Alternator

[goldenstate]

Final note: The best reason to go through the hoops of re-doing one's power system is that it forces you to understand what all the damn wires are there for.

 

[Pete the Cat]

Final note: The best reason to go through the hoops of re-doing one's power system is that it forces you to understand what all the damn wires are there for.

Yes, I guess we all need to go through that, at least mentally. But the trip really soured me on all the electrical sales folks over selling all the complexity and capacity to bedazzled yacht owners who may not be starting with an idea of what they actually need and will use. Understanding acceptance rate of batteries and the charge rate of smart regulators is the key. But having gone through all that, I now realize that a couple of old 100ah flooded batteries, the old Motorola 50amp alternator and a 100w solar panel and regulator probably meets the needs of most folks if not doing air conditioning or induction ranges.

 

[bsangs]

Yes, I guess we all need to go through that, at least mentally. But the trip really soured me on all the electrical sales folks over selling all the complexity and capacity to bedazzled yacht owners who may not be starting with an idea of what they actually need and will use. Understanding acceptance rate of batteries and the charge rate of smart regulators is the key. But having gone through all that, I now realize that a couple of old 100ah flooded batteries, the old Motorola 50amp alternator and a 100w solar panel and regulator probably meets the needs of most folks if not doing air conditioning or induction ranges.

Now you're talking my language. Though it's a 200w solar panel, and I bring aboard a couple large capacity rechargeable Bluetti batteries for anything that requires AC on our trips.

 

[peaman]

But having gone through all that, I now realize that a couple of old 100ah flooded batteries, the old Motorola 50amp alternator and a 100w solar panel and regulator probably meets the needs of most folks if not doing air conditioning or induction ranges.

That exactly describes my system after doing a significant rework 2 years ago. I also have dedicated start and house banks. All charging goes to the house bank and an ACR tops up the start bank. I replaced the common Off-1-Both-2 switch with a dual switch to keep the two banks separate. A Victron battery monitor keeps me informed on system status.

 

[Christian Williams]

Right, and when cruising no need to recharge anywhere near 100 percent. Discharge to 50 percent, charge back to 80 percent (avoiding the very slow charge rate when topping off a battery--the nonlinear factor). A bigger alternator with smart regulator can do that in somewhere around an hour of engine time. Which if you motor a little every cruising day, happens "automatically."

Add up the typical drain per day and see how close it is to 30 amps. Most appliances don't have to be on all the time, including the refrigerator.

 

[Navman]

I found an alternator shop which is rebuilding my old alternator so as to give it 70+ amps. I believe that will be enough. I am installing 2, 200.watt solar panels in the spring. I think the combination will supply my needs. I do a lot of coastal cruising to New England ever other year and 2 week vacations on the Chessie on the off years. Iand am always at anchor at night and have never stayed at a marina when sailing,so I don’t want to worry about ample power. I think this setup will meet my criteria. I do carry the Honda generator as a backup if needed.

 

[Navman]

I am picking up the rebuilt alternator tomorrow and going out for 5 days and nights, so I will be able to check it out. I will be picking up a ball in Annapolis on Thursday as my friend has never been there. Then over to San Domingo Creek and St. Michael’s . Might even get back to Oxford. All nice spots and usually quiet this time of year

 

[Loren Beach]

All nice spots and usually quiet this time of year

Nice! Fall, before we get snow and ice... is a great time to cruise the NW. Uncrowded docks and anchorages.

 

[Navman]

I usually pull out the 1st or 2nd week of December and launch the 1st week of March.That being said, I have some nice sailing coming up in the next month and a half.

 

[Joliba]

What manufacturer do you all recommend keeping budget in mind?

We also have 4 AGM batteries. We bought the boat 16 years ago. The PO had installed a high output alternator a few years earlier. It is an AmpTech alternator. (I can’t recall if it is rated at 100 or 105 amps). We have had no problem with it using an external voltage regulator. I believe it is a good alternative to BalMar and possibly less expensive.
Mike

 

[Navman]

I wold like to thank everyone for their help and advise. I had the alternator rebuilt so as to produce 70-75 watts. However, my batteries are still not charging up correctly. My thought is this. When I installed my house bank of 4, 110 AGM’s do to room restrictions, i had to place one battery in the designated battery compartment near the engine and the other 3 are located beneath the salon aft seat. The distance of separation/ cable between the batteries is about 10’. Could this be the cause? Because the batteries are not together is the one nearest the engine the only one getting charge? I’m at a loss.

 

[Dave G.]

How is the alternator and charger(s) wired to the batteries ? If the positive and negative are wired to the same(first) battery in line they will not all charge equally due to resistance in wires and connections. Best to wire positive to first battery and negative to last(4th) battery or vice versa. The 10' distance will also create more resistance than the distance between the other 3 so not ideal. Be sure you have correct gauge wire too. It may be ok if wired correctly.

https://www.solar-electric.com/lib/wind-sun/Iota_balanced_charging.pdf

 

[Pete the Cat]

Wire size is as important, and perhaps more than distance as far as voltage drop. Doesn't your alternator go directly to a battery switch?

 

[Vtonian]

...When I installed my house bank of 4, 110 AGM’s do to room restrictions, i had to place one battery in the designated battery compartment near the engine and the other 3 are located beneath the salon aft seat...

I was recently measuring the space beneath the salon aft seat in my E38, where the PO had aslo put 3 of my size 31M 110Ah AGMs, and thought I should be able to *just* squeak a set of 4 in there, without too much renovation/innovation.

Are yours bigger? If theres any way you can stuff 4 in there, you could then wire them for balanced charging.

 

[Christian Williams]

I put my third battery under the nav station seat. Short wire run to bank.

Note that the E38 battery compartment has 1" slats all around to support the lid. I removed the long ones, so the lid is supported by only the end slats. Gives two inches more access.

...

 

[Vtonian]

Just in case anyone following at home hasn't looked at how to wire a >2 battery bank for balanced charging, the essence is to connect to a mid-point, rather than opposite end points like for a 2 battery bank, so each battery reaches the charging device(s) through an equal combined length of wires. All interconnecting wires have to be equal length. The wires to charging/load can be any length (and of appropriate gauge for load/length).

In the drawing below, the house bank battery 1 has to charge through 1 interconnecting wire segment to battery 3 for positive, and 1 segment to battery 2 for negative, so 2 wire segments total. Battery 2 has to connect to positive through 2 wire segments, to battery 1 then battery 3, and negative connects directly, so again, 2 wire segments total. And so on...


Pay no attention to the 2 battery start bank, that's just me theorizing on how to make use of what's already on my boat.