Battery Question

[Compatico]

Not sure this is the right math, but for the MR-1 (1.0) below, the math would be A = 13/.29 = 44amp on the low side, unless i'm missing something.

That's correct Ohm's Law numbers in theory, but the stator current is an unknown value and it's not as simple with AC voltages that are rectified to DC, plus circuit losses. Obviously a larger stator coil with the same voltage output can produce more current, but using basic Ohm's Law calculation I=V/R doesn't directly apply here I think. Even if it was 1/4 of that though, 10+A is enough current to charge a lead-acid battery.

What we need is a volunteer with some electrical toys - someone with a high current ammeter who can put it in their boat and give us a realistic value...

 

[ifly4fun]

That's correct Ohm's Law numbers in theory, but the stator current is an unknown value and it's not as simple with AC voltages that are rectified to DC, plus circuit losses. Obviously a larger stator coil with the same voltage output can produce more current, but using basic Ohm's Law calculation I=V/R doesn't directly apply here I think. Even if it was 1/4 of that though, 10+A is enough current to charge a lead-acid battery.

What we need is a volunteer with some electrical toys - someone with a high current ammeter who can put it in their boat and give us a realistic value...

I thought the numbers seemed a bit high.. ive seen the number 28amp thrown around for these a lot but no official backing. My multimeter only does AC, I mayhave to pick up a dc and test after my upgrades are installed

 

[Compatico]

I thought the numbers seemed a bit high.. ive seen the number 28amp thrown around for these a lot but no official backing. My multimeter only does AC, I mayhave to pick up a dc and test after my upgrades are installed

A multimeter is usually low current limits like an few amps. If the charging system can push 10+ amps you'll probably just pop the fuse, but you might pop more than that. And you won't get anything but a max reading. What you need is an ammeter rated to something typical like 100-200A to be sure of the reading.

But if 28amps is true, then that's plenty to charge a 2-3 battery system at reasonable speed. It won't charge low batteries to full in an hour obviously, but it would be plenty for typical use. If you're like @Hoyt with a couple thousand watts and 3 batteries and liking it loud, you'll need a battery charger.

 

[Hoyt]

On board battery charger is a must for stereo systems in our yammies.
To answer the original OP question.... Yes your Pro sport will charge a AGM and a lead battery no problem. It will distinguish between the two no problem.
Now for my sound system I'm running two Duracell group 31 batteries (@redthumper9 recommended) with a wetsounds system putting out about 1500 rms watts roughly, and have room to turn it up. On board Battery charger is a must. I'm running the Noco Genius mini 3 to charge the two Duracells and the factory interstate battery. I installed A perko switch to keep sound system and boat battery separate. Only thing hooked to Duracell batteries are my amplifiers (2-syndx6 wetsounds). Stock Fusion radio and conext still hooked to house.
I can say our yamaha engines will not charge our batteries. After a long day at the sand bar, and driving boat back to ramp. They are not charged. When I get home I plug the charger in. Normally all night charges them up.

 

[Compatico]

I thought the numbers seemed a bit high.. ive seen the number 28amp thrown around for these a lot but no official backing. My multimeter only does AC, I mayhave to pick up a dc and test after my upgrades are installed

Just went through the AR195 service manual and based on the size of the stator magnet and coils, and the huge rectifier which is water cooled, I'd say 28 amps could be about right. Note that while it's a separate stator and rectifier, an alternator is the same thing but with both the coils/magnet and rectifier all in one unit. They both generate AC volts and the rectifier converts to DC for the electrical system. I think the charging system is plenty hefty enough for a single or dual battery system as long as runs back to the ramp are not just 5 minutes away.

 

[seanmclean]

Thanks for all the feedback - appreciate it. Now to decide whether to just do 1 AGM for the house or go nuts and get two.

 

[Maillis]

So has anyone actually put an ammeter on the charging system of a dual engine boat to actually measure the output? I keep hearing about how weak the charging system is but no one seems to have measured it...

 

[Beachbummer]

It needs to be a DC Ammeter , and it would need to handle the potential full load no less than 50 amps just in case?. Nobody on the board has done it and talked about it

 

[biffdotorg]

The fact that these are waverunner engines with stators and not alternators will tell you that they put out minimal juice. Albeit enough to maintain a battery for starting. Thus the reason the newer E-series came with the solar charging systems. Yamaha knew there was a need for something more. But anyone that has put in multiple batteries assumes the cost of a multi-bank charger to put a real charge on, and not just maintain.

 

[ifly4fun]

Back when this thread was active I bought a dc ammeter but the boat was in storage.. next time I go out and hook it up and see what it’s doing.

 

[Maillis]

Shouldn’t it be possible to upgrade the stator for a little more output?

 

[212s]

Shouldn’t it be possible to upgrade the stator for a little more output?

Doubt there's much room down there - the stator is driven directly off the crankshaft. I would like to see the results of the current output test.

 

[Gunner]

Cheap way to add a voltmeter is the add a plug in type with usb charger. Plugs right into cigar charger in glove box and gives nice digital readout of volts. I think they cost like 15 bucks on Amazon.

 

[adrianp89]

A little off subject, I have been re-building a golf cart and my research has made me realize, golf cart batteries are perfect for boats. I switched two of my old 12v batteries for two 6v batteries ran in series at $89 each (local battery supplier) and have a crap ton of reserve capacity now. Only been out once with the set up but ran the stereo for 5-6 hours and didn't even see a .1 drop in voltage.

 

[biffdotorg]

Doubt there's much room down there - the stator is driven directly off the crankshaft. I would like to see the results of the current output test.

Having swapped stators on Sleds and motorcycles, I have seen little variance in what they can output. That being said, if there were, it would cost a ton of money to pull those engines to install it. I can't imagine they could be swapped out by pulling the pump like a Merc SportJet. That's a costly venture for sure. A third party alternator would probably make more sense if there were access to a spinning flywheel, but it's all sealed up for application reasons.

Additional batteries and chargers are the cost effective way to go. Except for you guys in stack storage with no access to power. What a bummer. It does sound like a battery swap is part of the normal routine.

Now if I had to do a battery swap on a regular basis, I would be installing a bus bar, or anything I can do to make it a two wire install each time.

 

[mark_m]

A little off subject, I have been re-building a golf cart and my research has made me realize, golf cart batteries are perfect for boats. I switched two of my old 12v batteries for two 6v batteries ran in series at $89 each (local battery supplier) and have a crap ton of reserve capacity now. Only been out once with the set up but ran the stereo for 5-6 hours and didn't even see a .1 drop in voltage.

Where did you source the 6v batteries?

 

[adrianp89]

Where did you source the 6v batteries?

A place called Electro Battery, a local company here in St. Petersburg. No idea how good they area, reviews were great and so were the prices. So far so good but it’s only been a month or so. Plus when I can save money and support a local business, it’s always a win.

https://electrobatteryinc.com/