Thought 145amp alternator enough for additional accessories. Guess not?

[wayne49]

Assuming the 145 Amp in the thread title is the manufacturer's rated output on a test bench, that may (will) not be what actually is output in the real world.

Connections to the alternator, battery.
The material used for the studs, the washers, and nuts matter. Some materials transfer current better than others.
Cable gauge and length.
Temperature under hood.
Belt slippage.

This knowledge came from reading Sternwake's posts.

 

[bullfrog]

I sure miss reading Sternwake’s replies. Lots of good information and plenty of discussion. I especially liked when he would tell someone exactly how and why to test something then tell them what he thought of their methods when they didn’t because his way was better and he was right which without fail he was. This thread would already be over 10 pages and we all would know a lot more about powering a van with a bunch of loads using an alternator. I’m sure he would tell us it could be done with exactly what components but it is dumb when you can use solar so much more cheaply without wearing out mechanical parts with seven more pages to follow explaining exactly why. Miss you Sternwake if you are sneaking a peak.

 

[PineyCruisin]

Welp...just completed a couple tests to try to pinpoint problem.

1. RESTING VOLTAGE: First thing done was to get resting voltage of battery.  12.58 (we haven't had chance to get it to highway speeds to recharge more fully in last few days so this isn't surprising)
2. VOLTAGE DROP: Measured voltage drop to test for any ground-side resistance. Watched an EricTheCarGuy video who said first thing to do was to make sure no drop between battery and alternator by turning on every single accessory, except rear window defroster (for whatever reason), putting lead on battery negative and lead on casing of alternator, measuring voltage while revving engine around 2000rpm. There shouldn't be more than .1 to .2V. Our reading was .03 with regular accessory load and to be absolutely certain there was no additional resistance at higher loads, the Jackery charger and IndelB was plugged in. Absolutely no change in voltage reading. Since no voltage drop to alternator, didn't think a need to test any individual connections on the ground side (reminder: Kill switch connected on negative side) 
3. ALTERNATOR VOLTAGE OUTPUT: This test was done at Pepboys and because they said they got 13.95v under normal load but dropped to 12.4 when additional accessories were plugged in (I was not able to speak to the actual tech who test to see what specific items were plugged in when they ran test, but the Indel and the Jackery charger were in the van at time so assumed these were being plugged in), wanted to try to pinpoint exactly what accesssories were causing the drop. With all van accessories turn on (headlights, max A/C setting at full speed, radio/backup camera, windshield wipers, flashers) and the Jackery charger and IndelB plugged in and turned on, we got a reading of 14.02. Perplexing. There is no way to screw up this test and get a false reading since you merely read voltage at battery...or is there?
4. ALTERNATOR AMP OUTPUT per RPMs: Called Pepboys about this and it turns out they did do the test but did not give me the test result sheet for it. Since past results are not stored, I have an appointment tomorrow afternoon for them to redo it so I can see exact results. Will post tomorrow.

CONCLUSION SO FAR -- Still want to get that capacity-time test on battery. Also, I still think the most obvious thing to check is to get what the actual amp draw is for all accessories turn on and compare that to the actual number amps the alternator is putting out to be absolutely certain it can handle all our additional stuff. 

Because of that 12.4 alternator voltage reading PepBoys got, was thinking that the next thing to make sure the voltage regulator is working properly. EricTheCarGuy said something called a Full Field Test could be done that would bypass the regulator to see if voltage goes back up but now that we got the 14v reading, I'm completely flamboozled.

 

[abnorm]

You can still find Sternwake online................Here are the "Sternwake Files" on Gary's forum

https://vandwellerforum.com/forum-45.html

 

[PineyCruisin]

A simple way to tell if it is the battery is to substitute it with a known good one. It sounds like your battery has been run extremely low several times? Years ago I worked at a Mercedes dealership and fought a disconnect switch for hours. It was a parade car and immaculately clean as was the switch on the outside. The battery had been unable to charge due to the corrosion and when it finally went bad and wouldn’t start they brought it in. After finding the switch which I wasn’t informed it had I tested the battery, it passed but barely. I asked the parts manager to replace it and showed him the test sheet. He said he could not replace it based on the test. He pulled out a large hammer and beat the battery till it cracked around the post and said now I can replace it and gave me a new one! I would recommend you purchase a second battery and insure it is fully charged as well as charging the old battery and having it load tested at someplace like Batteries Plus. Newer vans have many small loads that include interior lighting, computer, radio and etc. Having a house battery that is isolated from the system is a good idea. The less load you put on a battery before fully charging it the better in most cases. I would install the new battery in the vehicle and have the charging system checked including voltage drops. There are discussions on disabling the interior lighting on line if you need to have the doors open so much it discharges there battery. You need to know how many watts you will use on your house system to determine your needs. A monitoring system for the house battery might be a good idea. In my opinion larger cables are always better until they become difficult to run, but that is just me. Once you know your needs the cable size can be determined and how large the system needs to be. Using the vehicles charging system usually takes a good 4 hours of high speed driving to fully charge a battery, not really a good primary system for charging a house battery unless you do drive 4 hours daily. The battery acts as a buffer and storage for power, you may just be running your battery too low for it to recover.

Bullfrog: We were so obsessed about making sure not to kill the new battery that we never let it drop below 12.4 (maybe 12.38 was ever lowest reading). Would be nice to get another battery to make absolutely certain we have a good battery but not feasible to purchase yet another one only to return it and so far, absolutely no indication we have a bad battery (save the Capacity-time test Spiff mentioned). Love that you took a hammer to that battery so it failed the test for replacement! lol

We already have the Jackery for our additional electric needs so don't want a 2nd lead acid. I could plug in the Indel into the Jackery while driving but would drive me nuts that we are not utilizing every bit of our van's charging system to power our Indel, and not only that it would be draining the Jackery even more. A solution may be to put solar panels on roof in addition to the folding ones we have, but we don't want to do that unless it is the absolute last resort.

I also remember reading SternWakes threads just to educate myself and found them extremely informative. Now that we have this problem, I was actually trying to find these threads and could have sworn there was a similar thread to this about alternator output, but couldn't find it again via the search.

 

[bullfrog]

I believe he moved and still posts on the vandweller forum. Maybe someone here can direct you to his new home.

 

[bullfrog]

Most older GM internal regulators have a metal tab that can be accessed with a thin small screw driver through a D shaped hole in the back of the alternator case at one end of the regulator that when grounded causes full output from the alternator while running if I remember correctly. The best test for me was using a large adjustable carbon pile load / volt / amp Sun Charging Tester. I really hated it when I gave it away.

 

[PineyCruisin]

Bullfrog, your post about the regulator got me to do a google search on whether our van would have an external regulator to be able to test it easily and found this GM bulletin that sounds exactly what is going on with the van!!!

"[font=roboto, sans-serif]Subject: Information on Voltmeter Gauge Fluctuation Due to Regulated Voltage Control System and Concerns About Camper/Trailer Battery Charging #07-06-03-009 - (12/05/2007)[/font]
[font=roboto, sans-serif] [/font]
[font=roboto, sans-serif]Models: 2005-2008 Cadillac Escalade Models[/font]
[font=roboto, sans-serif] [/font][font=roboto, sans-serif]2005-2008 Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe[/font]
[font=roboto, sans-serif] [/font][font=roboto, sans-serif]2[/font][font=roboto, sans-serif]005-2008 GMC Sierra, Sierra Classic, Yukon Models[/font]
[font=roboto, sans-serif] [/font]
[font=roboto, sans-serif]Voltmeter Fluctuation Condition[/font]
[font=roboto, sans-serif]Some customers may comment that the voltmeter is fluctuating between 12 and 14 volts on their full size pickup or utility vehicle. Starting with the 2005 model year, light duty full size pickups and utilities are equipped with a new Regulated Voltage Control (RVC) system. This system reduces the targeted output of the generator to 12.6-13.1 volts when in "Fuel Economy Mode" to improve fuel economy. The generator may exit "Fuel Economy Mode" if additional voltage is required. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems that usually maintain a more consistent reading of 14 volts. This fluctuation with the RVC system is normal system operation and NO repairs should be attempted.[/font]
[font=roboto, sans-serif] [/font]
[font=roboto, sans-serif]Camper/Trailer Battery Charging Concerns[/font]
[font=roboto, sans-serif]Some customers may comment that when towing or hauling a camper/trailer, the auxiliary battery for the camper/trailer will not stay charged. In most cases, this concern is blamed on the new RVC system. While the RVC system does reduce the generator's targeted output voltage to 12.6-13.1 volts when in "Fuel Economy Mode", this feature is bypassed if the tow/haul feature is enabled. With the tow/haul feature enabled, the RVC system will stay in "Charge Mode" and the targeted generator output voltage will be 13.9-15.5 volts, depending on the battery state of charge and the estimated battery temperature. To keep the generator in the "Charge Mode", use either of the following two methods.[/font]
[font=roboto, sans-serif] [/font]
[font=roboto, sans-serif]• The first method is to use the tow/haul mode when towing or hauling a camper or trailer.[/font]
[font=roboto, sans-serif] [/font]
[font=roboto, sans-serif]• The second method is to turn on the headlights, which will increase the generator's targeted output voltage to 13.9-14.5 volts."[/font]


[font=roboto, sans-serif][size=small]Although the 12.4 voltage reading sounds too low (it was lower than the battery voltage), I'm wondering if Pepboys tested the voltage with nothing BUT the fridge and the charger which would cause the system to go into so-called Economy mode and therefore a lower voltage reading. It may also be why the alternator wasn't recharging the battery with the devices plugged in while we were driving on the highway because we purposely had absolutely no other accessory turned on except the the devices plugged into the ciggie. This too forced the system into Economy Mode. But when we did the test this morning, ALL the van's accessories were turned on in addition to the fridge and charger forcing the charge system to go to "Charge Mode" therefore we got the 14V reading. [/font][/size]

[font=roboto, sans-serif][size=small]Does this sound correct???? If so, it sounds like a simple solution would be to turn on the headlights or something while driving to force it into Charging Mode, if indeed the charging system is causing the voltage drop purposefully!! Oh, I hope it is this simple!![/font][/size]

 

[PineyCruisin]

For anyone with 2005-2008 GM trucks/vans (still have to verify that our 2005 Express has this Regulated Voltage Control-RVC- system, but I'd be surprised if not), this article is very good describing charging systems in general and the different modes the 2005-2008 GM RVC system enters depending on various conditions, in particular. This might come in very handy for anyone reading this thread who is running into similar issues: 

https://www.motor.com/magazine-summary/trouble-shooter-september2015

[font=Arial,]Conventional charging systems use an internal temperature sensor to establish generator voltage set points. When the generator is cold, it raises the voltage output set point. When it’s hot, it lowers the voltage output set point. This type of system tends to overcharge the battery on long trips at highway speeds and undercharge it on short trips with low vehicle speeds. Regulated voltage control (RVC) regulates the generator’s output voltage, based mainly on estimated battery temperature and battery state-of-charge (SOC). The main benefits of this system are: improved fuel economy, extended battery life, extended lamp life and extended switch life.[/font]

[font=Arial,]The RVC system allows voltage changes, up or down, based on battery state-of-charge, the vehicle’s present electrical needs and other factors, so the voltmeter reading may fluctuate. Conventional systems usually maintain a consistent reading of around 14V. The RVC system voltage may range between 12 and 14V. This is normal system operation, but may be perceived as a problem by vehicle owners who are accustomed to seeing a relatively consistent voltmeter reading.[/font]
[font=Arial,]There are two types of RVC systems in use—integrated RVC and stand-alone RVC (SARVC). Integrated systems use a battery current sensor to inform a body control module (BCM) how much the battery is being charged or discharged.[/font]
[font=Arial,]SARVC systems (found mostly on trucks) do not use the BCM for operation. They have a generator battery control module mounted to the negative battery cable, to interpret battery current and voltage and battery temperature inputs. The battery current sensor is internal to the module. This module also directly controls the generator L terminal duty cycle instead of the ECM/PCM.[/font]
[font=Arial,]The purpose of the RVC system is to maintain the battery state-of-charge at 80% or above and support vehicle loads. To accomplish this, it has several different modes of operation. Six common modes of operation are Charge Mode, Fuel Economy Mode, Voltage Reduction Mode, Start Up Mode, Windshield De-Ice Mode and Battery Sulfation Mode.[/font]
[font=Arial,]The PCM/ECM (generator battery control module on full-size trucks) controls the generator through the generator L terminal control circuit. It monitors the generator performance though the generator field duty cycle signal circuit. The signal is a 5V PWM (pulse width modulated) signal of 128Hz with a duty cycle of 0% to 100%. Normal duty cycle is between 5% and 95%. The ranges between 0% to 5% and 95% to 100% are for diagnostic purposes.[/font]
[font=Arial,]The control module enters Charge Mode whenever one of the following conditions is met:[/font]

• [font=Arial,]Under WOT conditions and when the fuel rate (sent by the ECM/PCM) is greater than 21 g/S and the throttle position is greater than 90%.[/font]
  
• [font=Arial,]The headlamps are on, low or high beam.[/font]
  
• [font=Arial,]The wipers are on for more than 8 seconds.[/font]
  
• [font=Arial,]The electric cooling fans are on high speed.[/font]
  
• [font=Arial,]The rear defogger is on.[/font]
  
• [font=Arial,]The battery SOC is less than 80%.[/font]

[font=Arial,]When one of these conditions is met, the control module ramps up the voltage slowly to a level between 13.4 to 15.5V (depending upon the mode of operation the system is presently in) at a rate of 8mV to 50mV per second.[/font]
[font=Arial,]The control module enters Fuel Economy Mode when the following conditions are met:[/font]

• [font=Arial,]The calculated ambient air temperature is above 32°F.[/font]
  
• [font=Arial,]The calculated battery current is less than 15A and greater than –8A.[/font]
  
• [font=Arial,]The battery SOC is greater than 80%.[/font]
  
• [font=Arial,]The generator field duty cycle is less than 99%.[/font]

[font=Arial,]This mode’s targeted generator output voltage is 13.0V. The control module will exit this mode once the criteria are met for Charge Mode.[/font]
[font=Arial,]The control module will enter Voltage Reduction Mode when the following conditions are met:[/font]

• [font=Arial,]The calculated ambient air temperature is above 32°F.[/font]
  
• [font=Arial,]The calculated battery current is less than 2A and greater than –7A.[/font]
  
• [font=Arial,]The generator field duty cycle is less than 99%.[/font]

[font=Arial,]This mode’s targeted generator output voltage is 12.9V. The control module will exit this mode once the criteria are met for Charge Mode.[/font]
[font=Arial,]After the engine has started, the control module sets a targeted generator output voltage of 14.5V for 30 seconds (Start Up Mode).[/font]
[font=Arial,]The control module enters Battery Sulfation Mode when the battery voltage is less than 13.2V for 45 minutes. Once in this mode, the generator battery control module will set a targeted output voltage between 13.9 and 15.5V for five minutes. The control module will then determine which mode to enter depending on voltage requirements.[/font]
[font=Arial,]In RVC Mode, the control module bases the charging voltage on battery SOC, which is estimated during a key-off event every eight hours, after three voltage measurements every 24 hours thereafter, and then monitored constantly while the ignition is on. These voltage measurements are then compared to estimated battery temperature, as battery temperature vs. battery voltage directly corresponds to battery SOC. While the engine is running, the system uses both the battery voltage and estimated battery temperature to determine the battery current in and out of the battery. The control module then regulates the charging voltage to keep the battery above an 80% SOC.[/font]

Of note to my particular situation, all the devices I tried to use should draw less than 11amps therefore could've easily entered Fuel Economy mode.

 

[jonyjoe303]

fuel economy would kill the battery in no time, especially if you use other loads with the engine not running. You mention you never see more then 14.1 volts at the terminals, battery has never been fully charged except when pepboys tested it.

Even at 14.4 volts you need to do alot of driving to keep the battery at full charge. On my van I only drive to work and back maybe 3 miles roundtrip, and I would get slow cranks after a 2 day weekend without starting the engine. I have a small dc to dc 2 amp charger to top off the battery every day, and that has worked extremely well.

I would definitely get a voltmeter and monitor the battery voltage in realtime while your driving to see what alternator is putting out. According to the GM notes on the charging system, the alternator only puts out enough amps to run what you need when needed, at other times it doesn't do anything except produce barely enough amps to run the engine.

Your battery brand will show what the recommended charge voltage is, some require 14.4 volts, my agm battery requires 14.7 volts, maybe yours can get by on 14 volts or less without long term damage.

 

[Firebuild]

 I could plug in the Indel into the Jackery while driving but would drive me nuts that we are not utilizing every bit of our van's charging system to power our Indel, and not only that it would be draining the Jackery even more.

I have an Indel, and the Jackery wouldn't be a great solution anyway because unless they've changed something recently, the 12v lighter socket is unregulated.

 

[bullfrog]

I’m felling better about getting 10 MPG out of my old 1987 Suburban everyday. Least I don’t have some computer trying to save me fuel while killing my battery and I can turn on and off my interior lights with a switch!

 

[highdesertranger]

right on Mr. Frog. where's that like button. all this new stuff is great until it isn't. highdesertranger

 

[PineyCruisin]

fuel economy would kill the battery in no time,
I guess it could if this RVC system goes haywire, ignores its own parameters, and never allows the alternator to boot out of lower voltage when needed. I'm really relying that this thing will never enter Fuel Economy Mode if battery is below 80% SOC as stated in bulletin to cause such a drain. Right now, the biggest inherent design flaw in this RVC system is that it isn't looking at any other accessory load outside headlights, rear window fogger, a/c, or wipers. So any load from other items that causes the voltage to drop below 12.6 will be ignored, keep the alternator voltage low and take what's needed from the battery. Maybe the reason, this system was only used for 3 years before discontinuing it.

especially if you use other loads with the engine not running.
Not sure I understand. Battery is going to be killed in this scenario no matter what type of charging system, regulated or unregulated. Even if you meant "with the engine idling", still may drain battery...unless you have those fancy alternator meant to produce more current even while in idle like I talked about previously.

You mention you never see more then 14.1 volts at the terminals, battery has never been fully charged except when pepboys tested it.
Hope I didn't write something to cause confusion but, yes, we've had the battery fully charged many, many times. Our readings hovering around 14V was from the alternator, tested at the battery terminals. And from what I'm reading about regulated charging systems, it's not unusual for the alternator to sometimes only put out more than .5V of the battery voltage, even under load. Under that, seems to indicate a problem. 

Even at 14.4 volts you need to do alot of driving to keep the battery at full charge.
Surprisingly, when doing the original test (the one that started this whole thing)...it only took ~35 minutes of driving 50-55pm (we took the back roads going home, and weren't even on the highway) to get our alternator to charge battery from 12.4 to 12.6. I was pleasantly surprised!

I would definitely get a voltmeter and monitor the battery voltage in realtime while your driving to see what alternator is putting out.
Yes, I'm very curious now about this RVC system and would like to see what the alternator is doing under different modes. I'm hoping to replicate the first test with the fridge and Jackery charger plugged in only noting the voltage this time. Then turning on the headlights and checking voltage again. Hopefully, the voltage goes up and I know the RVC is working as it should--properly improper.  

According to the GM notes on the charging system, the alternator only puts out enough amps to run what you need when needed, at other times it doesn't do anything except produce barely enough amps to run the engine.
Yes, it is supposed to only put out what is needed. I'm at the mercy of it.  

Your battery brand will show what the recommended charge voltage is, some require 14.4 volts, my agm battery requires 14.7 volts, maybe yours can get by on 14 volts or less without long term damage.
Again, not sure what you mean since the concern with charging batteries is making sure voltage is not too high. Are you meaning that some system components, not the battery, could be damaged if the voltage is too low? Not sure when this can happen, but the battery should supply anything needed that the alternator does/can not, like powering accessory load during idle or, like what happened to me with this complicated "mode" system that forced the alternator to put out less than I *really* needed. It was just too stupid to know that I needed what I needed and to act accordingly.

At least, I'm hoping this is what is happening since I haven't tested this theory out yet.

 

[PineyCruisin]

Firebuild: Wait...what? Ok, now I am freaking out. I thought I had purchased the Jackery specifically because it had regulated output. It's been awhile but I even thought I had drained it down fairly low and the Indel worked fine. Gawd, I hope this is not true. (PS-love, love, LOVE your pickle story!)

Bullfrog: What you said is exactly why I have a weed sprayer and basin for our plumbing system (oh...guess I have to add a kitty liter container as grey water tank and 5 gal. bucket for the bathroom needs). I hate having to rely on complicated things that are impossible to troubleshoot and repair easily.

 

[PineyCruisin]

Update on testing---went to Pepboys today to get the amps put out by the alternator. Told guy at desk that they didn't need to do the whole system test, just the amp output for the alternator. (Btw, it was the manager I had spoken with yesterday who had said yes, the amp measurements per rpms are also included with the paid charge system test.) 

Van taken, van returned. Handed me the test report. It was the same exact sheet as the one given me a few days ago. I asked guy where the amp readings for the alternator were. He pointed to the cranking amps. Asked if there was another test result sheet for the output amps at various rpms. Another young dude came over and said, yes,  it was done but that it is only tested at 1500 rpms....pointing to the voltage chart. I said that the chart he was pointing to was voltage results, not amps (I was quite polite, really), and that Lee had said amp output, not just voltage, was included with charge system test. Young dude got Lee. Lee said nope, the voltage is all there is, sorry for confusion.

OK fine....misunderstanding. Went to parking lot. Called our regular mechanic. His associate answered. Asked if they had equipment to measure how many amps my alternator can put out at various rpms. Oh sure, he says, we not only do that but the whole charging system can be tested, including battery, for 14.99! hmm...pepboys charged 14.99 too. So I say....I need to be absolutely certain that amps will be measured and not just voltage. Oh wait, he says, I had this test just done recently so will check the report. Comes back...um, no, just voltage, sorry.

Ugh. Is it just me?????????

Guy says, try so-and-so repair shop, they may be able to do it. Called. Guy who answered said he didn't know. I need to call tomorrow to talk to the "guru".

Holy crow...why is this test so elusive? Am I mistaken...I thought you just needed one of those high amp multimeters??? Is there something I'm missing? We would do it but only have one that goes up to 20amp and didn't want to pay for one just for this test.

 

[PineyCruisin]

Firebuild: Phew! From Amazon: "The Jackery Explorer 1000 DC output voltage is regulated at 13.3 Volts DC". 

I did notice in a google search that the Jackery 240 is the only Jackery that has unregulated output. 

 

[bullfrog]

I feel your pain. The old analog testers had a variable resistance resister that would put a measurable load on the system while measuring amps and voltage. I saw one the other day on ebay for $80. You can load test batteries as well. You can do damage to batteries and charging systems if you don’t understand how they work and how to use them, even explode a battery if you are not careful. I guess in today’s world to complicated to give to some kid with little training and lots of liability.

 

[highdesertranger]

"Holy crow...why is this test so elusive? Am I mistaken...I thought you just needed one of those high amp multimeters??? Is there something I'm missing? We would do it but only have one that goes up to 20amp and didn't want to pay for one just for this test."

well they don't get asked to do it that's why it's elusive. most people don't give a flying rats ass what their amp output is all they want is their vehicle to start when they turn the key.

you are not quite understanding all this. first off you just don't put an amp meter on the alternator output. when testing those amps have to go somewhere. in other words you have to load the alternator under the RPM range and record what happens. for the best results you actually need 2 amp meters 1 to record the load and the other to record the alternator output. then a little math and you got it. that just is not a usual run of the mill test. I have never seen a machine that does that automatically. all those techs could do it if they just think about it.

another point abusing your charging system with this test could fry stuff if the tech is not careful.

highdesertranger

 

[bullfrog]

People need to learn how and why things work. Then learn how to problem solve. Most are trained to push a button, look at a result, compare it to the chart and replace either a battery or an alternator. I sure am turning into a grumpy old man! Sorry for the rant. Wonder how many even know how to install an amp meter that doesn’t clip on?