Mark Grasser alternator

[daletournier]

H all, ive just added a Mark Grasser 100amp alternator with matching smart regulator.

Battery bank is 440amp/hr. I find the alternator fluctuates output quite alot. It will hit 60 amps for a little while and then drop down to 20ish and then back up. Is this normal?

A balmar I had on a previous boat didn't jump around as much, wondering if this is hear sensor related, regulator algorithms being more conservative?

Its doing its job but behaves differently from the previous balmar.
I did worry the previous Balmar got to got hot.

Cheers Dale.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[john61ct]

Do you have any loads running that may be fluctuating?

Test for a while with no loads on the target bank.

[Mark_Grasser]

Dale,
A few possibilities. What is happening is related to temperature of the alternator affecting the regulator output. The regulator is set pretty conservative and cuts back output at about 220 degF. The alternator is easily capable of 275 degF. My recommendations: Run the engine a little faster for better fan speed, better cooling. Move the temp sensor to the side of the alternator away from the output stud. Try these two things and let me know. You will get better response contacting me directly at mark@markgrasser.com
Mark Grasser

[a64pilot]

I too have a mark Grasser alternator, a 125 amp.
First I'll say from what I can tell it's a very first class product, I am well pleased with it. However the regulator is a little too conservative in alternator temp, and mine would drop to float prematurely.
However for the price, it's an excellent buy.
I got a deal on a Balmar 614 and went that way, consigning my other reg to spares.
However Mark, I have heard rumor that you will soon be coming out with a much better upgraded regulator?
Is it too soon to ask about it?

[Mark_Grasser]

Being careful not to upset the administrator of the list, yes, two new regulators, a 20 amp and 100 amp Bat to Bat, all this year. Starting April 15th there will be notices on our web page about new device specifications and availability. Mark Grasser - DC Power Solutions

[daletournier]

Originally Posted by Mark_Grasser

Dale,
A few possibilities. What is happening is related to temperature of the alternator affecting the regulator output. The regulator is set pretty conservative and cuts back output at about 220 degF. The alternator is easily capable of 275 degF. My recommendations: Run the engine a little faster for better fan speed, better cooling. Move the temp sensor to the side of the alternator away from the output stud. Try these two things and let me know. You will get better response contacting me directly at mark@markgrasser.com
Mark Grasser

Thanks Mark, will do.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[DeepFrz]

Try mounting a fan blowing air on to the back of the alternator and see if that helps. There was another thread a while back of a vetus alternator that wasn't putting much out and the owner found that air flow was very restricted. He added a blower and his alternator produced much better power.

[daletournier]

Just to follow up. Ive followed Marks suggestion and moved the temp sensor wire to other side of alternator casing, its now working perfectly. Thanks Mark, I love stuff that works great.
Cheers Dale.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[darylat8750]

Thanks for the thread. Good information as I'm soon going to be putting a new regulator on my alternator that has a heat sensor.

[Keelhauler]

Hey Guys, anyone know if Mark Grasser is still in business? His website is no longer up and phone is not in service.
We were have new serpentine pulleys being machined up. Put half down to start the project. Just try to call to get an update and the phone number is not in service.

We hope all is well with him but are a bit concerned now? Does anyone have any news?

Thank you,

[Keelhauler]

Pheeewwww good news. Mark is well and all is good. A bit busy with all the work. Thank God cause he is the best there is.

[fxykty]

We bought externally rectified alternators and flat belt pulley kits from Mark about a year ago, with delivery 8 months later. Very good to work with and he responds promptly to emails. The pulley kits he made were new for our engine (Nanni 4.150) and fit perfectly. We can highly recommend his products.

We already had MC-614 regulators and the new alternators work perfectly with them.