Concerning Conversation With DB Electrical

[ratdude747]

My son’s BMW has a liquid cooled alternator.

As did Caddies with Northstar's. For "improved reliability"

[BigBrother-84]

Bill - That might be a great find, thanks! But I say "might be" as I thought it was the 3.0L engine that had the right alternator for us. No?

Anyway, while this thread is about my discussions with DB I did follow up with Power Bastards by sending this email since they didn't answer the phone:

I have an '85 F250 w/a 460 that I've converted to EEC-V EFI and a poly-groove belt system.  And on my forum we've found that a 3G from a 1994 - 1999 Taurus w/a 3.0L V6 has the right clocking and ear/ear distance to fit right in.  I'm running a stock 3G on the truck and it keeps the 1150 CCA starting battery and the 850 CCA aux battery charged - normally.

However, I also have a 12,000 lb winch and a 3KW inverter that powers a 1.5 HP 110 VAC onboard air system.  When one of those is running the battery voltage comes down into the 11's.  So I'm considering upgrading my alternator, and one of the members on my forum mentioned your alternators in this post, although he mentioned your 777-220 and I'm not sure that is the one that fits.  So I'm following up to see if you have a chart showing the output of your alternator as I'm checking the output of the one I have and would like to compare.  (I can do the math on the pulley ratios, which appear to be 6 1/2 & 2 1/2", to get to alternator RPM.)

Last, why are your alternators the "most reliable, highest output alternators on the planet"?

Thanks,

Gary

Gary, dummy question:

If the output amp is someway cranked, could the overall electrical system various protections (fuses and fusible links) become more sensitive and “fragile”, so they can break more easily?

[ArdWrknTrk]

Gary, dummy question:

If the output amp is someway cranked, could the overall electrical system various protections (fuses and fusible links) become more sensitive and “fragile”, so they can break more easily?

I'm not Gary but these 3G alternators have an internal (attached) regulator.

They should only be putting out enough current and voltage to stabilize the electric system at their set point voltage. 14.35V in most cases.

Something like a winch may be able to draw more than the alternator can provide (given the *alternator* rpms, but unless the regulator is grounded or the B (sense) wire is disconnected the alternator should never be able to set the voltage high enough to damage any components.

Realize that the alternator is constantly varying it's output, and in 99% of our cases a 130A rated alternator can provide double the output of a stock 2G or standard 1G.

Gary has an edge case vehicle with every do-dad under the sun. (3,000W inverter and winch being never envisioned by Ford)

But, as we *do* see he finds just running the AC at idle can make that voltage sag.

I personally think that with 1,800 CCA of battery he shouldn't see a voltage drop... but evidently data shows otherwise (even with a different regulator)

Forcing the alternator full field should show a voltage spike, but any alternator is limited in what it can put out by it's rotational speed.

I seriously doubt that even a 220A alternator would change this. Because (A) a belt can only transmit so much power (the 200A Mitsubishi ambulance alternator uses a 10 rib belt) and (B) alternator rpm at idle. (ambulances spend a *lot* of time idling). even on scene with all their lights and AC blasting)

 

[Gary Lewis]

I'm not Gary but these 3G alternators have an internal (attached) regulator.

They should only be putting out enough current and voltage to stabilize the electric system at their set point voltage. 14.35V in most cases.

Something like a winch may be able to draw more than the alternator can provide (given the *alternator* rpms, but unless the regulator is grounded or the B (sense) wire is disconnected the alternator should never be able to set the voltage high enough to damage any components.

Realize that the alternator is constantly varying it's output, and in 99% of our cases a 130A rated alternator can provide double the output of a stock 2G or standard 1G.

Gary has an edge case vehicle with every do-dad under the sun. (3,000W inverter and winch being never envisioned by Ford)

But, as we *do* see he finds just running the AC at idle can make that voltage sag.

I personally think that with 1,800 CCA of battery he shouldn't see a voltage drop... but evidently data shows otherwise (even with a different regulator)

Forcing the alternator full field should show a voltage spike, but any alternator is limited in what it can put out by it's rotational speed.

I seriously doubt that even a 220A alternator would change this. Because (A) a belt can only transmit so much power (the 200A Mitsubishi ambulance alternator uses a 10 rib belt) and (B) alternator rpm at idle. (ambulances spend a *lot* of time idling). even on scene with all their lights and AC blasting)

Jeff - Jim's answer is far better than anything I would have responded with. But if you still have questions lay them on us.

Jim - Thanks. But as for the voltage drop, remember that the resting voltage of the batteries is ~12.6V. So if you kick on a 150 amp load when the alternator can only put out 100 amps then the batteries are called on to provide current, and the system voltage will drop. Given that, I'm not surprised to see the voltage go down below 12.0V with the air compressor on.

I don't really know how much current the alternator is able to generate at idle, nor how much the invertor pulls from the the system when the air compressor is on, so the 150A and 100A numbers are just a guess. But I hope to find out today.

[ArdWrknTrk]

Jeff - Jim's answer is far better than anything I would have responded with. But if you still have questions lay them on us.

Jim - Thanks. But as for the voltage drop, remember that the resting voltage of the batteries is ~12.6V. So if you kick on a 150 amp load when the alternator can only put out 100 amps then the batteries are called on to provide current, and the system voltage will drop. Given that, I'm not surprised to see the voltage go down below 12.0V with the air compressor on.

I don't really know how much current the alternator is able to generate at idle, nor how much the invertor pulls from the the system when the air compressor is on, so the 150A and 100A numbers are just a guess. But I hope to find out today.

Oh yes! That's why I pointed out the 2.25hp draw of the compressor (plus inverter losses) and the winch as exceptions.

But I was going back to where you mentioned AC only dragging the system down, while your grandson was putting around the Church lot.

Compressor clutch and blower only (plus ignition) shouldn't be enough -in my mind- to cause that.

Though I don't know how much all the later electronics + fuel pump + ??? add to what a "normal" Bullnose would see.

Obviously these trucks managed okay with just the stock loads (wipers, lights, blower) on a 65 (or even 45A!) alternator.

But (A) they weren't usually left to idle, and (B) the stock ammeter was a pretty poor indicator of charge/discharge on a good day.

[Gary Lewis]

Oh yes! That's why I pointed out the 2.25hp draw of the compressor (plus inverter losses) and the winch as exceptions.

But I was going back to where you mentioned AC only dragging the system down, while your grandson was putting around the Church lot.

Compressor clutch and blower only (plus ignition) shouldn't be enough -in my mind- to cause that.

Though I don't know how much all the later electronics + fuel pump + ??? add to what a "normal" Bullnose would see.

Obviously these trucks managed okay with just the stock loads (wipers, lights, blower) on a 65 (or even 45A!) alternator.

But (A) they weren't usually left to idle, and (B) the stock ammeter was a pretty poor indicator of charge/discharge on a good day.

I think we may have a different understanding of what was meant in previous posts. And I'm sure my own understanding has changed over time. The post about taking the grandtwins out and putt-putting around the church parking lot is here, but it doesn't mention battery voltage. That came up later in the conversation, which had a lot of twists and turns - as usual.

And while I may have been thinking that the A/C system pulled the voltage down, as I've checked the system out further it looks like it is just that the regulator's set point is coming down as it heats up. I'm seeing 13.2V for system voltage, with or without A/C load, when everything is up to temp.

As you pointed out, 13.2V is fully charged on these batteries, assuming you've taken the voltage up into the 14's to top them off after starting, so 13.2V isn't a problem. IOW I think the system is working well and is adequate under most conditions. But the air compressor and winch are more load than the alternator can supply during the time they are on, so the voltage is going to go below 12.0 for a bit.

[ArdWrknTrk]

I think we may have a different understanding of what was meant in previous posts. And I'm sure my own understanding has changed over time. The post about taking the grandtwins out and putt-putting around the church parking lot is here, but it doesn't mention battery voltage. That came up later in the conversation, which had a lot of twists and turns - as usual.

And while I may have been thinking that the A/C system pulled the voltage down, as I've checked the system out further it looks like it is just that the regulator's set point is coming down as it heats up. I'm seeing 13.2V for system voltage, with or without A/C load, when everything is up to temp.

As you pointed out, 13.2V is fully charged on these batteries, assuming you've taken the voltage up into the 14's to top them off after starting, so 13.2V isn't a problem. IOW I think the system is working well and is adequate under most conditions. But the air compressor and winch are more load than the alternator can supply during the time they are on, so the voltage is going to go below 12.0 for a bit.

Oops!

Yes you mentioned water temp, and if the alternator could keep up with the additional load of electric fans.

My apologies.

The high flow Taurus/Lincoln fans DO draw a lot of current (hence the advent of the 3G)

It is very interesting that the set point would vary with heat soak.

I kind of wonder if that is due to the internal fans not being able to flush enough air out the back of the alternator, or just a symptom of ferocious underhood temps in these trucks when not (or barely) moving.

If it is a matter of the regulator temp exceeding operational limits Bill may be on to something, ducting ambient air from in front of the radiator support to the alternator.

If it's just down to the windings and regulator making too much heat there's not much you can do about heat=resistance without increasing air flow.

Certainly the dual internal fan design of the 3G is light years ahead of the single external 1G/2G fan.

So, is it the regulator or overheated stator/rotor/diode board?

 

[ArdWrknTrk]

I think we may have a different understanding of what was meant in previous posts. And I'm sure my own understanding has changed over time. The post about taking the grandtwins out and putt-putting around the church parking lot is here, but it doesn't mention battery voltage. That came up later in the conversation, which had a lot of twists and turns - as usual.

And while I may have been thinking that the A/C system pulled the voltage down, as I've checked the system out further it looks like it is just that the regulator's set point is coming down as it heats up. I'm seeing 13.2V for system voltage, with or without A/C load, when everything is up to temp.

As you pointed out, 13.2V is fully charged on these batteries, assuming you've taken the voltage up into the 14's to top them off after starting, so 13.2V isn't a problem. IOW I think the system is working well and is adequate under most conditions. But the air compressor and winch are more load than the alternator can supply during the time they are on, so the voltage is going to go below 12.0 for a bit.

You haven't encountered the Reeeeee! of the inverter putting up a fuss because of too low battery/system voltage yet, have you?

[Gary Lewis]

You haven't encountered the Reeeeee! of the inverter putting up a fuss because of too low battery/system voltage yet, have you?

No, the inverter hasn't fussed due to low voltage. But it can?

As for the set point, I don't think it is due to too much heat. I think it is designed that way. Both of the regulators I've tried did exactly the same thing - they go to 14.3ish on startup and then gradually come back down to 13.3ish.

I'd read about this before, but here's a blurb I found here. And that 60C (140F) is easy to reach in the confines of a Bullnose engine compartment with a big block lurking about, and my regulators both seem to be following that "curve".

I'm going to go look to see if I have any documentation in the Ford pubs on alternators and regulators...

[ArdWrknTrk]

No, the inverter hasn't fussed due to low voltage. But it can?

As for the set point, I don't think it is due to too much heat. I think it is designed that way. Both of the regulators I've tried did exactly the same thing - they go to 14.3ish on startup and then gradually come back down to 13.3ish.

I'd read about this before, but here's a blurb I found here. And that 60C (140F) is easy to reach in the confines of a Bullnose engine compartment with a big block lurking about, and my regulators both seem to be following that "curve".

I'm going to go look to see if I have any documentation in the Ford pubs on alternators and regulators...

Every vehicle inverter I've ever had will screech if it doesn't have enough voltage coming in.

Audible a!arm is far better than going to bed with the AC on and waking up to a very dead battery.

I understand temperature compensation. And I also understand how temperature affects almost any chemical reaction (like battery charging)

But I wasn't aware that these regulators put compensation into action at temperatures as low as 60©

Sure it makes sense. But again, consider the points I make about how heat shedding off a under cooled alternator might not reflect what's actually happening at the battery.

Though in an example like idle and an alternator overload in extreme freezing conditions the battery should be heating up fairly quickly.

*** visions of old DieHard ads at -40° in International Falls***.