Clarification about the manual's terminology Yamaha 30DEO

[gvp90000]

I have a 2stroke yamaha model 30DEO.
6J8K - L - 1003853
6J8-D0 Model 2004

1. I cannot understand what the service manual means with the terms "circuit" and "loaded" in the charging system chapter.

https://pasteboard.co/GKaRBBA.jpg

2. I've put a new 45Ah battery to my outboard and in 3500 rpm I measure a 12.9V on the battery. Is this voltage low or ok ?
According to the calculation in the picture is ok ... but I need a second opinion.

Before I start my motor the volatage on the battery was 12.6V.

[boscoe99]

Thanks for providing the details about the engine. It helps us help you.

First know that Yamaha service manuals, IMO, are crap when it comes to explaining the product, how to test it, and what values should be seen. I understand your confusion. But, it is what it is.

There are many circuits within an electrical system. An electrical circuit. With respect to the charging system there is first the "lighting coil" circuit that provides AC voltage to the rectifier. Then there is the "rectifier" circuit that provides DC voltage to the battery. The battery cables and the battery are sort of a circuit.

Loaded means that what ever is being tested is connected to the system. For instance, a rectifier connected to a battery is considered to be loaded. If the wiring to the battery is disconnected then it is not loaded. A lighting coil connected to the rectifier is loaded. If the lighting coil is not connected to the rectifier it is not loaded.

The SM is telling you to check the output of the rectifier. See if it meets the specifications at three engine RPM's. There is no comment made about the system being loaded so the inference is to test it in the unloaded condition. That is, not connected to the battery.

For the lighting coil the SM is saying to test it in the loaded condition. That is, the lighting coil is to be connected to the rectifier.

The SM says to check for peak volts. Is that what you are doing? The voltage you report of 12.9 volts seems low. Note that the SM says it should be 20 volts. Maybe the battery is connected or maybe you don't have a meter that measures peak volts.

Since the rectifier output is on the low side did you measure the lighting coil peak voltage output? If so, what were the values?