alternator replacement E34

Ah, the joy of upgrading your batteries from wet to AGM, and expanding the size of your housebank (to 400 ah)....The orginal alternator for the universal 25 on my Ericson 34 is no longer helpful. I'm looking for a good alternator replacement (size around 100 Amps) with smart regulator. Anyone good suggestions for which brand to go, and good places to buy? Did you have to go custom made in order to fit a larger alternator, and any adjustments to the belts/pulleys needed?

Thanks for the help,
Jolanda
Ericson 34 Lena
Berkeley, CA

Replacing with the old with a new, larger alternator.

Jolanda, Keep in mind that any alternator significantly larger than the factory one on your Universal 25 WILL draw horse power from the engine. How much is a function of the comparison between the output of your original and the one you decide upon. Years ago I read an article in Practical Sailor (still subscribe after all these years) that described a fellow going into his local small town auto parts store to order a Balmar or some such 100 amp alternator. The guy behind the counter persuaded him to buy a rebuilt GM diesel bus alternator of the same output value at a fraction of the Balmar price. This small morsel of food for thought brought to you today by, Glyn Judson, E31 hull #55, Marina del Rey, CA

All alternators are not the same

Please remember that alternator made for the auto industry generate sparks too. Not a problem in a open engine compartment in a parking lot. Sparks could ignite any fumes that are waiting in the bilge. I agree with the idea of not over loading your engine.

ml

"More Power!"

We have a marine alternator/starter shop in our fair city that has been routinely changing "stock" alternators like my Motorola 55 over to external regulation for a couple of decades.
If you want to switch from your 55 up to 75 or 90 amps, you might look for a local firm that does similar work for a reasonable price, starting with a different core, though.

If you want a "marine" purpose built alternator, I believe that one of the regular contributors on this site, Guy, has put some excellent commentary into several prior threads. (I do not know which threads, just off hand... some searching is in order...)

Let us know what you decide, since a lot of us have the same diesel as you.

Best,
Loren

Thanks for all your quick replies! Some more reading, studying is in order here, and yes, i will keep you posted on my decision. First thing to do tomorrow is find out if my current motorola 55 amp alternator can safely charge my AGM's at the moment. Any thoughts anyone?

Jolanda

Jolanda,
I believe that I understand where you got the "100 amp" idea. That's the old rule of thumb for the ratio of charge max to house bank size... i.e. 25%.
I'm also remembering, dimly, that that particular rule dates from wet cell days... and so am now wondering if the different charge acceptance rate of the AGM would call for a different size alternator.


As to getting by with the existing 55 amp, I would imagine that the recharge times would be longer, but nothing would be harmed, other than increased engine hours adding up if you anchor out a lot.

Anyone else? Class? Bueller?!


LB

ps: do some searching on this site for Alternators, batteries, and similar... lots (!) of threads to study.

Sparky alternators.

Mark and all, When I had the 30 or 35 amp factory alternator from my Yanmar 3GM rebuilt several years ago the technician when seeing it and when told what it was from, said something like, "Oh yah, a Mitsubishi alternator, they make them for all the Japanese cars". I could be wrong about the brand name but you get the idea. That spurred me to ask him to see if it had any sort of spark arrester inside and when I returned the next day to pick up the very same one I had dropped off, he told me that it was identical inside to every other automotive alternator he's worked on. This leads me to think that an alternator on a diesel engine just might not be spark-proofed, or at least not on Yanmar engines. Glyn Judson, E31 hull #55, Marina del Rey, CA

Mark Le Feber said:

Please remember that alternator made for the auto industry generate sparks too.

Click to expand...

I bought an alt once from a local shop, and told them it needed to be ignition-safe. They installed a fire screen in it for no extra charge.

We put a 70A alternator with a smart regulator on our 24hp motor with no noticeable problems. It was as big as I thought safe without having to jump up belt and pulley size, and plenty big for our relatively meager needs.

I realize this may not apply directly to your situation but two rules of thumb that Atomic 4 guru Don Moyer uses are that an alternator pulls 1HP for every 25 amps it produces, and that a 3/8" belt is acceptable up to 100 amps, at which point you need to go to 1/2".

His alternators are made by API, whom I found very helpful after calling them yesterday on a question about a pulley:
http://www.moyermarine.com/cgi-bin/...all&template=Templates/B000_storebuilder.html

I got what I think is a great deal (used) on the API 120-amp alternator he sells, and am about to mount it. Turns out that at Atomic 4 RPMs, the 120-amp alternator will probably never see 100 amps so at Moyer's suggestion I'm sticking with the 3/8" belt. He's got the same alternator and setup on his boat.

A couple of years ago I installed a 100 amp Balmar with a smart regulator on my '88 E34. I found that the stock alternator just couldn't keep up with the battery usage and after 3 days or so sailing around with a little motoring I needed to find a marina to plug into to recharge the batteries. That is no longer necessary. I run three Rolls house batteries and a starter.

I toyed with the idea of upgrading the original alternator but was talked out of it on the basis that the Balmar would be more robust, i.e. heavier bearings, better cooling, etc. I have to agree. Yes you will notice the engine working when the alternator is working hard, but I don't think it knocks me down more then a 1/2 knot and for not much more then a hour.

A note on the Balmar. The 100 amp uses a 1/2" belt, the pulleys on the 25XP are 3/8". I am running a 1/2" belt through the 3/8" pulley without a problem. You will have to fabricate a new support arm for the alternator, don't buy the "universal" arm they sell [I have one for sale] as it won't work on the 25XP, you'll need to have one made. The smart regulator is a must.

If you are not electrically inclined I'd suggest having someone who is install the regulator and set it up. It's not hard to install, but one wrong wire on the wrong terminal and you are buying a new regulator

Look in the archives there are many posts on this subject.

You can convert...

You can convert your stock alternator to external regulation. I have owned three of the M-25's in different boats and the max current I ever used is 90 amp due to the belt size.

Read the article bellow and it will show how to convert to a 90 amp alternator on an M-25 for a lot less money than a Balmar.

If I was to do it again, and I had AGM's, I'd simply buy an external regulation plate from Leece-Neville through Ron's Auto Electric and upgrade my stock alternator and be done with it. You will also want to use alt & batt temp limiting and current limiting with AGM's.

If you want a bigger alternator (read not really necessary in many instances) the Leece-Neville's stock regulator is adjustable so you don't fry your batteries by over charging them.

I've had two Balmar external regulators fail, older ARS regs but since those not a single one. The stock adjustable regulator that comes standard on the Leece-Neville is a simple little regulator and it works ok.

Our current boat spent five years as a full time live aboard, on the hook, cruising vessel using her stock 55 amp Westerbeke alternator and one 80 watt solar panel.

After much experience, with many alternator upgrades, I have discovered that it's mostly a very successful "marketing gimmick" and in a number of situations, but not all, and much of the time, these large alternators and fancy multi-stage regulators are not totally necessary for a weekend warrior.

I've physically compared a Balmar multi-stage regulator to the Leece-Neville pictured bellow, on the same alternator, on the same boat, and at a 50% discharge the difference getting back to 90% was about four to six minutes.. They both charged at the same rate. The only reason I did this comparison is because my ARS-4 failed and I had to swap out, and convert back, to the stock Leece-Neville regulator while I was patiently waiting for the Balmar replacement. I was curious if there was a difference so I measured it. I don't know to many other folks who have actually physically compared a "dumb regulator" to a "smart regulator", using the same alternator, to even know the difference or lack there of.

P.S. You can also buy the exact voltage regulator, pictured bellow, from Leece-Neville and bolt it to your existing alternator, and adjust the max output to match your AGM's, for pennies of what it will cost you to go to a Balmar.. Just know that if you run long enough your AGM's should eventually float and this reg won't do that.

Universal Diesel M-25 Alternator Upgrade



Leece-Neville adjustable voltage regulator:

After seeing Maine Sail's web based story about his Leece-Neville (Prestolite) alt. upgrade, I went that route also. I am happy with the results with only the built in regulator that he pictured here on the rear of his alt. I spent only about $167 for the 90 amp marine grade alt (regulator included) plus $7 for a pulley. There is another thread where I put some links in with specs & explanations. Search for Prestolite & you'll find it.

We have been happy with Ample Power
and have a house bank and alternator output on our E34 like the one you are planning for yours.

If you're pretty sure about your 400AH figure, you would be relatively safe but marginal with your 55A alternator, and you'd definitely need the Balmar smart regulator for AGM's. A 90A alternator would do very nicely...same brand.
Howard Keiper
Sea Quest
Berkeley

I don't disagree with Maine Sail that his "stock" L/N regulator might charge to 90% as quickly as a Balmar unit - but as I understand it, that's not the reason you buy the electronic, multi-stage regulators in the first place. I think you get your money's worth when you don't overcook the batteries! It's the way they top up the charge to as close to 100% as possible without boiling your electrolyte out and shortening the useable life of your batteries. Just my two cents worth.

Mike.Gritten said:

I don't disagree with Maine Sail that his "stock" L/N regulator might charge to 90% as quickly as a Balmar unit - but as I understand it, that's not the reason you buy the electronic, multi-stage regulators in the first place. I think you get your money's worth when you don't overcook the batteries! It's the way they top up the charge to as close to 100% as possible without boiling your electrolyte out and shortening the useable life of your batteries. Just my two cents worth.

Click to expand...

I would have to agree with Mike on this one. I went the Ample Power way with a complete package. If I had it to do again I would do a Leece-Neville with an Ample or other regulator. Spend the money on the regulator especially if you are doing AGM's or gel's. The whole point of the "special" regulator is that it is gentler on the batteries over time, hopefully increasing their lifespan. A single stage regulator can easily put out plenty of juice but it won't know when to back off at the end of the charge cycle to keep from cooking the electrolyte off. Just my 2cents, RT

I replaced my house bank with two 225 AH AGMs two years ago. I tried to run them with the 30 amp alternator on my Atomic 4. It didn't last long. I took it to a rebuild shop- they shook their heads when I explained how it was being used. Your existing alternator will run too long and get too hot. I installed a Maxpower high output marine alternator - 125amps. I bought it on Ebay for about $200 dollars. It runs using the 3/8s belt but I had to buy the kevlar belts from NAPA. They're more expensive but can handle the load. I use a Xantrex R2000 regulator. I have no worries with this system- lots of power, it charges quickly and it runs safely.

For the record...

They both charged at the same rate +/- .1% in the float stage.

Click to expand...

I read Maine Sail's post, composed an answer, and deleted it. I couldn't do it politely.

If anyone is contemplating upgrading their electrical system there are lots of posts on this site that do a good job of explaining what is needed. Pick any manufacturer you like, but make sure you get competent advice on how to design your system to do what you need.

Thanks again, everyone, this is a wonderful community! I wil keep you posted how I end up installing my system.

Jolanda

"OK you kids, don't make me pull over!"

...It's only another 20 miles to the next rest stop... Gotta hold on...
[heavy sigh]


Loren

ps: the next stage: http://www.youtube.com/watch?v=teMlv3ripSM