Charging 7ah battery from Honda 15hp

johnny81

Seaman Apprentice
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May 24, 2010
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I am thinking of buying a 12v deep cycle 7ah battery in order to provide power for my Bravo BP12 electric pump. I am wondering whether this can be charged from my Honda BF15 engine? It says 12v 6A from the output - I am wondering whether this will be too much for such a small battery. Many Thanks in advance.
 

Silvertip

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Sep 22, 2003
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28,771
This should not be a problem unless you tend to run very long distances at wide open throttle. The 6A output from the engine can only be achieved at or near wide open throttle. Typical charge rate for a battery that size is 1-1/2 to 2 amps. The battery will take what it needs. If it bothers you, you can add a couple of simple lights to absorb some of the output.
 

johnny81

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May 24, 2010
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34
I have eventually got round to buying this battery and it is currently on its way to me. The engine is a 2004 Honda 15hp 4 stroke - I'm just wondering whether this has a built in regulator/rectifier (if it doesn't do I need one) and can I just connect the output from the outboard directly to the battery? I have the original Honda connector - but no wiring attached - so was just going to make up a lead from 1mm lighting cable. I have also bought a mains trickle charger for the battery in case the process of charging from the engine is too complicated. Many Thanks in advance.
 

sam am I

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Jun 26, 2013
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Yes it does and it came stock and yes, directly connect it. There is a fuse inside the motor cowling.

I'm not sure I understand what ya mean by
I have the original Honda connector - but no wiring attached - so was just going to make up a lead from 1mm lighting cable.
Perhaps a picture? Otherwise, I believe In that year/model, the stock external power out connector should have came w a rubber cap/hood housing on it? If so, pop that off, look down inside of it, you should see two metal male spades pointing up down inside?.......Those un-wired male spades of course mate up with the females on the engine side when the plug is on and in place.

The male spades are both molded into a plastic boss that makes up the connector assembly to wire too!! Carefully slip it out by prying/pulling the spade assembly from inside the rubber cap/hood housing and you'll find two set screws on the backs of each spade to attach your + and - wires to. You'll have to drill a small hole/s(it's sorta molded/pre-drilled already) in the rubber to fish the wires through to set the spade assembly w wires attached back inside the housing.........Tricksters eh?

Run the wires(1mm, 18AWG?, I'd suggest 2/2.5mm, 12/10AWG for like a 6' run) then of course directly to the battery to be charged.........You can also upgrade to 12 Amps output by adding another set of parallel wingings(w same reg you have now) should you need/want .

BTW, Honda(very smart engineers IMO) uses a unique smart sensing type regulator in that it has to see a load(slight current draw) before it turns on the 12V output....just a side note :)

In looking at the spec's for the pump, manu states "fully loaded, it can draw up to 20A @ 12V"? (Double check me)......If so, depending on current limiting circuit design in/of the Honda's Reg.(I don't have that spec, but typically limits current by voltage fold back, lets guess starting @ 20 Amps) and how long you run the pump[7ah/20a = 0.35 hrs (ideal max run time w full load, full charge, battery only)] verses how well charged/low the battery is/gets, you could potentially take out the Honda's fuse(15 Amp I think on yours))overloading the Reg. when the battery drops out.


Just a heads up, but since you have the 6 Amp stator, the stator will just limit out @ 6 amps, the 12V should be dropping out before your 15 amp fuse goes, you should then in theory, just run out of battery in say 15 mins w/o any fuse loss.
 
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