Betting pool: The worst that could happen?

[InterBlog]

General comment:

If you want to drive what is essentially an experimental vehicle cross-continent solo, it helps to be just flat-out crazy, LOL.



Just keep that much in mind if you get a notion to do stuff like this.

@uncle_bob, it's a 200 A alternator but it's only shunting about 45 A toward the lithium cells at peak demand. The rest of it, on a GOOD day, is supposed to sustain the chassis battery. And sustain it preferentially.

Now, internet stories abound of lithium seekers who fried alternator after alternator. It's not uncommon for the average off-gridder to go through three alternators inside of a year or 18 months. But LB_3 thought he had figured out how NOT to kill this one. I sent the before and after voltage figures to him and I'll let him explain the upshot. But basically it appears that we had a damaged alternator (there was nothing wrong with the aforesaid suspect cable).

As for an on-the-road failure, it could hardly have gone better for me. I made it successfully into the inner city of Philly and Joel is an absolute gem. He dropped his entire afternoon to fix my problem as I'm 1,600 miles from my starting point and still 1,300 miles from my destination. The destination that I will try to reach without frying alternator #3.

And I needed a break. I really enjoyed sitting there and just talking with a fellow T1N enthusiast, as fatigued as I am at this point. I'm not going to post a lot of what we talked about, but he's on the cusp of quitting his day job to work exclusively on T1Ns. The demand is there, his work is excellent, and I think he is positioned to make a success of this gig -- and it couldn't happen to a nicer guy. I've got some business development ideas that he might be able to run with - stuff that LB_3 and I would like to see available to upfit T1N owners, but we certainly are not in a position to do anything about that stuff ourselves. More on that later.

It's funny how things go, eh? Before leaving Houston, I had entered his contact info into my Outlook just in case I needed it - it can't hurt to have it available. And quite suddenly, there I was in his yard today.

[Alex AVI]

Originally Posted by InterBlog

If you want to drive what is essentially an experimental vehicle cross-continent solo, it helps to be just flat-out crazy, LOL.



Just keep that much in mind if you get a notion to do stuff like this.

INTERBLOG - All I can say is cr**p. Why do things like this happen when you are halfway
through the continent? I have nothing to add to help, especially since your AI is in the good hands of an expert

But I have to add that my ONLY alternator breakdown in 45 yrs. of driving was during my 1st ever cross-country trip (Chicago to So. Cal.). I broke down at sunset at a rest stop high above the mountains on Hwy25 from CO to NM in 1981. This was before cell or sat phones. Luckily, with my CB call, a big rig stopped but he did not have the tools. So another CB cry for help from his much stronger wattage and another big rig stops. They get car started, by this time it was night and my lights were flickering, so they escort me (sandwhich-mode) to nearest town. We had dinner and told stories. I offered to give money, they did not even want me to pay for their dinner. I had to insist

[LB_3]

We installed another 200A Bosch alternator so the following should be an apples to apples comparison.

LiFePO4 Charging — 0A
............... old ...... new
Idle........ 14.00 — 14.12
2000 rpm 14.07 — 14.22

LiFePO4 Charging ~ 60A
............... old ...... new
Idle........ 13.67 — 13.83
2000 rpm 13.78 — 13.94

The subtle increase in voltage is consistent under all conditions we tested so I’m inclined to think we had a bad (or going bad) voltage regulator although it’s entirely possible that the old one just had a slightly lower set point.

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.

Lead acid batteries with high impedance and steep voltage curves see charging amps decrease to nearly zero as they get charged. This allows the voltage regulator to graduadly ramp down the field current over a long period of time. The lithium batteries see their larger charging amps turn on and off in milliseconds. This puts an enormous strain on everything from the belt interface to the regulator and windings in the alternator and leads to premature failure.

It would be ideal to be able to shunt the load over to a large resistor when the charging is complete then use a pwm circuit to ramp the current down over a few seconds or a minute but the complexity of such a device would be enormous and probably expensive. Maybe just using an alternator with a more robust external voltage regulator would be better.

I guess I’m off to the cruiser forums since many of them pioneered the use of LiFePO4 batteries and they can’t afford to be losing alternators when out to sea.

[uncle_bob]

Originally Posted by LB_3

We installed another 200A Bosch alternator so the following should be an apples to apples comparison.

LiFePO4 Charging — 0A
............... old ...... new
Idle........ 14.00 — 14.12
2000 rpm 14.07 — 14.22

LiFePO4 Charging ~ 60A
............... old ...... new
Idle........ 13.67 — 13.83
2000 rpm 13.78 — 13.94

The subtle increase in voltage is consistent under all conditions we tested so I’m inclined to think we had a bad (or going bad) voltage regulator although it’s entirely possible that the old one just had a slightly lower set point.

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.

Lead acid batteries with high impedance and steep voltage curves see charging amps decrease to nearly zero as they get charged. This allows the voltage regulator to graduadly ramp down the field current over a long period of time. The lithium batteries see their larger charging amps turn on and off in milliseconds. This puts an enormous strain on everything from the belt interface to the regulator and windings in the alternator and leads to premature failure.

It would be ideal to be able to shunt the load over to a large resistor when the charging is complete then use a pwm circuit to ramp the current down over a few seconds or a minute but the complexity of such a device would be enormous and probably expensive. Maybe just using an alternator with a more robust external voltage regulator would be better.

I guess I’m off to the cruiser forums since many of them pioneered the use of LiFePO4 batteries and they can’t afford to be losing alternators when out to sea.

Hi

A stock test in the alternator factory is to go from full load current to zero in no time at all. It's called a "load dump test". The main purpose is to stress test the diodes. The key trick is to check the alternator for function *after* the test is performed. Back in the day there *was* a major manufacturer who got that sequence of tests wrong. We .... errr ... they ... shipped a *lot* of alternators before the test setup was fixed. That was a *long* time ago ....

The voltage change could be due to a lot of things. Normal manufacturing tolerances are a good first guess. They aren't enough to explain the problem that's the really big deal here.

Based on watching my lithium's here, they do indeed "taper" at the end of the charge cycle. They do in minutes what lead acid's do in hours. They certainly do not do it in milliseconds.

What does the charge voltage / charge current look like on the chassis battery while the lithium's are doing their thing? That seems to me to be the "threat to life" issue here. Loosing all electronics on a modern vehicle at 60+MPH is *not* a good thing at all ....

Bob

[LB_3]

Originally Posted by uncle_bob

Hi
Based on watching my lithium's here, they do indeed "taper" at the end of the charge cycle. They do in minutes what lead acid's do in hours. They certainly do not do it in milliseconds.

What does the charge voltage / charge current look like on the chassis battery while the lithium's are doing their thing? That seems to me to be the "threat to life" issue here. Loosing all electronics on a modern vehicle at 60+MPH is *not* a good thing at all ....

Bob

The issue is that driving down the road at 60 mph, the charging amps for the chassis battery started going negative when charging the lithium batteries. A slow motion disaster in the making.

We're using a Sterling battery - battery charger to boost the alternator voltage to 14.6v and limit our charging amp draw to 60 amps. We also replaced the 90A factory alternator with a 200A Bosch alternator so we should have plenty of overhead to handle the added 60A load. Amirm charges his house battery bank at 120A and hasn't fried his alternator (yet).

The Sterling charger is supposed to be a safety feature that prevents drawing too many amps out of the alternator but once the alternator performance becomes degraded, the Sterling charger becomes a liability. One would normally expect the house battery charging to slow down as the alternator voltage sags given that it is at a higher voltage than the chassis battery but with the buck converter in the Sterling charger boosting the voltage, it actually draws more current (up to 60A) when the alternator voltage sags and will pull that current from the chassis battery if required.

Our LiFePO4 system is built around a pretty smart open source BMS which turns the charging on and off instead of relying on a charger to transition to a lower absorption or float voltage which is not needed on Lithium batteries. Given that the BMS is using MOSFETs to turn the charging on and off, the actual response time is on the order of about 200 nano-seconds. It's effectively instant.

I'm thinking we'll probably end up fabricating a bracket for a second alternator where the second AC compressor would be located on goes on the people movers. If we have room I'll try to design the bracket to support a large frame marine alternator that uses an external voltage regulator.

Using a programmable voltage regulator like the Balmer MC 614 (below) that can sense battery voltage as well as alternator temperature, and can limit total field current should solve these issues.



RV DIYers have been installing Lithium battery systems for many years now. These are complex systems and it's obvious why it's taken manufacturers so long to come out with them. We have the skills and education to play around on the on the bleeding edge of technology but it it were easy, everyone would have these awesome systems.

Even RoadTrek had major teething problems with the design of their lithium systems. They used to brag about their system and how advanced it was but they've been pretty effective at scrubbing all that information from the internet and hardly promote the system any more. Probably has as much to do with expectation management as it does protecting proprietary information.

Until our alternator issues, our system was running for over a year with almost not thought or maintenance as compared to our feabel lead acid system that we worried about constantly.

Once we have a better game plan, I'll update the My Lithium Adventures thread.

[Boxster1971]

LB_3 - agree that Lithium systems are complex and others have had many issues. Advanced RV was using a second alternator and regulator from Balmar. They found it was not adequate in some situations. They now also use a monster Delco unit with a special damper on the pulley called a Overrunning Alternator Decoupling (OAD) Pulley.
http://www.daycoproducts.com/what-ar...w-do-they-fail

[HiHoAgRV]

I had a vehicle years ago that when the charging system was taxed, it would shear the rear alternator bolt, start slipping the belt and fry the external regulator.
It's easy to look up the max capacity of a belt drive system and that was the weak link in my system. Slip=heat = death. Some of these high output devices almost need toothed drive belts.
Hoping ya'll have success!

[LB_3]

Originally Posted by Boxster1971

LB_3 - agree that Lithium systems are complex and others have had many issues. Advanced RV was using a second alternator and regulator from Balmar. They found it was not adequate in some situations. They now also use a monster Delco unit with a special damper on the pulley called a Overrunning Alternator Decoupling (OAD) Pulley.
http://www.daycoproducts.com/what-ar...w-do-they-fail

Thanks Boxter. Do you know if Advanced RV is still using the Balmer regulator? THat’s the top of my list after today’s limited internet search.

[uncle_bob]

Hi

If you keep the Sterling DC/DC, then there is no need for anything fancy on the second alternator. The Sterling will handle all the voltage conversion / current limiting / charge profile stuff.

You can take a look at the Bosh data sheet and see what it needs for RPM to get to full output. Translate that back to engine RPM based on your pulley setup. If the engine is running below that magic RPM (which it could be at 60 MHP) you aren't going to get full output from the alternator.

Bob

[Boxster1971]

Originally Posted by LB_3

Thanks Boxter. Do you know if Advanced RV is still using the Balmer regulator? THat’s the top of my list after today’s limited internet search.

I'm not sure what regulator they use with the Delco alternator.

[InterBlog]

QUOTE=LB_3;2138541]The issue is that driving down the road at 60 mph, the charging amps for the chassis battery started going negative when charging the lithium batteries. A slow motion disaster in the making.

.....[/QUOTE]

When I started this thread about a week ago, having a potentially life-threatening situation wasn't in the realm of my imagination.

If I hadn't caught the voltage sag when I did, the engine would have quit without warning in the middle of IH-59. In which case it would have been about 50/50 on getting pounded by a big rig (many blind curves and short-radius hills). Every other Sprinter person I know about who lost their alternator had that scenario. Nobody got totaled because of it (yet), but they all stopped spontaneously in the middle of the highway they happened to be on at the time of failure.

Moral of THAT story is obvious - know your vehicle. My Houston mechanic is an MB purist who hates squeaks and rattles and various other random noises. There's a couple of them that I let persist in our rig and he asked me WHY I would allow that?? Because they signify normalcy - each of them signals to me that all is well with this or that part of the vehicle. I try to keep tabs on every little thing that it does. It would have been extremely easy to miss this failure until it was too late to intercede. No matter what else we do with alternators, I'm putting a physical voltage read-out in the dash. The OBD did confirm what was going on, but I had to pull off the highway and cue the Bluetooth in order to see it. It calls for a continuous read-out instead.

[uncle_bob]

Hi

If the idea of an alternator failure is weighing on you .... get the second alternator. It the great scheme of things it's not that crazy expensive. I'm in no way suggesting that your concern is misplaced ....

Bob

[LB_3]

Originally Posted by uncle_bob

Hi

If the idea of an alternator failure is weighing on you .... get the second alternator. It the great scheme of things it's not that crazy expensive. I'm in no way suggesting that your concern is misplaced ....

Bob

Agree but it’s not quite that simple. Nobody manufactures a second alternator mounting kit so we’ll have to develop one. The only OM647 harmonic ballancer that supports two belts is for a v-belt which isn’t exactly my preference. It might be possible to add an additional idler pulley to get by on one belt, but it’s going to be tricky.

[InterBlog]

And then we’ll give the mounting ideas to Million Mile Sprinter so that he can sell the same stuff to others.
:-)

[Lotus54]

I thought the T1N had an optional second alternator? Perhaps I was mistaken, but I certainly thought I read that.
Of course- that doens’t mean it is available or if so may be astronomically priced.

I’ll see if I can find where I read that.
Mark

Edit:

https://sprinter-source.com/forum/sh...ad.php?t=45860

[slowmover]

Electricity. Causing it to become central to the definition of the thing (workplace, home or RV) skews perceptions. Believed to be a need. But is a desire. (Necessity for a slave and monitoring his output)

An engine starting battery is needed, and maybe enough juice to run a furnace fan for an RV.

Mechanical systems are also easier to diagnose or repair.

Propane is the reason we can call an RV a camper. The fuel source that changes a definition adequately. And simply. From a liquid fueled car.

Natural gas furnished the same for fixed dwellings. (Coal or wood or oil , you choose).

Water is the genuine limiting factor. Amp Hours are a distraction.

Get much past lighting, and electrical begins to become more trouble than it’s worth, IMO. HVAC is where I try to draw the line for a non-fixed abode.

To re-cast this, the problem isn’t the factory or owner-designed systems so much as it’s a lone female travelling without male relatives. Electrical system design genius & robustness won’t overcome what is a fundamental shortcoming. The strongest, best-trained, best-armed woman around isn’t even a match for an average man. And an attractive target. Dad is right. Let that sink in farther. Definition of “independence”.

A fine woman (education & culture) is more valuable than a handful of average men. Or an entire host of goblins. Right, Becky? (See the use of that). How does justice tilt these days? When it fails, do we see the lynchings necessary to ensure social continuity? No, we have total blackout. Silence. Failure. What we live in today is neither 1892 nor 1962.

Let’s not chase the white rabbit.

As to RVs in general, it’s a sad thing they may follow cars in being junked where body integrity and drivetrain (equivalents) are still good, but computers and controls are defunct.

FWIW, I concur on second alternator. Thanks for discussions on and examples of controls.

.

[Boxster1971]

SLOWMOVER - you post above is the weirdest thing I've even seen on this forum.

[slowmover]

Well. Turn off the TV. Read. It’s why you were afforded an education. Think. The problems are on more than one level. Reliability is one thing. Allying it with risk gives it yet another cast.

Why is there a bet?

And why does the nature of that matter?

.

[Sebtown]

Originally Posted by Boxster1971

SLOWMOVER - you post above is the weirdest thing I've even seen on this forum.

Me too! X2!

[LB_3]

I once assumed Mr. B was posting under the influence only to learn that he isn’t a native english speaker. I won’t make that assumption for slowmover and will agree with him that a good wonan is worth far more than a dozen average men.

As for the dual alternators, I just recieved an interesting email from an upfitter that specializes in armored and small volume military vehicles in addition to fleets of ambulances and the like. Apparently they designed a dual alternator bracket for the older T1Ns but don’t list it on their website anymore. He cautioned that due to a unique vibration environment in the location where the second AC compressor would go, a warranty and liability waiver would be required and that the mounting bolts would need to be retorqued on a prescribed maintenance schedule.

Any sophmore engineering student can calculate static shear and axial stresses and juniors should be able to calculate minimum thread engagements but dynamic loads can be a handful for even graduate students. This project just went from a 7 of 10 to a 14 on the difficulty scale if I’m going to have to consult some of the vibro-acoustic experts at work on this.

Maybe slowmover is right, we should keep it simple and lower our expectations of what electricity can do for us. Naw, what fun is there in that. We never would have walked on the moon if we restricted our use of fire to heating our domiciles and cooking our food.