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Enough Alternator Amperage?

Old 05-06-2008, 06:57 AM
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Default Enough Alternator Amperage?

I Need Help from the Board please. I have a single Yamaha F225 on my 23' CC. The F225 alternator puts out 45 amps(540 watts). I purchased a Raymarine c120 with 125 GPS, 2kw radar, a DMS300 FF modulator with a P66 (600w) triducer.
I am upgrading from the RayMarine SL70C chartplotter with 2kw radar and depth transducer. Obviously the new total load when all operational exceeds 540 watts, never mind the VHF, am/FM stereo and any lights.. If I install, what can I expect? Should I install? any experience with the whole pkg and only 1 alternator? ;?
Old 05-06-2008, 07:23 AM
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Default RE: Enough Alternator Amperage?

I am running everything you have mentioned plus some, with one of my 150 Yamaha's charging a electronics (house) battery ( not to drain the starting battery). I have never had any issues with killing the battery in one day of fishing.

Yamaha offers a nice feature of splitting the alternator to charge two batteries, it will charge the weaker battery first.

I can not speak from experience if one battery will carry the electronics load all day and still start the engine.

Old 05-06-2008, 09:54 AM
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Default Re: Enough Alternator Amperage?

Forget about the output of the radar and fishfinder in watts. You need to determine the inputs requirements of all devices, in amps. Then see if you will have a problem or not.

By the way, the stated output of the F225 (and for most all outboard motor generators) is total output. Since a portion of the output is needed to run the motor itself, what is available to us to run devices or charge batteries is somewhat less. The generator of the F225 is able to provide a net output of maybe 35 - 40 amps or so. And, even then only when the engine is spooled up well above idle.
Old 05-06-2008, 11:48 AM
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Default RE: Enough Alternator Amperage?

gb42 - 5/6/2008 9:57 AM

I Need Help from the Board please. I have a single Yamaha F225 on my 23' CC. The F225 alternator puts out 45 amps(540 watts). I purchased a Raymarine c120 with 125 GPS, 2kw radar, a DMS300 FF modulator with a P66 (600w) triducer.
I am upgrading from the RayMarine SL70C chartplotter with 2kw radar and depth transducer. Obviously the new total load when all operational exceeds 540 watts, never mind the VHF, am/FM stereo and any lights.. If I install, what can I expect? Should I install? any experience with the whole pkg and only 1 alternator? ;?
The radar and FF wattage you're describing occurs in VERY short pulses. The AVERAGE power consumption is much much lower than that. For example a 600watt output FF typically has something like a 3 amp fuse, a 2KW radar unit may have an 8-10 amp fuse. The easiest way to help determine your current (amperage) requirement is to look at the fuses required for each device and add them up. Those numbers will always be a bit more than actual.

Ken
Old 05-06-2008, 12:50 PM
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Default Re: Enough Alternator Amperage?

All that you have listed together isn't more than 20 amps. Big draw items are refrigerators (12 amp), spotlights (8 amp), huge stereo amplifiers running at full volume5 00w+ (20-50 amp). Most other items are small - water pumps (3-5 amps), navigation lights (1-2 amps), stereo (3-5 amps), vhf (4 amps on transmit).
Old 05-06-2008, 07:44 PM
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Default RE: Enough Alternator Amperage?

All great advice given above, as mentioned forget about the wattage numbers and concentrrate on amperage draw. You will be fine with what you describe. However you should add a house battery and isolate from your starting battery. Treat this as a non-negiotiable. You can use the aux output from your F225 or an ACR sensing device to charge your house battery. To answer your question on alternator output? this is where reserve capacity from your house battery will take over.



Nick





gb42 - 5/6/2008 9:57 AMI Need Help from the Board please. I have a single Yamaha F225 on my 23' CC. The F225 alternator puts out 45 amps(540 watts). I purchased a Raymarine c120 with 125 GPS, 2kw radar, a DMS300 FF modulator with a P66 (600w) triducer.I am upgrading from the RayMarine SL70C chartplotter with 2kw radar and depth transducer. Obviously the new total load when all operational exceeds 540 watts, never mind the VHF, am/FM stereo and any lights.. If I install, what can I expect? Should I install? any experience with the whole pkg and only 1 alternator? ;?

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