Up dated alternators

[atrick]

Just got my 2018 sierra dealer catalog and was checking it out to see what was new and I see they have a 75 and a 125 amp replacement alternators. Didn't look at what engines them fit but guess the are available for most engines. Just thought I'd throw that out there cause I see people asking about them all the time.

 

[hottoddie]

Two potential issues. 1. If V belt driven you would be limited to aprox. 90 amps before slippage would be a problem. 2. The positive wire to the batteries may need to be upgraded. Good idea if done right.

 

[Bt Doctur]

And I know of no small craft that would even need a 105 amp .You main wiring is #8 that limits you to what your breaker is 50A

 

[Wylie_Tunes]

Engine manufacturers like MP, PCM, Indmar and ilmar have been supplying their engines with 90A alternators in their tow boats for about 10 years. Even these smaller trailer boats (20' to 25') have seen a huge increase in electrical demand in helm system, audio, lighting and other. Dual battery system have been very common for may years.

although the total demand is far less, the larger capacity alternators work less hard then a smaller 55a alternator running and near peak capacity.

Even then, we still suggest an on-board charger to recharge the batteries, rather then rely on the alternator. We find that more Ah is needed, not more alternator amperage.

Yes, if you upgrade the alternator, the main supply feed should be upgraded.