UHG - why a separate alternator?

[avanti]

Originally Posted by kite_rider

Anyway, to the original point of this thread. All I'm trying to say is that adding a second alternator is expensive, complicated, and opens the potential for other failures. I back that up with the anecdotal evidence I've observed (for Promasters primarily) on the forums and FB pages. So I'm suggesting, if your additional loading is not all that high - which seems to be the situation for my camper - then you might want to just invest in a factory certified upgraded alternator rather than add a second one.

I guess whether something is "expensive" or "complicated" is a matter of perspective. I will say that it is less expensive than a genset. Complicated, I guess, depends on the host vehicle. When I installed a Nations alternator on my 2014 Sprinter I4, it was not complicated in any way. Any competent mechanic could have done it easily. But, it is true that the alternator bracket on my particular engine is particularly well-designed and accessible. I can't speak for other platforms.

As for "potential for other failures", I gather that there may be specific problems with certain platforms. There are none on mine.

However, I do have to comment that the "factory certified upgraded alternator" option is increasingly problematic. The reason is that the bottleneck is no longer the raw capacity of the OEM alternator. Rather, at least in the case of Sprinters, the maximum certifiable current take-off is 40 amps. A larger alternator does not raise this limit. This is because of the basic design of the LIN-controlled, energy-managed charging system. (I don't know about Promasters, but I assume that they are similar. If they are not, they soon will be.) The ONLY factory-certified way to take off more power than this is via a second alternator (or some other mechanical take-off). You may be able to get away with more, but it is not factory-approved and is more-and-more a bad idea.

[booster]

Personally, if I were building our system today, I would likely make it 24v, with a 24v standalone UHG. I replaced the inverter/charger anyway when I did the system, and even considered it then, but decided saving the space needed for the 24 to 12v converter to run the van stuff wasn't worth giving up. All this assumes I could get a Magnum MS2000 in 24v and a 24v alternator that would fit the Chevy UHG mount. The higher volatage makes more sense, and still make 4 GC2 six volt batteries a good choice.



Totally agree with the lack of information on systems, and particularly the issues with them. There certainly is a shortage of good data out there, especially on the lithium side. Getting accurate information is not easy and takes some effort, to be sure, but it is the only way you will know what the capabilities and shortfalls are. I know I have been very surprised at how much different our measured temps, amps, and net amp-hour accumulations are compared to what the specs, and quite a few claims that I had seen, would predict.

[InterBlog]

Look at the anecdotal reports just for the most prominent flagship users - if anyone should be able to achieve reliable operation, it's flagships like James Adinaro, who is himself an aerospace engineer. But so far, IIRC he has blown at least one alternator, and he just blew his rig's head gasket as well, and it's not that old. SOMETHING is going on there.

As for us, we are not done addressing the issue yet. Husband and I are going to install countermeasures to guard against future in-kind alternator failure while still engaging in limited, targeted single-alternator charging.

My husband is a mechanical engineer with a lot of electrical experience, and he is *insisting* on designing a circuit for this control purpose. He's in design phase right now, with a mountain of components strewn about his desk.

I keep telling him, "Look, just give me a second isolation switch that I can reach from the driver's seat, plus an in-dash live chassis battery voltmeter. MY BRAIN can take care of the logic if I have just those two things at my fingertips!"

But he won't have anything to do with that idea. It's inelegant, in his engineer's viewpoint. He wants the logic to be codified, rather than brain-ified. Ugh.

On one hand, we have posters who are close to 100% emotional (which drives me bat-**** crazy), and OTOH, we have posters like my husband who are 100% engineering/mechanical. Me, I fall on the continuum, but closer to the engineer endpoint.

[kite_rider]

Originally Posted by InterBlog

Look at the anecdotal reports just for the most prominent flagship users - if anyone should be able to achieve reliable operation, it's flagships like James Adinaro, who is himself an aerospace engineer. But so far, IIRC he has blown at least one alternator, and he just blew his rig's head gasket as well, and it's not that old. SOMETHING is going on there.

Exactly! I don't follow the FitRV all that close so I missed the one about a blown alternator (or alternators if it's plural). Please send a link on those since it's relevant to this discussion.

On his blow head gasket drama, he related this to the second alternator (UGH) installation and some interference with the cooling lines.
"It turns out there were issues installing that second alternator, but the dealer in question fixed the problem to specifications and at their expense, and Lance is no stranger to riding on a flatbed…"
https://www.thefitrv.com/blog/man-do...s-in-the-shop/

I can send links to other Promaster owners who have coolant leak issues related to their UGH. Seemed pretty common. I have not seen anecdotal reports that the extra loading from running the rooftop A/C has affected the Promaster alternator. I don't know just how big a load that is, but I'll guess it's much more than 40A.

To Avanit, I'm happy to hear that it's pretty straight forward to add a second alternator to the I4 Sprinter motor. It's a pity that motor is on so few Sprinter planforms. If I could get that on a 4x4 I would be seriously motivated to get one! However, on the Promaster; I don't think it's a matter of perspective to say that a UGH is expensive, complicated, and prone to other failures. I can point to lots of evidence to make the case that it's an objective conclusion.

[Boxster1971]

This YouTube is relevant to this discussion...

https://youtu.be/Wh5cPUvRiL0

[booster]

Originally Posted by InterBlog

Look at the anecdotal reports just for the most prominent flagship users - if anyone should be able to achieve reliable operation, it's flagships like James Adinaro, who is himself an aerospace engineer. But so far, IIRC he has blown at least one alternator, and he just blew his rig's head gasket as well, and it's not that old. SOMETHING is going on there.

As for us, we are not done addressing the issue yet. Husband and I are going to install countermeasures to guard against future in-kind alternator failure while still engaging in limited, targeted single-alternator charging.

My husband is a mechanical engineer with a lot of electrical experience, and he is *insisting* on designing a circuit for this control purpose. He's in design phase right now, with a mountain of components strewn about his desk.

I keep telling him, "Look, just give me a second isolation switch that I can reach from the driver's seat, plus an in-dash live chassis battery voltmeter. MY BRAIN can take care of the logic if I have just those two things at my fingertips!"

But he won't have anything to do with that idea. It's inelegant, in his engineer's viewpoint. He wants the logic to be codified, rather than brain-ified. Ugh.

On one hand, we have posters who are close to 100% emotional (which drives me bat-**** crazy), and OTOH, we have posters like my husband who are 100% engineering/mechanical. Me, I fall on the continuum, but closer to the engineer endpoint.

I would tend to agree with this, and add one more thing. If you aren't getting some failures sometimes in your projects and experiments, you aren't really pushing hard enough to get maximum benefit, either. If existing stuff works fine, that is one thing, but with all the emerging tech happening and getting applied to different things, you do wind up on your own fairly often. The question is if you see something that just doesn't work all that great, or you can see potential things that might be issues, what do you do? Lots of different ways to answer that one.


I am an engineer, but think more like Interblog on a lot of this. The cockpit mounted disconnect mentioned and the reasoning was actually done on on our van several system changes ago, and is still there in a updated form. Electronic logic can do lots of stuff, and is very consistent, but unless it is AI, it does nothing for the intangibles that are quick and easy for a person. Are you coming up on mountain with the alternator charging at the max it can without overheating? If so, it would certainly make sense to turn it off to save the hp for the climbing and save the alternator all the heat that is going to be in engine compartment from the climb at full engine output. The list of stuff like this goes on and on and as long as I have to be sitting there driving, it is literally not any work to do. It might even relieve driving boredom a little. I can see alternator(s) temps, coach amps and volts, coach battery amps, coach battery temp, all from the seat so the decisions are extremely easy to make, and the relay controlled manual separator is a simple push of a button, as is charge stage changes. I just have it locked in absorption (AGM batteries) until I get to an amp reading to the batteries that is within what the solar can put out under the conditions and then unlock the absorption and let it go to float while the solar takes over. Often I will also just turn off the separator as charging is from the engine isn't needed by then.


Of course, some like everything done automatically and are OK with whatever things may not get covered quite as well and the extra complexity, but I prefer simple and flexible. To each their own.

[Boxster1971]

Here is older FitTV Blog article from 2016 when they got their UHG installed and had their engine overheating event. Speculation that led to the current blown head gasket. But that seems unlikely since it happened soo long ago. Probably why FCA RAM is rejecting a warranty repair as they struggle to get it fixed.

https://www.thefitrv.com/rv-tips/our...-and-inverter/

[gregmchugh]

Originally Posted by Boxster1971

Here is older FitTV Blog article from 2016 when they got their UHG installed and had their engine overheating event. Speculation that led to the current blown head gasket. But that seems unlikely since it happened soo long ago. Probably why FCA RAM is rejecting a warranty repair as they struggle to get it fixed.

https://www.thefitrv.com/rv-tips/our...-and-inverter/

The last info I saw was that FCA is going to fix it under warranty but they needed to transport it to a dealer who was going to do it. The first dealer claimed they didn’t have the right kind of lift to do the work, even though you don’t need a lift to do the repair...

[booster]

Originally Posted by gregmchugh

The last info I saw was that FCA is going to fix it under warranty but they needed to transport it to a dealer who was going to do it. The first dealer claimed they didn’t have the right kind of lift to do the work, even though you don’t need a lift to do the repair...

I haven't seen a Promaster engine in place closely, so don't know for sure on them, but on a lot of crosswise front driver V6s you need to get under the vehicle to get the exhaust off the rear head to remove it. That might be the case, and in a van it might be a lot better, or a lot worse.

[Boxster1971]

Originally Posted by gregmchugh

The last info I saw was that FCA is going to fix it under warranty but they needed to transport it to a dealer who was going to do it. The first dealer claimed they didn’t have the right kind of lift to do the work, even though you don’t need a lift to do the repair...

You are basically right, but on the THIRD dealer. They also elevated FCA corporate with a case agent assigned and should get a warranty repair. Their blog post this week tells the full story.

https://www.thefitrv.com/blog/lance-...era-continues/

[Davydd]

It goes to show you don't assume any dealer in town, Chevy Ford, Ram, Mercedes Benz, etc. can service your Class B. For one, many don't like to service Class Bs that have been modified extensively such as Sprinter Roadtreks that you have to remove Roadtrek equipment to get after the NOX sensors as one person reported. They sometimes don't have the lifts to handle the extra weight or height of a Class B (I encountered that with my 2005 Sprinter at a Dodge dealer who sold T1N Sprinters at the time). They maybe don't have the right diagnostic equipment for all the computer stuff now a days. With Sprinters the only Mercedes Dealers capable of servicing them are dealers that sell Sprinters and not all of them do. I don't know about how the Dodge-Ram split works out. But if a Dodge dealer is not selling RAM Promasters you might not get service or satisfactory service.

[kite_rider]

Originally Posted by Boxster1971

This YouTube is relevant to this discussion...

https://youtu.be/Wh5cPUvRiL0

Interesting video. Yet another example of a potentially big issue attributed to the installation of a UHG. Still few examples of anyone reporting failed alternators for any reason - including having a Lithium battery. I was curious and had a look at my alternator, no fancy clutch; just a plain old pulley. Plus, I'm beginning to seriously doubt that it is 'smart' in the same sense that the modern Sprinter alternators are 'smart'.

[InterBlog]

+1 Booster - the example I gave my husband is that no logic circuit is going to be able to predict whether I'm planning to be near an electrical outlet later that same day (but my brain can do that). If there's one thing I've learned from a near-disaster in the middle of IH-59 in central Mississippi, it's that the alternator usage should be minimized in all scenarios, just to be on the safer side. Whereas we did not hook to shore power in during the 17 months prior to the alternator failure, I now do so when the opportunity presents itself - why not? Why not save alternator wear and tear?

Re: Boxster's video - like many amateur YouTubers, that dude needs to learn how to focus and edit. His presentation was a bit meandering - I didn't hear whether or not he has tried optimizing his tire pressures for his weight distribution. That alone can make a big difference in how the van handles. My husband and I recently tweaked ours, and I was kicking myself for not looking into this sooner, because it helped our stability noticeably. James Adinaro has published the general sequence:

https://www.thefitrv.com/rv-tips/how...re-in-your-rv/

[kite_rider]

I was looking for links related the 'blown alternator(s)' on the FitRV Promaster mentioned in a previous post, not about tires and loading. The claim that James blew at least one alternator got me so interested / concerned that I spent about an hour browsing the FitRV blog where I found several posts highlighting the complexity of adding a second alternator to the Promaster and all of the problems that have surfaced since then, but no mention of a 'blown alternator' anywhere. Add the video Boxter posted (just the part about the coolant hose that had a hole worn into it), then various FB pages where folks talk about coolant leaks related with UHG and I think there is a pattern emerging for the Promaster vans related to 2nd alternator installations and it's not a good pattern.

Additionally, I've also scoured the webs looking for any FCA OEM limitation (40A or any number) for power take off on the from the alternator on the Promaster and can't find it.

Originally Posted by InterBlog

If there's one thing I've learned from a near-disaster in the middle of IH-59 in central Mississippi, it's that the alternator usage should be minimized in all scenarios, just to be on the safer side.

Sorry, but that comment needs a lot more explanation. It almost feels like a comment posted by a fellow Axion owner on FB who doesn't use propane while camping 'just to be on the safe side'.?? If you're that worried, buy a Honda and stay at a motel..(not trying to be rude or snarky, but we're talking about the merits of a second alternator here...)

[avanti]

Originally Posted by kite_rider

dditionally, I've also scoured the webs looking for any FCA OEM limitation (40A or any number) for power take off on the from the alternator on the Promaster and can't find it.

According to this:

https://www.ramtrucks.com/BodyBuilde...AuApYqpN1xG%0A

the upfitters Auxiliary Power Connector (Sales code BC1) is fused at 50 amps up to MY2015 and 70 amps for MY2016 and beyond.

I do not know whether or not there is an explicit prohibition against acquiring power by other means, or if power takeoff has an absolute limit as there is with the Sprinter.

In any event, 70 amps is a lot more generous than the Sprinter's 40 amps.


I think if I were a Promaster owner, I would use a B2B charger powered by this source to enforce the 70 amp limit and declare it "good enough".

[booster]

A lot of good information and opinions on this discussion, and I think many are closer together than they may seem.

What Interblog is saying about not using the alternator for coach charging makes perfect sense to me, and all that is needed to do it is a disconnect switch, so it is an almost all gain, no loss thing. Alternators are "wear items" and all will need to be replaced if you run them long enough. When that is will happen is certainly going to influenced by how hard the alternator is run, so reducing high output sessions will almost certainly increase the time to failure on them. A single alternator failure can leave you stranded once your battery goes dead, but you can stretch that out by having the ability to start and run the van off the coach batteries which often have solar on them besides. If you get a belt, pulley, or bearing failure, you are stuck anyway as you lose the water pump on most vehicles.

I think that is worth noting that the UHG failures on the Promasters that have been mentioned here are positively not the typical UHG we have heard about for UHGs in general. The failure of peripheral equipment like the hoses is very specific and essentially 100% preventable both initially or after it is fixed. The "normal" failures seem to be most often the Balmar regulators or loose wires, and sometimes non catastrophic alternator failure. Even a pulley or belt or bearing UHG failure on a Sprinter of Promaster will not disable the vehicle as they are on a separate belt. It will stop you on a Chevy.

The 70 amps the Avanti found for the max limit on the auxiliary power on a Promaster actually sounds like a reasonable amount for a stock alternator depending the alternator and the systems. You could have something like 30 amps to run the van if the lights and AC fan are on and 100 amps continuous from a 240 amp alternator is reasonable for OEM style units, from what I have seen. Taking a temp reading at that output, hood closed, in hot weather will tell you for sure. A 12 to 12v charger is a good way to limit the current to the coach and will give a moderately better charge profile.

70 amps is nearly the long term charging limit of about 200ah of AGM batteries which seem to start getting hotter higher than that. It may or may not be too much for lithium depending on their input limits orif it is too slow for the user. More than 200ah of AGM might want more charging amps depending on use patterns. For our use pattern, we have found we very rarely need the 180 amps we can get continuously and could easily be OK with considerably less. We do have 300 watts of solar, though, and use 40-60ah per day normally and maybe 20ah more if it is really hot for the compressor frig and fans, so we are not one of the big power users like some are.

I think if one is very worried about an alternator failure, do whatever you want for stock alone or with an UHG, and carry a spare stock one.

[kite_rider]

Originally Posted by avanti

In any event, 70 amps is a lot more generous than the Sprinter's 40 amps.

I think if I were a Promaster owner, I would use a B2B charger powered by this source to enforce the 70 amp limit and declare it "good enough".

Good catch! I don't think Hymer used this specific power option, but it's telling that FCA has designed their charging system to handle it (or at least they should have ). Fully agree that a B2B current limiting charger would be the prudent thing to do if you expect a continuous heavy electrical load in excess of 70A (for Promaster!).

Of course if your application requires a continuous heavy electrical load that exceeds the 70A then I think a second alternator would be the only way get it done. Aside from off grid A/C, I struggle to imagine very many campervan situations like this.

[booster]

Originally Posted by kite_rider

Good catch! I don't think Hymer used this specific power option, but it's telling that FCA has designed their charging system to handle it (or at least they should have ). Fully agree that a B2B current limiting charger would be the prudent thing to do if you expect a continuous heavy electrical load in excess of 70A (for Promaster!).

Of course if your application requires a continuous heavy electrical load that exceeds the 70A then I think a second alternator would be the only way get it done. Aside from off grid A/C, I struggle to imagine very many campervan situations like this.

The heavy continuous electrical loads for most of us who don't use 12v to ever run air conditioning, will mostly come from battery charging and can be very long term for big battery bank. Even a smaller AGM bank will take more the 70 amps for a quite while if it is near fully discharged. The exception would for those that like to save battery capacity by running the engine if they are going use the microwave or heat up an Instant Pot. These loads can exceed 100 amps but only last a short time so are minimally hard on the alternator as it won't have time to get too hot, but if you are limited by 12 to 12 charger you won't be able to get that much and will take some out of the batteries, just not as much. Definitely a balancing act on where to be, and having two setting is a sweet setup if you can figure out how to do it well.

[InterBlog]

Originally Posted by kite_rider

edited -

(1) I was looking for links related the 'blown alternator(s)' ....

(2) Sorry, but that comment needs a lot more explanation. It almost feels like a comment posted by a fellow Axion owner on FB who doesn't use propane while camping 'just to be on the safe side'.?? If you're that worried, buy a Honda and stay at a motel..(not trying to be rude or snarky, but we're talking about the merits of a second alternator here...)

(1) The alternator mishap was referred to by James himself. I cannot recall where, but it might have been on his previous Sprinter-based rig. I am not sure that he put that content in print, or, that he sustained it after moving to his new rig (lest it confuse people searching his website).

I noted James's alternator because in my view, these things are dogs first, and collies, shepherds, and Dalmatians second. There may indeed be something about a particular make and model that has an impact on the performance of an alternator, but in trying to evaluate anecdotal reports of failures, I see them as vans first, and specific builds second. The fact that our alternator failed... the best information we have right now is that it failed because of (a) Bosch's construction and (b) our lithium system's construction. The fact that the host vehicle happened to be a Sprinter had very little, if anything, to do with it, AFAIK right now.

(2) If it would help, I published this PSA on the issue of alternator clutch failure.

There are other forums and other threads where posters speculated about the mode of failure in a way that went beyond that PSA. Nobody was definitive, but there were some interesting ideas. If this helps, here is a permalink to another discussion about this issue, as the failure was in progress (I was on the road; the poster LB_3 is my husband who was back in Houston helping me resolve the failure).

TL;DR - my husband said, "My new theory is that the things we love about charging lithium batteries like the flat voltage curves and low impedance that allows bulk charging all the way to full is what’s killing the alternators."

Suffice it to say that the failure apparently had nothing to do with the amps - the Sterling B2B takes care of that. But amps are not the only factor in the performance equation. As my husband speculated, it may have to do with the frequency and intensity of actuation of the alternator as a charging source for lithium, which doesn't have the same charging profile as AGM.

There was such skepticism about this point on Sprinter Forum that I actually felt compelled to post a pic of our Sterling to prove that it was (1) installed and (2) correctly spec'd. Vanners have been brainwashed to assume that if they have this magic Sterling, they'll have no alternator problems going forward. That's a dangerous assumption IMO.

[booster]

That is interesting about your husband's theory of the how the lithium contributes even though the current is limited. It would be interesting to see if he has done any current and voltage tracers in and out of the Sterling. They may have to be oscilloscope traces to show anything, though. I would think the traces should be able to show most anything that could be an issue.



All alternators have ripple (do you know how many poles the Bosch has?), and depending on the impedance they are working into, I would think that the voltage ripple would generate varying amounts of current ripple. He may have more knowledge of if that is true or or not. The Sterling is also taking the alternator output and may be increasing or decreasing it based on the charge profile and temperature. The Sterling is also limiting current in some way, and I don't think we have ever heard how it is done. If they are pulsing to get a lowered voltage, for instance, it may make for large spikes into a very low impedance like lithium batteries compared to higher impedance loads. If the Sterling itself is doing in it's process that throws spikes back at the alternator it could be and issue.



It is a something the does potentially affect some of the basic thoughts about current limiting, and how it is done, not only in cases like this but in lithium batteries that have built in current limiting and such.


Has anyone contacted Sterling to ask them about it? Their response would of interest, especially if you have some ugly waveforms to show them.