Yamaha 55 el charging rate.

jurgenscraft

Petty Officer 1st Class
Joined
Nov 6, 2004
Messages
227
Yesterday I spoke to the owner of the local boat shop, I asked him about the output of the Yamaha 55el charging system output in amps,he reckons I should be getting about 5 amps at 13 to 14 volts, so in other words a 65 amp hour battery should take 13 hours to charge ( theoretically speaking, not taking losses, etc ,into account) is this about right, ie, the output in amps of the Yamaha 55el. Kind Regards William Wright.
 

amirm

Petty Officer 2nd Class
Joined
May 7, 2005
Messages
176
Re: Yamaha 55 el charging rate.

I don't have the spec for the 55el but the new 50 HP from Yamaha has a max output of 17 amps. Maybe he is talking about low-RPM output. Anyway, if he is right, and your battery is dead, then it would take that many hours.<br /><br />In general, charging a dead battery with a standard alternator is not a realistic situation. You are better off charging the battery with an external charger from A/C (away from teh water). Most people would not want to drive long enough to charge the battery and a non-smart charger on the outboard is probably not the best way to put juice in the thing...<br /><br />Amir
 

jurgenscraft

Petty Officer 1st Class
Joined
Nov 6, 2004
Messages
227
Re: Yamaha 55 el charging rate.

Amir, thank you very much for the reply, yes you are right , it would take that long for a completely flat battery to be charged, my batteries are okay that was a therotical situation, I keep my boat batteries charged with a trickle charger when not in use,I was wondering if the electrical accesories mounted in the boat would be using the same amount of power or more than the charging system could supply , but none of the accesories run long enough to cause a serious drain on the battery, the fish finder and the gps are about all that are on all the time. navigational lights and docking lights are not used constantly unless night crusing takes place and then only the navagation lights are on and then do not draw that much current, I calculated a total draw of 7.5 to 8 amps @ 13 volts if all the accessories are in use at the same time excepting the bilge pump, if I add the bilge pump which hardley ever runs I suppose the load would be 10 amps, this is well witin the capabilities of the battery fitted,( I have the choice of a 65 amp hour or a 120 amp hour battery) I monitor the batteries with a panel mounted volt meter, I would appreciate any other comments from the forum members. Kind regards William Wright,
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,762
Re: Yamaha 55 el charging rate.

If you have a choice of battery, you cannot buy a battery with "too much capacity". You can only buy a battery with "too little". While I don't have specs at hand for your engine, I question the 17A charging system output. The current four-strokes do have higher output. The current mid-range two-stroke Yamaha's have only 6A alternators according to my literature.
 
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