Outboard alternator to charge battery?

[BuffsBoat]

How come the manual for my Honda 15HP O/B clearly states that the alternator is not designed to charge a "deep-cycle" battery? I know what a deep cycle battery is. What's the difference between charging one of those, or another type of battery?

Thanks in advance for the replies

[Nick Hearne]

On my little 15hp Yam the powers take off is ment to just run nav lights not for charging batteries if I remember correctly!

[ashbypower]

The Output is most likley to be AC, hence NOT for battery Charging..

[BuffsBoat]

This is what the manual says. I'm confused:

[Peter_C]

Does that motor have a rectifier and a voltage regulator, or just a rectifier?

Many batteries don't take well to voltages higher than 14.5v or so, and a rectifier alone will hit 17 volts.

[BuffsBoat]

Originally Posted by Peter_C

Does that motor have a rectifier and a voltage regulator, or just a rectifier?

I have no idea what that is. Sorry

[m chappelow]

Some outboards have a separate lighting or charging coil alongside the primary ignition coils inside the flywheel ,
To charge a battery you need Dc current , the coil produces Ac ok for lights so you need a Rectifier to change it to Dc if ones not fitted ( most motorcycle ones will fit )

The 2 wires that you may have coming out on your engine will run Nav lights But the faster you go the more electric the engine makes and without some sort of voltage regulater the bulbs will get brighter until they blow or if it's a battery it will over charge .

[forsberg_se]

Old post but someone might need the correct answer.
Your charge controller is not buildt to load a flat battery.
The controller might overheat and burn up if connected to a totally drained battery.
In other words it's intended for like a MC- battery, not a car battery and definitly not a large deep-cycle marine battery that you drain much between charges

[BuffsBoat]

Thanks for the reply! Very informative, and makes sense!

Happy boating season, all! it's been a long, brutal winter!

[forsberg_se]

Heh, wasn't really expecting you to be waching this still.
Anyway I should perhaps explain it a bit further.
A flat start battery dont draw much current initially when you start to charge it.
A flat deep cycle battery sucks up Amps like mad when you start to charge it.
So actually a car battery might work fine.

If concerned run the motor in 5 minute intervals and let it cool down between.
Or better yet install an Amp-meter and keep the charge below your engines maximum rating. This could probably be done by keepeing the rev's down.

At idle there should probably be no risk of damaging the regulator or coils no matter what battery you use.
Some regulators may not charge at all at idle though.

[BuffsBoat]

Originally Posted by forsberg_se

Heh, wasn't really expecting you to be waching this still.

LOL! I have it as a subscribed thread, and got an e-mail notification



I was surprised to see it resurrected! Still, good info is good info, and never gets old!

Happy boating!

[stul]

Leisure
Car
deep-cycle" battery
( how many amp Hour)


I have used a leisure and car battery over the last 6 years (if I remember correctly about 85amp) Changing after 2 years
I run chart plotter,garmin 550 plus several instrument gauges also have VHF Radio wired in
One battery (prob only room for one)
always take one those car starter kits
Car Battery Booster Jump
Not had any reel problems am I pushing it
like to keep it to one battery
Going to buy new which one
Stuart

[stul]

eBay item number:271414476334
75hp 2 stroke engine)

I was thinking some thing like this
What do you think

Suitable for
Caravans, Boats, RV, Leisure use and more.
This is a Heavy Duty Domestic battery and it's purpose is to run applications with it's deep cycling capabilities
Warranty
4 YEARS
Description
This range of Leisure / Marine batteries are of a lead calcium construction which means the plates have been hardened, therefore giving the battery a longer life and better starting capabilities than your conventional leisure batteries. These batteries come with a 4 Year Warranty and are perfect for domestic use.

This battery comes fully charged and ready for use

It is a DEEP CYCLE battery, which means unlike a car battery, they can handle being discharged to a higher capacity and recharged again without affecting the future performance of the battery. Another thing to note about these batteries which is vital is that when charging and discharging they have 250 life cycles.

[rik_elliott]

I'd get a gel cell if possible and you can find one big enough. AGM as an alternative. They don't have unsupported plates or liquid electrolyte that are more shock sensitive and may release gas when charging (though the one you have found looks to be a sealed unit so this may not be a problem)