Real time alternator info fron a FSM needed if possible

[100 TD]

I am having trouble with my alternator not putting out enough volts.
It is intermittent in its control, it appears to be the voltage regulator but I am hoping to get some specific info on how the regulator functions which may be in a FSM. It appears that the regulator is in all the 100's and possibly the same in some 80's.

My problem is that I start up and the alternator charges to 13.5 volts. This is solid or steady no matter what revs you give it. Therefore it does not get high enough for my second battery isolator to come in (13.65V required) so the second battery does not get charged. The next day you start it might fire up to 14.1V (great). But most times 13.3 or 13.5 etc. The other day I had to manually jump start off the second battery because the main battery was low and may not have been getting a proper charge. Unfortunately my current meter is cactus so I cant monitor the output current of the alt to see if it is putting out decent amps, but it appears to be due to the fact that it still holds its voltage with all lights on high beam etc.

First thoughts to me is a crook regulator, have checked connections etc, have removed sense volt supply to the alternator and it was climbing to 14.3 so the sense is OK, but it appears to be a regulator issue, but I was wondering if the FSM says anything about its operation in case there is an inherent design algorithim which I don't know about.
I am about to go away for a few days and don't want battery troubles!
Edit: I can't do anything particularly before I go, but the information if available, my put my mind at rest, or it may entice me to carry some spare batteries!

 

[NMuzj100]

My FSM says Standard Voltage can vary between 13.2 - 14.8 V and be within spec (from idle to 2000 rpm). CH-4 (9)

For less than standard voltage it points to the generator/alternator and for more than standard it says to replace the regulator.

If you get low voltage it says to pull the back off the generator, ground terminal F, start the engine and read volts off terminal B. If less than standard (13.2V) then check generator. Checking the generator looks to be a lot of work and involves draning the engine coolant.

Good luck. What time is it in OZ ?

 

[100 TD]

Thanks for that NMuzj100,

The downloaded manual I have from the US techinfo site says 13.2 to 14.0 at 5000 rpm. But that is just mentioned with the charging circuit. I was hoping on more specific info, although I know that may not be given from Toyota, but I had to ask before spending the bucks on a regulator. (I doubt they would have one in stock either, not that I can order until after New year, dependant on price, I may ship one from the US, if that is the problem)
Time here is 9.00 PM, I will be up till midnight probably, cleaning up the garage!

My FSM says Standard Voltage can vary between 13.2 - 14.8 V and be within spec (from idle to 2000 rpm). CH-4 (9)

For less than standard voltage it points to the generator/alternator and for more than standard it says to replace the regulator.

What time is it in OZ ?

 

[100 TD]

BUMP

 

[mobi-arc]

What type of isolator are you using? Most conventional units lose about 1.5 volts which means you're correct, your second battery DOESN'T get charged. Disconect the second battery, disconnect the isolator, and see how the alternator performs.

 

[100 TD]

Solenoid type isolator controlled by a voltage detection circuit. No voltage drop across the solenoid. My problem is not the solenoid or controller. The problem is the alternator, as mentioned before, I had to use the second battery to jump the main battery the other day due to the alternator no doing a good enough job at charging. (Yes I would love a perfect switch but they cost to much and it would not cure my problem)
EDIT: At 6 amps draw from my fridge on turbo mode, there is .01 volt drop across the solenoid. It is a Redarc rated at 100 amps continuous.

What type of isolator are you using? Most conventional units lose about 1.5 volts which means you're correct, your second battery DOESN'T get charged. Disconect the second battery, disconnect the isolator, and see how the alternator performs.

 

[mobi-arc]

Is it possible that one or both of your batteries has too high internal impedance?

 

[100 TD]

No, both batteries are fine and charge fully on my 6A battery charger, once the main battery comes up to 13.6 the relay switches in and then charges both and it continues charging up to 14.4 and the current falls off to approx 1 A as you would expect. The engine cranks fine when the main battery is charged. The problem is in the alternator regulator system. When you start the engine sometimes the alternator outputs 14.1 volts and works fine, however more often than not it regulates at 13.5 or 13.3 (or maybe lower when I haven't monitored it) and doesen't charge the main battery very well, as well as not get high enough to bring in the second battery relay and charge it. I have now put an LCD display on the voltage output to monitor it more closely. As mentioned before I am trying to find out if Toyota put a charging algorithim in the regulator circuit (I doubt it) which senses current, voltage and charge time, and then adjusts the regulator to suit. I don't think this is the case, (but I want to make sure first) I do think there is a fault in the regulator or voltage sense circuit of the regulator creating these erratic outputs. The alternator holds the regulated output voltage while all lights and air conditioner and high beams are on etc, so the alternator output current is available, it is just regulating at too low a voltage in most instances.

Is it possible that one or both of your batteries has too high internal impedance?

 

[mobi-arc]

Have you checked to make sure alternator casing ground is the same as both battery ground connections? Lugs? Posts? What's the differential at higher current?

 

[100 TD]

All grounds/posts/terminals checked, no corrosion, extra grounds have been added. No volt drop while charging, as mentioned before, only load I have for second battery is 2 fridges. Have done 10 short runs today and the regulator has been 14.1 to 13.6 and inbetween for each run!
As mentioned before, no matter what load or voltage, the regulator is solid as a rock no matter what revs. It just depends what it regulates to when it first fires up.
I am ecstatic that it has held up today because I am going away tomorrow. I hope it continues to do so. It just hasnt been doing the right thing for the past couple of weeks.

Have you checked to make sure alternator casing ground is the same as both battery ground connections? Lugs? Posts? What's the differential at higher current?

 

[mobi-arc]

Does it fluctuate with engine temperature or it moves around regardless?

 

[spressomon]

100 TD: If you are still having issues with this I would recommend (even though you sound completely convinced your problem has nothing to do with the second battery circuit) isolating your primary battery circuit: Disconnect the second circuit.

 

[100 TD]

Update

Update below

100 TD: If you are still having issues with this I would recommend (even though you sound completely convinced your problem has nothing to do with the second battery circuit) isolating your primary battery circuit: Disconnect the second circuit.

Does it fluctuate with engine temperature or it moves around regardless?

Thanks Spressomon/Mobiarc
The second battery circuit is disconnected totally from the primary circuit and stays isolated until the alternator voltage reaches 13.65V. The problem as stated before is the alternator output has not been getting up to 13.65V and generally has been hanging around 13.5V

Mobiarc the voltage wanders around regardless of temperature

I have come back from 5 days away and fortunately the alternator did the right thing this week (not like the previous week with low voltages). Each time I started the engine the alternator output came up to 13.7 to 14.1 and closed the second battery circuit so it received a charge.
The alternator output voltage however wandered between 13.2 and 14.2 but mainly wandered 13.3 to 13.8. This was OK due to the second battery solenoid having been energised each time at start up, and it stays connected until dropping to 12.7 volts, so no problems there, but it still wandered a lot regardless of load and temperature. This is driving 7 hours straight on 2 different days or lots of stop starts on other days. I am still contemplating changing the regulator but I might PM LexusBen and see if he has any additional info. I cant afford to have it play up while away and not keep the food/WINE cold!

 

[mobi-arc]

I would make sure the alternator is grounded properly to the battery negative....don't depend on mechanical grounds between casing, bracket, chassis, battery negative. Run a cable direct from alt. casing to batt. negative. If that doesn't solve the wandering voltage issue, I would say change out the regulator and see what haapens at that point.