This is a premium high performance "small case" alternator and it is Denso hairpin based. For a small case alt these do quite well. When ever possible, when charging massive banks, it is best to fit a large frame alternator designed specifically for heavy duty applications. The alternator pictured here is a 165A Balmar hairpin wound alternator. Its performance to size ratio is extremely impressive but you may not need this level of performance.



Despite everything I have just written the answer may actually be; no you don't. What you need will depend largely on use, bank size and desired daily Ah use when compared to maximum desired daily engine run time.


What should I do if I have a?


Dumb Regulator W/Low Voltage Set Point - If you have an old 13.6V - 13.8V regulator, and wet cells, ditch it and get a regulator that is a minimum of 14.2V - 14.4V or even 14.6V and you will charge a lot faster. Battery gassing generally begins above 14.3 volts, though is temp dependent, so a dumb reg that does 14.5V - 14.6V will cause your batteries to need water added more often. 14.4V would be better maintenance wise but 14.6V will charge even faster and is arguably going to fend of sulfation better. If you are a coastal cruiser doing 40 engine hours per year this is a perfectly adequate option. Best case here is to convert to external regulation.


Dumb Regulator - (Non thermistor model) This can do fine provided you have minimal voltage drop in the system and it regulates to around 14.4V or so and matches the absorption set point of your batteries. While a single absorption voltage is arguably less than ideal if you are not a full time cruiser an arrangement like this can work perfectly fine. Be aware that with a large bank you can literally burn up a "dumb regulated" alternator because it has no self protective features.


Super Dumb Regulator - (temp compensated) If you tie to a dock after each sail and shore charge, you can probably keep this alternator. If you actually cruise regularly, & deeply cycle the batteries convert it to external regulation or upgrade to a higher performance alternator & regulator.


Voltage Sensing Improvements: On top of the voltage gradient issues stock alternators usually suffer horribly from voltage drop issues between the alternator and battery bank. Many stock alternators can be set up or wired to provide external voltage sensing at the battery terminals as opposed to the back of the alternator itself. Please do not try this if you don't know what you are doing. Any good alternator shop can help you with this and it can make a big difference in charging performance. The only accurate way to get accurate voltage sensing is for the negative regulator lead and the positive sense lead to be direct wired to the battery bank.


How Do I Measure The Voltage Set Point Of My Existing Regulator?


With the batteries at 100% state of charge run the engine and test the voltage output at the B+/Output terminal of your alternator with the DVM neg lead to the case or neg terminal of the alternator. The voltage should be somewhere between 14.2V & 14.4V but I would not go much above above 14.6V with a "dumb" regulator. Many regulators on Universal engines were factory set at 15.0V to try and compensate for the horrible factory wiring.