How to not blow up your Alternator when charging Lithium

In this video, we put both a traditional and a regulated alternator through its paces. Using different RPM's, we charge a 300ah lithium battery and test the results.
For technical questions, see our support page: www.victronenergy.com/support or contact your Victron dealer, distributor or installer.
You can also have a look at our Victron Community page to see if your question has already been answered there. Or join in the conversation to help others: community.victronenergy.com

[@VictronEnergyBV]

🎯 Key Takeaways for quick navigation: 02:53 ⚠️ Charging lithium batteries at low RPM (revolutions per minute) can cause the alternator to overheat, potentially leading to internal coil damage. 03:22 🔥 The Balmar alternator includes a temperature probe and regulator that monitors alternator and battery temperatures. It automatically adjusts the output current to prevent overheating. 05:53 🚗 Charging lithium batteries with an alternator poses challenges because lithium batteries can draw high currents even at low alternator speeds, potentially causing overheating and alternator wear. 06:22 🛠️ Solutions to prevent alternator overheating when charging lithium batteries include using larger alternators, regulators with temperature sensors, or current limiters like Buck-Boost, BMS 12/200, or the Orion Tr Smart DC to DC Charger. 07:16 🔄 Disconnecting lithium batteries from the charging source once fully charged can damage the alternator regulator if not done properly, and Victron offers equipment to protect alternators and battery systems.

[@PiDsPagePrototypes]

2:54 - Well, Duh,... This whole 'bench' test is silly, because more then half of the cooling air for an alternator is provided by the the forward motion of a car and the cooling fan in the Radiator moving air over the running gear when the car is at standstill. You compounded this error by running the Alternator at RPM that it will never see in daily use, as the drive pulley on a standard engine crankshaft is much bigger then the one on an alternator, precisely so the alternator always spins at high enough RPM to function properly. The majority of modern cars, at engine idle, the alternator is shut down by the Engine Management system by turning off the feed to the field charge terminal, so at the RPM you get the smoke, the Alternator should be spinning but not powering. Very disappointed in how badly this test was done.

[@PiDsPagePrototypes]

3:23 - You never ran the Balmar Alternator at the lower RPM, this alone tells us that the 'test' was was not done to repeated scientific standards where every device is tested in identical manner, but instead was done specifically to cause Only the standard unit to 'fail'. The Victron products may be of high quality, but this video is disingenuine. It's a short step away from being a Marketing Dept Lie.

[@johannesboonstra6917]

Correct, this is not a scientific test! There were no professors involved and most likely you are able to find many things in it that could be debated if that's you intention. It was never intended to be more than a way to show in a few minutes that charging lithium isn't straight forward and that it needs consideration. That doesnt mean its a lie but its there to prevent endusers of spending money on a lithium system and then face costly issues with the alternator. And believe me when I say that this clip alone showed many endusers what went wrong in their system and they learned from it. @@PiDsPagePrototypes

[@johannesboonstra6917]

Ever measured the alternator in a summer traffic jam while charging a large lithium bank or even a machine room of a boat? @@PiDsPagePrototypes Could you please take the test on your own car and show the results honestly?

[@PiDsPagePrototypes]

@@johannesboonstra6917 If the charging system is set up correctly, it won't be charging while you sit still in a traffic jam. As mentioned before, at idle the cars ECU will turn off the field activation voltage to save fuel and protect the alternator from overheating. The machine room of a boat should be well ventilated, both to stop build up of dangerous gases and vapours, and to keep the room cool. If it isn't, it won't matter what brand of electrical equipment is fitted, the results will be failures.

[@eugenepohjola258]

Howdy. Good info of the basics. Regards.

[@tristramsnowdon5256]

In an internal combustion engine situation, the alternator typically runs at 3 times crank speed. So 1500 crankshaft rpm = 4500 alternator rpm = way out of danger zone. Your test rig seemed to run alternator rpm = motor rpm = overheat problem

[@johannesboonstra6917]

An engine is often at idle or just above...At idle this is 800x3 is 2400rpm, which is quite nicely in the danger zone. Even on 4500 rpm with an output at 110-120% of the design power is problematic as well.

[@tristramsnowdon5256]

@@johannesboonstra6917 An IC engine does not operate at constant rpm. Most are now automatic, so there is no direct correlation between rpm and gear ratio. On acceleration, engine rpm will flare to 2000-2500 and hold there. That's 6000-7500 alternator rpm. At urban cruise speed, torque converter lock-up does not occur, and transmission does not shift into 1:1 drive ratio or above, keeping engine rpm high. On cold start up, powertrain management inhibits higher gear ratios to enhance driveability and reduce warm-up time. Idle speed is also increased during engine warm-up In open road driving, engine rpm is easily 2000rpm until warmed up A 50Ah battery that requires 10Ah to recharge (ie is 20% depleted), will only take 6 minutes to recharge @ 100A. The car is still warming up after 6 minutes The maths does not support your position

[@johannesboonstra6917]

;-) , I did a few hundred installs so I do know how an alternator works, thank you! . But your theory is a bit off I am afraid. Of course when the battery is about full you dont need to worry, but that's quite rare on a household battery. And we not only talking about a 50Ah battery in a small truck, We are talking about serious lithium systems up to a few hundred Ah. These will not raise the battery voltage until full so this means the alternator will go more the full throttle. This because the regulator steers max current to the rotor until the voltage on the battery does go up ( THATS the major difference with a lead battery here) often 110-120%. When the alternator 100A a quite large part goes into the engine when its a little bit modern one and its connected system itself, so perhaps there is 40-60A to charge the lithium. When charging the battery with an alternator in a boat machine room for example, the average rpm is just above idle. So then the rpm is way below the optimal cooling speed and the output is far over 100%. This means simple that for a 200Ah lithium the alternator needs to work max for a couple of hours. The heat is generates is 50% of the output power , so that's immense. Believe it or not, but this will make sure the lifespan is pretty short. I have given others also this advise when you want to prove I am wrong, Take an empty 200Ah ithium battery and use the jumper cord on you car , just let the motor idle and see whats happening (only when you still have warranty on the car). to add to this, if you feel you dont want to protect the alternator, that's fine with me of course, we just want to warn as we have seen many alternators fail that way... @@tristramsnowdon5256

[@tristramsnowdon5256]

@@johannesboonstra6917 in any situation where rpm is limited to low rpm range (like motor yacht or diesel), try using a higher overdrive pulley set. This will raise the alternator rpm for the same crankshaft rpm. Instead of a 3:1 step up in a petrol application, try a 5:1 or 6:1 step up. This may require an additional pulley sheeve, but also allows for the addition of a second alternator. 800 crank rpm x 5 = 4000 alternator rpm (or 4800 alternator rpm if 6:1). Also, consider fitting a temperature sensing switch that disconnects the lithium charging contactor if alternator temperature rises too high. It's an easy way to avoid heat failure, like the "thermal fuse" fitted to many power supply transformers - it interrupts the output until the temperature falls to a safe level FYI I have built our house battery to 800Ah 48V lithium (repurposed EV NMC cells), charged by solar. I am an automotive sparky with 40 years experience

[@ntal5859]

@@tristramsnowdon5256 For your information this most likely targeting sail boats and yes they do run at constant speeds for long periods.

[@Phantom-mk4kp]

An engine running at idle is about 700/800 rpm but the drive ratio to the alternator is at least 1:2. So an alterternator speed of 1500 is not greater than an engine at idle

[@johannesboonstra6917]

We know, its also not saying the time to failure will be as in the clip, but in time there will be an alternator failure for sure as the temperature will be to high for coil/bearings ect.

[@tcuster55]

This explained a few things. Would have been nice to see the details on how the orion works to protect alternator and system in more detail.

[@keesras763]

It is a pity you barely mention the issue of Li BMS shutting off the battery while charging. This will destroy the dynamo much faster than the overheating. How is the victron system coping with the BMS shut off?

[@campnut6076]

Great question, wish they would answer this one .

[@caminhoesemusicas4234]

Maravilhoso Meu sonho ter um aparelho desses

[@fourfortyroadrunner6701]

Your comment about the 1500RPM test "the engine running at idle" is incorrect. Typical engine crank to alternator ratios vary from at least 2:1, more typically 3:1 to 4:1. I have not documented modern stuff very much, it is possible that some engines are a higher ratio yet. In my day, my 440 Plymouth was 4:1, meaning, that if the engine was spinning 6K RPM, the alternator was screaming at 24,000 RPM. I did fail a couple of them.

[@johannesboonstra6917]

when you have a diesel engine idling on 750 rpm , the 2:1 makes that 1500 for the alternator right? , could also be 2200rpm but that's not that relevant here, the point is that an alternator needs much more (from 4000-5000) to be able to cool itself.

[@bobjarrard]

I know that voice well. Hope you and the dog are well. Bob in Nevada

[@VictronEnergyBV]

Thanks for watching Bob! Molly says woof!

[@philippschneidenbach]

Ok, so the actual perception is: 3000 alternator rpm if created from a 1000rpm engine with general overdrive of ratio 3 gives healthy 40ish degrees and 78.9 Amps off of a 70a Citroen Alternator. Good. Real verdict of this video without the voice is that a fully loaded alternator should not be operated below 1000 engine rpm (=do not 100% load in idle, which is not hard to understand) but is very fine when driving (lets say approx. 2000 engine rpm). Regarding Lithium everybody should know that a lead acid battery as a buffer to avoid load off voltages and then DCDC off to a Lithium with current limiting to a current value/number below (80%) the alternator limit is a good ballpark.

[@johannesboonstra6917]

The moral of the video is that due to the lithium battery the voltage during charge will not go up until the battery is charged and this causes the alternator to get overworked. 3000rpm is still low for an alternator to be cooled well! So over time bearings/coils ect will suffer and fail. the ballpark for a dcdc converter to limit the output would be about 50%

[@andrewcheshire244]

I'm gonna design and build my own. Nobody seems to have the simple idea of a dump load.

[@leblancexplores]

You mean to address high voltage scenario?

[@gaidin58]

2 things: 1, you did not simulate the engine compartment of the vehicle which typically has a radiator fan located very close to the alternator and blows air on the alternator helping with cooling. 2, as far as sudden shut down of the lithium charging which could damage the alternator, most vehicle engine scenarios include a lead acid battery in the charging loop which will absorb the output of the alternator when the lithium suddenly stops accepting a charge because the BMS shuts down charging.

[@VictronEnergyBV]

What about boats that 1, don’t have a radiator fan and 2, have a dedicated alternator for service batteries? We have experience with tens of thousands of systems and know this can damage lithiums. We have made this video to try and help people. Please read the replies to other concerning questions in the comments below.

[@pops91710]

Very interesting. My tow vehicle is a 6.7 diesel and under the hood I have two 12v lead-acid batteries and in my trailer I have 3 x 12.8v 200ah LIFEPO4 batteries. So, from what you say, my alternator is safe as long as the crank pulley to alternator pulley is 4 to 1? I haven't towed my trailer since I installed these batteries so I am curious (anxious)!

[@DennisPochenk]

So the balmar is just a alternator with a DC-DC attached and some PLC to trim amps according to temps.. So a DC-DC connected to a alternator would do essentially the same

[@keysersmoze]

Alternators are typically run faster than your tests.

[@johannesboonstra6917]

yes, but the effect overall is the same, We felt that if the test was 3 hours on a high RPM there wouldn't be many people looking at it.

[@LiveMedia123]

I am about to connect an extra wire from my alternator to my Victron non isolated DC/DC charger. With how much Newton Meter do I turn the bolt back on the alternator while securing the cable shoe to it? This video was very helpful and convinced me buy to buy the DC/DC charger!

[@utubepro7742]

I’m adding some lotion batteries for the back of box truck can I mix a regular battery from my vehicle with a relay to charge my rear lithium ?

[@TopNoTchVSOP]

New inquiry need help with this question, I have a dual battery lithium 12v 135amh profile and also an alternator cap output at 250amp for Jeep Wrangler. I also have a dual battery relay isolator that can handle lithium batteries. Will I also need a Victron shunt battery protector and of DC2DC converter for this setup?

[@herkko61]

If your relay isolator does not *limit* the current, then yes it would be useful for you too. On the other hand 250A is good output and 135Ah not so high capacity, so, you may be on safe level with your present system (your lithium battery does not draw very high current from your alternator even when the battery is empty).

[@richardstubbs6484]

Does the Orion dc to dc charger prevent overheating of the alternator ? Does it not also need a temperature sensor on the alternator ?

[@herkko61]

Yes, it limits the charging current to be max. 30A which does not load the alternator too much in case the (high capacity for example 200Ah) lithium battery is almost empty.

[@mohammadinamshah8370]

good explanation I have one question can you explain I have 420 amp battery then how many amp alternator need to install that vehicle

[@huwbishop6995]

Look at the C rating for charging your battery. 0.5c charge would be a constant draw of 200amps. I would install a regulator or limiter similar to what's shown in the video. It's a pretty big alternator to supply 200+ amps.

[@herkko61]

You definitely need to limit the charging current to 60A - 90A max. to protect your alternator. 420 Ah is a high capacity battery and it is very willing to draw way more than 100A current from your alternator in case the battery is empty. You'll cook your alternator.

[@campnut6076]

I am currently putting a system together using a Balmar mc -618 regulator, it is capable of adjusting field power to alternator using temperature input from the alternator along with other programable input data. Have you done any testing using Balmar's regulator with a standard OEM alternator instead of with a $1500 Balmar alternator?

[@JohannesBoonstra-ol2nz]

With an exteral regulator its safe as well (if set up correct of course)

[@blogdoriomCamicleta]

I installed an Orion 1212 30 to charge a 230A lithium. Do you think it will be safe for my truck alternator?

[@herkko61]

It's safe for sure. Even with two Orions and 60A it would still be safe.

[@yuanmei6642]

Wondering how it would look if you set up a fan on the alternator…

[@johannesboonstra6917]

yes, if you would have a fan which is able to cool the alternator down it would be nice, problem is that because the efficiency of the alternator is so low, the amount of heat which you need to get rid of is the same power as what the alternator generates.

[@pijanysamuraj]

I don't understand very much out of it ;/ could you tell me what should I use between alternator and powerstation to prevent issues? like adjustable inventer? would be thankful for any info

[@JohannesBoonstra-ol2nz]

I understand this this can be quite technical. Please contact the local dealer (found on the website) and discuss you system and needs. Surely they can explain this to you.

[@TurboAdam]

What’s the difference between an alternator charging a lithium battery at maximum capacity, versus running a victron inverter at the exact same amount of dc load? I’ve put together dc systems that routinely pull hundreds of amps from alternators to run electronics and rooftop air conditioners. I guess I just have a hard time believing a properly sized lithium bank and alternator setup will have an issue other than potentially not generating a high enough voltage to fully charge the lithium battery…

[@skinnerMTB]

DC DC is the way to go. You know it, I know it, we all know it :) Especially when you are increasing the aH. I'm upgrading my diesel pusher from 450ah flooded to 920ah LifePO4. It would have been so easy to replace my BIM-225 with a Li BIM-225, but the idea of stressing the alternator with such a high load forced my hand. So I'm losing my AUX start function, but my alternator will have a long healthy life!

[@superformOG]

victron should make an external alternator regulator

[@JohannesBoonstra-ol2nz]

Agree, would be nice! but we prefer doing thing we are really good in ;-)

[@superformOG]

@@JohannesBoonstra-ol2nz like charging batteries?

[@JohannesBoonstra-ol2nz]

Yes ! and making AC from DC for example .. @@superformOG

[@elredoble]

I'm charging my AGM house battery using a solenoid . Can I switch to a Lithium Battery using the same solenoid ?

[@JohannesBoonstra-ol2nz]

preferably not, a dcdc converter wil be best most likely in your case

[@MyGoogleYoutube]

"Charging lithium batteries at low RPM (revolutions per minute) can cause the alternator to overheat, potentially leading to internal coil damage." For the 1500 RPM test "....note this is still above the typical speed of an engine running idle" This indicates a fundamentally flawed understanding of how alternators are driven in vehicles by these folks in the video. The alternator in this video was underdriven WAY below what it was designed for - no wonder it fried. Most alternators are going 3X (3:1) the speed of the engine RPM. What is the average engine idle speed? 800 RPM? Making the lowest alternator RPM of around 2400? The video shows an alternator running at 1500 rpm - so a 500 RPM engine idle? Why wasn't the Balmar tested at a super low RPM? I am sure Balmar wouldn't have been happy with you smoking one of their alternators when it was tested outside of it's design capabilities? I don't understand the comment about BMSs disconnecting the batteries when fully charged? Fully charged is 3.65V per cell - and by then it's constant voltage and current is just trickling into the batteries at that point. How would this harm the alternator if a load of a 50W or less was suddenly disconnected? I charged a 200ah LFP house bank for several years using a standard Victron Cyrix combiner with zero issues. I would see around 70a going to the house batteries. I would only use this when needed and recognized I couldn't full top the batteries so I stopped charging around 90% SOC. I also monitor the alternator's output. When I upgraded to 600ah I did have go with a DC to DC because without I was getting 120A to the house batteries with a 160A alternator at idle. I went with Sterling's new DC to DCs which I think is much better than what Victron is offering currently with their Orions and Buck Boosts. If you don't want to dive into the weeds on how this stuff works and don't want to actively control your house battery alternator charging like I am - get the Orion, get the Buck Boost, or some other DC to DC.

[@ReubenHorner]

I totally agree with you here. Not a total test. Worth nothing that I have installed a lot of victron products and a couple balmar ones as a OEM and have no issues with the product, however this video is no good

[@teeanahera8949]

Isn’t pulling 120 amps out of a 160 amp alternator risking damage, I’ve just completed a DC to DC (Renogy 50 amp) charger install for a 100 amp/hr deep cycle AGM house battery in the car and everything I read said make sure you’re not pulling more than about a third of your alternator’s output (110 amp smart alternator in my case)? I just added a 200 watt solar panel on the car roof which connects directly to the Renogy DC to DC charger. The battery is from Aldi and I couldn’t be happier, resting state is always 13 volts and a hundred bucks cheaper than a “rebranded” battery which comes from the same factory anyway.

[@PiDsPagePrototypes]

3:1 is about right for most passenger cars and trucks - engines that run at high RPM, such as Sports cars, supercars, race cars, will have the crank pulley altered to lower the alternator speed to within manufacturer specifications when the engine is at high RPM. Larger deisel trucks will have a pulley ratio closer to 5:1, as the engine RPM is usually lower. What's also missing, is that the vast majority of engine management systems - ALL of the OEM ones and most of the aftermarket ones - now turn off the voltage feed to the feild terminal of the alternator when the engine speed drops below around 1200 rpm - this reduces fuel used at idle, removes issues with alternators overheating, and for passenger vehicles, reduces idle loads on the pulleys, making the engine idle smoother with less NVH transfered to the passengers.

[@PiDsPagePrototypes]

​@@teeanahera8949The majority of the 'smart' DC-DC chargers measure the incoming voltage on the connection from the cars main battery, and will not turn on their output to your secondary battery untill the main battery shows a voltage that indicates it is fully charged. This way the current being pulled from the alternator never exceeds the alternators limit specifications. You will probably have a small wire coming from the DC-DC that the instructions said 'could' be connected to an over-ride switch to disable that safety feature in special cases, but is best left disconnected for standard OEM alternators.

[@max00200]

thankyou for your explanation that really helped me grasping this concept, although this video was just to show how a person need to buy their product nothing else

[@JouniKyyronen-nv1ep]

if starter battery is charging and there is another agm battery parallel, does it boil starter battery

[@JohannesBoonstra-ol2nz]

AGM in parallel with the Lithium? Thats not how you should use lithium, but then also this is not protecting the alternator

[@masonjeffers]

My alternator is right behind my radiator fan. So even at idle has heavy air flow. I wonder if I can safely charge lithium.

[@JohannesBoonstra-ol2nz]

depends on the load on the alternator. if you want to be safe...

[@trevork3924]

Them results would be expected when your using just a 70 amp out put alternator

[@marke.8334]

People use them in car audio and there have been people to use them on their vehicles for a while now and I haven't read of anybody having a problem with their alternator

[@JohannesBoonstra-ol2nz]

Its more boat thing as then the alternator gets less cooling, but sitting in a traffic jam in the summer will have the same effect/

[@liljasere]

I must by chance have a really good alternator fitted as standard on my vw transporter i regularly idol charge and run my 700w inverter to charge up my lithium PowerStation i measured the positive coming off my starter battery onto my 400ah lead battery bank and when the inverter is running at full load i get 86A with an idol engine speed of 950rpm i must do this for around 2 hours continually 5 times a week i wonder why my alternator hasn't burnt up yet its also 12 years old I think is got a max output of 140A

[@johannesboonstra6917]

Most likely because you are driving and the ambient isn’t high , when you would have this setup on a boat or such it was a different story

[@liljasere]

@@johannesboonstra6917 I idle charge mostly so stationary and summer gets around 30c here I think what they are not accounting for here in this demonstration is the auxiliary pulley ratio I don’t think engine speed and alternator speed are mirrored

[@timandres6410]

Yeah but you are direct driving that alternator. Typically vehicle alternators are overdriven at least 3:1. Im not arguing against DC/DC converters, but your abusing that alternator to no end. The testing here is not realistic.

[@johannesboonstra6917]

the test is done to show what the result is of charging a lithium battery. This is not real life testing as that would take too long, it's only a few minute clip. But the alternator in real life (even with 3:1 or such) will suffer and break down soon.

[@MyGoogleYoutube]

@@johannesboonstra6917 The alternator doesn't know what it's sending current to - lithium isn't special it's just a load on the alternator. It was underdriven and overloaded at the same time - failing and spectacular fashion to help sell DC to DCs. Your comment would hold water if Victron disclosed that in their video but they didn't. Leaving someone who knows nothing of alternators to draw the wrong conclusions. The moral of the story is don't overload an alternator - which is still one hundred percent possible even with a DC to DC. You actually have to monitor alternator output to know if you're overloading. How many actually do that? I do. It's easy and cheap with an Amazon hall sensor.

[@johannesboonstra6917]

It's not at all that we did post this to sell more dcdc converters. The point is ( and many alternator and engine manufactures that we work close with have discovered) that alternators do fail on lithium banks as not protected. Lithium is not "just a load" ! Lithium has a an extreme low internal resistance and the character its voltage will not raise during charge until full. This means a typical alternator will send its maximal rotor current by the regulator as its designed foe lead batteries, This maximal rotor current will cause the alternator to generate current often above spec. Knowing the efficiency of a typical alternator is just around 50-60%, you know how immense amount heat is generated. This will happen at lead also but only for a limited period as then the voltage will raise after 10-30 min. Just imagine a 20kWh lithium bank on a 100A alternator, this would take 16 hours of power above spec from an alternator. This alternator will fail, perhaps not as fast as in the clip, but it will fail as we have seen with many many systems worldwide. If you dont trust this, please come by with your car and we will connect a large empty lithium battery to it so your car can charge this in a few hours on idle rpm. You claim nothing will happen, and of course in a few minutes this might be true, but for a reliable system there is no other way then to protect the alternator @@MyGoogleKZbin

[@MyGoogleYoutube]

@@johannesboonstra6917 I sincerely appreciate your reply - I'll get back to you in a few days.

[@gf-xy2of]

@@johannesboonstra6917 Wouldn't a more sophisticated AVR with current (or power) limiting be the obvious solution?

[@funlovingJohn]

Please a video of a 12V lithium battery being charged from Toyota Hibridi inverter

[@Zombiemeat00]

70amp citron alternator, no wonder it overheated, you wouldnt even use the car it comes from to use dual batteries. most dual battery cars have a 150amp alternator at a min. Redo the test with realistic conditions. ie air flow from a fan like on the radiator of the car and also wind flow from the car moving. also use lithium batteries with on board bms that regulates overcharge and heating issues. these test results are unrealistic to normal conditions. FYI yes it is best to use a DC-DC charger either way but lots of tests have shown it is not required and in some cases your lithium batteries can handle the direct input to lithium of 80amp like the test done by Mercedes.

[@johannesboonstra6917]

It's not just cars , its also boats, there is less airflow there right? BMS with internal regulation is fine! as long as its being regulated, The point we are trying to make here is not that the battery can handle the current, of course it can. Its the alternator that with its 50% efficiency get far warmer then designed for and will have a short lifespan..

[@Pinkielover]

Similar problem with the AGM it doesn't properly charge it get a proper dc to dc charger

[@otm646]

2:46 This is absolutely deceptive. Yes, that is less than typical engine idle speed, but you are not driving the alternator at a conventional ratio of 3:1.

[@VictronEnergyBV]

Please see the many comment replies from Johannes about this.

[@ericmed]

What if it has a BMS like a Battleborn?

[@JohannesBoonstra-ol2nz]

Then the charge isn't limited and the alternator will still be overloaded. the BMS takes care of the cells, not anything else.

[@ericmed]

@@JohannesBoonstra-ol2nz Thank you. Guess there is something limiting the charge to exactly around 50 amps on a 180 amp alternator which is definitely a good thing because correct me if I am wrong but I'd think the batteries would pull even more without that

[@fc436]

ts possible to charge a lifepo4 battery directly with alternator. If you now what you do. if you now the parameter and specs of alternator at low rpm, if the max current is compatible with your battery and also the charging voltage. Victron produce an intelligent relais to do that. I have a 65A alternator. and 200ah lifepo4. During travel I have 20-30A of load for many utility like e-bike, fridge, evaporative conditioner etc etc. with a dc-dc of 30-40A I don't have any current to charge the battery. with a simple rele of 230A and 35mmq cable I charge 30A with 30A of loads. My alternator, a low rpm in poor cooling conditions (es at stoplight), don't can produce more of 20-25A, even in short circuit. its not depends from type of battery. lithium, lead, nichel...its depend from the delivery curve of the project of alternator

[@johannesboonstra6917]

hello, not sure which type alternator this is , sounds as this is not a typical used AC alternator type with internal regulator.

[@fc436]

supertypical Bosch or magneti marelli 90s years.. work perfectly. why victron produce a reel to charge lifepo4 directly?? why master volt do the same? all alternator in the world have a curve of current teeth depend from rpm. But depend to the curve and to the reduction ratio of the crankshaft. Its totally possible charge lithium battery with direct alternator in total safety if you now what you do@@johannesboonstra6917

[@petermcgonigal851]

The bms will never shut off, as the max voltage of lithium higher than other batteries, the alternator will only charge lithium to 80 ish %. In a motorhome application, most have 1 starter and 2 leisure. Therefore hard to imagine 1 lithium more damaging than 2 leisure at low charge. Disinformation only damages the brand and its reputation.

[@JohannesBoonstra-ol2nz]

The point of the clip is to warn of overloading the alternator, this is the result of extreme low internal resistance and is not related to the BMS or state of charge. Due to the low internal resistance of the battery the alternator is running at a far higher power then designed for often....thats the issue. We have seen many many situations that the alternator gave up on lithium. Of course if you choose to run the alternator directly to the lithium, thats up to you.

[@skye1212]

I'm thinking you just should not charge these lithium batteries with an alternator period.

[@johannesboonstra6917]

with a DcDc converter this surely can be done safely.

[@alanclark9000]

​@@johannesboonstra6917link?

[@LostDeadSoul]

Pmax : Routside = Rinside. Battery resistance 28 mOhm, Generator resistance 58mOhm. Guess where energy will be dissipated. And yes you over unity generator people. Energy is always lost in energy transformation!

[@hussypunter1975]

230V three phase???? 🤔🤔🤔🤔🤔

[@johannesboonstra6917]

is there a question in here?

[@TheRayDog]

It's the motor turning the alternator. What's the problem?

[@boatingcharlie1]

This test has nothing to do with the type of battery charged and more running the alternator at max output at low RPM. Lower RPM than it would see in a car by the way. Any load that pulls max current on the alternator at these low RPMs is going to heat it up. This is such a bogus test on so many levels. Put a regulator between the alternator and battery of 20 amps or so and it would run all day long. Alternators weren't designed to run at max output 100% of the time.

[@VictronEnergyBV]

Please read the many replies from @johannesboonstra6917 below for more information.

[@44hawk28]

You've got the speed of the driver with the wrong size polly. The driver running at 1500 RPM on an automobile engine has a much larger pulley driving the same size pulley on an alternator making the alternator spin faster than the engine. I might have guessed that an engineer would not quite realize that never having actually turned a wrench on a car does not qualify you to be an engineer for automotive uses or for figuring out how an alternator supposed to work. The rest of your demonstration is pretty good, but you're way low on the speed of the alternator by measuring the speed of the motor that's driving it. Why don't you enter Spurs lead acid batteries of some type or design within the circuit so that they can help regulate the power draw?

[@johannesboonstra6917]

its a test/demostartion of something what would happen over a longer period. but indeed

[@celalkocapinar67]

Überschrift Deutsch dann auf English Dokumentieren.

[@EduardoGarcia-ie5ou]

Fake

[@johannesboonstra6917]

Really? having a alternator with a 50% efficiency running idle on a half empty lithium battery for a while doesnt burn the alternator? If you want we could repeat the test on your car, we take a lithium and connect its with jumper cables to your alternator and let it run for a while. We let you do the temp reading then.