2nd alternator

[Sdd-ClassB]

I’m looking at the new ford transit cargo van coming out this fall with a second alternator. I was hoping to get a self contained lithium battery system like the yeti goalzero 3000 and have it charged by the 2nd alternator. I’ve been searching everywhere for information but can’t determine if it is even possible let alone how do do it. Looking for help.

 

[hbn7hj]

My bet is you don't need a second alternator to charge the Yeti 3000.

It only has 120 watts of 12 volt power. The battery itself is only 10.95 volts, I think.

There are better, cheaper, solutions. Just an opinion.

 

[avanti]

There are better, cheaper, solutions.

How much is the Transit 2nd alternator option?

 

[Sdd-ClassB]

Not sure yet, waiting for 2020 models to come out

 

[Sdd-ClassB]

Fair enough! Let’s say a 6000 watt system is available, and it has two input options - solar or standard 110 plug. Would that change your answer?

 

[booster]

Fair enough! Let’s say a 6000 watt system is available, and it has two input options - solar or standard 110 plug. Would that change your answer?

Are we talking 6000 watt capable as in 50amps of current in a 12v system, or are we talking about 6000watt hours of power available as in 60 watts for 100 hours?

 

[jon-ClassB]

I have a 2019 transit with the 250 amp alternator and 400 amp-hrs 12v batteries. That's 4800w. The shop that converted my van only added a 40w batt to batt charger and It was taking forever to charge. I was thinking about adding a second alternator so I could run my roof AC while driving.....
Then I learned of the Sterling 120 amp batt to batt charger. The transit with the HD alternator has three 60 amp customer connection points for a total of 180 amps. I changed to a 120 amp vehicle charger (with pain-in-the-butt larger wiring) and now I can run my rear rooftop AC with the HD alternator without running my battery down.
It's as good as having a second alternator.

 

[booster]

I have a 2019 transit with the 250 amp alternator and 400 amp-hrs 12v batteries. That's 4800w. The shop that converted my van only added a 40w batt to batt charger and It was taking forever to charge. I was thinking about adding a second alternator so I could run my roof AC while driving.....
Then I learned of the Sterling 120 amp batt to batt charger. The transit with the HD alternator has three 60 amp customer connection points for a total of 180 amps. I changed to a 120 amp vehicle charger (with pain-in-the-butt larger wiring) and now I can run my rear rooftop AC with the HD alternator without running my battery down.
It's as good as having a second alternator.

We again have mixed units here. 400ah of 12v batteries is 4800watt hours as it is stored energy. The charger units are correct at 40 watts if it is about a 3.5amp/12v charger, which seems useless as anything but a trickle charger as it is instantaneous power.

 

[jon-ClassB]

We again have mixed units here. 400ah of 12v batteries is 4800watt hours as it is stored energy. The charger units are correct at 40 watts if it is about a 3.5amp/12v charger, which seems useless as anything but a trickle charger as it is instantaneous power.

OOPs, My BAD. I had a 40amp battery charger installed that I changed to 120amps.

 

[Jim-C]

I have a 2019 transit with the 250 amp alternator and 400 amp-hrs 12v batteries. That's 4800w. The shop that converted my van only added a 40w batt to batt charger and It was taking forever to charge. I was thinking about adding a second alternator so I could run my roof AC while driving.....
Then I learned of the Sterling 120 amp batt to batt charger. The transit with the HD alternator has three 60 amp customer connection points for a total of 180 amps. I changed to a 120 amp vehicle charger (with pain-in-the-butt larger wiring) and now I can run my rear rooftop AC with the HD alternator without running my battery down.
It's as good as having a second alternator.

Did you add the second alternator ? I have a new 2020 Transit and want to add a second alternator. A 24v alternator would be really nice.

 

[jon-ClassB]

Did you add the second alternator ? I have a new 2020 Transit and want to add a second alternator. A 24v alternator would be really nice.

No. I didn't need a second alternator with a 120 amp charger. The only time the charger won't keep up with demand is when I'm cruising down the freeway running my roof 120 volt air conditioner and trying to charge my batteries. But it's close. I've never not been able to run my roof AC.

 

[PLSchroeder27]

Given that The 2018/19 HD alternator provides enough amperage at idle to start and run a typical rooftop AC with a good 2kW inverter, can you recommend the HD Alternator as an ongoing day to day source for doing so, or is that placing too much load on the HD Alternator, leading to potential overheating and early failure?

I have a 2019 with the HD Alternator and Dual Batteries, and would like to use them to run my rooftop air continuously, but only if it is long term sustainable.

Or is it necessary to install a battery bank to support running the rooftop air unit, and use the alternator to keep the batteries charged?

 

[PLSchroeder27]

No. I didn't need a second alternator with a 120 amp charger. The only time the charger won't keep up with demand is when I'm cruising down the freeway running my roof 120 volt air conditioner and trying to charge my batteries. But it's close. I've never not been able to run my roof AC.

Are you able to continuously supply 120 Amps long term from the alternator without overheating it?

 

[PLSchroeder27]

No. I didn't need a second alternator with a 120 amp charger. The only time the charger won't keep up with demand is when I'm cruising down the freeway running my roof 120 volt air conditioner and trying to charge my batteries. But it's close. I've never not been able to run my roof AC.

jon, which rooftop air unit do you have, how many BTU's, and how many amps and watts does it pull at full load?

 

[avanti]

Taking high-current power from a late-model vehicle really isn't a very good idea. It isn't just whether you can make it "work". Recently-designed vehicles have elaborate energy management systems that were not designed for such loads. That is why Sprinters, for example, have upfitter guidelines that forbid taking more than 40A from the chassis electrical system. In practice, this never really mattered much on the NCV-3 with the 6-cylinder engine. But, the I4 engines had a much more elaborate energy management system that (among other things) had a shunt mounted on one of the battery terminals. Which side of that shunt should one steal the power? This obviously matters, but as far as I know, nobody knows the correct answer--there probably is none.

I have no detailed knowledge of other makes, or even of the new Sprinters, but I doubt that the systems have gotten any simpler. A second alternator totally avoids this can of worms. I, for one, will never consider hacking into these systems. No certified upfitter will do so.

 

[Boxster1971]

Taking high-current power from a late-model vehicle really isn't a very good idea. . .

I have no detailed knowledge of other makes, or even of the new Sprinters, but I doubt that the systems have gotten any simpler. A second alternator totally avoids this can of worms. I, for one, will never consider hacking into these systems. No certified upfitter will do so.

I've looked closely at the 2020 Transit body builder documents - that have similar ECM controls of the alternator output. I think most vehicles have such systems today as the manufacturers try to squeeze every drop to meet MPG and emissions requirements.

 

[booster]

I would also think that pretty much all new vehicles are doing the selective charging to save fuel and increase power to the wheels, as it makes sense for them and is nearly free to do as an OEM.


Along with that, I would really not want to pull over 40-50% of rated capacity, for long periods, with any factory alternator as the alternators themselves are not normally designed to do that kind of output for long periods and will most likely fail prematurely from the load and heat. This would be particularly true if it is also 100+* outside and you have the cabin AC on full blast and it is making the engine compartment run even hotter.

 

[jon-ClassB]

jon, which rooftop air unit do you have, how many BTU's, and how many amps and watts does it pull at full load?

Mach 8 Plus - Cub

Cool/Heat Capacity: 9,200
Electrical Rating: 115 VAC, 60HZ
Cooling Amps-High: 11.7
Running Watts Standard: 1270
EXTERIOR SHROUD
Height: 8.25” Width: 28.40” Length: 41.10”

I run it off a 3000 watt inverter that the shop that built my van installed.
I do have the 250 amp HD alternator with the dual batteries and a 400 ahr house lithium battery so actually I'm running it through the batteries but the charger keeps up with the current draw.

I installed the 120 amp charger myself and I didn't by-pass any systems like the comments imply. The HD alternator dual battery set up gives you three 60 amp CCPs. I just combined all three into a 150 amp fuse then a big ass wire (I forgot the gauge) to the charger.

I don't know the exact numbers because I don't trust that the shop wired all the loads through state of charge meter exactly correct but I know that when the van is running I can turn the AC on low and I don't show negative current being drawn from my house battery.

 

[PLSchroeder27]

Taking high-current power from a late-model vehicle really isn't a very good idea. It isn't just whether you can make it "work". Recently-designed vehicles have elaborate energy management systems that were not designed for such loads. That is why Sprinters, for example, have upfitter guidelines that forbid taking more than 40A from the chassis electrical system. In practice, this never really mattered much on the NCV-3 with the 6-cylinder engine. But, the I4 engines had a much more elaborate energy management system that (among other things) had a shunt mounted on one of the battery terminals. Which side of that shunt should one steal the power? This obviously matters, but as far as I know, nobody knows the correct answer--there probably is none.

I have no detailed knowledge of other makes, or even of the new Sprinters, but I doubt that the systems have gotten any simpler. A second alternator totally avoids this can of worms. I, for one, will never consider hacking into these systems. No certified upfitter will do so.

Avanti, do you think continuously pulling 40-60 amps from the 2019 Ford Transit Heavy Duty 250 amp alternator would be too much of a continuous load for it to handle? I understand the Ford energy management system dilemma. This would be a 16% (40 amp) to 24% (60 amp) load on the alternator.

I know a second alternator would be better, but the expense of $1,500 to $2,000 is quite high. I currently run a 5,000 BTU window air conditioner mounted in the rear window on about 500 watts at 110 volts continuously. This should translate to about 40-50 amps at 12 volts from the alternator needed to run to a 1,500 watt inverter to power the 5,000 BTU window air conditioner. Do you think this is long term sustainable on the 250 amp alternator? I can pull the 40-50 amps from the Ford CCP terminals. Would appreciate your insight on this configuration.

 

[booster]

Avanti, do you think continuously pulling 40-60 amps from the 2019 Ford Transit Heavy Duty 250 amp alternator would be too much of a continuous load for it to handle? I understand the Ford energy management system dilemma. This would be a 16% (40 amp) to 24% (60 amp) load on the alternator.

I know a second alternator would be better, but the expense of $1,500 to $2,000 is quite high. I currently run a 5,000 BTU window air conditioner mounted in the rear window on about 500 watts at 110 volts continuously. This should translate to about 40-50 amps at 12 volts from the alternator needed to run to a 1,500 watt inverter to power the 5,000 BTU window air conditioner. Do you think this is long term sustainable on the 250 amp alternator? I can pull the 40-50 amps from the Ford CCP terminals. Would appreciate your insight on this configuration.

I am not speaking for Avanti, but the alternator itself should handle up to about 40% of rated without too much issue. I think what is being talked about at the lower levels like you would use at 50 amps continuous is what the control system for the alternator in the van might do in relation to turning it down or some such thing. My guess would be it would not be much of an issue at the 50 amp level as that is in the range of seat heaters and window defogger use levels. Be aware you will likely pull considerably more than 50 amps when the AC compressor starts so the 1500w inverter may have some issue depending on how much overload space it has and the quality of the waveform (pure sine wave needed for sure).