load drop damaging alternator

[Treker20]

I have just finished my LiFePo install with Renogy equipment. To protect the alternator I installed to Circuit boards to drop the charging amperage of the DC/DC charger by 1/2 if voltage drops too low. I was mainly concerned about temperature and have been reading up on loads and operating temperature. While doing this research i came across 2 articles that say that load dump to due shutting off high current draw, either turning off load or blowing fuse, while charging can damage alternators. Has anyone had this issue? I see that Sterling makes an alternator protection device, but we are leaving on a trip next week so don't have time to look into this.

Thanks
terry

[booster]

Originally Posted by Treker20

I have just finished my LiFePo install with Renogy equipment. To protect the alternator I installed to Circuit boards to drop the charging amperage of the DC/DC charger by 1/2 if voltage drops too low. I was mainly concerned about temperature and have been reading up on loads and operating temperature. While doing this research i came across 2 articles that say that load dump to due shutting off high current draw, either turning off load or blowing fuse, while charging can damage alternators. Has anyone had this issue? I see that Sterling makes an alternator protection device, but we are leaving on a trip next week so don't have time to look into this.

Thanks
terry

You need big drops of amperage and all the way to zero, as far as I know, as is 200 amps and shutting off completely with no battery in the system to take up a the surge.


So on single alternator with another battery that stays on the load side and low to moderate amperage to the coach it is probably unlikely you would have a problem. If it it is a standalone alternator with only coach on it, there would be concern.


It would be of interest to put a meter on it to see what you get for voltage spike, it the meter is fast enough. Vehicles routinely shut of fairly large loads without issue when you shut them off.

[woodbri]

Originally Posted by Treker20

I have just finished my LiFePo install with Renogy equipment. To protect the alternator I installed to Circuit boards to drop the charging amperage of the DC/DC charger by 1/2 if voltage drops too low. I was mainly concerned about temperature and have been reading up on loads and operating temperature. While doing this research i came across 2 articles that say that load dump to due shutting off high current draw, either turning off load or blowing fuse, while charging can damage alternators. Has anyone had this issue? I see that Sterling makes an alternator protection device, but we are leaving on a trip next week so don't have time to look into this.

Thanks
terry

I installed a switch inline with the ignition sense wire to the the Balmar, so I can turn off the UHG when the LiFePo are mostly charged to prevent this issue, but it requires you to monitor your SOC. It is a quick solution, having something more automated would be better long term.

[jakegw2]

There is a Precision Instruments load management device that automatically connects and disconnects your alternator from your LiFEPO4 batteries at 15 minute intervals to prevent alternator overheating.

I installed a switch that lets me disconnect my coach batteries from the alternator so I could prevent overheating and used it for a while disconnecting instantly under high current charging from the alternator. I never had any problems, my understanding is that the AGM chassis battery absorbs the transient spikes and protects the alternator. After measuring the alternator temperature all through a charge cycle I came to believe that overheating the alternator was a non-issue on my van and if I were to do it again I wouldn't bother with the disconnect button.

[booster]

Originally Posted by jakegw2

There is a Precision Instruments load management device that automatically connects and disconnects your alternator from your LiFEPO4 batteries at 15 minute intervals to prevent alternator overheating.

I installed a switch that lets me disconnect my coach batteries from the alternator so I could prevent overheating and used it for a while disconnecting instantly under high current charging from the alternator. I never had any problems, my understanding is that the AGM chassis battery absorbs the transient spikes and protects the alternator. After measuring the alternator temperature all through a charge cycle I came to believe that overheating the alternator was a non-issue on my van and if I were to do it again I wouldn't bother with the disconnect button.

How are you reading your alternator temp while in motion?

[jakegw2]

I haven't read it while in motion, but I did a test where I measured the alternator temperature with an infrared thermometer every few minutes during the better part of a charge cycle while at idle.

[booster]

Originally Posted by jakegw2

I haven't read it while in motion, but I did a test where I measured the alternator temperature with an infrared thermometer every few minutes during the better part of a charge cycle while at idle.

Do you get full charge rate at idle?

[phantomjock]

A electrical disaster that can happen on a boat occurs when the battery switch is turned OFF and the alternator remains ON. This can result in a huge spike and the damages alternator diodes. Bad. Because you'd also loose the possibility to charge the batteries.
A "bright spark" developed a small device and marketed it as the "Zap-Stop." Balmar sells a couple of versions - one now called the "Alternator Spike Protector" which looks exactly like the Zap-Stop, right at 35 bucks.



The more expensive is the Balmar Alternator Protection Module - at around 70 bucks. If anyone is adding a disconnect switch in their circuitry, either of these might be cheap insurance.



A quick note - the Balmar Alternator Protection Module, the GREEN LED flashes to let you know it is good. If it turns RED - its TOAST.

Not associated, but I have used the Zap-Stop onboard.

Cheers - Jim

[phantomjock]

Had to add the following:


Under 20 bucks on eBay (not mine either).
You'll not the inline fuse, forgot to mention that.

Cheers - Jim

[InterBlog]

Relatedly, you might want to glance at this PSA below. Lithium charge duty cycling can lead to alternator clutch pulley failures. This happened to us, and has happened repeatedly to some well-known Class B-ers on social media. It’s particularly hazardous because the alternator dies and strands the vehicle wherever it happens to be at the time (for example, in the middle of a 20-lane freeway). Unless one is attuned to the subtle signs of impending failure, it happens without warning.

We keep a spare alternator specifically for that reason, but it’s inefficient to lug that huge lump around - it’s not what I would call an elegant solution. So what we do instead is only use alternator charging when absolutely necessary - which is the opposite of how we designed our system. Charging was supposed to be touchless and automatic, but we were not warned about clutch pulleys - that info was not out there. Fortunately we built our van with 4-way charging, so we have other options.

PSA: ALTERNATOR CLUTCH PULLEY FAILURES ON LITHIUM SYSTEMS

[peteco]

Originally Posted by InterBlog

Relatedly, you might want to glance at this PSA below. Lithium charge duty cycling can lead to alternator clutch pulley failures. This happened to us, and has happened repeatedly to some well-known Class B-ers on social media. It’s particularly hazardous because the alternator dies and strands the vehicle wherever it happens to be at the time (for example, in the middle of a 20-lane freeway). Unless one is attuned to the subtle signs of impending failure, it happens without warning.

We keep a spare alternator specifically for that reason, but it’s inefficient to lug that huge lump around - it’s not what I would call an elegant solution. So what we do instead is only use alternator charging when absolutely necessary - which is the opposite of how we designed our system. Charging was supposed to be touchless and automatic, but we were not warned about clutch pulleys - that info was not out there. Fortunately we built our van with 4-way charging, so we have other options.

PSA: ALTERNATOR CLUTCH PULLEY FAILURES ON LITHIUM SYSTEMS

Fortunately we have a great alternator shop in town. When my Toyota Corolla alternator failed (diode failure) the shop also replaced the clutch pulley with a solid pulley. They do that routinely just to eliminate that common failure point.

[booster]

Originally Posted by peteco

Fortunately we have a great alternator shop in town. When my Toyota Corolla alternator failed (diode failure) the shop also replaced the clutch pulley with a solid pulley. They do that routinely just to eliminate that common failure point.

That is interesting.


Nations recommends the clutch pullies to preserve belt life, tensioner, bearings and to smooth out the speed so less voltage ripple. I have them on both high output alternators on the van.


I guess the good is that they never really see high load as we have 530amps of alternator and charge max at 18o amps plus what every the van takes so way under 50%.

[InterBlog]

Originally Posted by peteco

…..replaced the clutch pulley with a solid pulley. They do that routinely just to eliminate that common failure point.

We tried to get this done, but the repair place to which we had taken our 200 A Bosch would not do it.

IIRC, they were afraid of the liability that might arise because to change Bosch’s product design and then have that product fail - and it could fail in a way that puts the vehicle and passengers at risk via spontaneous vehicle stranding - that right there is a perfect recipe for a business-killing lawsuit.

This is how our society works. As long as they put the alternator back together exactly the way Bosch designed it, the consequences of any subsequent imperilment are on Bosch, not them.

Given that we had to live with that ridiculous failure point, the conservative thing for us to do is to carry an identical spare alternator around with a functioning clutch pulley. They are relatively easy to swap out in the field.

If you found a shop that was willing to change the design, that’s great - but number one, what are the downstream effects of that, and number two, will that shop be around long term?

[peteco]

Originally Posted by InterBlog

We tried to get this done, but the repair place to which we had taken our 200 A Bosch would not do it.

IIRC, they were afraid of the liability that might arise because to change Bosch’s product design and then have that product fail - and it could fail in a way that puts the vehicle and passengers at risk via spontaneous vehicle stranding - that right there is a perfect recipe for a business-killing lawsuit.

This is how our society works. As long as they put the alternator back together exactly the way Bosch designed it, the consequences of any subsequent imperilment are on Bosch, not them.

Given that we had to live with that ridiculous failure point, the conservative thing for us to do is to carry an identical spare alternator around with a functioning clutch pulley. They are relatively easy to swap out in the field.

If you found a shop that was willing to change the design, that’s great - but number one, what are the downstream effects of that, and number two, will that shop be around long term?

Good point on the liability aspect. That is why I stress the importance of OEM specification tires on our class B vans, which I also do on my cars. Many tire shops will not install tires other than OEM spec for this very reason.

You may want to also consider carrying a spare pulley and special tool to change it if needed. And if you can find a solid pulley to carry along that might not be a bad idea either.

Regarding our local shop, they have been around for decades. They told me that the Toyota dealer sends their failed Toyota alternators to them that come from cars on their used lot.

[InterBlog]

Clarification on what I said above about clutch pulleys -

My husband notes that the shop also told him that the shaft on the Bosch 200 amp alternator is too short to attach a solid pulley. For that reason alone, they would not attempt it.

This was a few years ago now, and I am remembering successive bits of that conversation. I am remembering that the shop speculated that Bosch might have created that short shaft specifically because they wanted to prevent people from switching to solid pulleys.

This whole thing sounded and still sounds wacky to me. They make a very expensive but failure-prone automotive part, and then prohibit people from hardening it? Why not just fix the freakin’ design?!

[jakegw2]

So what is a clutch pulley for then? The video in the link never gave a plausible reason for including them in the design. I doubt they are there for no purpose.

Chesterton's fence - If you don't fully understand why it was put there you are not qualified to decide if it should be removed.

[booster]

Originally Posted by jakegw2

So what is a clutch pulley for then? The video in the link never gave a plausible reason for including them in the design. I doubt they are there for no purpose.

Chesterton's fence - If you don't fully understand why it was put there you are not qualified to decide if it should be removed.

I think it was ARV that had a video explaining how well it could reduce belt bouncing and wide tensioner movements that can wear them both out. Nations told me that the pulleys help wear on those parts plus the beaings in every item connected to the belt plus the pullies even out the speed of the alternator to lower power ripple %.

[InterBlog]

Context matters quite a bit here.

Under normal automotive use, clutch pulleys may indeed reduce wear and extend the life of certain parts. They may perform as designed (I actually don’t know because I haven’t researched it).

But we are not talking about normal automotive use. We are talking about retrofitting a supplemental power system into which automotive alternators were never designed to be integrated.

Upfitters responded to the potential mismatch preemptively with a number of responses: Number one, larger alternators, which theoretically could handle the extra demands more effectively. Number two, intervening mechanicals, such as the Sterling battery-to-battery charger.

None of those measures protected a number of us who had our new alternators fail and who have chosen to discuss these things.

It’s worth nothing that ARV gave up entirely on the idea of somehow making stock alternators work for this purpose. I know that ARV is a dirty word (acronym) to some vanners, but if you haven’t seen this video, it might be worth 6 minutes of your time.

https://www.youtube.com/watch?v=XANYxoEF_HY

[avanti]

Since that venerable ARV video keeps reappearing, I should probably repost the video I made of my stock Nations' setup in order to see if I was suffering from the alleged problem they were trying to solve:

https://www.flickr.com/photos/412063.../in/datetaken/

As you can see, my van exhibited little evidence of the oscillation or noise issues reported in the ARV video.

It should be noted that they were showing a V6 engine and mine is an I4. There is also some ambiguity as to whether their "before" shot represented a stock Nations' bracket or some home-brew setup of their own.

A long discussion can be found here:
https://www.classbforum.com/forums/f...html#post44432

My conclusion at the time was that if the increase in total capacity (especially during idle) is worth the 3X price increase to you, then their setup has merit. But barring that, the Nations' solution is likely just as good.

[jakegw2]

That was a helpful video, I'm still not sure I understand the mechanism whereby the clutch pulley reduces vibration, but I can accept that it does.

Avanti - I am in full agreement that you engineer a system to the reliability and cost that makes sense for your situation. If you have redundant power systems in your RV an alternator failure is a manageable issue and not necessarily worth spending large amounts of money to reduce its probability.

In my case I am pretty sure I can buy a replacement from most auto part stores and do the work myself if I need to. The house batteries, generator, and charger can replace the power from the alternator for an extended period of time if needed, so while inconvenient I am unlikely to be stranded.