Beta Marine alternators

[Frank Holden]

Here I am at anchor off the coast of Isla Chiloe using the marvels of modern telecomunications while my shiny new Beta 35 putters away charging my batteries.
Now, to the best of my understanding this has what is known as a 'machine sensed' alternator which I thought was unsuited to marine use being designed for motor vehicles and giving simply a big belt at start up and then just keeping up with the load.
This one - after 30 minutes - is sitting on 50 amps with 13.7 volts on both banks. Going by yesterday's experience this will drop to 40 then 20 and then trickle as the batts come up to 14.2 V over the next 30 minutes or so.
This is the behaviour I would expect from a 'battery sensed' alternator.
What am I missing?
Has technology moved on since I fitted a battery sensed Bosch to my Volvo 25 years ago?

 

[Tranona]

That sounds pretty normal to me. Similar pattern to my Beta 30 - although I would prefer not to use the engine for that length of time just with the alternator load on it.

 

[Frank Holden]

That sounds pretty normal to me. Similar pattern to my Beta 30 - although I would prefer not to use the engine for that length of time just with the alternator load on it.

The Beta book says to run at not less than 1200 rpm when charging and I imagine 60 amps is putting a fair load on things. With the Volvo MD17D and the 80amp Bosch alt you could hear the engine easing off when it went from 60 to 40 to 20.
Its a bit of a case of neccesity. I would prefer to charge when motoring out of an anchorage at start of day but we are weatherbound today. Yesterday was downhill for 6 hours in 30K true and pouring rain so ran the heater last night and again this morning to dry things out a bit. Today between showers the solar is giving half an amp.
Apart from the run down from Algarrobo a few weeks ago where we relied on solar and the towed gen this is my first time 'off grid' with this engine, out until after Easter with a day sailing + overnight anchoring regime.

 

[GHA]

That's what happens with lead acid. they'll take a load of current up to maybe 80% SOC or more depending on how much is going in then tail off and take hours and hours to get actually up near 100% full. Hardly any current going in towards the end, it takes a loong time to fully charge lead acid, unlikely to happen running the engine unless you're motoring a good part of the day. Big plus for LiFePo4 on a cruising boat, they'll pretty much take what you give them all the way up.

 

[VicS]

The Beta book says to run at not less than 1200 rpm when charging and I imagine 60 amps is putting a fair load on things. With the Volvo MD17D and the 80amp Bosch alt you could hear the engine easing off when it went from 60 to 40 to 20.

Slightly less than the equivalent of 1 horse power.

 

[Alex_Blackwood]

That sounds pretty normal to me. Similar pattern to my Beta 30 - although I would prefer not to use the engine for that length of time just with the alternator load on it.

I think you will find that Beta alternators are Battery sense, at least the ones I have met are, and that goes back 20 years. Give Beta a ring to double check, very helpful people.

 

[Frank Holden]

I think you will find that Beta alternators are Battery sense, at least the ones I have met are, and that goes back 20 years. Give Beta a ring to double check, very helpful people.

Mine is certainly behaving like a battery sensed alt yet when I asked Beta ( last year when I ordered the engine ) about getting a battery sensed Alt they said they didn't supply them. My old Bosch had a white sense wire to the batteries, this one has no such wire. This is why I am wondering if there is some new elektrickery in machine sensed alts these day.

 

[GHA]

Mine is certainly behaving like a battery sensed alt yet when I asked Beta ( last year when I ordered the engine ) about getting a battery sensed Alt they said they didn't supply them. My old Bosch had a white sense wire to the batteries, this one has no such wire. This is why I am wondering if there is some new elektrickery in machine sensed alts these day.

Nope. It's how batteries work. Very little difference to the alternator anyway, just be a bit of voltage drop down the cable which will drop off as the current reduces. Yours is behaving like an alternator connected to a lead acid battery.

 

[B27]

I would think it's a 'machine sensed' alternator which just means there is no external sensing wiring to compensate for voltage drop between alt and battery.
Unless you have too skinny wiring which makes alt and battery voltages significantly different, what I would guess is happening is that the alternator is current limiting at 50A, it regulator is asking for max output, but that's all it can do at those RPM into that battery voltage.
You might get a few more amps at higher revs.
You might get a few more amps if your wiring resistance was lower

When the alternator voltage gets close to 14.4 or whatever the regulation voltage is, but the battery voltage is notably lower, that is when the regulator will be controlling the alternator and the difference between machine and battery sensing really makes a difference.

Battery sensing also tends to get bundled in with sophisticated charging profiles rather than just a dumb aim for 14.4 Volts or so, soft start, and other complications.

Alternators for marine and plant engines may also be more optimised for running at 'operating revs' of 1800 or 2000 or more, whereas a 'modern' car alternator may be more optimised for lots of current at low revs of idling and slow urban driving at 1200rpm or even less.

Whoever spec'd the alternator for a Kubota digger engine originally was probably not expecting a big house bank.

 

[VicS]

Mine is certainly behaving like a battery sensed alt yet when I asked Beta ( last year when I ordered the engine ) about getting a battery sensed Alt they said they didn't supply them. My old Bosch had a white sense wire to the batteries, this one has no such wire. This is why I am wondering if there is some new elektrickery in machine sensed alts these day.

The Beta Instalation and Operation Manual (q.v.) does show circuitry for battery sensing with this size of engine when diode splitting is installed.
It's purpose in that situation is to increase the alternator output voltage to compensate for the volts drop across the diode splitter.
.

 

[Tranona]

I think you will find that Beta alternators are Battery sense, at least the ones I have met are, and that goes back 20 years. Give Beta a ring to double check, very helpful people.

I was only commenting on the charging pattern, not whether the alternator is battery sensed or not - I don't know.

 

[Alex_Blackwood]

I was only commenting on the charging pattern, not whether the alternator is battery sensed or not - I don't know.

Sorry, reply was meant for OP

 

[Frank Holden]

So, its a mystery.
Yesterday after motoring for 4 hours in a glassy Patagonian calm and the batts were sitting on 12.3V when I rose from my slumber. Alt started at 13.6V 60 amps, four hours later 14.2 V and about 12 amps ie covering load which is basically autopilot and fridge.
Acting just like my old batt sensed. Friend has pointed out very short - about 1 metre - cable run from Alt to Batts may have something to do with it.
Note - no diode splitting.
I'm left wondering whether Sterling regulator is required or not, I'm thinking not.

 

[Boater Sam]

If your battery was at 12.3v it was less than 60% charged and I would doubt that it was full charged after only 4 hours.
You will have been getting nothing like 60A for all the 4 hours. Sealed LA should be charged at 14.4v. Flooded cell at 14.8v.
After you stop the engine and wait an hour without drawing any current the battery should be at 12.6v to 12.7v if fully charged, anything less and it not 100%.
Carry on like this and your battery will be toast, you have to ensure that they are fully charged at least once a week.
A Sterling alternator controller will greatly enhance the battery charging as it senses battery voltage and keeps the alternator at a higher rate until the voltage is high enough.

 

[B27]

So, its a mystery.
Yesterday after motoring for 4 hours in a glassy Patagonian calm and the batts were sitting on 12.3V when I rose from my slumber. Alt started at 13.6V 60 amps, four hours later 14.2 V and about 12 amps ie covering load which is basically autopilot and fridge.
Acting just like my old batt sensed. Friend has pointed out very short - about 1 metre - cable run from Alt to Batts may have something to do with it.
Note - no diode splitting.
I'm left wondering whether Sterling regulator is required or not, I'm thinking not.

Whether you 'require' a smart regulator surely depends on whether you are happy with what you have.
If you want the fastest recharging with minimal engine hours, a smart reg might be part of that solution.
If you mostly charge by solar and very rarely rely on the alternator, keep it simple?

I think from what you wrote, this episode is an exception, not how you normally operate?

You should be looking at getting back to full charge, but that could be solar, a generator, shore power or a towed generator.
14.2 is the low end of charging. More appropriate for a plant engine running 8 hour shifts than a yacht trying to charge house batts quickly.
How big is the house bank?

When people say 'x type of battery should be charged at y volts' they normally need to add 'and switch to float when current drops to z' or something. Any lead -acid battery will charge at 14.2V, but it will take a couple of days!
It's possible to destroy most LA batteries by overcharging at as little as 13.9V, but it takes a long time.

 

[DanTribe]

In 2016 I swapped a dead Yanmar for a new Beta 20. When I tried to connect my Adverc gadget I couldn't make sense of where to connect into the new Mahle alternator. Several emails and phone calls to Beta, Mahle and Adverc got me nowhere, Beta and Adverc kept giving me diagrams and advice obviously wrong. Beta seemed to think that an Iskra alternator was fitted. Eventually Adverc said that the new alternator was "computer controlled" [can't remember the exact phrase] and that the Adverc douldn't be used and wasn't necessary. Would have been good if they had told me earlier.
Some while later the Mahle alternator died. Possibly due to a failed battery or maybe because of my fiddling to connect the Adverc.
My local auto electrician who can usually fix anything was stumped. Never seen one before and couldn't get parts.
Beta replaced it under warranty although it may not have been their fault.

 

[Supertramp]

It's always hard to tell from a post rather than reality but your alternator is behaving pretty much like mine. Beta 60, 15 years old, original Beta alternator, 180 ah engine, 2x180 ah domestic. I have a split charge diode so the engine battery gets the first dose of charging and a Sterling Regulator which I'm not convinced adds much to the party. I have a battery monitor to check the voltage of both banks. The pattern of charging is much like yours with the voltage and current dropping to cover load after several hours motoring and presumably a bit of float. I do have a sensing wire which goes to the Sterling.

My batteries are 4 years old SLA and show 12.8v a few hours after charging if not under load. I have a small solar panel which just about keeps the domestics topped up when sailing (autopilot, instruments).

I would monitor and log your battery voltages carefully for a bit before adding lots more complication or overworrying. I carry a laminated card I got from a post on here showing battery voltages at different SOC's and loads which is really useful for keeping track of things and checking if the battery voltage looks right.

 

[oldmanofthehills]

The Beta Instalation and Operation Manual (q.v.) does show circuitry for battery sensing with this size of engine when diode splitting is installed.
It's purpose in that situation is to increase the alternator output voltage to compensate for the volts drop across the diode splitter.
.

Wish I had known that. I added a diode splitter for my 3 batteries. Engine/Aux/(Emergency backup-gas sensors etc). I have noticed the aux does not charge fully very quickly unlike with my old engine. Probably not worth modifying and awkward to do as which one would take the sensor anyway?

 

[Frank Holden]

Thank you for all the replies.
Today a 7 hour motor fron Rilan back to Anihue. Started the day with batteries at 12.5V with normal morning loads switched on and after about 30 minutes with the Espaker. By end of day we were looking at 14.2/14.3 V and trickle plus load.
So this alternater while not dumb is not as smart as it could be as that will be the voltage regardless of battery type.

So I reckon I will fit the Sterling regulator when I get back to town.
Today isn't an unusual day here in Patagonia, we do lots of big motoring days.

My set up?
About 350 A/h sealed lead acid.
On passage - AquaGen which gives 5 amps at 5knots plus a modest solar array which gives 4/5 amps through a Victron MPPT on a sunny day.
In port a Sterling 12/60 Procharge Ultra power supply.
Day sailing/ night anchoring my shiny new Beta.
I also have a Honda which I use at anchor - just puts in 12.8V but lets us do stuff without taking from the batts, handy when 'waiting on weather' for maybe a week.
As fitted a month ago shunt hadn't been reinstalled to see what was going on, did that last week so this is the first outing.
Again, many thanks.

 

[Supertramp]

Good luck. I'm sure the winds will pick up as you move South! I think it's the area I would most like to sail in.