Yanmar (Hitachi) 80amp alternator output question

[Fortyeighter]

I noticed that my batteries were not charging very much after running the engine several hours between anchorages. This boat is new to me, and I never paid attention until recently. After 3-4 hrs running at 2600 rpm, my house battery bank would only charge about 4-5 %
I have 2 8D batteries (house bank) and the Hitachi 80amp alternator with no regulator. Batteries are fine as they charge without issue with 110 / battery charger. At this point I'm just curious if I have an issue or not.
Thanks in advance

 

[SEMPERAVANTI41]

Did you check the voltage of the house batteries before and after running the engine? How do you know the percent of charge? How do you know the alternator has no regulator?

 

[Rick486]

I noticed that my batteries were not charging very much after running the engine several hours between anchorages. This boat is new to me, and I never paid attention until recently. After 3-4 hrs running at 2600 rpm, my house battery bank would only charge about 4-5 %
I have 2 8D batteries (house bank) and the Hitachi 80amp alternator with no regulator. Batteries are fine as they charge without issue with 110 / battery charger. At this point I'm just curious if I have an issue or not.
Thanks in advance

Back in July my generator was down for a couple of days while I was waiting for a part. I believe I have the same alternator you have and I was trying to charge my batts (3 6D house - 1 6d start) and it was tough. The hitachi only puts out around 13.4 or so volts - takes forever too charge.

 

[artboas]

Back in July my generator was down for a couple of days while I was waiting for a part. I believe I have the same alternator you have and I was trying to charge my batts (3 6D house - 1 6d start) and it was tough. The hitachi only puts out around 13.4 or so volts - takes forever too charge.

The alternator has an internal regulator. It's a very simple one, and doesn't have bulk, absorb, float stages.
For larger battery banks it is limited

 

[Gunni]

I noticed that my batteries were not charging very much after running the engine several hours between anchorages. This boat is new to me, and I never paid attention until recently. After 3-4 hrs running at 2600 rpm, my house battery bank would only charge about 4-5 %

Yeah, so you maybe have a 450Ah house battery being charged by an alternator that is putting out 25 amps. Add in charging loss, battery acceptance, and you will quickly come to the realization that your mobile charging source is not up to the job.
read this: http://www.pbase.com/mainecruising/automotive_alternators_vs_deep_cycle_batteries
Google Balmar.

 

[Stu Jackson]

The alternator has an internal regulator. It's a very simple one, and doesn't have bulk, absorb, float stages.

so you maybe have a 450Ah house battery being charged by an alternator that is putting out 25 amps. Add in charging loss, battery acceptance, and you will quickly come to the realization that your mobile charging source is not up to the job.

Google Balmar.

Here's Maine Sail's original writeup about Hitachi alternators. Save yourself a lot of looking on Google:


Hitachi/Yanmar Alternators: (by Maine Sail)


Some alternators though, such as those made by Hitachi and found on Yanmar diesels, are dumber than a pound of beetle poop. Actually, to the alternator, they are pretty smart but to your batteries and the speed of charging they are flat out stupid. Why?

Hitachi alts with dumb regulators, and some others, 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. Remember voltage is the pressure that allows more current to flow. So, if we reduce the absorption voltage, then we also reduce the current the alternator is supplying.. The battery simply will not accept the same current at 13.4V that it did at 14.4V and as a result the alternator will run cooler. What do you suppose this does to your batteries over time.......?

The problem is that when cold you will get 14.3V to 14.4V out of the Hitachi but as the alternator heats up the dumb regulator begins to reduce the CV/voltage limit based on the alternators internal temperature. It is not uncommon to find a Hitachi alternator at 13.4V when hot. This is REALLY, REALLY DUMB....

If you have a dumb regulator, and notice the voltage dropping, it is likely a temp compensated dumb regulator. Get rid of it or plan to buy new batteries more often.

If you have a temp compensated alternator or a Hitachi alternator on a Yanmar you really are in dire need of external regulation if deep cycling a larger battery bank.


This is from:


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


and these, too:


http://www.cruisersforum.com/forums...d-smart-regulator-instal-question-125843.html





http://www.cruisersforum.com/forums/f14/most-practical-way-to-upgrade-yanmar-alternator-142083.html

 

[Fortyeighter]

Thanks all! I did notice that it was only putting out 13 amps, so looks like its working as expected- but inadequate. I did speak to the Balmar rep at the boat show and got some good information.

 

[Stu Jackson]

I did speak to the Balmar rep at the boat show and got some good information.

IIRC, Maine Sail's website has some alternatives to the "pricey" Balmar. Good luck.

 

[Gunni]

I just did the full alternator upgrade - Balmar 60 series 150 amp (fits the Yanmar engine mount) and serpentine belt with coaching from Maine Sail. Couldn't be happier with the results (and the amperage!)

(anyone need some free Yanmar 4JH3e OEM drive belts? )