What is my alternator doing?

[Na Mara]

With my new electrical system I can see in real time exactly what my alternator is doing and I am a bit perplexed.

Its a Balmar 100A alternator that is regulated by a WS500 regulator and it charges a 3x200Ah LFP 12V victron Smart batteries managed by a lynx 500 BMS.

What it is doing is that it is charging at between 60 and 70% of its max capacity (field input is between 60 and 70%) and seems to be targeting an alternator temp of 70C. If, however, I put a big load on the system (boil a kettle through the inverter say), then all of a sudden it goes to 100% output and it doesn't have a problem with allowing its temperature to go all the way into the 90's. I would very much like it to charge at 90-100% and can't really see why it isn't doing that as the temp limit on it is set, according to recommendations if memory serves, to 95C. It seems that the BMS is limiting the changing amps for some reason and I can't figure out why. The batteries can easily take, and regularly do take when we hook up to shore power, 120 charging amps.

So why is my alternator not outputting as expected?

[GordMay]

I presume you have the manuals; but if not:

Lynx Smart BMS Manual
➥ https://www.victronenergy.com/upload...BMS-pdf-en.pdf

Wakespeed WS500 Advanced Alternator Regulator Manual
➥ https://www.wakespeed.com/wp-content...30-2022-V2.pdf
➥ https://www.wakespeed.com/wp-content...30-2022-V3.pdf

[CharlieJ]

OP: This is a programming change for the WS500.

Note that per Balmar the continuous rating for their alternators is a max temperature of 85C. And, make sure that the alternator temp sense is at or very near the hottest point on your alternator.

[hjohnson]

Originally Posted by Na Mara

With my new electrical system I can see in real time exactly what my alternator is doing and I am a bit perplexed.

Its a Balmar 100A alternator that is regulated by a WS500 regulator and it charges a 3x200Ah LFP 12V victron Smart batteries managed by a lynx 500 BMS.

What it is doing is that it is charging at between 60 and 70% of its max capacity (field input is between 60 and 70%) and seems to be targeting an alternator temp of 70C. If, however, I put a big load on the system (boil a kettle through the inverter say), then all of a sudden it goes to 100% output and it doesn't have a problem with allowing its temperature to go all the way into the 90's. I would very much like it to charge at 90-100% and can't really see why it isn't doing that as the temp limit on it is set, according to recommendations if memory serves, to 95C. It seems that the BMS is limiting the changing amps for some reason and I can't figure out why. The batteries can easily take, and regularly do take when we hook up to shore power, 120 charging amps.

So why is my alternator not outputting as expected?

Are you running a fully integrated power system? (ie is the BMS controlling all your charging sources?)

On my boat, my REC BMS is setup to normaly allow 120A of charging into the battery which is a nice conservative 0.25c on my battery (460Ah). I can theoretically hit that when I have the engine running and shorepower connected. It will drop that to 2A if it decides it needs to balance the cells, and it will also taper it off as it approaches 100% SoC.

Anyhow, assuming your Wakespeed is actually in slave mode to the BMS (check the colour of the blinking light on it to confirm), it is simply doing whatever the BMS is commanding. If the BMS is limiting the power to 60A, then that would explain the behaviour you're seeing. When you add the big load, the alternator ramps up to keep the BMS current at its specified level.

[CrispyCringle]

What is your engine RPM? Also, you wont get an alternator to put out 100% continuously without really good cooling. But if your at 70c, it seems like it should handle an intermittent spike for a load like a kettle. More RPM will give more cooling. Go through the settings for the WS and BMS.

[Na Mara]

QUOTE=hjohnson;3792760]Anyhow, assuming your Wakespeed is actually in slave mode to the BMS (check the colour of the blinking light on it to confirm), it is simply doing whatever the BMS is commanding. If the BMS is limiting the power to 60A, then that would explain the behaviour you're seeing. When you add the big load, the alternator ramps up to keep the BMS current at its specified level.[/QUOTE]

Are the lights under the cover of the WS500? I to think it must be the BMS. It communicates through the data cable with the WS500. If it is that though then I don’t know how to reprogram the BMS to bump up the charging amps.

[Na Mara]

Crispy Cringle

I was at 2800 rpm which is cruising rpm on my yanmar. As stated the alternator is happy going to 100 when required, it just doesn’t when charging.

[hjohnson]

Are the lights under the cover of the WS500? I to think it must be the BMS. It communicates through the data cable with the WS500. If it is that though then I don’t know how to reprogram the BMS to bump up the charging amps.[/QUOTE]

Just the main one that's visible through the lid. As I recall, when it's in remote controlled mode, it shows a specific colour or pattern (I'm not aboard right now). If you're running a Lynx BMS and the Victron batteries, I don't think there is anything you can do to bump the amps. I think it figures that out by the serial connections to the batteries themselves.

[Ballsnall]

Originally Posted by Na Mara

Its a Balmar 100A alternator that is regulated by a WS500 regulator and it charges a 3x200Ah LFP 12V victron Smart batteries managed by a lynx 500 BMS.
What it is doing is that it is charging at between 60 and 70% of its max capacity (field input is between 60 and 70%) and seems to be targeting an alternator temp of 70C.

60 to 70 amps continuous from a 100a alternator is a pretty good result especially at only 70C and considering it also ramps up for short durations depending on load is excellent and should bode well for longevity. Sure, you could bump the temp up but I don't see you getting much more than 70amps continuous at max temp.

[N Coast Murray]

Isn't the minimum recommended alternator be at least 25% of the total amp hours even for a lead acid battery bank? Considering the the OP's bank is 600ah, wouldn't that suggest at least a 150 amp alternator for lead acid, and even bigger for LFP?

**I'm a knuckle dragging, slope foreheaded, unibrowed lout when it comes to all things electrical**

[Na Mara]

Originally Posted by hjohnson

. If you're running a Lynx BMS and the Victron batteries, I don't think there is anything you can do to bump the amps. I think it figures that out by the serial connections to the batteries themselves.

This is my fear, but if it improves the longevity of the alternator then maybe it’s worth the extra engine time.

The biggest alternator I could fit without a belt upgrade was 100A I am reasonably happy with that as I want to mostly rely on other greener charging sources. The lower than expected output is a nuisance rather than anything else.

[hjohnson]

Originally Posted by Na Mara

This is my fear, but if it improves the longevity of the alternator then maybe it’s worth the extra engine time.

The biggest alternator I could fit without a belt upgrade was 100A I am reasonably happy with that as I want to mostly rely on other greener charging sources. The lower than expected output is a nuisance rather than anything else.

Assuming your WS500 has the blinking orange light on it (which tells you that it's being externally controlled by the Lynx), a larger alternator isn't going to do anything. The Lynx is setting the current limit for the battery, and the WS500 is doing precisely what it's programmed to do, driving that much current into the battery.

You can check this on your Cerbo/other gx device by picking your battery from the Device List, then navigating to Parameters. You should see the "Charge Voltage Limit" and the "Charge Current Limit" in there. These are what's being generated by the BMS as the limits for charging sources, and your wakespeed is using those as its limits. Adding a bigger alternator will only cause it to reduce the field current further to keep the current within those limits.

[Ballsnall]

Originally Posted by Na Mara

This is my fear, but if it improves the longevity of the alternator then maybe it’s worth the extra engine time.

The biggest alternator I could fit without a belt upgrade was 100A I am reasonably happy with that as I want to mostly rely on other greener charging sources. The lower than expected output is a nuisance rather than anything else.

Your achieving 60 to 70 amps continuous from a 100amp alternator, what was your expectation?

[Na Mara]

I checked the charging voltage on the BMS today and it’s 13.5V. Full charged my bank sits at 13.47V. I’m pretty sure that you are right hjohnson. I think the BMS is limiting the alternator to not exceed the recommended charging voltage. Not sure how, or even if it is a good idea to try, to change the charging voltage from the recommended value.

Ballsnall, the alternator merrily puts out 100A when there is a large load on the system. It just won’t charge the batteries at that, which is a bit of a shame.

[newhaul]

Originally Posted by Na Mara

I checked the charging voltage on the BMS today and it’s 13.5V. Full charged my bank sits at 13.47V. I’m pretty sure that you are right hjohnson. I think the BMS is limiting the alternator to not exceed the recommended charging voltage. Not sure how, or even if it is a good idea to try, to change the charging voltage from the recommended value.

Ballsnall, the alternator merrily puts out 100A when there is a large load on the system. It just won’t charge the batteries at that, which is a bit of a shame.

How low have you ever taken the battery bank when needing to charge by the alternator?

Go into town and see about getting a big alternator from Scania