External regulator?

Don12364 · Apr 25, 2011

Two possible approaches: Yes a smart regulator will make a marked improvement in keeping your batteries up with the limited amount of engine running you expect.
And, you will sometimes run low no matter how neurotically you try not to use battery power. Anyway why make life miserable just in the name of saving electricity?

The job of 'converting' the alternator is very quick and simple and any competent person could do it given the instructions contained in the smart regulator kit.

Alternatively you could fit an 'Adverc' system which does not require replacement of the alternator's existing regulator but overrides it. One only needs to bring out a single new wire from inside. This has the benefit that, should the 'smart' regulator fail then the original regulator will take over as before.
See http://www.adverc.co.uk/
Also http://www.adverc.co.uk/cm/files/pdf/MARINE_BROCHURENEWFULL.pdf particularly questions 13-15.
Good luck with your intended voyaging.

Maine Sail · Apr 25, 2011

Roger Long said:
Next question in my never ending quest to bankrupt myself.

My alternator is coming off soon to rebuild the mounting. 55 Amp alternator, 158 Ah battery bank, very light electrical usage, expensive AGM batteries that have lasted well enough to suit me.

Should I be thinking of having the alternator converted to an external smart regulator? If I ever do draw the bank down low, I'm willing to keep in mind that I may need to idle for a while and then motor slowly for a period of time and not just go go charging off at full RPM. With my re-pitched prop, normal cruise RPM will probably be only about 2200 anyway. I'll still try to get 1/4 to 1/2 hour at 2600 daily but I usually do that near the end of a power run when the engine is good and hot and I'm ready to be there.

With your batteries in the engine compartment (read HOT), and being AGM, an external reg is not a bad idea.

If you want a good understanding of how VR's work that you won't get from the "marketers" feel free to read this: Musings Regarding External Regulation

Rich Stidger · Apr 25, 2011

Roger,

Another consideration-

I agree that an external regulator will give you the ability to drive the alternator harder to recharge faster. However, I would consider the capability of the alternator itself for such service.

I suspect that your OE 55A unit is the 'normal' automotive-type alternator with a single external fan next to the pulley. If so, it is probably rated at 55A peak current when cold. 55A peak current translates into about 70% of 55A or about 38-39A average DC current. This value is de-rated when hot, so you might expect only about 30A of DC current maximum when the alternator is hot.

Using the standard internal automotive-type fast taper-off regulator, the drive to the alternator is relatively low as compared to an external regulator and thus the alternator will not generate as much heat as with an external regulator that is keeping the alternator drive high.

Alternators that are designed for high current output are constructed quite differently. They use internal fans and two of them- one on each end to push and pull the cooling air through the case. The windings are much more robust and the actual rating of the alternator is for full DC current when hot.

So, what to do? If you install a temp sensor on the alternator, the external regulator will back off the drive as the case becomes very hot. This is the minimum that you would want so that you protect the alternator from over-heating and failure. Beyond that, if you could provide some external cooling air directly to the alternator, that would be beneficial also. If you have an automatic fire extinguisher in your engine compartment, be careful as you can heat up the compartment hot enough to trip the extinguisher. Been there, done that.

My two cents- since you claim that your electrical demand is modest, I would look at installing a single 135W solar panel. I think that you will run your engine enough on your cruise to keep the batteries charged and that a solar panel will provide the extra kick to your batteries without burning more diesel.

There. Have I spent enough of your money yet?

Maine Sail · Apr 25, 2011

Roger,

Your LR-155 is regulated to 14.3V (+/-0.3V) so the 14V you measured could be within the "range" of +/-0.3V for that regulator. A regulator pushing .4 v more could certainly increase your charging speed if you are in fact not seeing the 14.3V or more at the B+ terminal with a 100% charged bank.

I have seen plenty of the LR series alts externally regulated and they do okay. Your bank is small so you'd do fine, especially with temp sensing. I have a 80A Yanmar on my bench that suffered a dead short to ground but it regularly put out 75+ amps when the batts were low, even when hot...

Bill Roosa · Apr 25, 2011

with only 158 AH in the batts why even bother. the max charge acceptance is only about 30% of the AH of the bank or 158*.30=47.4 amps. going to a "bigger better" anything is not going to do anything noticable except drain your wallet.
Yes, you do get that 2 minutes of "ramming speed" charging but the batts quiclkly put a stop to that.
IMHO you would be better served (read happer) with a modest solar panel.

Maine Sail · Apr 25, 2011

Bill Roosa said:
with only 158 AH in the batts why even bother. the max charge acceptance is only about 30% of the AH of the bank or 158*.30=47.4 amps. going to a "bigger better" anything is not going to do anything noticable except drain your wallet.
Yes, you do get that 2 minutes of "ramming speed" charging but the batts quiclkly put a stop to that.
IMHO you would be better served (read happer) with a modest solar panel.

Bill,

Rogers batteries are not wets, and are AGM, which can take substantialy more current in bulk than wets can. I have physically watched a 110Ah AGM take 85-87 amps from an IOTA DLS 90 the entire 25-30 minutes I watched it. That is an acceptance rate of about 77% but I suspect the IOTA 90 amp charger was what was maxed out..

I still think he got good life out of the previous bank @ 5 years so why mess with the system especially within budget constraints? Yes temp compensation is nice but it's a small bank. If he drains the batts dead he can always limit the alt temp by keeping the revs low until the batts get some charge back into them, thus not cooking the alternator by running it at max output..

Maine Sail · Apr 25, 2011

Roger Long said:
That's the answer I would like at this point but I'm confused because you said temperature compensation would be a good idea.

It is always a good idea, especially when batts are in a hot engine space. BUT you got five years out of them and I doubt that even with temp compensation you'd get a lot more than that so on a purely $$ cost perspective 5 years is good life compared to the slight increases you might see by spending upwards of $400.00 by the time all is said and done. $400.00 is more than an entire new bank so if you got one extra year it would still take many years to recoup the expense and upgrade costs.

Roger Long said:
Bill, I'm not trying to increase charging speed but avoid cooking my alternator.

And that can be done by not allowing the alt to spin at an RPM that would see it producing it's max output. The throttle can be your temp compensation if necessary. Yes, you will charge slower but also not risk burning up your alt recovering a dead bank by running at full cruise RPM.

Roger Long said:
Now that I have a battery monitor and more knowledge about how these things work, it seems like a direct reading temp gauge on the alternator case would keep me out of trouble. If the monitor tells me I've drawn the bank way down, I'll keep an eye on alternator temperature as I run. I'm not going to be in a situation where the wife has to be home for bridge and I have to be back at work on Monday so I'll have the flexibility to run at reduced RPM if necessary to control charging rate.

Yes you will have a much better handle on it and if you can find a remote sensing t-stat to attach to the case it will allow you to see trends in your alts temp and know what the norms are.

Roger Long said:
I've run the engine 8 - 10 hours continuously at times and it doesn't seem to have hurt these batteries.

At the stated voltage your alt is putting out it should be fine and 8-10 hours gets you a lot closer to full, even at just 14v. Topping up AGM's is one of the best things you can do to prolong life.

Roger Long said:
I'm still trying to figure out if an external regulator is just a good idea (I know it is) or something that will look a lot cheaper to me way out in the boonies than it does right now.

They are never a bad idea just not always 100% necessary when other projects need to be taken care of too. We already know you can get five years out of your batts with; dumb regulation, batts in a hot compartment and witout even a battery monitor. You may find that with the monitor alone you can increase longevity by knowing where you stand.

I don't run external regulation on my own boat as it is not necessary for our situation which is wets with solar and in a compartment that never gets above 75F or much below 60F and a stock alt putting out 14.4 v.

I am on year five with WAL*MART

batteries and they still test within 3% of when they were brand new (as tested with the battery analyzer) and I just completed a 20 hour test on one of them yesterday where they are still going more than 20 hours before hitting 10.5V.

I am doing this as an experiment to see how many years I can go on $79.00 batteries with, SHOCK

, dumb regulation... OMG it can't be done the dumb regulator will kill your batteries........

Hasn't yet....

Bill1565 · Apr 25, 2011

Not to worry. It will go!!

Don12364 · Apr 25, 2011

Roger,
You say you have a battery monitor so you can see how much current the alternator is putting into the batteries (less any small usage from the instruments etc).
So you will know if the alternator is being overloaded. It is a 55 amp unit like mine on my Yanmar. The charge rate starts at about 40 amps and drops to only about 25 amps after only half an hour or less - and I have 400 Ah of batteries installed.
I doubt you will overcook the alt and the temp gauge would be unnecessary complication and expense.

Benny17441 · Apr 26, 2011

Read an article recently about how these high efficiency batteries accept more charge than the old lead/acid thus causing the alternators to energize for longer periods and overheat resulting in premature failures. It seems like the marriage of new technology batteries with old technology alternators is not such a happy one. I would think a smart external regulator may correct that situation . Rmember the output drops signigficantly as an alternator heats up. New batteries are excellent technology for those that absolutely need them to operate their electrical system but are they really necessary or even a wise investment for those weekend sailors with average electrical systems?

kloudie1 · Apr 26, 2011

Like Benny, I read the Nigel Calder article in the newest Sail magazine..Interesting.. Talks about some alternator makers not warrantying (?) alternators used on AGM's .. Talks about installing a blower to keep the alternator cool enough to be effective..
Good article.

Maine Sail · Apr 26, 2011

kloudie1 said:
Like Benny, I read the Nigel Calder article in the newest Sail magazine..Interesting.. Talks about some alternator makers not warrantying (?) alternators used on AGM's .. Talks about installing a blower to keep the alternator cool enough to be effective..
Good article.

I don't get Sail any more but am glad to FINALLY see the big dogs like Calder bringing this issue to the forefront. I have been railing on this for many years and some have even dismissed it as un-true. I have seen numerous alts cooked by banks of AGM batts.

We also need to keep in mind that any bank that far exceeds the size of your alt in Ah's can do the same. For example a 400 Ah bank of wets can take about 100 amps in bulk. If you have a 35-50 amp alt it can be asked to produce its full capabilities for long periods of time and it too can cook itself wet cell or not.

The best tip is if you begin to smell a funny smell slow down your engine RPM and check the temp of the alt. Running the engine slower will reduce the alts output and allow it to cool off some.

kloudie1 · Apr 26, 2011

Article talked about the advantages of the regulators that sense temp of alt and adjust output to keep from frying the alt.. The temperatures he was talking were allowing the alt to go to 237 F before the regulator started cutting output.. apparently the Balmar allows that to be adjusted up to a max of 248 F..