Regulator needed between Yamaha Outboard and Battery?

[scottburch]

I have a sailboat with a Yamaha 9.9 outboard with a generator. I am going to wire it to the cabin battery. Does anyone know if I need to put a regulator between them or not?

[boatman61]

Its worth the few $'s...

[GordMay]

Greetings and welcome aboard the CF, scottburch.

The "alternator" (80W, or < 6A @ 13.7V) on the Yamaha 9.9 is actually made up of a couple of lighting coils under the flywhee,l that generate Alternating Current.

You will need a Rectifier & a Regulator

See Page 13, of the Manual
➥ http://www.yamaha-motor.com/assets/s...rrent_1793.pdf

[GrowleyMonster]

Is this an electric start outboard? Does it use a start battery that is charged with an alternator mounted on the engine? If so, you can simply connect the start battery of similar size, age, and rating, in parallel with the house battery, using proper battery cables. Or use a two-bank battery switch, such as the popular red Perko brand switch.

[Cheechako]

I would imagine Yamaha made it so you just connect to a battery...? Why would they make it any differnt than that?

[GordMay]

Originally Posted by Cheechako

I would imagine Yamaha made it so you just connect to a battery...? Why would they make it any different than that?

To power a lighting circuit.

[Lake-Effect]

On some small outboards that run lights and say they can charge 12v batteries, the charging circuit is dead simple (coil, rectifiers and a fuse), and they don't put out that much current, especially when the battery's near full up. There's no regulator, they rely on the 'sturdiness' of a flooded-cell battery to withstand a small continuous overcharge. In fact, for our little Suzuki o/b, they mention not to use this type of charger on AGM or gel-type batteries, which can be damaged more easily by overcharge.

To the OP - have you hooked up your outboard's generator to your battery yet, and made any charging current measurements, at different motor speeds? If your motor can push more than 1 or 2 amp into a fully-charged battery, I'd say a regulator is necessary.

Some of our friends who have charging outputs on small outboards said that they found it mostly useless, unless they were doing extended motoring at flank speed. I haven't yet hooked up the charger from our o/b, I just top up with a portable solar panel.

[noelex 77]

You don't mention what size battery you have.

You will probably need a bridge rectifier, as Gord says. These are very cheap from any electronics store. Go for one that's overspecified say 25A.
Then fit a fuse and switch.
I don't know that particular motor but although its is rated at 80w you will only get 3-4 A.
This is still enough to overcharge a small battery bank. Rather than a regulator simply switch the charging off if the battery is reasonably full.

It's better to only switch it when the motor is stopped. If you do switch it with the motor going you are unlikely to do any damage, but you may blow the bridge rectifier.

[CaptLinda6pack]

Originally Posted by scottburch

I have a sailboat with a Yamaha 9.9 outboard with a generator. I am going to wire it to the cabin battery. Does anyone know if I need to put a regulator between them or not?

HEY! I wouldn't wast my time with it! You will get only good power out at higher speeds only. I have one and at low speeds... .001ah and 1/4 throtle .010ah now at 1/2 you get charging your battery. Now at top-end speed your now getting what they speck!!

Good luck; Capt. Rob for Linda

[scottburch]

Thanks for all of the replies. All had really good suggestions.

Gord May: Thanks for sending the manual, it stated the rectifier/regulator is optional. I will see if mine has it, if not, you may have saved my battery life..

[Rapanui]

If it is the 9.9 4 stroke electric start I have had 3 of these and the regulator is built in. In fact you don't need to do more than connect the battery for the electric start. Depending on model they can deliver 7-10 A at full chat, so not a great deal

[scottburch]

Rapanui: Thanks for the note. I found a service manual for that exact model and it seems you are correct. It seems to have a "rectifier regulator". I plan to add a small solar for a trickle charger anyway.

[northoceanbeach]

I've got this yamaha 9.9 and it's all pretty new to me. Couple weeks. Up until today it would charge the batteries and stop at 14.6. Gel batteries. 2. 98ah each.

Today right when I was getting to the anchorage I looked and the voltage was 14.92. Does anyone low if this is a problem or not? Anything I need to do?

For most of the five hour motor trip it was keeping them around 13.6 but I was was using an autopilot and stereo and chartplotter. It was when I approached the anchorage and started turning things off that it topped them off and reached 14.92.

[noelex 77]

Those voltages are too high for gel batteries.
Most gel batteries have a maximum charge voltage of 14.2-14.4v.

You need to regulate the input down to these levels.
The safest is to to just turn on loads to keep the voltage acceptable.
You can make up a simple manual regulator out of some diodes (each diode introduced will drop the voltage by about 0.6v)
On most outboard charging you can can turn the charging off without damaging anything. I have even used a solar PWM regulator successfully. This is a great solution, but do this at your own risk there is no guarantee that the charging system will cope with this sort of treatment.

[Rapanui]

If its electric start 9.9 then it charges the starter battery via the start cables so you don't have to do anything. It has a regulator in the outboard. I had 2 of these for years on my FP Maldives and as others have reported they don't give a lot but it's useful. With this type, you would have to modify the outboard itself to fit another regulator which is not necessary. Ok its not a 3 stage charger regime, but you would have to motor for days without using power to make that worthwhile - unlikely. Motoring 90nm across the English Channel and the battery voltage still would not achieve 14V while charging
The others are 9.9s manual start with a separate power output plug. The manual will tell you if it is AC (rectifier and regulator required) or DC regulated or not.