Print

Please login or register.

[SV Sand Pebble]

  Just a follow up on my 100 amp alternator upgrade. I installed with the good advice here the Leece Neville 8MR2401UA, I'm glad I spent the extra cash for the peace of mind. My attempt on my boat is to do everything as right as possible and as good as I possibly can. This takes everything down to a snails pace. It took me a complete day Saturday with the wire, terminals, breaker, heat shrink and associated hardware ordered in advance. Man that's a tight spot. The smallest things seem to bother me when it comes to my boat. I install a 120 amp breaker in my 100 amp alternator circuit, our diodes can't afford nuisance tripping. One is tempted not to install a breaker at all if it wasn't for the small possibility of a short and a fire at sea, no thank you. I have worked on electrical and around machinery all my life and I don't think I have come upon anything that has required so much discipline and patience as Boatwork, if done right or the attempt to do it right 😁
  I think it's the special nature of all the parts, material and their price along with a certain pride boaters have in being the best possible all around sailors they can be. What a great sport, hobby or lifestyle for one at any age. For most of us we are 50+ and we have to use it or lose it. I think as I said before, our boats are fixing us, all the bending and stooping, all the mental challenges keeps our minds sharp, I hope, One thing for sure as I crawl out of the aft cabin this morning and have my first cup of coffee, although I’m happy with myself with my completed alternator install, I feel beat to hell, strange it feels good and bad at the same time.
  This morning if I can get my belly down on the deck I will be installing my new windlass shelf, this time with 3M fast cure UV 4000 cocking, last week I just did a test fit. My goal is to have my windlass project with both forward and aft controls done by the end of May, all the earlier the better. I think boatwork is like sailing, don’t try to sail to a schedule, rather allow in the case of sailing weather and conditions to dictate when our boats leave or return to the dock. And in the case of boatwork, it’s conditions also, the condition of my wallet, the condition of my preparation and the condition of myself. Did I mention I have both knees replaced, total reconstruction of my right ankle with bolts going through two toe bone canals from toe to heel to support my arch, if I can upgrade my boat anyone can. Most of my sailing is solo. Why do I write this? Two and a half years ago after thinking for a long time I was to old and beat up to own a sailboat I watched a guy with one arm and one leg missing solo sailing around the world, that nudged me to purchase my own boat. Through all the ups and downs and uncertainty I have not regretted a single day, ok maybe one or two Lol. I think our greatest enemy is our own thoughts causing insecurity. Those thoughts appear to cease the moment the wind passes 15 knots and are replaced by the call of attention from our boats, what better friend is there then a friend who makes you forget about your troubles. My friend is The Sand Pebble. See you on a windlass thread.

[KWKloeber]

@S/V SP

Gongratulations on the install done!! 

I install a 120 amp breaker in my 100 amp alternator circuit

I don't follow you on the above?  What do you mean "breaker."  Where?

-ken

[Jon W]

I wondered the same thing Ken. Could it be to shut the power off in the engine compartment for maintenance?

[KWKloeber]

Unsure, Jon

But I’m thinking coming from the industrial electrician side and not DC boat systems, he might have fused the output cable from the new alternator.

[SV Sand Pebble]

    Hello all.
  I fused my alternator at the battery large enough hopefully to avoid nuisance tripping yet offer protection in the extremely unlikely case of some sort of a short. The whole engine is ground so the wire breaking off, falling off or an object falling upon or being dropped will hopefully trip the breaker limiting damage. I know it's unlikely that such a thing should happen and we would lose our alternator diodes but that maybe a small price to pay. I am open to other opinions always. Below I leave a link to Pacific Yachting's video on why suggest fusing and or I take breakering the alternator, all they do at a large scale is electrical on boats. Again I'm always open to take a new look at things.

   
https://youtu.be/Y5HNd7S59RM

[KWKloeber]

@S/V SP

Ohhhhhhhhhj, gotcha. Of course!
EVERYTHING should be fused at the power source. 

I don’t buy into PY’s statement that he doesn’t recommend it on the starter - below in the comments he explains it’s because of “Do I have a spare fuse if it blows?” and cost.  Really? MBRFs aren’t a budget buster.
What B.S.!  And then he admits that he has his starting circuit fused at the battery. 
So which is it - Do as I don’t say, or Say as I don’t do? 

If you want to see a top, top shelf electrical upgrade read Jon’s write up on Della Jean the TechWiki!!

[Stu Jackson]

   
  I fused my alternator at the battery large enough hopefully to avoid nuisance tripping yet offer protection in the extremely unlikely case of some sort of a short. The whole engine is ground so the wire breaking off, falling off or an object falling upon or being dropped will hopefully trip the breaker limiting damage. I know it's unlikely that such a thing should happen and we would lose our alternator diodes but that maybe a small price to pay. I am open to other opinions always. .....................
.....................

Sand Pebbles,

Putting a fuse on the AO (alternator output) is a wise thing to do.  While the AO sends electrons TO the batteries, the fuse actually provides protection FROM a battery short whether the alternator is running or not.  While most think incorrectly that the alternator is the source of power being protected, it is actually the BOMB of the batteries that this fuse is protecting you from. If you've run your AO directly to the house bank, then the fuse/breaker can be used as a disconnect for when you work on the alternator, which is always live otherwise.  Maine Sail recommends an alternator disconnect switch and a fuse.  I just remove my MEGA fuse when I work on the alternator.  I also added a ground wire from the alternator to the engine ground when I installed my 100A Blue Circle alternator eons ago.

[SV Sand Pebble]

     Stu Jackson wrote: Putting a fuse on the AO (alternator output) is a wise thing to do.  While the AO sends electrons TO the batteries, the fuse actually provides protection FROM a battery short whether the alternator is running or not.  While most think incorrectly that the alternator is the source of power being protected, it is actually the BOMB of the batteries that this fuse is protecting you from. If you've run your AO directly to the house bank, then the fuse/breaker can be used as a disconnect for when you work on the alternator, which is always live otherwise.  Maine Sail recommends an alternator disconnect switch and a fuse".

  Response: I used a 120 amp breaker AWG 1 wire for my alternator. My starter circuit is fused at 200 amp, so far its been good. You have enlightened me on the fact that it's the battery more so then the alternator that it's a great idea to fuse or breaker the alternator circuit. I installed a breaker for the convenience of safety and as you said an on-off switch. A note: I ran my alternator wire straight to my starter battery/windlass battery under the forward compartment of my salon table. For now till I find away to add an external regulator I am charging my four Trojans through a 30 amp DC to DC charger. Later with an external regulator I have enough wire to shorten my alternator wire and take it to the house bank. Then I will charge my starter battery with the DC to DC charger getting 3 stage charging for all in every way.   
    With all Victron charging equipment I can upgrade to lithium when prices fall and all have to do is reprogram. Hey anyone, my DC to DC charger has setting for lithium and two presents for AGM yet nothing for plain lead acid. A user can put in his own set points for bulk, absorption and float? Right now I have the DC to DC charger on AGM 1 as seen in my attachment. I want to get it as perfect as possible, thanks again. Stu, I think it was your diagram for the most part I followed for my upgrade. I loved what I think was Jon's design but I decided to reach for the moon and not the stars, Jon my God, well done. Stu, your was simple and to the point. Both appear to be excellent and an asset to any of us doing such an upgrade, thank you.

   

[SV Sand Pebble]

 
  Ken

  Ken wrote: If you want to see a top, top shelf electrical upgrade read Jon’s write up on Della Jean the TechWiki!!

  Response: I did read all that. I was blown away at all the attention to detail. Sometimes I feel this site is just full of engineers.