Installing New Balmar alternator

Benny17441 · Mar 4, 2012

Just keep the 55 amp for a spare as you may need it. Check the archives, there are various postings about the pros and cons of high amp alternators and info on their installation.

Bill1565 · Mar 5, 2012

bugsboat said:
We just purchased a Balmar 100amp alternator for our Yanmar 4JH2E. The original 55amp alternator just does not work for us. The new alternator charges the batteries at idle, not at 1500rpm's. Has anyone else installed the newer alternator? We have great plans for cruising the east coast on the boat and continue to make improvements that will make living aboard easier. We added a stackpac,new mainsail, dinghy davits, replaced most of the running rigging, new 16000btu ac with heat(not reverse air), folding wheel, new st 70 autopilot with linear drive, new ST 60 depth/speed/wind instruments in new navpod with new pedestal guard and more... Our plans are to add a new headsail and electric head in the next year. Any more suggestions???

Go!! sail!! Cruise!! Keep your money in your pocket till you actually experience "need".

When we lived aboard, we had work done and things added all down the river system and up the east coast. Only one bad experience, lots of great folk, good mechanics out there.

Rick D · Mar 5, 2012

Charge RPM

While the Balmar will charge at idle, you don't want to do that. The Yanmar Field Rep recommended an RPM of 17-1800 for battery charging (while not endorsing using the engine to charge batteries with that being the only load). Besides, you will push a lot more amps through, so you will save some charge time. Have fun!

Bill Roosa · Mar 5, 2012

Unfortunately the use of a more than 50 amp alternator would require that you have more than a 200 AH bank and it be deeply discharged or that you have a very high amp device and run it when the engine is running.
So even if bugsboat runs the motor at 1800 his batts control the charge acceptance and that is only about 25% of the total AH storage in the bank max. That would mean a bank capacity of 400 AH. Most of the time we charge our batts at 50% SOC or more and the acceptance is even lower, much lower like 10%.

As you can probably tell I'm not a fan of trying to cure all your electrical charging needs with just a bigger alternator. needs to be designed as a loads-storage-production SYSTEM.

But he will have hot water and that can go a long way toward making things even.

Rick D · Mar 5, 2012

Oh, yea...

Bill Roosa said:
Unfortunately the use of a more than 50 amp alternator would require that you have more than a 200 AH bank and it be deeply discharged or that you have a very high amp device and run it when the engine is running.
So even if bugsboat runs the motor at 1800 his batts control the charge acceptance and that is only about 25% of the total AH storage in the bank max. That would mean a bank capacity of 400 AH. Most of the time we charge our batts at 50% SOC or more and the acceptance is even lower, much lower like 10%.

As you can probably tell I'm not a fan of trying to cure all your electrical charging needs with just a bigger alternator. needs to be designed as a loads-storage-production SYSTEM.

But he will have hot water and that can go a long way toward making things even.

I didn't even think to look at the battery capacity you are planning. In my case, I have about 500 AH. I drop it to 250 - ish before charging (with the engine).

robertsapp · Mar 8, 2012

bugsboat said:
Any more suggestions???

A deep third reef in the main and the rigging to put it in (unless you have a furling main of course). Jacklines and harnesses. Fenderboards on the stanchions to secure extra fuel and water jugs. A drouge of some sort. A riding sail. Another anchor. And then another one to back that one up. A cockpit cover or boom tent and side curtains. Screens for every opening. A place on deck to store the dinghy for when you're transiting. A backup GPS, and some basic navigation tools to allow at least coastal navigation for when the electronics fail. A suitable supply of engine and rigging spares, filters, fluids and consumables. You can never have too many flashlights and batteries. An EPIRB would be nice, and some personal locator beacons if your budget supports it. You might consider a liferaft if you're going to go offshore. Some good foul weather gear. Get the commercial fishing stuff, not the West Marine yaching stuff, as it's better and cheaper, if not as stylish. A couple of solar showers for when the water heater springs a leak. I could go on, but you get the idea. If you want to go cruising, the comfort items are great and make life pleasant, but don't overlook those things that you hope you'll never need, but that might save your boat or your life in those 1% of the times when it all goes to hell in a hurry.

robertsapp · Mar 9, 2012

Outstanding. Best wishes for a wonderful voyage!