New 250A Alternator

[Brandonloos21]

I have come to notice that Malibu now offers a Balmar 250a alternator for their 2023 boats, ontop of their 170a alternator. I have been asking around, as I would like to install it on my boat, and my dealer informed me that it would not be possible to install on 2022 M6di engine. The mounting style and everything looks the same as the 170a. In addition, @Jbcain ordered his new T250 with the 250a alternator, and looks to be an m6 engine. 

Any real world experience here?

250A Alternator

170A Alternator

Looking at the both of them, I would have reason to believe that they would be interchangeable.

[JeffK]

When I upgraded to the 170 amp on my current boat, I also had to upgrade a few harnesses.  Could it be that while the mounting accepts it, the wiring isn't beefy enough?  That's a pretty big amperage bump. 

[Brandonloos21]

10 minutes ago, JeffK said:

When I upgraded to the 170 amp on my current boat, I also had to upgrade a few harnesses.  Could it be that while the mounting accepts it, the wiring isn't beefy enough?  That's a pretty big amperage bump. 

Could be quite possible. I would make sure wiring would be able to carry the amperage. What harnesses were needed for your upgrade? Did they come with? How was the replacement?

[JeffK]

The positive and negative harnesses to the alternator were upgraded and had larger fuses as well, IIRC.  It wasn't hard to do.  Just need small hands.

[Brandonloos21]

31 minutes ago, JeffK said:

The positive and negative harnesses to the alternator were upgraded and had larger fuses as well, IIRC.  It wasn't hard to do.  Just need small hands.

Awesome! So big 3 upgrade essentially. 

[JeffK]

I just have no idea if there is a need for some larger piping back up to the helm/observer, plus wherever the other wires on the main posts on the motor are headed.  I'm guessing that's the reason for proclaiming it isn't possible, but I could be wrong.

[Brandonloos21]

25 minutes ago, JeffK said:

I just have no idea if there is a need for some larger piping back up to the helm/observer, plus wherever the other wires on the main posts on the motor are headed.  I'm guessing that's the reason for proclaiming it isn't possible, but I could be wrong.

I would upgrade up to the switch, also will most likely upgrade the switch as well. 

[MLA]

Typically on boats, the alternator supply cable, terminates to the starter's main B+. This keeps the cable short and smaller. It also means the engine supplier provides a more plug-n-play product to the boat builder. No need for the assembly line to route and connect a dedicated alternator cable. The main starter cable from the switch/battery, sould be large enough as its already taking starter draw into account.  

This main cable would be the only cable that might need upgrading when going with the higher output 170A or 250A. The control harness connector would onlt need to be changed if it was different from what the Belmar. I would expect this to be the case. You can only sup up an alternator so much, before a larger chassis is needed. id bet the Belmar is a larger unit then the base OEM alternator. 

[Slurpee]

So a long time ago I put a 200A alternator into my 2001 to replace a failed 60A alternator.  I had to do some changes to the pulleys and belt and such, but it wasn't bad.  I noticed when I was done that the boat felt more loaded down.  That's hard to quantify of course.  But I wasn't the only regular driver who felt that way back then.

I spec'd in the 250A alternator on my build because... more power.... and it was only a couple hundred more. But I have no need for it.  Will that bigger alternator provide more than a trivial load on the engine during operation compared to the 170A?

[roeboat]

1 hour ago, Slurpee said:

Will that bigger alternator provide more than a trivial load on the engine during operation compared to the 170A?

Only if you are drawing more than 170A. The load on the alternator and engine increase with the electrical load. Energy cannot be created or destroyed, only transferred.  

The most you would lose with the bigger alternator is 2-3 hp over the 170A alternator, but that's assuming that you are consuming 250 amps .

[Slurpee]

That makes sense. A bigger core isn’t going to put that much force back on the engine. It’s just going to be very close to a similar smaller alt until you need more and it can do that. Thanks for the insight. 

[Slurpee]

The next interesting question for the electrically minded out there is this. With a 250A alternator, will a 170A ACR be fine for battery isolation?  That’s a standard size for instance from Blue Sea. 

[MLA]

Based on the numbers on parper, no, the 170A rated ACR would be a weak point. In reality, I doubt you would ever surpase 150W output from the 250A alternator, except for a spke now and again. Now, when it comes to practical application, I tend to overbuild in these areas. Its one thing to push a speaker or woofer with a bit of extra wattage, but im not a fan of pushing the supply cabling and circuit protection. I would look for a higher rated ACR/VSR thats a closer match to the potential alternator output.  

[Slurpee]

Thanks mate. I feel better with your answer. I’m leaning towards not over buying the alternator for bragging rights, but instead get the 170A alternator since the 250A really only exists for Stern Turn. 110A or 170A is sized correctly I think for boats most of us use. For all those reasons MLA stated I agree it’s a case of you’re probably okay, but do it right to start off. That is if you’re going with a factory or after market (Me) ACR setup, then don’t get carried away with the alternator. 

[Brandonloos21]

3 hours ago, Slurpee said:

The next interesting question for the electrically minded out there is this. With a 250A alternator, will a 170A ACR be fine for battery isolation?  That’s a standard size for instance from Blue Sea. 

I was wondering this as well. Also, if you upgrade with the normal 1, 2, combine switch, should you get upgraded switch (it’s gray vs red) 
 

Will stock upgraded alt boats come with upgraded switch too? 

[Slurpee]

I just went standard option 2 so all the cables and dual batteries are present. If I decide to care, then to save nearly double the cost I can crimp my own cables and install an ACR and get effectively option 3 and buy more gas. I’ve always gotten buy with option 2 though.  

Stil… compulsive upgrader here. So, I also deleted the battery charger on my order. It’s the easiest thing in a boat to install besides a throw cushion and sun block.   I wondered about what could be done different this time.  

Because I’m intrigued by the Blue Seas BatteryLink 20A charger.  Anyone used that? I get no Google hits on this site when I try.  Anyways, that is what prompted my earlier question to the community about the 250A alternator.  It’s built in ACR is 170A.  And I started wondering about matching the system up so weak links didn’t present themselves so easily like MLA pointed out.  And for the price of any other good charger I’d also get isolated batteries and ACR and do something different.

 

[shawndoggy]

12 hours ago, Slurpee said:

Because I’m intrigued by the Blue Seas BatteryLink 20A charger.  Anyone used that? I get no Google hits on this site when I try.  Anyways, that is what prompted my earlier question to the community about the 250A alternator.  It’s built in ACR is 170A.  And I started wondering about matching the system up so weak links didn’t present themselves so easily like MLA pointed out.  And for the price of any other good charger I’d also get isolated batteries and ACR and do something different.

 

That looks pretty cool!  Thanks for sharing.  You'd still need a new switch (blue sea 6011 likely plug and play to factory location (or 6011200 if you want to go murdered)), but that's not to hard to change out, and it would kill two birds with one stone.

Blue Sea does make higher amperage ACRs, but not in the kit.  Even the smaller blue sea m-series switches that Malibu specs appear to be rated for 300A continuous, so no problem there with any of the alternator options.

[Slurpee]

You're welcome.  I like that product.  But I also like to follow the idea of KISS.  So two different pieces has an appeal.

[shawndoggy]

33 minutes ago, Slurpee said:

You're welcome.  I like that product.  But I also like to follow the idea of KISS.  So two different pieces has an appeal.

I will say that it's not easy at all stacking lugs on that super tiny m-series switch.  I added an ACR and battery charger to my A24 as soon as I got it, and did quite a bit of swearing to get everything to line up.  There's just not a lot of room on that switch, and adding the 4th post (vs the 1-2-all-off m-series switch that malibu installs on non-acr equipped boats) makes it a bit of an ordeal.  

Edited January 6, 2023 by shawndoggy

[Slurpee]

I did an install on my father in laws camper and didn't even try to stack the lugs.  I just ran the lugs over to standard stereo distribution boxes I had in the spare parts box.

Edited January 6, 2023 by Slurpee

[Brandonloos21]

I have decided that 170A will suffice. Now the question is:

Should I go with Mechman 170A or Balmar 170A.

[Brandonloos21]

Went with Mechman 170a alternator. What all should I upgrade here wire wise? I noticed that the ground wire did not have a stud on the Mechman like it did stock to run to, so I had to ground it to alternator frame/casing. 

Seemed that the harness was plug and play, same as stock.