What is the Best Alternator for my Boat?

[@Kevin-ru8mx]

How much drag do alternators put on engines? Does the drag on the engine reduce when the battery is charged? Can the drag be managed?

[@imageislandmarine4988]

Skip the Balmar, if you want a serious charging alternator go with ElectroMaax 215 and the remote mounted rectifier. The problem with Balmar is the powder coating traps the heat. ElectroMaax is anodized and more surface area for cooling.

[@sailingkeylimepie-pirateflag]

Jeff, the 120amp Balmar doesn’t start charging until 1500rpm. How is that considered “low rpm” charging on a diesel engine?

[@sailinghelios2023]

I thought the same thing when I looked at the profile but I did notice that it went up to 6000 rpm for the one I was looking at. Then I noticed that this was the alternator RPM which is different to the motor rpm due to the different sizing of the pulleys. So if it is 2:1 then 750 rpm is a very reasonable motor RPM. In fact my motor idles at 800 RPM.

[@MrMeetthedas]

Hello Jeff, i have 300 outboard And i have two both starter and a house flooded batteries(135ah),i recently brought two 200ah deep cycle gel batteries also i am puting 420 warta solar panel to The new gel batteries, with a 50a dc to dc mppt charger will i be able to charge all 4 batteries from The starter battery? Or if i add a battery isolator will that help ? Thanks! Dasmon Fl

[@SkypowerwithKarl]

If you have banks of hungry big AGMs or Lithium batteries, alternators just not putting out lots of amps and at low rpm, but heat. Even the best alternators will be cooked unless it has thermal management. And the better ones do.

[@PacificYachtSystems]

Hi Karl, your correct, we use alternator temp sensors on the external regulator for this exact reason.

[@SkypowerwithKarl]

Excellent, I stand corrected!

[@nonetasker4551]

what alternator is the most reliably and easyest to modify of I want an universal solutions for more then one boat?

[@PacificYachtSystems]

Hmmm, not one comes to mind, so much choice. Aftermarket, a popular choice is Balmar.

[@lyfandeth]

Jeff, if you get the right size pulley, you can match rpm's very nicely, and some Delco "car" alternators will put out a great charge at low rpm without any problems at high speed either. Any machine shop can turn a custom pulley, no big deal.

[@MrLeifR]

There is a downside. The wear will increase since you will overspeed the alternator at normal rpm. Do expect shorter lifespan on the alternator.

[@12vLife]

regardless of speed.. Do marine alternators charge batteries in a special way vs automotive alternators? I'm just wondering if my 160A automotive alternator on my 2018 4 cylinder van will have any issue charging a dual purpose marine battery (100AH/160RC vs OEM 70AH/120RC). My gut feeling is it will be fine.

[@PacificYachtSystems]

Hi NoSunBeach, marine alternators with internal regulators provide a similar charger to car alternators. Your gut is right, your battery will be fine.

[@freeloader69]

Hi! I would like to know what you think about turning an alternator into an electric motor for a 1960's Cat 30. I just got a Cal 30 for free, and I want to go electric. However, I'm not rich, so I would love to be able to rig an alternator up instead of paying big bucks for a diesel engine. If you agree that it's a possibility, what kind of alternator would you recommend? If you don't agree that it's a viable option, why not? Thanks! P.S. I'm in the process of watching your marine electrical systems series. Very informative! Thanks so much for sharing that.

[@ralph9987]

what doyou lot think of the integrel system that claimes to offer 9kW @1800rpm!! what output does your 125A alternator deliver and at what rpms in comparison. thanks

[@PacificYachtSystems]

Looks promising! No experience yet with this system.

[@ralph9987]

So what is your output? At what rpm please?

[@asennaydenov6461]

Hi Jeff, great video! Might I ask you how bring down my alternator from 125A to 100~110A. The thing is that I bought new engine Yanmar and the alternator way to big for my battery bank. I’ll appreciate your advice!

[@PacificYachtSystems]

You need to install a external regulator that will limit the field voltage so that you alternator doesn't output to it's max capacity.

[@nobodynoone2500]

RPM just depends on pulley size. Marine alternators are made for salt resistance more than anything.

[@PacificYachtSystems]

Tks for sharing.

[@reelmckay68]

How hot does a alternator suppose to get while running

[@PacificYachtSystems]

Smoking hot, you definitely cannot touch it.

[@cooletti]

@@PacificYachtSystems 220 deg max

[@marklong8608]

@@PacificYachtSystems I've heard anecdotally that alternator output drops when it gets hot, but I haven't been able to find an output vs temp chart. When it reaches temp, will you get rated power? 80%? 60%. Thanks

[@SkypowerwithKarl]

I’m seeing people changing marine alternators out to high performance automotive alternators. Primarily on ski boats with hungry sound systems. This is not safe, legal or insured if the SHTF. Balmar makes high performance, marine, low rpm with high output alternators that are thermally regulated. Mechman make one that’s a marine drop-in for LS based engines but not it’s not as high output and thermal regulated. Please use either of these brands. They must be ignition protected for use on a boat!

[@PacificYachtSystems]

Hi Karl, absolutely right! All of us need to use ignition protected alternators on our boats.

[@haydenwatson7987]

@@PacificYachtSystems Is ignition protection required on a diesel-powered boat that has no volatile fuels on board?

[@Actrealsurprised]

Why it not good at idle

[@PacificYachtSystems]

Hi Ray, engines like to run loaded, many mechanics say about 85% of Wide Open Throttle (WOT). When you have your engine at idle and the only load is the alternator, it's hard on the engine to NOT be really loaded. Hence, why it's always a last resort to run your engine at idle to recharge your batteries.

[@jackreynolds1150]

C. Ca

[@PacificYachtSystems]

Hi.

[@preppervol]

Not to rain on anyone's parade, and I know this video is 5yrs old, but for an "electrical engineer" you still have not figured out how to fix the problem with the alternator and charging... the fix is so simple people will feel dumb for not realizing it right off... I know I did before I did what I did lol.... good channel but the electrical advice needs updating and actually help the boaters out there instead of selling things....

[@ericneering6357]

What the hell does speed have to do with the alternator output has to do no matter if you’re in a car or in a boat it has to do with how many RPMs in most alternators make their full power at 1000 RPMs boy they always want us to eat all this bullshit not saying this in a good alternator I’m just saying that his information is skewed he’s trying to make you believe something that isn’t true