Alternator burn out charging lithium

[Ulstue]

The video from Victron makes one very skeptical as to why this company needs to do this. The test setup is specifically designed to smoke the alternator. The alternator is run at a typical engine speed - but in the engine there is a gear ratio with the V-belt pulleys that causes the alternator to spin much faster (typically up to 5 times) than the engine speed, and therefore cools much better. In the "test", the alternator is demanded to run at high load with a speed far below the idle range for the alternator = deliberate poor cooling. It is not said how long the alternator ran like this. Apparently that was not enough to get the engine smoking. That's because the speed controller is turned down (cooling stopped altogether) before the alternator smokes.

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

(3:09), not the other way around.

There is a video of Sterling (

https://www.youtube.com/watch?v=ShtGB07fCSs

), where he also tries to maltreat the alternator, and still attaches a large additional load. The alternator then gets measurably hot, but it does not smoke off. Sterling has in his video the opinion that a normal sized alternator of today's standards will not smoke. But it may wear out faster.

A charge booster is supposed to ensure that the alternator will continuously perform as if the lead-acid battery were empty. This power demand is not necessarily lower than the one by LFPs, which signals the alternator controller by the high voltage of 12.8V (even if they are almost empty), it would be a full lead battery. The internal resistance of the LFPs is also not as low at the local temperatures and low charging currents as many assume.
According to the practical experience of many LFP users, modern and sufficiently dimensioned alternators therefore regulate down to about half the rated power of the LiMa quite quickly after an initial high charging power.

Of course, this does not mean that an old alternator that is too small cannot be overloaded with an LFP battery (or lead acid and a charge booster).

One should not forget: empty lead batteries also draw as many amps as possible. Just not as so long. Unless you use an extra charge booster. That the alternators are challenged accordingly is certainly not uncommon with cruisers, when after several days at anchor with empty Lead acid batteries the anchor is lifted with the electric windlass by very low RPM.

In the Victron video the alternator runs extra much too slow if I remember correctly first indicated with 3000, then with 1500 (the type plate of the engine indicates only 2800 rpm for 230V). Of course it starts to smoke. How long it runs is not specified. There are cuts in between, which wouldn't be necessary if it stinks and smokes right away. Speed range of a typical alternator is depending on type between 3000 and 21000.
In the Sterling video an undefined load is switched on and off, the test setup is not really comprehensible. In both cases: these are promotional videos.

This is not to say that temperature monitoring and control of the alternator resp. the charging process is unnecessary in any case. But you should also not be tricked by promotional videos with fake or nonsense information...

[Hermia II]

Dear Ulstue, I beg to disagree.
I have a very rugged and well built Mastervolt 24v/75A alternator with an Alpha Pro regulator trying to charge a 24v/800AH Victron LiFePo4 bank. Running the engine at about 1000 rpm it will charge at 60A (net to batteries, i.e. probably 70A gross) it reaches a very unhealthy 270°F (130°C) on the casing after one hour, still rising so I have to stop the engine and cut the field current. And even though my engine compartment is well ventilated the temp inside is about 140°F (60°C) in running conditions, not so in the Victron video. My set up include a Maretron temp monitor with 6 channels so I have a temp sensor on all critical parts inkl the Gen Set. I have discussed this problem with Balmar whos' regulator also measures the alternator temp. Even so they do not recommend their 24V/140A (94LY-24-140-IG) alternator, claiming it is undersized. The only alternator recommended is the 220A (98-24-220-IG-BL) big frame unit (massive) with the MC-624H regulator. It is prudent to take these issues seriously and keep a good margin from the maximum performance of the alternator. There is no easy way around it.

[Gary Bode]

Looks like 1:1 pulley to me.

[Ulstue]

Dear Hermia II
You know: It depends. Of course, a reconfiguration of the charging technology may be necessary. May be, in your case it is a must. A 75A alterntor seems actually very small for your Battery. But it does not have to in every case, and this question does not change anything about the advertise video from Victron, which seems dubious to me and with which this thread began. You probably know that there are now countless "drop in" LFP batteries (Liontron, Relion, etc) that replace the old lead-acid batteries 1 to 1 without reconfiguring the charging technology. Which in not always, but in the vast majority of cases, works well.

Is a very expensiv Ballmar the only solution? Why not a "normal" Alternator with more power for 100 somthing bucks? 800A 12V Winston on a Cat with 2 x 120A Alternator no problem without any changes in alternator management and control.

[Hermia II]

There is a simple solution, if both starter battery (lead acid) and house bank (Lithium) are the same voltage (not so in my case). If so you can use a Mastervolt Charge Mate Pro to limit the charge. It is simple and relatively inexpensive.

[Ulstue]

Originally Posted by Gary Bode

Looks like 1:1 pulley to me.

Yes. What I meant was: in the Victron "Test" 1:1 pulley.

In real life in a car or a boat it is 1:3 or 1:5 (and more), so the rpm of the alternator are normaly much faster as in the "test" and the cooling much better.

[noelex 77]

Originally Posted by Hermia II

Dear Ulstue, I beg to disagree.
I have a very rugged and well built Mastervolt 24v/75A alternator with an Alpha Pro regulator trying to charge a 24v/800AH Victron LiFePo4 bank. Running the engine at about 1000 rpm it will charge at 60A (net to batteries, i.e. probably 70A gross) it reaches a very unhealthy 270°F (130°C) on the casing after one hour, still rising so I have to stop the engine and cut the field current. And even though my engine compartment is well ventilated the temp inside is about 140°F (60°C) in running conditions, not so in the Victron video. My set up include a Maretron temp monitor with 6 channels so I have a temp sensor on all critical parts inkl the Gen Set. I have discussed this problem with Balmar whos' regulator also measures the alternator temp. Even so they do not recommend their 24V/140A (94LY-24-140-IG) alternator, claiming it is undersized. The only alternator recommended is the 220A (98-24-220-IG-BL) big frame unit (massive) with the MC-624H regulator. It is prudent to take these issues seriously and keep a good margin from the maximum performance of the alternator. There is no easy way around it.

Smart adjustable temperature regulation can be used with the Mastervolt Alpha Pro device. At least on the later versions.

This would solve your problem.

[lmxr]

Originally Posted by Ulstue

Yes. What I meant was: in the Victron "Test" 1:1 pulley.

In real life in a car or a boat it is 1:3 or 1:5 (and more), so the rpm of the alternator are normaly much faster as in the "test" and the cooling much better.

Could you please give an example of a common marine engine, in its from-the-factory belt configuration, with a 1:3 or more ratio?

[Hermia II]

Originally Posted by noelex 77

Smart adjustable temperature regulation can be used with the Mastervolt Alpha Pro device. At least on the later versions.

This would solve your problem.

I have looked at the Alpha Pro 2 and Alpha Pro 3 and they only have a temp sensor on the battery. The Balmar MC-624H has two sensors, one on the battery and one on the Alternator. I guess both are needed in this case.

[noelex 77]

Originally Posted by Hermia II

I have looked at the Alpha Pro 2 and Alpha Pro 3 and they only have a temp sensor on the battery. The Balmar MC-624H has two sensors, one on the battery and one on the Alternator. I guess both are needed in this case.

There is only the provision for one temperature input on the Alpha Pro. Not ideal, but this input can, and generally is, much better used to regulate/protect the alternator from high temperature.

With lead acid batteries the battery set points will probably need to be manually adjusted a couple of times a year for temperature.

Some of the other Mastervolt products can be used to add the battery temperature to the system if needed.

[JustMurph]

We've recently changed from lead acid to LiFePO4 in a mates cat and have found no change in the outputs of the alternators (3GM30s, one with a standard Hitachi 55A and one with a larger alternator of unknown spec). In fact both produce slightly less power, as the voltage the alternator sees is higher.

Likewise in the old setup in my cat, there was no issue charging a LiFePO4 bank with my 3YMs, from their pair of standard Hitachi 55s. Just as with the lead acid, they charge at a high rate for a while, then output drops as they get hot.

So what's the issue here? Standard relatively modern internally regulated alternators seem to have temperature limiting. Do the big aftermarket externally regulated alternators not? How does a big $ master volt not have temperature limiting?


It think the idea that lithium batteries will kill your alternators by making them output huge amounts of power (supposedly due to their low resistance), is simply wrong. Alternators regulate to a voltage, they don't care about the resistance. An alternator (on any any battery that can accept its full charge, include big LA bank) with a regulator that doesn't sense the temp of the alternator, seems to be the issue here?

What am I missing?

[lmxr]

Originally Posted by JustMurph

[...]An alternator (on any any battery that can accept its full charge, include big LA bank) with a regulator that doesn't sense the temp of the alternator, seems to be the issue here?

What am I missing?

Good to know that your setup works. The Hitachi ones appear to be protected quite well, yet this seems to be more the exception than the rule.

[more]

Originally Posted by JustMurph

Likewise in the old setup in my cat, there was no issue charging a LiFePO4 bank with my 3YMs, from their pair of standard Hitachi 55s. Just as with the lead acid, they charge at a high rate for a while, then output drops as they get hot.

So what's the issue here? Standard relatively modern internally regulated alternators seem to have temperature limiting. Do the big aftermarket externally regulated alternators not? How does a big $ master volt not have temperature limiting?


?

Also my new original expensive (110€) Perkins 12v/110A High Output Alternator in beginning charge +- 100A and soon drop to 70,50,35A depend temperature. **** i must buy this no name 1-2000 € alternator.
Balmar,Mastervolt,victron is no name because all this company don't have factory for producing alternator there simple find somever in China some garage manufacture and put sticker on alternator.

alternators is dominated mainly by four companies: Denso, Valeo, Mitsubishi Electric, and Hitachi Automotive. Collectively, these companies occupy nearly 80% of the global market.

[goboatingnow]

Originally Posted by JustMurph

We've recently changed from lead acid to LiFePO4 in a mates cat and have found no change in the outputs of the alternators (3GM30s, one with a standard Hitachi 55A and one with a larger alternator of unknown spec). In fact both produce slightly less power, as the voltage the alternator sees is higher.

Likewise in the old setup in my cat, there was no issue charging a LiFePO4 bank with my 3YMs, from their pair of standard Hitachi 55s. Just as with the lead acid, they charge at a high rate for a while, then output drops as they get hot.

So what's the issue here? Standard relatively modern internally regulated alternators seem to have temperature limiting. Do the big aftermarket externally regulated alternators not? How does a big $ master volt not have temperature limiting?


It think the idea that lithium batteries will kill your alternators by making them output huge amounts of power (supposedly due to their low resistance), is simply wrong. Alternators regulate to a voltage, they don't care about the resistance. An alternator (on any any battery that can accept its full charge, include big LA bank) with a regulator that doesn't sense the temp of the alternator, seems to be the issue here?

What am I missing?

Many stock alternators do not have temperature compensation ( ie in case temp sensing ) ( see https://www.onsemi.com/pdf/datasheet/cs3341-d.pdf, or BOSCH cR729 regulator ic ) some have high temperature fault cutoff . This is because car companies rate the alternator for the task at hand.

However on a boat that alternator is now in a situation of greatly reduced airflow and higher ambient conditions. A situation the stock alternator was never designed for.

This means that many alternators cannot charge at anything like their “ plated “ power. On my case I have a 70 A alternator. I r never seen that alternator output more the 30 A into my lead acid system

Change to lithium and now the battery will pull the max output from the alternator. The stock regulator is simply not setup for battery charging , it’s setup for system power supply ( cause that’s what car alternators do , they don’t charge batteries )

Hence Li combined with inadequate ventilation tends to defeat the temperature compensation built in stock regulators ( its typically not actually sensed but included in the regulator feedback control as a de rating curve ) the temperature sensor being integrated into the regulator IC chip.

Hence on boats the windings tend to overheat because the stock compensation isn’t sufficient.

Aftermarket regulators can add upto two physical temp sensors to get an accurate understanding of alternator case temps

The reality is stock alternator regulators are woefully setup for any sort of battery charging , they reality should all be replaced by regulators that are properly profiled To charge batteries including these days lithium.

[JustMurph]

Right, so in seems that some stock alternators have decent temp compensation and some don't.

I totally agree that all of them should. It kinda seems mad that any sold in the last ten years wouldn't. Lithium isn't a new thing, a nor are cruising boats with 800AH+ of lead acid, which will also take every last amp from a 70A alternator.

I'd just like to see the story that gets pedalled everywhere on the internet change from "your alternators WILL burn out with lithium", to "this is a risk, and something you need to test". In addition, if you do change to an external regulator, it must be one with alternator temperature sensing.