Does anyone have experience with larger alternators (65-80 amp)with the Sabb g-10? Standard was a 35 amp.

Thank you.
Tom Winkler

We have the Sabb G-10 engine with the 35 amp S.E.V original alternator. I replaced the regulator with a Balmar regulator. The 35 amp alternator will deliver about 25 amps continuously when the charging cycle is in the balk charging phase at an engine rpm of 1,200. ?

We are considering a larger alternator. Because each 25 amps of alternator output requires about 1 hp of engine power, the largest alternator we could turn is about 80 amps when we do not need shaft horsepower and 40 amps when we need shaft horsepower.

The Balmar regulator can be set at will to delivery full alternator power or 1/2 power.

If I upgrade, I am considering a rebuilt car/truck alternator. The Balmar alternator is rated at 80 amps at 8,000 rpm. We motor a 1,600 rpm. Even though, the alternator-to-engine rpm ratio is 2-to-1, the alternator can only turn at 3,200 rpm. This is significantly less than 8,000 rpm, hence power delivered may not be much more than from the 35 amp alternator.

I plan to research amps output as a function of alternator rpm for different amp rated alternators.?Any information is appreciated.

On a side-note, the more I understand about electrickery, the less I understand.?

Fair Winds,?Rod

Hi Tom,?

Yes, I have a Sabb 10hp with a 35 amp delco-remey alt.

I tried a 65 amp once (on loan) and it loaded the engine up enough that I could feel the power difference (lack of) when motoring.?I found that for charging batteries on anchor the 35 is enough to put out a steady 20 amps (regulator cut out of the system), but you have to watch not to overcharge.?

How do you like the Sabb? We love ours…hand start only so never worry about lack of battery power.

In pursuing the Balmar site, looking at the power output curves, to achieve the desired 80 ampere your looking for it appears to be necessary to jump up the the 100 ampere range of alternator; using a 2 to 1 ratio pulley to run the engine at 1,200 RPM to achieve the alternator 2,400?RPM and 80 ampere output. You will not achieve the full output capacity of the alternator but you will get the desired output you are looking for.However, with the maximum rated horsepower of the Sabb G-10 is 10 HP and the continuous rating is 8 HP, considering 1 HP/25 ampere of charge, leaves you with 5 HP to make way. This configuration is fine for charging at anchor, but if you attempt to leave anchorage under power with low batteries, the alternator will kick in, leaving you some what under-powered underway.

You could install a simple on/off switch in the field circuit, this would stop your alternator from charging and get back the 3 HP if needed in an emergency.

Best Wishes,
Marty Chin, BCC Shamrock