Hey, 

I have a question and want to make sure i am not over thinking this,

I did the conversion a few weeks ago when my regulator in the ECM decided to go crazy and cook my alternator

i did the conversion that in the tech article but did come changes because it tried to overcharge (bad reference voltage sampling point)

with that fixed, I am now getting 14.4 with a high of 14.5 and a low of 14.3

 

so here is my question and concern, 

from what i understand, the ecm would cut the alternator when the grids would cycle.

this conversion does not allow this provision. now i do have a circuit designed that will cut the alternator when the grids are energized.

currently the voltage will drop to ~12.8 volts at idle when the grids cycle

but is this really an issue? I am worried about stressing the diodes and alt fuse  needinglessly.

what is everyone else doing?

I did install a manual alternator kill switch just in case I see an overcharging event again.

 

thanks again

 

truck is a 99 2500

I've heard some say that the alt kicks out when the grids go on.  But I personally do see that to be true.  If it was, then why would the alt on my 97 bog the engine down so much it tries to die every time the grids kick on!  And when running the 99 with completely dead batteries, it should have died as well (it would die, but I disconnected the grid relays, and that fixed it)  I'm almost positive the engine grunts a little more with the grids on as well...

On my old 12 valve the alternator stays online when the grid heaters run. You can hear it pull the engine down it is working so hard.

Alternator stays going with the grid heaters. With my truck running in 3 cylinder high idle and exhaust brake on it can actually roll coal every time the grid heaters hit.

 

As for the external regulator remember you've now lost the battery temperature sensor that regulates battery voltage by temperature of the battery. So on a cold morning the cold temperature read by the sensor would increase charge voltage even more since cold batteries are resistant to charging. Then the same is true in the summer the battery temp sensor would turn down the charge voltage to prevent gassing the batteries with excessively high charge rate. This is why the old school regulator where given up on. Because the old school regulator based its charge rate on the temperature under the hood. So if you running with a winter front you might be charging to low. Then if the cold air blowing on the regulator it might be over charging a already warm battery.

ok Thanks, looks like i have little to worry about then,

Alternator stays going with the grid heaters. With my truck running in 3 cylinder high idle and exhaust brake on it can actually roll coal every time the grid heaters hit.

 

As for the external regulator remember you've now lost the battery temperature sensor that regulates battery voltage by temperature of the battery. So on a cold morning the cold temperature read by the sensor would increase charge voltage even more since cold batteries are resistant to charging. Then the same is true in the summer the battery temp sensor would turn down the charge voltage to prevent gassing the batteries with excessively high charge rate. This is why the old school regulator where given up on. Because the old school regulator based its charge rate on the temperature under the hood. So if you running with a winter front you might be charging to low. Then if the cold air blowing on the regulator it might be over charging a already warm battery.

 

So you're saying the optimal charge controller would be one that either reads the battery temperature, or uses the signal from the PCM (if it's still good) and does all the heavy lifting it's self....  

 

Would anyone know off hand what kind of temperature sensor it is?  I'd imagine it's just a thermistor.

Yes. It a thermistor. But like my house system runs on the very same thing. It's got a temp sensor that monitors battery temperature and adjust battery voltage properly for the current battery temperature. This is one of the reasons I can get 10 years from standard lead acid batteries. It's even more critical for sealed batteries because if there are overcharged and become gassy the the moisture is lost and there is no way to maintain electrolytes.

 

Here is a great example. Here is the Temp probe lead it sandwiched between the batteries.

 

Here is actual voltage which is higher to compensate for the cold garage.

 

Then here is the temperature adjusted voltage.

Its need a little while since i posted an update. so far all is working with the conversion., 

 

I do have a question, the Voltmeter on the gauge cluster, does it ready real time voltage or its is driven from the ECM? 

The Reason i ask is the voltage that is displayed from my scan gauge seems to jump around from 14.1 to 14.5 voltage but the lights and gauge cluster appears to be stable. just right of the 14 volts,  

 

I am sure i am over worrying about this, but she is my daily driver.  I have also been watching for signs of over charging (excessive heat in the alt, batteries etc). the alt is only every just warm to the touch after my 25 mile commute and the battery's are cool. no signs of venting

 

I would be interested in seeing the chart for tracking battery temp vs charge rate tho...

 

but one thing the strikes me as odd with the battery tray temp sensor is how accurate would that be. with the sensor snapped into the tray but the with the battery sitting above it often with an air gap created by the bottom of the battery and the forming of the sheet metal tray. so is the temp sensor just needing to get the ambient air temp where the battery is sitting?., 

 

Thanks again 

http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures

 

Ed

Thanks, interesting read,. from what i read, the charge level is about where it needs to be at the given air temp.  I will keep an eye on things as we move from winter, spring and into summer (which from the article, the engine bay is the last place these batteries should be) 

maybe by then i will be ready to replace the ECM. 

of course i found something that the "engineering" type may have fun with http://www.st.com/web/en/resource/technical/document/datasheet/CD00046504.pdf

I took a quick look over your datasheet, I don't see temperature adjusted, anywhere.  Maybe I missed it though.

 

What are out there for temperature adjusted voltage regulators? 

 

I think it would be an interesting project to make ones own charge controller, maybe even use a ATtiny or something of the sort.

I just glanced over it also, but down on page 11 and 12 iirc has the charts that so the charge curve based on temp. 

I am assuming this is how the "modern" external units work also. its reading the ambient temp at the regulator not the at the battery. 

(if i am reading this right) 

anyways i have come across over control circuits that are completely adjustable with running voltages north of 26 volts. 

something like that, one could design a control system that will falling the "charge" parameters to the letter.. 

 

If you like i can dig them up 

Oh, you're right, I missed that.

 

If you've got them handy that would be cool.   This thread is making me want to dig into the battery/charging side of the truck... 

I just glanced over it also, but down on page 11 and 12 iirc has the charts that so the charge curve based on temp. 

I am assuming this is how the "modern" external units work also. its reading the ambient temp at the regulator not the at the battery. 

(if i am reading this right) 

anyways i have come across over control circuits that are completely adjustable with running voltages north of 26 volts. 

something like that, one could design a control system that will falling the "charge" parameters to the letter.. 

 

If you like i can dig them up 

 

Correct the external regulator uses air temperature for charging values instead of the PCM using the battery temperature. So the PCM would be a milder charging voltage. What happens is a battery will sulphate some over time and the sulphated lead will shed off the plates and pile up over time creating a mild short in one or more cells. As this happens the battery tends to get warmer as it charged. So batteries tend to get gassy and go dry which is even worse. But its also good to over charge you batteries once a month to deal with the sulphated plates. The over charging tend to recondition the plates some.

 

How you charge and discharge your batteries will determine how long they last. Like my OE Batteries lasted 10 years.

In my world as a small engine wrench.

I have found atlernators don't like deep discharged batteries and neither do the batteries.

Solinoids and relays tend to not like the low voltage.

They will stick and burn if they don't get enough amps to connect well.

How this relates to our trucks I can only imagine its more important because everything is much bigger and much more expensive.

Chris

Oh, you're right, I missed that.

 

If you've got them handy that would be cool.   This thread is making me want to dig into the battery/charging side of the truck... 

Sorry for the delay, this is a good write up for homemade regulator including a battery temp sensor.. 

this is something i may have to do when i have time or when i find in the summer time that conversion is over charging the batteries

http://www.amsterdamhouseboats.nl/voltage_regulator.htm