How To: Marine Electrical Seminar - Alternators - Ep 05/30 

This is like getting lectured at a university. Easy to understand even for a non native speaker and a beginner as I am. Clear and concise. Thank you very much for the effort to put these invaluable videos out on RU-vid.

“starter solenoid poist” 😂 gotta give ya credit for not screwing up more words with how much there needs to be said. Great videos and keep them coming! super helpful for a marine electrical apprentice such as myself. Happy Holidays from ft. lauderdale!

Loved the video. OFI - Would be good if questions from the audience were repeated by the instructor so we would know what the questions were without trying to guess them from the answer given.

Great Instructor, THANKS!

Thanks for sharing your knowledge Jeff. Just about to installl my new alternator today and will definitely be running a fused wire straight to the battery now.

Best statement ever, about engineers ... Blue seas do make a battery swich with an alternator field disconnect auxilluary swich to prevent alternator failures.

l really love how you are explaining, l going to completely wire my sailing boat which l refining now. This will be useful.

Always interesting, thanks. It would be good to repeat questions from the audience otherwise we often don’t know the context of your answer . Sometimes it is obvious, sometimes not.

Great video!! I am in the process of redesigning and improving my boat's electrical system. My boat has the daisy chain system. I traced the circuit last fall. I was amazed at how asinine this design is. When I start the engine the electricity has to travel from my battery the starter post to another wire that goes all the way across my boat to a switch in the cabin and then to another wire back across my boat and then finally to my starter. WTF!! I always assumed 'The Switch' only energized the solenoid and the starting power was routed directly from my battery to the starter, they are only 24 inches apart!! I want a system where the alternator goes directly to 2 battery banks, I bought a Victron ARGOFET Battery Isolator. I plan to eliminate the need for The Switch in my cabin and mount a switch close to my batteries that is normally on both. I also want my starting power routed directly from my batteries to my starter. I have a yanmar 2GM I am not sure how the yanmar wiring to the starter switch is routed. Can I route power directly from my batteries to my starter. How would I do this? I also would like to have a switch the panel in the cabin of my boat to turn the power to the start key off. My the ignition key is in my cock pit and I would rather not have it energized when I am not at the boat. Is this possible? How would I wire it? What is your process of designing electrical systems for DIY customers that plan to install the components? I have a rough idea of what I want and what my needs are. I think what I want is a conceptual design of how this will all work. I am starting my youtube channel and plan to document and review this project.

hi. I have subscribed to your channel by suggestion of "Nick the naval architech"

How about a high power marine car alternator on a brushless electric trim inboard motor

Great video nice job. Really eye opening for charging Lithium batteries off of a dedicated alternator. If you have a dedicated alternator for the lithium battery bank and the lithium BMS shuts off the connection, either because of full charge or low temp cut off, that would disconnect the battery from the alternator and could damage the alternator. Have you had to overcome that issue?

The main reason alternators fail when switching battery switch off is that you end up frying the diodes in the rectifier. The alternator is an AC current device which outputs a DC current.

Aren't there still 1-both-2-off switches that are dual contact switches? They disconnect the field wire, which immediately shuts the alternator, when the switch is shut. So the switch CAN be set to safely shut all batteries without hurting the alternator. The same design is used to switch an alternator's battery voltage sense lead between two battery banks. Whether you switch the voltage sense lead, or the field lead, is your choice, but either can be done.

One small point: If you properly size the alternator pulley to the flywheel pulley, considering the engine idle/cruising/battle speed RPMs, you can SOMEtimes select an alternator that will provide 80-90% power at idle speed, without exceeding the maximum continuous rpm at full engine speed. Boat makers don't size them this way, but if you look at alternator output specs and do a little pulley ratio math, it is possible. We did it and cut our battery charging time in half--even on the internal regulator. And yes, this may mean having a custom pulley machined up, but that's fairly cheap.

The best setup I had was a off/1/2/all switch where the common was the house battery. This way you never actually disconnect the join between an alternator and it's engine's start battery. start battery has lasted over 10 years!! and still going.

It’s funny, as an auto mechanic I have had to argue with people who still think it’s ok to “test” an alternator by unplugging the battery while the engine is running. I’m glad it’s not just me who gets to try and explain why this is bad to stubborn people. I had a guy try to “prove” to me this was an ok thing when I was selling auto parts. He disconnected the battery and the engine died. So he says it’s a bad alternator. Well yea, but hopefully you didn’t destroy your computer too. He asked how could this destroy his computer. I told him if the diodes are bad, the battery becomes the diode by sacrificing some of its charge to keep things DC. Well now you introduced AC current to DC devices and they are usually not hardened against that. Yea… his car wouldn’t start again, and my scan tool wouldn’t communicate with the computer. He literally proved my exact points I had been trying to teach him by “teaching” me how to work on cars. (I have been a mechanic for over 30 years at this point). Go ahead “teach” me.

Okay, so I gather from the presentation that it is better to connect directly to the battery from the alternator. So I know why its better because the switch is a potential death to the alternator component, either because of user error, or wear on the switch contacts....right? So please tell us about the specifics on how to connect directly to the battery please...... conductor size, fuse, where to connect.

i accidentally switched off the power with the engine running, my alternator still seems to be working… will it be okay? does this mean its safe to switch off while the engine is running?

Really interesting video, thanks! I have a question about the two options in your diagram: "Standard Alternator Wiring" & "Improved Alternator Wiring". In the 'Standard' diagram the alternator feeds the starter solenoid but in the 'Improved' version it doesn't, presumably there's a reason the alternator was doing this which you take away in the Improved version. How does the Solenoid work in the Improved version?

God i hate guys like the one at 18:30

How about a high power marine car alternator on a brushless electric trim inboard motor