Outboard Charging Coils

[rwoofer]

I've just learnt that my 5HP Honda outboard has a charging coil and some sort of regulator so you can literally plug it straight to a battery. Now I want to get a Raymarine ST1000/2000 autopilot for my Jeanneau Sun 2000, so the question is will my outboard charge the battery enough (let's say an hour of motoring for 3 hours sailing) to power the autopilot? I seem to remember the autopilot draw around 1 to 2amps on average, but no idea how effective outboards are at charging.

Any thoughts on whether this will work, or will I need solar back as well?

In which case can I plug that in independently or will I need some form of combined regulator to ensure the battery is charging properly, irrespective of input?

 

[TQA]

Your outboard will be pretty ineffective.

Solar is the way to go.

Or take the battery home with you and charge it there. Cheapest option!

 

[Rigger Mortice]

You really need to check to see what the output of the coil is. You also need to check if it really does have a regulator or is it just a diode?

Assuming it is a diode, if it is only a few amps and you will only run the engine for short periods then a direct connection may be best. If you are likely to use the engine for longer periods then there is a greater risk of overcharging the battery and a regulator may be essential.

If, however, it really does have a regulator fitted, there is no point in fitting another one.

FWIW I used to have an outboard which I ended up fitting a regulator to because it was taking my battery up to 16 volts.

Whether or not you need a regulator for the solar panel depends on the size of the panel.

 

[Seajet]

rb_stretch,

the charging coil will probably not be enough alone; they are rated at around 3 amps, 6 on ' sailor ' outboard models for cruisers.

I have a 30 watt solar panel & 60 amp/hour battery, as well as the charging coil.

I only plug in the coil if motoring long distances with the autohelm on, otherwise the solar panel and battery do fine for weekend trips, or with careful use on holiday cruises.

A Battery Monitor is crucial, or one can get left with no autopilot, lights including the compass, GPS or VHF...ask me how I know !

 

[VicS]

I've just learnt that my 5HP Honda outboard has a charging coil and some sort of regulator so you can literally plug it straight to a battery. Now I want to get a Raymarine ST1000/2000 autopilot for my Jeanneau Sun 2000, so the question is will my outboard charge the battery enough (let's say an hour of motoring for 3 hours sailing) to power the autopilot? I seem to remember the autopilot draw around 1 to 2amps on average, but no idea how effective outboards are at charging.

Any thoughts on whether this will work, or will I need solar back as well?

In which case can I plug that in independently or will I need some form of combined regulator to ensure the battery is charging properly, irrespective of input?

Your Autopilot will draw between 0.5 and 1.5 amps. 1.5 when it is actually operating 0,5 when not. The average will depend upon sea state and other factors.

Your Hond BF5 has a maximum output of 3 amps but it will be rather rev dependent.

Potentially then motoring at a decent speed for and hour should give you enough power for at least 2 hours sailing and hopefully rather more.

I believe 1997 and later engines have a combined rectifier and regulator. Earlier engines just an unregulated rectifier.


For a small boat with an outboard small solar panel ( 10watts or even only 5 if deck space is limited) can make a useful contribution... Enough to make all the difference between taking the battery home for charging periodically and not having to.

A voltmeter will be useful to monitor the state of charge of the battery.

 

[bluerm166]

Rb : Coincidentally I had a Jenneau S2k with a Honda 5 with charging coil and a separately connected 10W solar panel with Solsum regulator,and an 80ah battery.
And a 1000 model tillerpilot.Boat kept on a trot mooring with a useful orientation so with the boom held well to one rail the panel (on the hatch) got clear exposure and did it's job in topping up the battery between weekly sails.
My impression was that the charging coil would sustain the battery when motoring and using the autopilot.But with such an efficient yacht (large sail area) it was only necessary to clear the creek before the sails took over.So the ratio of motoring to sail was clearly less than in your situation.As a result over-use of the pilot when sailing would deplete the battery,particularly if the unit had to work hard e.g.in a following sea ( the manual says don't do this anyway).It's unlikely that you'll have a much larger battery so you can't start off with a handsome no. of a/hours.And if you are on a 'cruise' it's unlikely that the panel will contribute much.
I did tend to go on longish trips on our boat rather than 'day sail'.
I found that the boat was very well balanced and sailed very effectively when close hauled using a tiller tamer in lighter winds - in fact I often thought that with the sails trimmed properly she held up to the wind better than I could.You could also investigate other 'sheet to tiller' methods.
I was puzzled by the test that PBO carried out on Dylan's Minstrel with a variety of outboards.None of the units produced anywhere near the kind of charge that the manufacturers stated but it doesn't really make sense that such sophisticated manufacturers have for years sold units that don't work in this respect.I would have thought that another test specific to charging coils is warranted.

 

[seumask]

We ran a hunter delta powered by an outboard for five years. The outboard gave out negligible charge so the solution with autopilot and chart plotter was to have good 85-100 ah battery connected to a solar panel. Only when we were on board for a week did we need to get into a marina once during the week to connect the battery to a mains charger. The solar panel is silent and will charge pretty much all the time!
I think we parked next to you at bembridge beach one summer when you had a RM.

My view is that you want to keep the outboard as simple as possible. Good luck.

 

[William_H]

The rating for the outboard coil if it is 3 amps will be at 12v. This means that you could run lights nav gear etc up to 3 amps and not discharge the battery. However this is a world wawy from what is needed to charge a battery. you need something like 14v to push real current into a battery and generally certainly older o/bs just would not do it.
So first off you need an amp meter or use a 10 amp scale on a multimeter to see exactly what your o/b will put into a partially discharged battery at reasonable RPM.
This will quickly answer your question. If indeed it has a regulator and charge capability like the electric start o/bs then you might get a useful charge current.
I did find with my old Johnson that charge current into a battery was only about .3 amp at cruise revs. ie not worth the trouble. I made up a bridge rectifier with schotke diodes in (this case 6 diodes ) these have a lower volt drop than silicon so did improve the charge to 1 amp. But to be honest i have never bothered using it in anger relying on solar for recharge. good luck olewill
http://www.ebay.com/itm/20pcs-1N582...0V-/181275236745?ssPageName=ADME:L:OC:AU:3160

 

[rwoofer]

Thanks all. Sounds like I really need to focus on solar, which unfortunately is much more of a pain to install. Swinging mooring and large stackpak means the only really viable position, the campanion way hatch will be shaded much of the time. Other positions not big enough, flat enough etc. so will have find some good ideas on that front.

Seumask, Bembridge beach is one of my favourite mooring spots, so you'll probably see me again in the little Jeanneau.

 

[seumask]

Our solar panel was a relativly small flexible one which I simply left on the cockpit seats when we were not in the boat or tied to various points on the sprayhood or cabin top when we were on board, we had a small 10w ( on the mooring) and a bigger 30w used when we were cruising.
When not in use they lived under a bunk cushion. Used a simple volt meter to see approximatley how much charge was left in the battery.