External vs Internal Regulator

[Dockhead]

I have an Adverc external regulator, which is a bit of an oddball as instead of producing a classical three stage charging profile, it alternates between very high voltages for half an hour or so, and then lets the batteries rest.

It works OK, but I suspect that this regime overcharges my batteries on long motoring days. I sometimes have to water them a lot, and aging batteries tend to fail just in this regime.

I have just bought a new Leece Neville 8SC3133U alternator (100 amps @ 24 volts so about 2.5kW) and put my old 8SC3014U into spares, and I'm wondering whether I really want to hook up the Adverc or not.

I was reminded of this article by our electrical guru, Maine Sail:

http://forums.sbo.sailboatowners.com...d.php?t=125392

By a post in another thread.

What would be the consequences of simply using the internal regulator? The set point on this particular alternator is 28 volts. That's not enough for a good absorption charge, at least not quickly, but that will get me to at least 90%, won't it? I understand from MS's article that up to the dumb alternator voltage set point, performance is identical to external regulation.

And I don't suppose 28 volts will cook the batteries, as I think the Adverc has been doing.

Any comments? The alternative would be to buy a Sterling conventional three-stage regulator, or one of their alternator-to-battery chargers, but I'm not so keen on spending the money unnecessarily.

[kmacdonald]

Depends on the batteries somewhat. Flooded lead acid are pretty flexible in charging and the lower charge voltage might be better for the alternator. It will keep charge current lower and therefore temperature of the alternator. A lot of alternators will burn themselves up if they output full rated current for long periods of time. The lower charge current doesn't really increase the total charge time to 100% very much anyway. (see Maine Sails article on that) I know of people that have put bigger pulleys on their alternators to limit their output. A $125 90 Amp Leece-Neville 8MR alternator will last a LONG time set up that way.

Maine Sail also stresses the importance of using "belt manager" on the Balmar external regulator to limit output current of the alternator. The objective is to limit the output current of the alternator during bulk charge so the alternator does not burn up. During absorption charge is where the lower charge voltage comes into play. If you use solar to charge from 80% to 100% the regulator doesn't really matter much. If not, why not?

[lateral]

That alternator seems to have 8RL3136 regulator, which, as you say, is 28V. No mention of a higher Vset model integral reg available? The delco have a variety of Vsets
for the their alternators.
I would have thought long haul motoring would have been worse for over-charging with an internal regulator, (no auto set to float) as most external smart ext regulators are time adjustable on absorbtion and then resort to float. Not familiar with Adverc.

I am happy just turning the ign off and on again to get a another cycle until I'm happy with the tail current minus any loads that are on.

[Stu Jackson]

Same answer from years ago:


How Alternators & Regulators Work PLUS External vs. Internal Regulators (by Maine Sail): http://forums.sbo.sailboatowners.com...d.php?t=125392

[Dockhead]

Originally Posted by Stu Jackson

Same answer from years ago:


How Alternators & Regulators Work PLUS External vs. Internal Regulators (by Maine Sail): http://forums.sbo.sailboatowners.com...d.php?t=125392

Well, that was the article had I re-read before starting this thread.

As usual, Maine Sail is really persuasive on these issues, and I take it as read that up to the set point of the internal regulator (ignoring voltage sensing issues if any), it's all the same no matter what kind of regulator you have. So I guess the question is (a) what kind of state of charge will I get to at 28 volts; and (b) is 28 volts a safe voltage to hold the bank at even on a long motoring trip; and (c) will the state of charge get stuck at 85% or whatever, or will it continue creeping up?

What bothers me about the Adverc is that it keeps blasting the batts with 28.8 volts indefinitely -- it has no float regime. It does this for 10 or 15 minutes at a time, then drops down to 28 volts for some time. The idea is that it doesn't keep the batts above the gassing voltage for long enough to make them gas. But gassing is not the only issue, right? I know that the positive plates will corrode if you overcharge FLA batteries so I'm not sure if this is really OK or not.

The big Leece Neville is great for pumping power into the batteries whenever the main engine is on, and great for powering the bow thruster and windlass, but it's also nice to get a finishing charge on the batteries when motoring during periods when we're off the grid. I guess the last thing I won't get with the internal regulator, so the question is whether I should hook up the Adverc again, or spend the money on something else.

[conachair]

Originally Posted by Dockhead

What bothers me about the Adverc is that it keeps blasting the batts with 28.8 volts indefinitely -- it has no float regime. .

Always wondered how the cars and vans cope with this, aren't most regulators set to 14 point something these days? Newish Beta I have is set 14.6v so I've never bother splashing out on an external reg.

[john61ct]

FLA are very robust, just keep the water topped up.

Other chemistries, if the bank is expensive then may be worth buying more precise control.

[kmacdonald]

I'd keep the internal regulator. It will fully charge the batteries even set at 28V but will take a long time. Motoring for long periods at 28V charge won't hurt the batteries either. Long haul trucks do it all the time, even at higher voltages. They shouldn't even consume much water at that voltage.

[roland stockham]

An internal regulator is useless on a sailboat but OK on a motor boat. If the enging is normally running the alternator will work as it does in a car, supplying power to the curcuits and topping up the battery with whats left. In a sailboat with battery that are regularly cycle it will kill the batteries as they will not fully charge in a reasonable time (or often ever). A three step external regulator is a must.

If you regularly anchor overnight in a motor boat you might want external regulation as it will dramatically shorten charging time 3/4hr instead of 8-10 assuming 30-50% discharge.

[Dockhead]

Originally Posted by roland stockham

. . . .If you regularly anchor overnight in a motor boat you might want external regulation as it will dramatically shorten charging time 3/4hr instead of 8-10 assuming 30-50% discharge.

OK, but how is that? Have you read Maine Sail's article? Up until the end of the bulk phase, that is, until about 80%-85% charge, there is no difference in charging time, as the alternator is producing full power no matter what kind of regulation it has.

It's after that where things start to get different. Getting a good finishing charge from a longish motor passage is awfully attractive, though, and I think about re-connecting my Adverc.

[Stu Jackson]

Originally Posted by Dockhead

OK, but how is that? Have you read Maine Sail's article? Up until the end of the bulk phase, that is, until about 80%-85% charge, there is no difference in charging time, as the alternator is producing full power no matter what kind of regulation it has.

It's after that where things start to get different. Getting a good finishing charge from a longish motor passage is awfully attractive, though, and I think about re-connecting my Adverc.

Good reply. The major takeaway from MS's article is that HOW you USE your boat is the singlemost important determinant in the choice of external vs. internal.


I used to have an AutoMac on a puny OEM 55A alternator, essentially a cross between an internally regulated alternator and a newer external one. The AutoMac was there to fool the field and put out more by manually adjusting the field, even though it was called AutoMac. It was a nifty piece of gear for its time.


I replaced it with a larger alternator and a MC-612, and agree with MS that sometimes I'm a trawler with a stick here in BC compared to SF. I anchor out a lot, motor a lot, and use Small Engine Mode instead of belt manager. I've had that discussion many times with MS over on sbo.com. My boat, my choice, I just find it easier to flip the SEM toggle switch than derating my output all the time. It's an operational choice I deliberately made.



I agree, folks should read this important article. One size does not fit all.

[kmacdonald]

Good reply Stu. I agree. It depends and in some cases it really doesn't matter what way you go, only the price goes up with external regulation. The size of the battery bank and alternator also factor in.

[Pizzazz]

I had a Balmer external regulator on a 50A Hitachi alternator for a while. The benefit was that the external regulator would increase the charging voltage to 14.4V and allow faster charging in the final minutes of the Accept stage. I never got to the float stage because I do not motor long enough.

Later, I got an 80A aftermarket alternator, set for 14.7V which goes down to 14.3-14.4V at the batteries (voltage drop, I guess). I have not bothered to modify the alternator and connect the Balmer charger.

I think we just have to accept that on a typical sailboat, we would rarely, if ever, run the engine long enough to justify a regulator. However, make sure that the alternator you have is set to 14.4V. If not, replace the alternator.

You say 28V, if this is measures at the batteries, it is probably OK but if you find an alternator set for 29V, it would be better, I think. A simple off switch can be used in case you need to do a long upwind leg under engine.

The other point to consider is that the electronics of an external regulator cost less than $10 in bulk. It would not be so hard for builders to have this capability built in. Yet, I am not aware of a single boat/engine manufacturer that offers this option.

[lateral]

Originally Posted by Pizzazz

I had a Balmer external regulator on a 50A

You say 28V, if this is measures at the batteries, it is probably OK but if you find an alternator set for 29V, it would be better, I think. A simple off switch can be used in case you need to do a long upwind leg under engine.

+1 but use the Adverc to get 29.4v. Or get an ext reg with more configurability.

[roland stockham]

An external 14.4v regulator is not what I think of when talking about external regulators. Think more 3step charger. Bulk phase will be 14.8v. Compared to a 14.4v charger that will give more than twice the current. The issue with bulk charge is that as the battery approaches 80% it will self limit the current depending on the voltage so by using 14.8 instead of 14.4v you can maintain full alternator output far longer.

Once 14.8v is reach the 3 step charger will maintain a high output for a preset time before dropping to float at 13.8v. This means the last 15% of charge continues to take less than half the time it would at 14.4v.
Once charging is complete it drops to 13.8v. This is a safe voltage to maintain the battery at full charge without gassing or eroding the positive plate connections. 14.4v is OK but not ideal
With a 3 step regulator int a 400a/hr battery and a 85a alternator you can generally get from 60% to 95+% in 3hr and will see about 30a at the end of the bulk phase dropping to 15A at full charge. At that point a 14.4v regulator is probably giving around 15a and will drop to 5a or less at the end of the the charge. Effectively this means it never gets to 100% and is why so many people only get 3-5yr life from FLA batteries instead of 10-15yrs