Alternator

[Slownsy]

2015 6.7 Lariet do anybody know how many Amps the heavy duty alternator is, and how many Amps it can supply continues.
Frank

[time2roll]

The chassis alternator charging is designed to charge the chassis battery.

12.9 and through a long wire is too low to charge any deep cycle battery even at 120F.

[pnichols]

time2roll wrote:

pnichols wrote:
Once we started traveling in scorching heat after camping and the alternator voltage read only around 12.9 volts ... which I interpreted as A) the ECU throttling the alternator to keep it from getting too hot, or B) the ECU throttling the alternator to keep it from boiling the coach batteries.

This is why the DC/DC charger can work so well. Even with sagging voltage directed by the computer you can have 14+ volts on the trailer battery.

When traveling in our RV with it's alternator topping up the coach batteries after camping ... if the ambient air temperatures are high ... I want the alternator charging voltage to be adjusted lower in accordance with battery charging curves that show the dependence of charging voltage to use versus the ambient air temperature surrounding the coach batteries. What the curves show is that higher ambient air temperatures require lower float, bulk, and boost battery charging voltages for lead acid based batteries - regardless of whether the batteries are liquid type or dry (AGM) type.

So far, the above seems to be pretty much what our Ford E450 alternator seems to be doing - probably under ECU computer and/or sensor control of it.

[time2roll]

pnichols wrote:
Once we started traveling in scorching heat after camping and the alternator voltage read only around 12.9 volts ... which I interpreted as A) the ECU throttling the alternator to keep it from getting too hot, or B) the ECU throttling the alternator to keep it from boiling the coach batteries.

This is why the DC/DC charger can work so well. Even with sagging voltage directed by the computer you can have 14+ volts on the trailer battery.

[pnichols]

Chum lee wrote:

pnichols wrote:

Chum lee wrote:
To a certain extent, your chassis alternator output (voltage and current) is dependent on the current state of charge of your chassis battery(s) and the loads placed on the alternator by the VEHICLES electrical system. If your chassis battery is fully charged, expect the alternator output to be a fraction of it's maximum rated capacity until the existing loads drop the charge in the chassis battery. Ford engineers designed their charging system that way to improve fuel mileage and to prevent people from doing what they want to do . . . . . charge the batteries in their camper with the chassis alternator.
Chum lee

I not talking about a pickup truck here ... but with respect to our small Class C motorhome on an E450 V10 chassis with "only" a 130 amp alternator: The V10 engine battery I have installed is an overkill Ford OEM battery model intended for their diesel trucks. The coach has two 115 AH Group 31 AGM batteries wired in balanced parallel.

Whenever the V10 is running, the two coach batteries and one engine battery are all connected together in direct parallel via a high amperage continuous duty 12V solenoid. I know this because I have an engine battery readout voltmeter mounted on the dash and a coach battery readout voltmeter also mounted on the dash - and they both read nearly the same all the time - which means that all three batteries are connected in direct parallel when the engine is running. There appears to be no isolation diodes involved between the engine battery and coach batteries.

I've also mounted on the dash an ammeter that reads the current going into, or out of, the coach batteries.

After drycamping a bit, whenever the coach batteries are down to around 50% (12.0-12.1V reading on their dash voltmeter), I sometimes start up the V10 and idle it for an hour or so to conveniently and very quietly to partially top up the two coach batteries. The coach battery ammeter (on the dash) will sometimes spike to as high as 80 amps at first (V10 idling), and then gradually taper down as the coach batteries are being boost and bulk charged via the 130 amp Ford alternator. The voltage output of the alternator (as indicated by the voltmeter on the dash) will start out at 14.X volts at first, and then gradually taper down as the coach batteries charge up.

So the bottom line is ... yes, some stock engine alternator systems can indeed be used to charge camper battery systems just fine.

As a sidenote, the performance curve for our V10's 130 amp Ford alternator indicates that it can indeed output around 70-80 amps at engine idle RPM speeds, so it's performing as expected ... at least in our 2005 E450 based motorhome. Even though the engine itself may be idling at only 550-650 RPM, the pulley system powering the alternator spins it a lot faster. In order for an engine alternator to output high currents at low engine speeds, the engine merely has to be able to delivery enough horsepower at idle so as to spin the alternator at whatever RPM the alternator's power vs RPM curve requires for the desired amperage output in the application. It may be difficult to locate the power-vs-rpm graphs for many alternators, however.

Yes, my '99 F53 (V10) does the same thing and on some mornings I often run the engine at idle to put a little charge (little is the key word) in the house batteries. As theoldwizard1 mentioned, the newer vehicles are more sensitive to charging conditions. The problem is, when idling with the alternator putting out close to the maximum voltage/current, even though the alternator is over driven, the cooling fan on the alternator needs to be able to dissipate the additional heat generated with the engine at idle. Since the idle is stabilized, available horsepower isn't the issue, . . . . IMO, cooling is. I'm not saying that it will fail overnight, it just gets hotter. Heat kills, . . . . . more heat kills more quickly.

Chum lee

Of course the control computer in my 2005 may be more advanced than your '99 - just guessing.

Are you saying that perhaps my 2005 Ford's engine/system control unit doesn't know alternator temperature and back off it's output voltage (and hence output current) accordingly, so as to keep alternator heat from being detrimental?

I do know that my alternator's output voltage digital readout that I've installed on the dash does show nicely tapering down of alternator output voltage if, and as, outside temperatures rise

Once we started traveling in scorching heat after camping and the alternator voltage read only around 12.9 volts ... which I interpreted as A) the ECU throttling the alternator to keep it from getting too hot, or B) the ECU throttling the alternator to keep it from boiling the coach batteries.

[landyacht318]

Regarding alternator belt squealing. Mine only does so with a depleted enough battery and a cold damp belt and with my voltage regulator asking for 13.8v plus.

My solution is to lower regulator voltage till things warm up. I can get 120 amps from a single v belt if it is tight enough. But that is undesirable for water pump bearings. 75 to 80 battery charging amps is possible at normal belt tightness with all loads off other than fuel pump and ignition. I can run dual v belts but have issues with harmonics as matched belts are not so matched and my ac compressor pulley does not align perfectly anyway.

My v belt is old. Should likely change it or at least have a new spare instead of a used one.

[BFL13]

Slownsy wrote:
Yes I intended to run a heavy cable to rear for charging FW, I know that the is a orange wire with 40A fuse from factory but as plugs and som of harness have been changed when right hand conversion was don. 6gage wire is often used for this here in Australia but wondering about fuse for use near alternator.
Frank

People here have had good luck with fatter wires back to their slide-in truck campers, and also by attaching the wires to the alternator instead of the battery.

For trailers, you are pretty much onto a loser there. Even with fat wires you can't stop it charging at 13.x instead of at 14.x.

Your only real hope is to get the DC-DC gizmo mentioned, or do it by having an inverter run a battery charger, where the battery charger is doing 14.x while the input to the inverter is at 13.x. (Which is easier to arrange when parked, and hard to arrange while driving down the road.)

On the last, I had to do it parked with the inverter on the engine battery and hanging over the fender with the hood up. With the inverter on the fender top, it got too hot from engine heat and quit running.

Going down the road towing a 5er, with my portable gen in the truck bed and running a charger in the trailer from the gen, I could pass a 120v wire from the gen back to the trailer, holding it up off the road wih bungee cords, but the wind seemed to affect the gen (wind blows backwards into the back of the truck-vortex)and it would quit running sometimes.

Anyway, you can try different things, but it is mostly a loser for when driving down the road. However solar still works while driving if you have any. Watch out that solar voltage at 14.x is higher than alternator at 13.x, so the solar will kill any alternator amps--they will only add their amps if both are at 14.x or both at 13.x. Note that both at 13.x is not very useful--you want 14.x..

[Matt_Colie]

landyacht318 wrote:
I have an insulated(from underhood air/windflow) temp sensor on the alternator casing/stator of my externally regulated alternator, and I spin a potentiometer on the dashboard to control that regulator's maximum allowed voltage which of course controls the field current and ultimately alternator amperage output.

At 65mph, with alternator maxed out in the 120 amp range, the stator will not exceed 140f. I added more insulation to protect thermocouple from airflow, as I found this number to be too low, yet it remained nearly exactly the same.

At hot Idle, with ~50 amp maximum output, stator temperature will climb to over 200F in about 4 minutes and likely keep rising, but I lower the voltage, thus amperage into the well depleted battery, or shut off the engine as I do not like Idling excessively for any reason, not even testing.

Obviously rectifier temperature will be different, as will each vehicle at different speeds and alternator outputs. the point is heat does kill, and idling at maxoutput makes much more heat than at highway speeds. On My vehicle, speeds under 25mph a yield little difference in temperature, than Idling parked.

The voltage regulator seeking to bring system voltage to 14.7v is asking the alternator which is charging depleted batteries,to work much harder for much longer than simply maintaining 13.6v. I spin a dial on my dash and can watch voltage and amperage change in accordance with my wishes.

My observations usually irritate people who have an incomplete understanding of the relationship between voltage and amperage when charging batteries. It's sad, yet amusing, that such people give advice and present themselves as authorities. I'm referring to people on Automotive based forums, not necessarily this one, so nobody get their panties all bunched up someplace unpleasant.

Land,

The alternator temperature sounds like an interesting instrument to have. I have to think about that more.

I had some interesting times that you would understand. The coach has a main engine that is a 455 and an 80 amp rated Delco 27SI alternator. The original house bank was very near to the main engine, but it was originally a Grp 27. Later a grp31 and finally a 4D when I purchased it. After any cold night on our own, the belt would squeal for a minute or more and they never lasted very long and were a bear to change. From the electric upgrades that I used to do for performance cruisers, I knew that the functional limit for a single automotive V belt was about 100 amp, but hey, it's only an 80amp machine....

Finally, after replacing the belt again, I did an experiment. I got out my current probe and meter and set the display where I could see it and fired up the main engine. The current to the house bank was 95amps! That didn't include that for the main engine battery. No F~king wonder I was cooking belts. Even tough the 27SI is remote sensing, there is no easy way to make in back off. If it was a Balmar with a programmable regulator, that would be easy. I did consider that, but that kit would be about 600$us (then). A new belt routing, pair of new belts and a double sheave was a whole lot less.

I now have a real battery monitor (I didn't then) and that is good because I wouldn't want to leave the current probe and meter in the rig. And yes, when I do the cold start after a cold night boondocking, it gets up there. The belts now last and the house bank has been a pair of T105s (GC2s) for a while. Those are WAY easier to manage than a single 4D.

I still might consider putting a thermocouple in the alternator. But I don't know what I could do if I did not like what I saw.

Matt

[landyacht318]

I have an insulated(from underhood air/windflow) temp sensor on the alternator casing/stator of my externally regulated alternator, and I spin a potentiometer on the dashboard to control that regulator's maximum allowed voltage which of course controls the field current and ultimately alternator amperage output.

At 65mph, with alternator maxed out in the 120 amp range, the stator will not exceed 140f. I added more insulation to protect thermocouple from airflow, as I found this number to be too low, yet it remained nearly exactly the same.

At hot Idle, with ~50 amp maximum output, stator temperature will climb to over 200F in about 4 minutes and likely keep rising, but I lower the voltage, thus amperage into the well depleted battery, or shut off the engine as I do not like Idling excessively for any reason, not even testing.

Obviously rectifier temperature will be different, as will each vehicle at different speeds and alternator outputs. the point is heat does kill, and idling at maxoutput makes much more heat than at highway speeds. On My vehicle, speeds under 25mph a yield little difference in temperature, than Idling parked.

The voltage regulator seeking to bring system voltage to 14.7v is asking the alternator which is charging depleted batteries,to work much harder for much longer than simply maintaining 13.6v. I spin a dial on my dash and can watch voltage and amperage change in accordance with my wishes.

My observations usually irritate people who have an incomplete understanding of the relationship between voltage and amperage when charging batteries. It's sad, yet amusing, that such people give advice and present themselves as authorities. I'm referring to people on Automotive based forums, not necessarily this one, so nobody get their panties all bunched up someplace unpleasant.

[Chum_lee]

pnichols wrote:

Chum lee wrote:
To a certain extent, your chassis alternator output (voltage and current) is dependent on the current state of charge of your chassis battery(s) and the loads placed on the alternator by the VEHICLES electrical system. If your chassis battery is fully charged, expect the alternator output to be a fraction of it's maximum rated capacity until the existing loads drop the charge in the chassis battery. Ford engineers designed their charging system that way to improve fuel mileage and to prevent people from doing what they want to do . . . . . charge the batteries in their camper with the chassis alternator.
Chum lee

I not talking about a pickup truck here ... but with respect to our small Class C motorhome on an E450 V10 chassis with "only" a 130 amp alternator: The V10 engine battery I have installed is an overkill Ford OEM battery model intended for their diesel trucks. The coach has two 115 AH Group 31 AGM batteries wired in balanced parallel.

Whenever the V10 is running, the two coach batteries and one engine battery are all connected together in direct parallel via a high amperage continuous duty 12V solenoid. I know this because I have an engine battery readout voltmeter mounted on the dash and a coach battery readout voltmeter also mounted on the dash - and they both read nearly the same all the time - which means that all three batteries are connected in direct parallel when the engine is running. There appears to be no isolation diodes involved between the engine battery and coach batteries.

I've also mounted on the dash an ammeter that reads the current going into, or out of, the coach batteries.

After drycamping a bit, whenever the coach batteries are down to around 50% (12.0-12.1V reading on their dash voltmeter), I sometimes start up the V10 and idle it for an hour or so to conveniently and very quietly to partially top up the two coach batteries. The coach battery ammeter (on the dash) will sometimes spike to as high as 80 amps at first (V10 idling), and then gradually taper down as the coach batteries are being boost and bulk charged via the 130 amp Ford alternator. The voltage output of the alternator (as indicated by the voltmeter on the dash) will start out at 14.X volts at first, and then gradually taper down as the coach batteries charge up.

So the bottom line is ... yes, some stock engine alternator systems can indeed be used to charge camper battery systems just fine.

As a sidenote, the performance curve for our V10's 130 amp Ford alternator indicates that it can indeed output around 70-80 amps at engine idle RPM speeds, so it's performing as expected ... at least in our 2005 E450 based motorhome. Even though the engine itself may be idling at only 550-650 RPM, the pulley system powering the alternator spins it a lot faster. In order for an engine alternator to output high currents at low engine speeds, the engine merely has to be able to delivery enough horsepower at idle so as to spin the alternator at whatever RPM the alternator's power vs RPM curve requires for the desired amperage output in the application. It may be difficult to locate the power-vs-rpm graphs for many alternators, however.

Yes, my '99 F53 (V10) does the same thing and on some mornings I often run the engine at idle to put a little charge (little is the key word) in the house batteries. As theoldwizard1 mentioned, the newer vehicles are more sensitive to charging conditions. The problem is, when idling with the alternator putting out close to the maximum voltage/current, even though the alternator is over driven, the cooling fan on the alternator needs to be able to dissipate the additional heat generated with the engine at idle. Since the idle is stabilized, available horsepower isn't the issue, . . . . IMO, cooling is. I'm not saying that it will fail overnight, it just gets hotter. Heat kills, . . . . . more heat kills more quickly.

Chum lee

[pnichols]

Chum lee wrote:
To a certain extent, your chassis alternator output (voltage and current) is dependent on the current state of charge of your chassis battery(s) and the loads placed on the alternator by the VEHICLES electrical system. If your chassis battery is fully charged, expect the alternator output to be a fraction of it's maximum rated capacity until the existing loads drop the charge in the chassis battery. Ford engineers designed their charging system that way to improve fuel mileage and to prevent people from doing what they want to do . . . . . charge the batteries in their camper with the chassis alternator.
Chum lee

I not talking about a pickup truck here ... but with respect to our small Class C motorhome on an E450 V10 chassis with "only" a 130 amp alternator: The V10 engine battery I have installed is an overkill Ford OEM battery model intended for their diesel trucks. The coach has two 115 AH Group 31 AGM batteries wired in balanced parallel.

Whenever the V10 is running, the two coach batteries and one engine battery are all connected together in direct parallel via a high amperage continuous duty 12V solenoid. I know this because I have an engine battery readout voltmeter mounted on the dash and a coach battery readout voltmeter also mounted on the dash - and they both read nearly the same all the time - which means that all three batteries are connected in direct parallel when the engine is running. There appears to be no isolation diodes involved between the engine battery and coach batteries.

I've also mounted on the dash an ammeter that reads the current going into, or out of, the coach batteries.

After drycamping a bit, whenever the coach batteries are down to around 50% (12.0-12.1V reading on their dash voltmeter), I sometimes start up the V10 and idle it for an hour or so to conveniently and very quietly to partially top up the two coach batteries. The coach battery ammeter (on the dash) will sometimes spike to as high as 80 amps at first (V10 idling), and then gradually taper down as the coach batteries are being boost and bulk charged via the 130 amp Ford alternator. The voltage output of the alternator (as indicated by the voltmeter on the dash) will start out at 14.X volts at first, and then gradually taper down as the coach batteries charge up.

So the bottom line is ... yes, some stock engine alternator systems can indeed be used to charge camper battery systems just fine.

As a sidenote, the performance curve for our V10's 130 amp Ford alternator indicates that it can indeed output around 70-80 amps at engine idle RPM speeds, so it's performing as expected ... at least in our 2005 E450 based motorhome. Even though the engine itself may be idling at only 550-650 RPM, the pulley system powering the alternator spins it a lot faster. In order for an engine alternator to output high currents at low engine speeds, the engine merely has to be able to delivery enough horsepower at idle so as to spin the alternator at whatever RPM the alternator's power vs RPM curve requires for the desired amperage output in the application. It may be difficult to locate the power-vs-rpm graphs for many alternators, however.

[time2roll]

Slownsy wrote:
Yes I intended to run a heavy cable to rear for charging FW, I know that the is a orange wire with 40A fuse from factory but as plugs and som of harness have been changed when right hand conversion was don. 6gage wire is often used for this here in Australia but wondering about fuse for use near alternator.
Frank

I would get a 20 amp DC/DC booster mounted near the trailer battery. Alternator will not even know.

https://www.renogy.com/12v-dc-to-dc-on-board-battery-charger/

Voltage on the trailer battery is the issue, not alternator amps.
This converter will put 14.7 volts and 20 amps right on the battery terminals.

[skyhammer]

As most people know, diesels take awhile to warm up and provide heat to the cabin.
Supplemental Heat provides heat to the cabin on start up and within a few minutes is providing 1000-1200 watts to the cabin. When the engines is warm enough to provide heat, supplemental heat automatically shuts down.

[theoldwizard1]

Chum lee wrote:
If your chassis battery is fully charged, expect the alternator output to be a fraction of it's maximum rated capacity until the existing loads drop the charge in the chassis battery.

Partially correct. The actual current (amps) output will be what ever is required to MAINTAIN the desired charging voltage. The point is, within a few minutes of starting the computer adjusts that voltage down to between 13.2V and 13.8V

Chum lee wrote:
Ford engineers designed their charging system that way to improve fuel mileage ...

Not just Ford. Every light and most medium duty vehicles. It has been that way for over 15 years.

Chum lee wrote:
... and to prevent people from doing what they want to do . . . . . charge the batteries in their camper with the chassis alternator.

Slownsy wrote:
Yes I intended to run a heavy cable to rear for charging FW, I know that the is a orange wire with 40A fuse from factory ...

You can still charge your house batteries, but it will require a DC-DC battery charger like from CTEK or Renology. And you won't need to use huge oversized wire to eliminate voltage drop !

[Slownsy]

Yes I intended to run a heavy cable to rear for charging FW, I know that the is a orange wire with 40A fuse from factory but as plugs and som of harness have been changed when right hand conversion was don. 6gage wire is often used for this here in Australia but wondering about fuse for use near alternator.
Frank