps. Amps create heat. 12 volts x 10 Amps=120 Watts. 120 watts/6 volts= 20 amps. More amps means more heat, more heat means (potentially) lots of smoke! This is one reason why auto makers went from 6 volt electrical systems to 12 volt. They could use thinner gauge wiring. Hope this helps. Jack Dancoe

 

[THuebner]

Hi JDancoe,

I assume that the bad battery somehow causes an increase in how many watts or amps are being drawn to start the engine and so more heat in the wireing.

Tom

 

[JDancoe]

Tom, To further explain, When the battery voltage is low, the amperage being supplied to whatever piece of equipment will increase to attempt to supply the required wattage. this can cause the item to heat up more, also cause the wiring to the unit to become hotter. In time, the excessive heating will cause premature failure. In the case of the alternator, it will attempt to charge the battery and if it can't achieve the voltage regulator setting it will attempt to do so, by raising the amperage. Eventually this will overheat the alternator. If you have a battery charger with an amp meter, you can see a demonstration of this. When the battery voltage is low, the amps reading will be high, and as the voltage rises, the charge rate (amps) will taper off. One sure indication of a bad battery is, if you put it on a battery charger, and the meter never drops from the high end, the battery is at the end of it's useful life. The bottom line is, batteries are going to get old and less reliable (just like this old guy) and it's better to retire them (both) before they really let you down. And don't forget to clean and tighten the cables & connections.

 

[THuebner]

Hi JDancoe,

Yes, thanks for taking the time to send that excellent explanation. I am pretty good with mechanical things, but wiring and electricity are not my strong suits by any means. I appreciate your expertise.

Tom