Balmar 90 and 7 series. What to expect?

[Maine Sail]

Originally Posted by akopac

The current one is a Balmar 91-150-D. Sytem works awesome. Just need a good backup for a rainy day.

This would work: CMI-100-ERM



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[akopac]

OK. This is the exact original alternator.
Balmar Model 9115
Output 125amp
Dual output. I bridged them
This is the current/old alternator manual
https://sbo.sailboatowners.com/downl...n_83982702.pdf

I like the 12SI(better cooling..), but how hard would it be to rewire it to work as a spare dropin with the Next Step regulator? Is there a DN version of the 12? like10DN... Doesthat seem right for having external regulation

[wingssail]

Originally Posted by carlo de leo

Hi folks!

I have to change my original Yanmar Hitachi 80A alternator. I have a 600A bank (service+start) and bump into two Balmars that the vendor says its new but a long time in stock (I think they have some use). Well, I know these two models are not comercialized anymore. The question is if they are going to deliver what they promise, the 90 series is 100amp and the 7 series 80amp or the new ones has much more cost/benefit improvements? The price asked is less than half a new 100amp. Should I buy a new regulator with? Or should I skip this offer and pull the trigger on a new one?

Thanks all! Fair winds!!

I have experience with these two alternators (my 90 is a 90-130 and the 7 series is a 7-110) both with various Balmar regulators over the years. I also have the original Hitachi 80A which came the engine in 1993, converted to external regulation.

The 90 series is my favorite. It runs cooler than the 7 series when the regulator Bulk Voltage is set to 14.7. I can run it for over an hour at about 80A average (starts at 130amps, for a few minutes, but stabilizes at 80A after about 20 minutes) and the temp rarely goes over 90c. This is at 2000rpm on my Yanmar with a 2.5" pully. I have had three of these 90 series alternators in the last 25 years. When one failed in 2012 I bought a 7 series 110. Balmar said the 90 series was no longer available. With the same regulator settings it heated up to over 104c and began to de-rate within 30 minutes. Balmar told me how to increase the temperature setting and I did, to 112c. It still tends to overheat and derate.

I now have had the 90 series rebuilt and I prefer it, however the diodes seem to have failed this time and it has now been removed. Back on with the 7 series, which is OK but won't pound 80A into the batteries for 1.5 hours like I wish it would. It simply gets hot and de-rates.

So I would choose the 90 series if it is good price, in fact I might buy one myself since mine looks to be close to the end of it's useful life. Where is it sold?

[akopac]

Not sure. Haven't tried to buy one yet. Still researching. The cooling part might not be as hard to handle as we might think. I was researching and posted some cooling solutions previously but can't find the thread, but if you google it you find some great cooling duct/manifolds for alternators. I might be going to the junkyard to do some scouting around.

https://www.google.com/search?q=alte...w=1440&bih=719

[Maine Sail]

Originally Posted by akopac

OK. This is the exact original alternator.
Balmar Model 9115
Output 125amp
Dual output. I bridged them
This is the current/old alternator manual
https://sbo.sailboatowners.com/downl...n_83982702.pdf

I like the 12SI(better cooling..), but how hard would it be to rewire it to work as a spare dropin with the Next Step regulator? Is there a DN version of the 12? like10DN... Doesthat seem right for having external regulation

There are no off the shelf externally regulated 10/12Si alternators. We have a dummy-regulator specifically built for us so we can custom manufactured ER alternators, they cost us about 10X what a standard 10/12SI regulator does because production runs are small and hand made here in the US. Dummy regulators for a 10/12SI used to exist, but were discontinued a number of years ago. Unless we could give our vendor an order for 3000 there was no way to get them back into production unless on a custom basis.

I would also not assume the 12SI cools better than a well built 10DN frame. In fact they run considerably hotter than a well built 10DN. Key word here is well built. We build ER alternators on both frames, & hybrids, but the 10/12SI is really quite limited in how much heat the rectifier can dissipate when compared to a custom built 10DN rectifier..

The problem with the 10DN frame today is finding the components to build it like Balmar and Ample power used to unless you find a custom winder and have the tools to assemble the rectifier.

We still build a 10DN based alternator, the CMI-HD125-ER, and the stators are custom wound. The diodes we use are 75A X 400V. Ample Power and Balmar used 50A X 200V, when they built this frame.

You will not find anything even close to this off-the-shelf. Most of the 10DN frame alts today are coming from China with low amperage/voltage rectifiers. This means more heat to dissipate, and with banks getting larger, and larger this is the reason we went to 75A X 400V diodes. It means less work for the rectifier and less heat for the alternator to have to dissipate. If you just need a super cheap spare then a low amp 10DN would be a better choice than a cheaply built 100A+ 10DN..

Off the shelf 10DN's are also not using a real high amp stator that is wound specifically for a 10DN frame. They are using 10SI or 12SI imported, thin-stack, stators that are fitted with extension-leads, basically a butt splice, to make them fit a 10DN frame and this is a point of failure and potential high resistance.

The biggest problem you will have is your Ample regulator lacking alternator temp sensing/protection, unless your bank is small and bulk is short. If you've made it this long your bank is likely not too big.

Back when Ample was producing their high performance 10DN frame alternators, GEL batteries were just hitting the market and most use was for FLA. Banks were also much smaller than today. They could get away with it back then but today we see lots of the older alternators running Ample regulators completely cooked due to over-heating.

[akopac]

Ok. I’ve got a 400amphr bank I’m going to upgrade to fireflys. Will I need to change out the regulator for lack of alternator temp. sensor? I have a cowl with duct&blower exhausting heat off the Balmar 9115 overboard. I will be living aboard and cruising full time in the tropics long term.

[akopac]

Originally Posted by akopac

Ok. I’ve got a 400amphr bank I’m going to upgrade to fireflys. Will I need to change out the regulator for lack of alternator temp. sensor? I have a cowl with duct&blower exhausting heat off the Balmar 9115 overboard. I will be living aboard and cruising full time in the tropics long term.

Think I got it figured out. I do have current limiting