55 amp alternator to an 80 challenge!!!

[motretu]

be aware that as you increase alt capacity, more belt power is required. this can lead to early belt failure from slippage. i installed a balmar 100amp alt on a yanmar 2qm20 [stock alt was probably 30amp] and had to have a special crank pulley built [$200] to accommodate a fatter belt [i still have that pulley if anyone is interested, bolts onto existing crank pulley]. although external regulators can sometimes be programmed to do a slow ramp up, in my case that did not help.

[Martkimwat]

Originally Posted by motretu

be aware that as you increase alt capacity, more belt power is required. this can lead to early belt failure from slippage. i installed a balmar 100amp alt on a yanmar 2qm20 [stock alt was probably 30amp] and had to have a special crank pulley built [$200] to accommodate a fatter belt [i still have that pulley if anyone is interested, bolts onto existing crank pulley]. although external regulators can sometimes be programmed to do a slow ramp up, in my case that did not help.

I second this. I believe Nigel Calder and other aficianados say that 70 Amps is about the limit for a single belt pulley system. Above that you need to go to twin belts (a pain to match) or a serpentine type belt such as is used on modern cars (multi groove)

[Lepke]

If you can mount it, a General Motors CS144 alternators are easy to find and put out 140 amps stock. To get proper charging you need an after market external voltage regulator. Several on the internet. I have a CS144 on each of my mains and another converted to 48 volt for house banks.
At 140 amps you need two belts or a wide belt to transfer that much hp.

[Dave Lochner]

Originally Posted by motretu

be aware that as you increase alt capacity, more belt power is required. this can lead to early belt failure from slippage. i installed a balmar 100amp alt on a yanmar 2qm20 [stock alt was probably 30amp] and had to have a special crank pulley built [$200] to accommodate a fatter belt [i still have that pulley if anyone is interested, bolts onto existing crank pulley]. although external regulators can sometimes be programmed to do a slow ramp up, in my case that did not help.

The Balmar Smart regulators have Belt Manager feature. It controls the field current to reduce resistance thus reducing wear on the belt. The Balmar ARS-5 also has a soft start to take some of the stress off of the belt.
Balmar Voltage Regulation Technology | Balmar

[fritzdfk]

I put this alternator on my Yanmar 3HM from pbase.
https://shop.marinehowto.com/product...ally-regulated

Along with a external regulator both purchased from him. Single belt and slightly downrated with the regulator. It works great.

[tml]

Go with the serpentine belt. Tried cog belts, dual belts etc for years with various alternators. Result was always the same. Anytime alternator was over 75 amps it ate the belts every 50 to 75 hours after a continuous messy output of black dust and would produce over 50 amps only when the belt was tight, and in reality probably over tight.
When we repowered ordered the Yanmar with a serpentine belt. Belts will now go 1500 hours plus and easily drive 100 plus amps.No belt dust.
TML

[kenbo]

Originally Posted by pcmm

You can pick up an 80 or 100amp hitatchi replacment alternator for around $100, find yourself a Pro-RegD external alternator and their instructions actually show you how to modify the alternator for external regulation. Its really simple in reality, just need to solder a couple of wires onto the brushes (you don't even need to remove the internal regulator, its that easy!) lead them out of the case and connect it up to the Pro-regD. That's the hardest part. follow the instructions and you'll have an 80amp externally regulated alt with internal reguolator backup for probably less than $200 if you keep an eye out on ebay and the like for a Pro-RegD

That's what I did. all the Original yanmar connections still fit too!

The issue I have with wiring the Sterling ProRegD the way you have described it is this. The two voltage regulators are wired in parallel. When the ProRegD finishes absorption and falls to float, then the internal regulator takes over and goes back to it's set point, whatever that is. In essence you don't have a 3 stage external regulator at all, you're constantly at absorption voltage. I don't have a problem with this necessarily but understand ,you are not getting what you think you are getting in a 3 stage regulator.

Now if you install a SPDT switch to power both regulators, external and internal, one at a time then you have what I believe you have what are looking for.

[glcalahan]

Good information! Thank you!

[01kiwijohn]

I don't think I would be rewinding stuff.
I did a similar conversion and it has worked well for the past 6 years. I have 4 T105 Trojan batteries.
Bought an 80 A Yanmar foot alternator from BD Electrical (they're on line and based in SE USA. Kentucky??) Anyway, delivered to my house, less than $100. I married that to a Sterling, remote regulator (you'll have to follow their instructions and wire the brushes correctly. Not a big job if you know a little about electrics and can solder properly. Mark Grasser alos makes a similar regulator, and his has a "push to float" feature. Both regulators have "soft start" which makes it easier on the belt. With this set up you don't need to go to double, or serpentine belts either. This will also be a big help on your, smaller, engine as it won't kill it when initially starting up.
One other thing; since you'll be charging at a higher rate, for a longer period, up-size the alternator output wire that connects to the starter solenoid/ main positive lead, to about an 08 or 10 gauge. (Mine just started to melt the insulation off the first 2 inches of this lead. That little 14 Ga wire temperature can get up over 130 degrees F pretty quickly).
My wife and I live aboard for 5 or 6 months each year so it gets plenty of use.
If you need any help, let me know and I'll do what I can for you.

[01kiwijohn]

I'm not sure that's correct. Contacting Sterling, they informed me that their regulator basically tricks the original into maintaining full output. If it fails, the original regulator takes over. It'll still charge, at the original rate, just takes a LOT longer.

[01kiwijohn]

Depends on the belt size; A 3/8" belt will handle an 80 amp alternator quite well. If you go to 100A, then you're getting into more expensive territory

[glcalahan]

Thanks for the offer/help! I am in N. Fl......St Augustine.

[01kiwijohn]

Ah one of my favorite spots.
ANyway, if you have any questions, or need pictures/ sketches, just let me know. I've help a few others out with this.