Internal alternator regulator or external

[conachair]

Originally Posted by barnakiel

I am glad you told me I was wrong. I might save some bucks when buying our future inboard.

Cheers,
b.

A recent UK beta 35 came with one of these - AAK compact 120A, says nominal 14v but will sit at 14.6v at the batteries. Glad I didn't buy a smart reg at the same time

http://www.iskra-agv.cz/us/pdf/alternators.pdf

[geoffr]

In reading
Musings Regarding External Regulation | SailboatOwners.com Forums
I see for my 3YM30 it is suggested:
Dumb Regulator / Temp Compensated (Hitachi/Yanmar) - These alternator regulators are horrible for deep cycling applications. IMHO nearly every Yanmar engine with a Hitachi alternator, if used regularly in a deep cycling application, should have it converted to external regulation or convert to a new alt & regulator.

How hard is it to convert a Hitachi to an external regulator?

[GrahamHO]

I converted to an external smart regulator for my 80 amp Hitachi on my 2GM20It was not without teething problems.


Firstly belt slip and overheating of the alternator. I cured that with custom made double belt pulleys with the alternator pulley 10 mm greater diameter than standard. That decreased the load and increased the belt wrap. It didn't make any difference to the charging rate at cruising revs.


Then it took me a long time to find out why my Navman wind gauge with an analogue direction indicator would go 90* / 180* off direction when the motor was started.


Eventually I closely wrapped the cables from the alternator to the Next Step regulator in tinned copper braid including the battery cables to provide shielding for their 5' length. The braid is connected to the engine earth connection.


Doing that immediately fixed the instrument interference from electromagnetic radiation from those cables. I had seen an article by a professor from the University of Oregon that mentioned in passing that those cables to smart regulators can be a source of interference. In my case that was correct.


Now the whole system works well but it was more involved than simply wiring in an external regulator.

[Nicholson58]

Much good advice above. We have a Balmar on our 24 VDC 1.5 KW alternator. I followed the advice in the install manual and located the device remote from the engine (heat). To do this, I spliced in enough wire to get to the nav station. I can check on the Balmar any time. It survived a massive lightning hit that blew out the alternator diodes a year ago and keeps going. Happy with it. I suggest you put a multistage regulator on and put the stock controller in a baggy as spare.

[reed1v]

Originally Posted by Nicholson58

Much good advice above. We have a Balmar on our 24 VDC 1.5 KW alternator. I followed the advice in the install manual and located the device remote from the engine (heat). To do this, I spliced in enough wire to get to the nav station. I can check on the Balmar any time. It survived a massive lightning hit that blew out the alternator diodes a year ago and keeps going. Happy with it. I suggest you put a multistage regulator on and put the stock controller in a baggy as spare.

Which raises an interesting question: Why not just convert to a 24 volt system throughout the boat? Or even higher voltage. Would open up a whole world of commercial equipment and options for a boat.

[geoffr]

Originally Posted by GrahamHO

I converted to an external smart regulator for my 80 amp Hitachi on my 2GM20It was not without teething problems.

GrahamHO - other than the problems you had to solve, how much work was it to remove the internal alternator on the 80 amp Hitachi. Where did you find the documentation on the Alternator, or is it pretty obvious?

[GrahamHO]

Originally Posted by geoffr

GrahamHO - other than the problems you had to solve, how much work was it to remove the internal alternator on the 80 amp Hitachi. Where did you find the documentation on the Alternator, or is it pretty obvious?

It was very easy. I took the alternator to an auto elecrician and they did it for not much money.

The belt slip problem needs to be expected with a smart regulator. A larger (by 10 mm dia) alternator pulley alone may have solved that without going double but I did both. The larger pulley provides more belt wrap and less load ( like a larger cog on a bike wheel) It didn't alter the output; usually cruising at 2900 revs. Possibly there is a little less charge and load at very slow speeds which is a good thing when accelerating. The new pulley was machined with plenty of belt contact area. The standard Hitachi alternator pulley is simply 2 pieces of pressed steel held together by the nut on the shaft and doesn't provide much belt contact area.

My instrument interference problem may or may not be a problem for others as it depends on the instruments, their location and the length of the alternator to regulator cable length. That is around 5' in my case into an adjoining quarter berth. My instruments are on the same side as the alternator and regulator because of an earlier motor swap. Knowing what I know now I would anyway run that cable through tubular tinned copper braid earthed to the engine earth point on installation. Doing that later, I wrapped braid around and around to avoid pulling it all to bits again. That made the necessarily longer braid more expensive but saved disassembly. It cured the interference. The braid I used is similar to that used sometimes for earth straps. In my case what I could locate was a flat braided tube. It was hard to locate but an electrical supplier told me of the factory manufacturing it in a variety of sizes.

Before I modified the alternator pulley and after being at anchor overnight with a small electric fridge running, the alternator belt would slip and the engine was under an obvious load for a while. Now there is no slip noticeable. I am using a Next Step regulator made by Ample Power which is or was based in Seattle. I'm sure similar teething problems would occur with any make as they all do the same job. Next Step has been very reliable for me.

[GrahamHO]

By the way Geoffr, I see you are in Ottawa. It is a beautiful city. I was there again a couple of months ago visiting my daughter. Do you take your boat down the Rideau Canal? It must be frustrating to be confined to the Ottawa River.

[01kiwijohn]

Actually, the Hitachi regulators do a fine job of keeping the system in good shape; the reason I used the Sterling regulator was that it did not require removal of the Hitachi regulator; just leave it in place and it will default to that if the external regulator fails; Some regulation is better than NO regulation.

[GrahamHO]

Originally Posted by 01kiwijohn

Actually, the Hitachi regulators do a fine job of keeping the system in good shape; the reason I used the Sterling regulator was that it did not require removal of the Hitachi regulator; just leave it in place and it will default to that if the external regulator fails; Some regulation is better than NO regulation.

Sounds good but too late for me and possibly not available when I changed to smart. I do have a spare external standard regulator that I thought I could mount alongside the Next Step and somehow quickly change over to but I'm not sure how to connect that. The Next Step has kept going though.

I'm speculating that with a catamaran which probably has an engine in each hull, it might be a good idea to have a bigger alternator with a smart regulator on one engine for the house batteries and a smaller alternator with its standard regulator for the start batteries on the other engine. Also an emergency parallel switch if one system fails. Maybe that is how it is done??

[Hobie_ind]

I've recently switched back and forth between my regular hi-output regulator (135A/24 V) with an external regulator and my internally regulated spare (50A/24 V). While I realize there's a huge difference in the size between the two I thought the data might be worth throwing into the mix here anyway.

The hi-output normally puts out about 90 amps to start and quickly settles down to about 45 amps for bulk charging. The house bank is 450 Amp-Hrs @ 24 Volts (8 - Trojan T-105 (6 V) batteries arranged in two banks of 4 batteries).

As a cheap backup I carry a 50 Amp/24 V alternator I found at a parts shop for trucks and heavy equipment. It's a saddle mount (slightly narrower so I just spaced it out on the mount with washers to get the belt alignment right) with a similar size double pulley to my hi-output alternator. It had a vacuum pump on the back that I simply removed. At a similar state of charge on the batteries it typically starts out at a bit more than 50 amps but quickly settles down to 30 Amps for about 15 minutes and then down to 20 amps. I got to try it out for a few months recently as our hi-output alternator packed it in (bad field coil) just out of Bora Bora, so we ran the spare for a couple of months until Fiji where I just had the coil rewound. I used it for charging the house bank a number of times underway and St anchor when we had extended cloudy periods to see how it was as a spare if the generator or battery charger also went. Marginal, but fine as a spare.

I think that even given the difference in size, the 'plateau' clearly isn't as long as the external regulator given the batteries aren't charging as fast. However, it works great for us as a backup given that I've got a lot of solar and a generator. Underway I typically need less than an hour or so of charging a day even with the backup alternator capacity and if it's sunny out only an hour every 2-3 days due to the solar. Cloudy days underway with the autopilot working hard on a swelly downwind run would be closer to 3 hrs per day which isn't great, but would be workable in a pinch. Frankly, before the solar panels were I stalled 3 hrs/day on the generator underway was the norm.

Just another option when looking at spares.

[01kiwijohn]

There are many possibilities but, whatever you do, keep it as simple as you can. Mounting a spare regulator close by, would work. Just make up a wiring harness, to match the one already fitted, and use a plug to connect them. That way, when one fails, you won't have to think about it, just unplug the one and plug in the next.
The option of adding one larger alternator, on one engine, has been done before. You'll have to calculate what size to match your battery bank, but this would give you an almost foolproof back up system.

[OceanSeaSpray]

Originally Posted by geoffr

In reading
Musings Regarding External Regulation | SailboatOwners.com Forums
I see for my 3YM30 it is suggested:
Dumb Regulator / Temp Compensated (Hitachi/Yanmar) - These alternator regulators are horrible for deep cycling applications. IMHO nearly every Yanmar engine with a Hitachi alternator, if used regularly in a deep cycling application, should have it converted to external regulation or convert to a new alt & regulator.

How hard is it to convert a Hitachi to an external regulator?

When I read:

"Hitachi & many other automotive alternators with dumb regulators, limit voltage but also reduce voltage based on alternator temperature. This is a self protective feature installed in the internal dumb regulator to prevent the alternator from cooking itself. In cars it is usefully "safe", due to super high engine bay temps, but on boats temp sensing should be done directly at the battery not inside the alternator.
..."

I can't help but wonder who is "really, really dumb" to borrow a few more words from the author. It is an idiotic statement. Sensing alternator temperature is a protective measure intended to prevent alternator failure by overheating indeed. So, by extension, the smart move is allowing it to cook itself instead. Sensing battery temperature is intended to correct the charging voltage according to ambient temperature. The two purposes are completely different.

Alternators also get much better cooling on vehicles where there is ample air circulation than within the confines of an engine compartment on a boat. Trying to cool them with air at 50degC already is not that great.

Ducting the engine bay air supply to the back of the alternator would help a great deal for a start.

[OceanSeaSpray]

When I face an unknown alternator with a built-in regulator, the first things I do are:

1. I hook up a voltmeter to the battery, start the engine and watch where the voltage levels off. That is the regulation voltage. Then I keep it running and watch if that voltage steps down after a while. Sometimes it does, sometimes not. If nothing has happened after 20-30 minutes at constant voltage, it will never happen.
2. While doing the above, I also measure the voltage at the back of the alternator to get an idea of the voltage drop in the wiring. Do this early, while the alternator is still putting out full current. If I have a clamp meter available, I also measure the current. If you are losing significant voltage, the B+ and/or ground (B- if applicable) cabling is too small: replace it before doing anything else. It commonly is, because heavy cable is more expensive.
3. I look for any hint that the alternator is externally sensed. In this case, there is a small wire going straight from the back of the unit to the battery, or sometimes to the starter motor/solenoid. Also, if the alternator output voltage is highest as the voltage reaches its limit and then drops a bit while the battery voltage stays constant, you can bet it is externally sensed.
4. I look for any voltage adjustment pot on the back of the alternator, but those are rare/never found on automotive units.
5. I look for any splitter and similar devices in the path of the charging current and measure any voltage drop there. It must be compensated for, through external sensing, or will result in poor performance.

Modern SLA batteries have an amazing ability to recombine gases without venting or losing water and they tolerate relatively high sustained charging voltages. Some stock modern alternators found on marine engines are precisely designed to operate with them and do a very decent job.

My experience is also that external regulators (with a special mention for the blue ones potted in silicone with cooling fins) are remarkably prone to just-out-of-warranty failure, while the factory built-in ones are rather reliable. I avoid removing built-in regulators as much as possible, because they normally also offer some thermal protection.

Some built-in automotive regulators are quite hopeless, for example charging up to 14.3V for a few minutes and stepping back down to 13.8V. When that happens, replacing the whole alternator with another model with better characteristics can be a cheaper and smarter move than a "smart regulator". If you know what you are looking for, second-hand alternators can often be had for very little.
A Mitsubishi A003TR0093ZT is a seriously marinised 14V/115A alternator that delivers 14.3V continuously, which is pretty good in normal temperatures and even better in the heat. It also has a built-in over-temperature thermostat as a last resort. It is found on all the new D-series Volvo engines.

Internally sensed alternators can usually be modified to sense externally at little cost. The process varies a little from model to model. Adding a small diode in the sensing line of an alternator bumps the voltage up by 0.4-0.65V depending on the diode model.

Last but not least, I am yet to find a smart "smart regulator" on the market. Since they don't measure output current - ever - they have no idea of what the battery is doing. They just deliver a dumb profile based on voltage setpoints and an absorption time set by the owner and if it hurts the battery, well, "who actually configured that?" I hear them say...
Charge and go through the stages, stop the engine, restart it and watch them happily over-charge the battery.
Many "smart regulators" are set incredibly aggressively - not such a great idea.

This being said, external regulators can be useful and make life much easier at times. I walk away from any model that gets warm, i.e. features cooling fins etc. Considering the current they handle (field currents are typically 3 to 8A or so) there is no excuse for designing electronics that run hot. This indicates that someone is saving money on power transistors in there at the expense of reliability and unit life, or the design itself is very poor.

[01kiwijohn]

BTW; the Sterling regulator has both alternator and battery temperature sensing/ protections.