Second alternator mount

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Second alternator mount

Postby maxmikeb » Mon Oct 01, 2018 9:06 am

I’ve just pulled the trigger on a large case 200 amp alternator from Compass Marine for my ‘74 32 with a single Lehman. I got what I think was a great buy on a what I will use as second alternator to charge my future six T-105 AGM house bank. I plan to keep the original 55 amp alt. to charge an isolated start battery and set up the second alt. as a separate charging system with a three stage external regulator and monitor.
Now comes the fun part- I’ll need to fabricate a mount. I’m thinking I’ll leave the original in it’s place and mount the second alt. low on the starboard side of the engine. The engine already has a 3 v-belt pulley on the crank from a compressor that the original owner had installed at the factory (the compressor is gone). So I’ll use that. I’ll have the alt. built with a two belt pulley.
Does anyone have a picture of a similar setup? I’m a pretty good fabricator so the installation doesn’t scare me. Just looking for ideas for the mount.
Thanks!

(Posted originally in ‘specifications’ and moved here)
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Re: Second alternator mount

Postby Jastafford » Mon Oct 01, 2018 8:25 pm

You going to run those batteries to an inverter for your 110 power? I am contemplating a change in batteries, charger, inverter, etc.
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Re: Second alternator mount

Postby maxmikeb » Tue Oct 02, 2018 6:27 am

Jastaford,
I do plan to install an inverter to run the refrigerator and a small air conditioner for the v-berth in the future. I also see future solar panels to help complete the battery charge.
My plan is to take it in steps. First step is what I consider the heart of the system- the alternator. Super excited about the beast that Compass is building for me.
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Re: Second alternator mount

Postby jmcj » Wed Oct 03, 2018 2:00 am

I mounted a 125 amp alternator on the starboard side of Unicorn’s FL120, leaving the original in place on the port side switched so it can be brought online. Normally it runs as an idler. In any event what you need for the mount is available from American Diesel. I can post photos when back from holiday if you are still interested. In fact I think I’be done so before so a search may turn it up.
Jim McJannet
Unicorn V
1981-633
36CL
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Re: Second alternator mount

Postby maxmikeb » Thu Oct 04, 2018 7:00 am

Jim,
Thank-you for the reply.
I did a search, as you suggested, and found a picture posted by another member.
Question- any issues with belt alignment?
Thanks
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Re: Second alternator mount

Postby FrugalWife » Thu Oct 04, 2018 12:34 pm

I run a single 140A alternator and charge a bank of four 6V T105's and one 8D deep cycle. No issue ever providing enough charging juice and the bank provides 100% of the house power including refrigeration (many of the interior lights are now LED). Yes, three is also an inverter. I pulled the AC generator that powered the original Grunert refrigeration (has been replaced with 12V Frigoboat) and never even considered the need for a 2nd alternator ... that was 10 years ago and all is still well. BTW, the house battery bank is good for at least 3 days anchored out without a re-charge. Why complicate your maintenance life with redundant alternators?
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Re: Second alternator mount

Postby Charlie0 » Fri Oct 05, 2018 5:17 am

We have a 100 amp Balmar and Balmar regulator on the boat with 2 8D’s for the house. Also a Victron battery monitor. I started the engine the other day after running the fridge overnight and the Balmar was giving me 82 amps of charge with the engine at 800 RPM. Pretty impressive.
Charlie O
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Last edited by Charlie0 on Fri Oct 05, 2018 10:22 am, edited 1 time in total.
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Re: Second alternator mount

Postby maxmikeb » Fri Oct 05, 2018 8:27 am

My big concern (challenge) is to provide enough juice to occasionally run a small AC to cool the v-berth and then be able to recharge efficiently.
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Re: Second alternator mount

Postby Charlie0 » Fri Oct 05, 2018 10:27 am

“My big concern (challenge) is to provide enough juice to occasionally run a small AC to cool the v-berth and then be able to recharge efficiently.”

Not sure that you will ever get that out of a battery bank / inverter satisfactorily. Maybe others can comment and prove me wrong.
Charlie O
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Re: Second alternator mount

Postby jmcj » Fri Oct 05, 2018 9:52 pm

There were no alignment issues with the belt but as I was going to use two belts to spin the alternator was necessary to add a double sheave which I also bought from American Diesel. The original belt stayed in place to turn the water pump and old generator which served as an idler but can also be switched to be brought on line if the larger alternator fails.

The new alternator mount replaces the OEM mount on the block and required a shim, actually a machined block, to fit to the flexible mount. Works very well.

At 200amps your alternator is probably a large case. You will need a alternator bracket to fit which will bolt onto the new mount. If alignment adjustment is needed, it can be done there. Good luck.
Jim McJannet

Unicorn V

1981-633

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Re: Second alternator mount

Postby jmcj » Fri Oct 05, 2018 10:04 pm

Further see my post of Feb. 15, 2011 and following with photos and explanations.

Search “+ alternator +mount” with jmcj as author
Jim McJannet

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Re: Second alternator mount

Postby maxmikeb » Mon Oct 08, 2018 12:02 pm

Thank-you, Jim!
I searched as you suggested and found the excellent pictures you posted. Your info will be a big help to me.
And...I also learned some search tricks. :-)
Thanks again.
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