Jump to content

48v alternators


Antrepat
 Share

Featured Posts

For electric propulsion, 12v is no good unless you like using steel ingots as conductors.  48v seems to be the minimum advisable, and for me LFP chemistry is the way to go.  That means a charging source that is powerful enough to charge something like 400Ah in a reasonable time (say 0.3C) and which can be regulated for LFP rather than LA chemistry.

 

The Wakespeed WS500 or the Mastervolt Alpha Plus seem to be the off-the-shelf devices of choice for regulation - pricey but if you've just spent £4k+ on a battery, I reckon you should have the best management and protection equipment you can afford.

 

Alternators to charge at 48v, though?  Not so easy.  I haven't found anyone who recommends stringing two 24v ones together in series (after rectification).  The Wakespeed can control dual alternators but I bet that means parallel ones, not in series.  I have found only three 48v alternator products available: the Balmar ones, very expensive; these monsters, designed to mate in line with the engine shaft; and this Mahle model, which as far as I can see is used on lawnmowers, presumably big ride-on ones and the alternator provides the power to spin multiple sets of blades.

 

I stumbled across this post by @nicknorman.  He mentions Ed Shires of Four Counties Marine Services, who I read is clear that there's no need for the expensive alternators (thought he doesn't seem to be talking about propulsion supply or 48v) and that any standard alternator should be able to be controlled by an external regulator.

 

The Mahle doesn't appear to be inherently unusual - I'm no expert on alternators but as far as I can tell it has what's needed to work with external regulators like the Wakespeed WS500.  Using this reference, I spy R(W), which appears to be the stator AC, and DF for the rotor field current.  According to the Wakespeed docs, these are the connections that the WS500 needs to control an alternator.

 

image.png.12532f3a4b90341b44b17dbb03cb88d4.png

 

BUT DF is behind the internal regulator, so presumably it'd be necessary to bypass that or remove it altogether so the Wakespeed does the job instead.

 

So, who knows anything about modifying standard alternators to control them with an external regulator?

Link to comment
Share on other sites

Modifying alternators to take an external controller, like an Adverc, is a pretty routine bit of soldering. Normally the internal regulator is left in place but if you are ok with a soldering iron/scalpel/Dremmel then removing/disabling one should be quite manageable.

 

It is very very unlikely that an external controller will bring a 12 volt alternator up to 48volt. You could ask somebody like Cox's automotive to rewind one for you. You might need to replace the diodes, possibly with an external diode bridge.

 

Balmar look like the best option for 48 volt alternators (and controllers) but as you say, they are very expensive, but still might work out cheaper than getting a rewind.

 

The Mahle jobbie looks interesting, have you got a price for it? If my sums are right then its 8.5kW, it will break your engine if you are not careful 😀 (I know of one big automotive company who fitted a big alternator then had problems with the side of the block falling off.)

 

I really don't like the idea of alternators in series, twice the diode losses, almost twice the mechanical losses, twice as many things to go wrong, and more space taken up on the engine. Two lower power 48 volt alternators in parallel would be nicer 😀

  • Greenie 1
Link to comment
Share on other sites

I don't think the Adverc route will work for Lithium batteries because that type of controller can only rise the charging voltage above the alternator's own regulator. If the external regulator wanted to drop to float the internal one would just take over. The internal one needs disconnecting and from the looks of the diagram a pair of wire cutters would do the job and the external regulator would go to L or D- depending upon if it is positive or negative regulating.

  • Greenie 1
Link to comment
Share on other sites

1 hour ago, Antrepat said:

For electric propulsion, 12v is no good unless you like using steel ingots as conductors.  48v seems to be the minimum advisable, and for me LFP chemistry is the way to go.  That means a charging source that is powerful enough to charge something like 400Ah in a reasonable time (say 0.3C) and which can be regulated for LFP rather than LA chemistry.

 

The Wakespeed WS500 or the Mastervolt Alpha Plus seem to be the off-the-shelf devices of choice for regulation - pricey but if you've just spent £4k+ on a battery, I reckon you should have the best management and protection equipment you can afford.

 

Alternators to charge at 48v, though?  Not so easy.  I haven't found anyone who recommends stringing two 24v ones together in series (after rectification).  The Wakespeed can control dual alternators but I bet that means parallel ones, not in series.  I have found only three 48v alternator products available: the Balmar ones, very expensive; these monsters, designed to mate in line with the engine shaft; and this Mahle model, which as far as I can see is used on lawnmowers, presumably big ride-on ones and the alternator provides the power to spin multiple sets of blades.

 

I stumbled across this post by @nicknorman.  He mentions Ed Shires of Four Counties Marine Services, who I read is clear that there's no need for the expensive alternators (thought he doesn't seem to be talking about propulsion supply or 48v) and that any standard alternator should be able to be controlled by an external regulator.

 

The Mahle doesn't appear to be inherently unusual - I'm no expert on alternators but as far as I can tell it has what's needed to work with external regulators like the Wakespeed WS500.  Using this reference, I spy R(W), which appears to be the stator AC, and DF for the rotor field current.  According to the Wakespeed docs, these are the connections that the WS500 needs to control an alternator.

 

image.png.12532f3a4b90341b44b17dbb03cb88d4.png

 

BUT DF is behind the internal regulator, so presumably it'd be necessary to bypass that or remove it altogether so the Wakespeed does the job instead.

 

So, who knows anything about modifying standard alternators to control them with an external regulator?

 

Using 2 24V alternators in series with external (series) field coil regulation is a known solution for 48V, for example it's what Hybrid Marine do, and it's what I was going to do before I decided to go series hybrid -- the Beta 43/50 can have 2 Iskra/Mahle 80A or 100A 24V alternators fitted (isolated ground, configured (Beta can supply brush boxes to do this) for external regulation e.g. Wakespeed, field coils in series).

 

Output is actually a bit higher than the Balmar 48V alternators (see attached curves) and the solution is *much* cheaper (£700 on top of standard engine price (including pulleys/belts) compared to about £2000 for the Balmar) -- even more so than a travelpower. The belt load on the engine is also better since it's split across 2 polyvee belts with alternators on opposite sides of the engine.

 

The Wakespeed needs to be set up to reduce current at speeds close to idle though, or the huge torque load will pull the engine rpm down -- also alternators don't like high currents at low rpm, they tend to overheat. Efficiency is a bit lower than a 48V alternator, but considerably better than 12V ones.

 

alternators.png.cc2b2190f9a6ada9d4d4a6f8fc4cd3d7.png

Edited by IanD
Link to comment
Share on other sites

2 hours ago, Antrepat said:

 

So, who knows anything about modifying standard alternators to control them with an external regulator?

Depends on the alternator but it’s usually not difficult. Here are photos of my Iskra 175A alternator (standard fit on Beta 43) showing the plastic cover removed. You can see the brush and regulator module held in by 3 screws.

 

A3496E58-69C9-4BBF-A0DD-B485048110EB.jpeg.48953f8f33842e96a2c7c17d056ac8c7.jpeg
 

 

and the brush module removed, then turned upside down to reveal the wires connecting the brushes to the regulator. Snip relevant wires and add flying wires to connect brushes direct to external regulator.

 

E681BB32-D912-4053-930A-7A95BAF00B5B.jpeg.f798b32a48aaff0457efb52a049f5bb2.jpeg
 

EB11E015-3CA6-414F-BB53-E9569230AEDE.jpeg.b59dc292303ce38a27e5c855e5935456.jpeg

Link to comment
Share on other sites

4 minutes ago, nicknorman said:

Depends on the alternator but it’s usually not difficult. Here are photos of my Iskra 175A alternator (standard fit on Beta 43) showing the plastic cover removed. You can see the brush and regulator module held in by 3 screws.

 

A3496E58-69C9-4BBF-A0DD-B485048110EB.jpeg.48953f8f33842e96a2c7c17d056ac8c7.jpeg
 

 

and the brush module removed, then turned upside down to reveal the wires connecting the brushes to the regulator. Snip relevant wires and add flying wires to connect brushes direct to external regulator.

 

E681BB32-D912-4053-930A-7A95BAF00B5B.jpeg.f798b32a48aaff0457efb52a049f5bb2.jpeg
 

EB11E015-3CA6-414F-BB53-E9569230AEDE.jpeg.b59dc292303ce38a27e5c855e5935456.jpeg

 

Indeed it's not that difficult. Or Beta can just supply the brush boxes (with holes for wires to external regulator) which you swap for the ones with the regulators in, which at least gives a temporary backup option (swap them back!) if your external regulator dies... 😉

 

Don't forget that you can't just drop high-current alternators in, you also need the polyvee pulleys and belts to drive them if the engine doesn't already have these fitted. Beta also recommend using pulleys with over-running clutches fitted to reduce transient belt loads and wear, and these are only available in a limited range of sizes.

Edited by IanD
Link to comment
Share on other sites

1 minute ago, IanD said:

 

Indeed it's not that difficult. Or Beta can just supply the brush boxes (with holes for wires to external regulator) which you swap for the ones with the regulators in, which at least gives a temporary backup option (swap them back!) if your external regulator dies... 😉

Yes I kept my original brush/reg unit and bought a spare from ebay for about £15 for the surgery! But so far, reversion not needed. 

Link to comment
Share on other sites

1 minute ago, nicknorman said:

Yes I kept my original brush/reg unit and bought a spare from ebay for about £15 for the surgery! But so far, reversion not needed. 

Always good to have a backup, especially if it's cheap 😉

Link to comment
Share on other sites

6 hours ago, dmr said:

The Mahle jobbie looks interesting, have you got a price for it? If my sums are right then its 8.5kW, it will break your engine if you are not careful

About £1000-£1200, but no uk supplier has stock (wonder why).  If it's 75% efficient then that's about 15hp, but that's at full tilt.

 

6 hours ago, dmr said:

I really don't like the idea of alternators in series, twice the diode losses, almost twice the mechanical losses, twice as many things to go wrong, and more space taken up on the engine. Two lower power 48 volt alternators in parallel would be nicer 😀

Me either.  The only 48v alternators I've found are the ones I listed, but I think there is a 100A Mahle one too.  Two Balmar 60A ones...but I expect that'd cost even more.  I'm very open to posters here pointing out other 48v alternators on the market.

6 hours ago, Tony Brooks said:

I don't think the Adverc route will work for Lithium batteries because that type of controller can only rise the charging voltage above the alternator's own regulator. If the external regulator wanted to drop to float the internal one would just take over. The internal one needs disconnecting and from the looks of the diagram a pair of wire cutters would do the job and the external regulator would go to L or D- depending upon if it is positive or negative regulating.

This was my understanding to: the internal regulator needs to be discarded altogether and its function replaced with the external device.

Link to comment
Share on other sites

25 minutes ago, Antrepat said:

About £1000-£1200, but no uk supplier has stock (wonder why).  If it's 75% efficient then that's about 15hp, but that's at full tilt.

 

Me either.  The only 48v alternators I've found are the ones I listed, but I think there is a 100A Mahle one too.  Two Balmar 60A ones...but I expect that'd cost even more.  I'm very open to posters here pointing out other 48v alternators on the market.

 

 

There are alternators controllers that can limit the alternator output so you could do that with the Mahle, but I think they only reduce field current to a fixed limit, I don't think anybody makes one that actually measures current and does a proper feedback control. A project for NickNorman???

£1200 is much better than the Balmar, I think thats almost £4000, you could get an engine for that 😀.  You might be able to order in the Mahle but if its that hard to get I would be concerned about future replacements.   Maybe a quick call to Mr Cox to see if he would rewind a 12 volt up to 48.?????

The other option is a 24 volt alternator and a battery to battery charger device stepping up to 48. I think they exist but probably won't do as many amps as you would like.

 

I was looking at this as I was thinking of doing a big domestic 48volt lithium bank but I gave up due to the lack of alternators and other components. I might think again in a couple of years time, things might improve quite a bit.

Link to comment
Share on other sites

16 minutes ago, dmr said:

 

There are alternators controllers that can limit the alternator output so you could do that with the Mahle, but I think they only reduce field current to a fixed limit, I don't think anybody makes one that actually measures current and does a proper feedback control. A project for NickNorman???


I’m not quite sure I understand your point. I can dynamically set the max field current and the chip measures (and reports) the instantaneous actual field current - it’s how I control the alternator temperature. Is that what you meant? Limiting field current to a specified value is a really good way to do things because it more or less sets a torque limit so you get less current at lower rpm, more at higher rpm. And of course there is more cooling fan action at higher rpm.

  • Greenie 1
Link to comment
Share on other sites

2 minutes ago, nicknorman said:


I’m not quite sure I understand your point. I can dynamically set the max field current and the chip measures (and reports) the instantaneous actual field current - it’s how I control the alternator temperature. Is that what you meant? Limiting field current to a specified value is a really good way to do things because it more or less sets a torque limit so you get less current at lower rpm, more at higher rpm. And of course there is more cooling fan action at higher rpm.

 

No, I was thinking of measuring the output current (probably a Hall type current sensor) and then limiting this to a fixed value (or even a speed dependant value).

I have never really thought about this but I had assumed there is not a fixed relationship between field current and output current....You suggest its speed dependant which makes sense?

With an 8kW alternator I suspect a torque limit, a maximum current limit, and a low speed torque limit would all be needed.

 

Link to comment
Share on other sites

15 minutes ago, dmr said:

 

No, I was thinking of measuring the output current (probably a Hall type current sensor) and then limiting this to a fixed value (or even a speed dependant value).

I have never really thought about this but I had assumed there is not a fixed relationship between field current and output current....You suggest its speed dependant which makes sense?

With an 8kW alternator I suspect a torque limit, a maximum current limit, and a low speed torque limit would all be needed.

 

A single alternator that can put out 8kW is probably going to need wider than normal polyvee belts/pulleys to prevent belt slip and probably an idler wheel to increase the belt wrap angle -- see what Integrel do, for example.

  • Greenie 1
Link to comment
Share on other sites

1 minute ago, IanD said:

A single alternator that can put out 8kW is probably going to need wider than normal polyvee belts/pulleys to prevent belt slip and probably an idler wheel to increase the belt wrap angle -- see what Integrel do, for example.

 

Thats exactly why I suggested that a controller doing current/torque limiting would be required.

  • Greenie 1
Link to comment
Share on other sites

1 minute ago, dmr said:

 

Thats exactly why I suggested that a controller doing current/torque limiting would be required.

Even with that, an alternator outputting 8kW means something like 15hp through the belt, which is a *lot* of torque -- might need a 10V or 12V belt (IIRC Beta use 6V for big alterators) as well as an idler pulley. I talked to Beta at length about this when I was looking at fitting a single big alternator...

Link to comment
Share on other sites

23 minutes ago, dmr said:

No, I was thinking of measuring the output current (probably a Hall type current sensor) and then limiting this to a fixed value (or even a speed dependant value).

I have never really thought about this but I had assumed there is not a fixed relationship between field current and output current....You suggest its speed dependant which makes sense?

With an 8kW alternator I suspect a torque limit, a maximum current limit, and a low speed torque limit would all be needed.

 


My point is that a current limit isn’t useful. It is belt load aka torque that is relevant, whereas current is (effectively) the product of that and rpm. More rpm = less torque for a given current. Although if you add in an rpm term it does become useful. But that is the same as field current limiting, so no point in complicating the issue!

Link to comment
Share on other sites

At one point Hybrid Marine offered something they called the "Power Station" , a Beta 43 or larger with an Electrodyne 100A 48V (model GE100-48) brushless alternator. As noted above, wide polyvee belt with idler wheel. These brushless alternators are more efficient I believe and need external regulation, may even have external diode packs. You can get these alternators from the US but $3,000 or so before importing, no idea about UK or European suppliers. Photo I saved from Hybrid Marine and curve as supplied by Electrodyne.334360216__wsb_694x668_Powerstationrev2.jpg.90875904726d69425fad39abe5e8e88f.jpgScreenshot_20221013-233738_kindlephoto-579937310.png.530ce5829b4cfc797409ef1b870f8680.png

Link to comment
Share on other sites

10 hours ago, PeterF said:

At one point Hybrid Marine offered something they called the "Power Station" , a Beta 43 or larger with an Electrodyne 100A 48V (model GE100-48) brushless alternator. As noted above, wide polyvee belt with idler wheel. These brushless alternators are more efficient I believe and need external regulation, may even have external diode packs. You can get these alternators from the US but $3,000 or so before importing, no idea about UK or European suppliers. Photo I saved from Hybrid Marine and curve as supplied by Electrodyne.334360216__wsb_694x668_Powerstationrev2.jpg.90875904726d69425fad39abe5e8e88f.jpgScreenshot_20221013-233738_kindlephoto-579937310.png.530ce5829b4cfc797409ef1b870f8680.png

I looked at that in the past too (before it disappeared) and asked Beta about it. They said there was almost no demand because it was *very* expensive, and that two 100A 24V alternators in series with standard polyvee pulleys/belts did the same job for a fraction of the cost...

Edited by IanD
Link to comment
Share on other sites

23 hours ago, Tony Brooks said:

I don't think the Adverc route will work for Lithium batteries because that type of controller can only rise the charging voltage above the alternator's own regulator. If the external regulator wanted to drop to float the internal one would just take over. The internal one needs disconnecting and from the looks of the diagram a pair of wire cutters would do the job and the external regulator would go to L or D- depending upon if it is positive or negative regulating.

 

This makes a lot of sense to me.  Having two regulators fighting each other surely would be bad, and anyway the whole point of using something as fancy as the Wakespeed is because it is capable of charging LFPs properly (until absorption is properly complete and current has fallen right off and those pesky memories are erased and whatever the other reason is to be able to charge them properly fully when required).

17 hours ago, dmr said:

£1200 is much better than the Balmar, I think thats almost £4000

I recently got a quote for £3052 plus VAT for the 100A one from RJS Marine, which is the best price I've found in the UK.  I can see you share my excitement about the Mahle.

Link to comment
Share on other sites

17 hours ago, dmr said:

You might be able to order in the Mahle but if its that hard to get I would be concerned about future replacements

It only seems to be scarce within the UK.  Can't imagine why.

17 hours ago, dmr said:

Maybe a quick call to Mr Cox to see if he would rewind a 12 volt up to 48.?

Who?  Actually there's a chap here in Scarborough who does motor rewinds and suchlike.  He refurbished a motor for me about six years ago.  If he's still in business, maybe I could ask him - ACR Rewinds, that's him.

Link to comment
Share on other sites

16 hours ago, nicknorman said:


I’m not quite sure I understand your point. I can dynamically set the max field current and the chip measures (and reports) the instantaneous actual field current - it’s how I control the alternator temperature. Is that what you meant? Limiting field current to a specified value is a really good way to do things because it more or less sets a torque limit so you get less current at lower rpm, more at higher rpm. And of course there is more cooling fan action at higher rpm.

 

Let me check I understand.  It's possible to cap the engine effort by capping the field current, and hence reduce the risk of overtaxing a slightly puny engine (mine is 14hp)?

Link to comment
Share on other sites

Found this one as well: https://www.dfjauto.com/product/electrodyne-brushless-alternator/ but it doesn't seem to be listed in the manufacturer's catalogue anymore: http://www.electrodyneinc.com/ge-series.  They do have a different 48v one but the information isn't really there.

 

Isn't brushless better?  I'm not sure if this one can be externally regulated, though - I see a "voltage adjust" which presumably is a screw in a hole.  It does say "full field", indicating another mysterious hole.

 

 

Link to comment
Share on other sites

Just now, Antrepat said:

Found this one as well: https://www.dfjauto.com/product/electrodyne-brushless-alternator/ but it doesn't seem to be listed in the manufacturer's catalogue anymore: http://www.electrodyneinc.com/ge-series.  They do have a different 48v one but the information isn't really there.

 

Isn't brushless better?  I'm not sure if this one can be externally regulated, though - I see a "voltage adjust" which presumably is a screw in a hole.  It does say "full field", indicating another mysterious hole.

 

I think regulation for brushless might be a bit different from normal brushed - not sure, but one needs to bear in mind that the control input is to the field of the “field generating sub-alternator” part. That sub-alternator goes on to provide the field current for the main alternator. And so the field current for the main alternator is dependant not only on the field current supplied to the sub-alternator, but also the rpm. Hence the bigger variation in output current over a broader range of rpm than you see with a normal alternator.

Link to comment
Share on other sites

26 minutes ago, Antrepat said:

 

This makes a lot of sense to me.  Having two regulators fighting each other surely would be bad, and anyway the whole point of using something as fancy as the Wakespeed is because it is capable of charging LFPs properly (until absorption is properly complete and current has fallen right off and those pesky memories are erased and whatever the other reason is to be able to charge them properly fully when required).

I recently got a quote for £3052 plus VAT for the 100A one from RJS Marine, which is the best price I've found in the UK.  I can see you share my excitement about the Mahle.

 

Two years ago (late 2020) Beta quoted me £670 on top of the standard engine price for 2 24V 80A alternators with brush boxes fitted, including pulleys and belts -- not much point fitting the 100A ones for charging at 1200rpm, see curves I provided.

 

To fit a big 48V 100A alternator like the Balmar the quote was £570 (including special pulleys and belts and testing) PLUS the cost of the alternator.

Link to comment
Share on other sites

16 hours ago, PeterF said:

At one point Hybrid Marine offered something they called the "Power Station" , a Beta 43 or larger with an Electrodyne 100A 48V (model GE100-48) brushless alternator. As noted above, wide polyvee belt with idler wheel. These brushless alternators are more efficient I believe and need external regulation, may even have external diode packs. You can get these alternators from the US but $3,000 or so before importing, no idea about UK or European suppliers.

Just saw this, which happens to be exactly the one I was just talking about.  I'm not sure that alternator is still made, but a similar setup with the Mahle is what I'm trying to explore.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.