Battery, LED light and GPS wiring question!

[Zagato]

I now have a little Drascombe Coaster and simply want to wire up the charging cable from the 5HP outboard engine to a battery to power an interior light and GPS. The smaller the batteries physical size the better but an average size one could be fitted.

How do I do it and what should I buy. Thanks

 

[yoda]

Provided the outboard has a built in rectifier then the output can be connected direct to the battery. I would also put a fuse in line capable of coping with maximum output from the outboard. For lighting I would go for a simple LED strip (the flexible self adhesive type) wired via a fuse and switch, low current and cheap. The gps can again be supplied via a fuse and switch. As for battery size, I would say a simple 80AH deep cycle battery would be fine but best off in a simple battery box. I have seen a battery box with built n fuses and switches but can't remember where!

Yoda

Something like this may suit you:

http://www.alpha-batteries.co.uk/battery-boxes/accubox-deluxe-leisure-battery-box/

 

[Zagato]

Thanks Yoda, I'm not sure if the 2012 Marina 5HP as a rectifier. I was hoping to maybe just use a double cigarette lighter socket for the GPS so I can remove it. I havn't heard of the flexible LED light strips but I have a hanging LED light I could also put in a fag socket if it makes things easier.

Do you think a chandlers could advise me if I find out what the output of the outboard is. I havn't a clue what size cable, fuse, how to connect etc :ambivalence: And don't want to pay someone to do such a simple job. I wouldn't want to rely on a chandlers though.

Can anybody tell me what I need to buy, where to put fuses etc Many thanks.

 

[yoda]

The battery box I linked to has a cigar lighter socket and a doubler plug / socket would allow you to plug in both light and GPS. The engine is unlikely to have a rectified output (ie DC) so I suggest you go to the local agent with it to ask. A rectifier can normally be added if there is an output from the engine. A hanging LED light will be fine and may well have a built in fuse within the plug. The size of current you are going to have only needs light flex but you will need to find out what current the engine can produce. Given where you are I think you may want to try and befriend another forumite in Chichester to come and go through what you want to do and help show you what is needed. First thing is to find out about the engine output.

Yoda

 

[William_H]

I use one of these little guys for cabin light hard wired in., The sticky back sticks to the cabin top and does not detract from headroom.
http://www.banggood.com/Wholesale-T10-36-SMD-LED-Light-Festoon-Dome-Bulb-Lamp-White-12V-p-24565.html

It is quite likely that your outboard if it does have a ligthing coil will not produce much DC for battery charging. My old Johnson would put about .1 amp into a battery at normal revs.
I did make up a rectifier pack of 6 Schotky diodes which improved it up to 1 amp.
Regarding fusing. A single fuse at the battery is all that is needed. My guess is that 5 amp fuse will cover all services and protect the wiring. Use lower fuse rating 3 amp for lighter wire guage. All you need then is a switch mounted ina convenient place for lights.
Regarding the battery. There is a whole range available from a new SLA battery starting at about 7 amp hour up to 40AH.
Other forumites have advocated second hand car batteries from car breakers.
You might check out yacht clubs for dumped used batteries but these may be too heavy.
I have also used Sub C NiMH batteries 10 of them in series for 12v.
I think you will end up wanting a battery you can remove for charging or charge when you get home with a trailer boat.
I think you might also end up using a solar panel for recharging between voyages. Might be more succesful than O/B charging.
It is probably worth fitting a amp meter for charge current if you rely on o/b. And a volt meter to know when battery is low. good luck olewill

 

[Zagato]

Thanks Will that gives me a headstart. There is nothing in the manual about charging output or in fact anything at all about the charging capability or lead supplied! More investigation needed!

Yoda I like the battery box, it says it's sealed which is confusing if batteries give off gas!

 

[Rigger Mortice]

It is quite likely that your outboard if it does have a ligthing coil will not produce much DC for battery charging. My old Johnson would put about .1 amp into a battery at normal revs.
I did make up a rectifier pack of 6 Schotky diodes which improved it up to 1 amp.

I don't understand how a rectifier pack can increase output by ten times? Were you measuring the unrectified output when you got a reading of .1 amps? Most multimeters can only measure DC current and will give a false reading if you attempt to measure AC current.

 

[LadyInBed]

When you get your 12v sorted out, if you want to go the cigarette lighter socket route, then a cigarette lighter usb socket adaptor and a clamp on usb light is easy see:
http://www.amazon.co.uk/s/?ie=UTF8&...vptwo=&hvqmt=b&hvdev=t&ref=pd_sl_58z7xz0hmy_b

Regard your battery, if you are trail sailing, then you could charge the boat battery enroute via the trailer board 12v outlet.
If the boat is kept on the water, the simple alternative is to carry the boat battery to and fro in the car and charge enroute.
A flexible solar panel is also an option, but quite an expensive one.

 

[William_H]

I don't understand how a rectifier pack can increase output by ten times? Were you measuring the unrectified output when you got a reading of .1 amps? Most multimeters can only measure DC current and will give a false reading if you attempt to measure AC current.

The current was measured as DC amps into the battery. (using an analogue meter) So actual charge. I beleive the AC output of my engine was designed to drive 12v incandescant lamps off the AC.
By fitting a bridge rectifier the AC is turned to DC. The actual current into a battery on charge is very much dependant on voltage. or more specifically the charge voltage that is over the inherent voltage of the battery. So 13v might get some charge into a battery until the voltage of the battery rises with charge but 14v will give vastly more charge current.
So my first test was with a silicon diode bridge. Unfortunately a bridge has in effect 2 diodes in series each dropping .7 volt or loss of 1.4 volts. Schottky diodes tend to drop about .25 volt each so when I tried the schottky diode bridge it lost just .5 volt so giving .9 volt more voltage for charge so much more charge current.

A bridge diode is the common most efficient way to rectify AC. From one AC line we have two diodes a cathode and an anode connected. This means that if the AC cycle is +ve the current flows through the diode anode connected through tot he cathodse which is connected to +ve DC o/p. The other diode in effect steers the -ve half of the cylce to the -ve output. Two more diodes are connected to the other AC line each diode steering the AC pulse beit +ve or -ve to its appropriate output lead.

Now to confuse things my Johnson lighting coil has 2 coils connected together on one common wire. So one pair of diodes handles the common wire and 2 more pairs handle the 2 coil ends. I tried the 2 coils in series which sort of works but the 2 coils being displaced around the flywheel housing provide AC cycle out of phase with one another by about 15 degrees. So they are rectified separately to feed one DC output.

Schottky diode http://www.altronics.com.au/index.asp?area=item&id=Z0042

good luck olewill

 

[coopec]

Most multimeters can only measure DC current and will give a false reading if you attempt to measure AC current.

Eh?

My $A6 multimeter bought on eBay measures DC 200m - 600V and AC 200V 600V. On top of that it measures ohms and some other stuff

 

[Rigger Mortice]

Eh?

My $A6 multimeter bought on eBay measures DC 200m - 600V and AC 200V 600V. On top of that it measures ohms and some other stuff

But what are the settings for current rather than voltage?

 

[coopec]

But what are the settings for current rather than voltage?

Yes, of course you are correct. Thanks

 

[Fantasie 19]

Zagato - if you have such limited power requirements you may want to consider a golf trolley battery... they're smaller in size, as well as Ah, but much lighter than a full size battery, and therefore easy to take home between trips for a charge??

Examples here.. http://www.ebay.co.uk/itm/like/3107...ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=95&ff19=0

 

[Rigger Mortice]

The current was measured as DC amps into the battery. (using an analogue meter) So actual charge. I beleive the AC output of my engine was designed to drive 12v incandescant lamps off the AC.
they are rectified separately to feed one DC output........................
...........
...........
Schottky diode http://www.altronics.com.au/index.asp?area=item&id=Z0042

good luck olewill

Cheers Will. That all makes sense though I must admit that I'm a bit surprised at the scale of improvement.

The problem is to translate it into something the OP can use.

I think OP needs to start by telling us what engine he has. Somebody may know how much power (electrical) it churns out.
For just powering GPS and one light he won't need a big battery.

 

[Zagato]

Zagato - if you have such limited power requirements you may want to consider a golf trolley battery... they're smaller in size, as well as Ah, but much lighter than a full size battery, and therefore easy to take home between trips for a charge??

Examples here.. http://www.ebay.co.uk/itm/like/3107...ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=95&ff19=0

Thanks for that, maybe a plan. I'm not sure I am going to get much charge out of a 5hp outboard to even keep a 5" screen GPS going. There is nothing in the engine manual at all about charging but they do provide a charging lead! I will be away on the boat for several days at a time so do need someway of keeping the batteries charged. Maybe take 2 bigger batteries as weight in the boat is not a problem and they would put ballast where it is useful to have it.

I did buy a couple of 25W rigid solarpanels and a 'control box' so could maybe use one of those on the rear deck where there is loads of room. I can store it in the lazarette when not needed.

This however brings in another whole load of confusion which is why I didn't fit them on the last boat. I really need an idiots itemised drawing of how to wire it all up...

 

[LadyInBed]

Idiots guide, start here:
https://dl.dropboxusercontent.com/u/90169230/12volthandbook.pdf

 

[Rigger Mortice]

Thanks for that, maybe a plan. I'm not sure I am going to get much charge out of a 5hp outboard to even keep a 5" screen GPS going. There is nothing in the engine manual at all about charging but they do provide a charging lead! I will be away on the boat for several days at a time so do need someway of keeping the batteries charged. Maybe take 2 bigger batteries as weight in the boat is not a problem and they would put ballast where it is useful to have it.

I did buy a couple of 25W rigid solarpanels and a 'control box' so could maybe use one of those on the rear deck where there is loads of room. I can store it in the lazarette when not needed.

This however brings in another whole load of confusion which is why I didn't fit them on the last boat. I really need an idiots itemised drawing of how to wire it all up...

If your outboard has a charging/lighting coil then it will provide at least enough power to drive some basic navigation lights, so it should be able to power a GPS. However, if you don't give more information about what engine you have and exactly what equipment you want to drive, then people can only make guesses about how best to tackle it.

 

[BarryH]

I mainly use a solar panel to charge my batteries. 10 amp output per 100ah is a rough figure to work with. So working on your 20 watts you could if needs be have 2 100ah batteries. I think one would be more than enough for your needs. Wiring the solar regulator to the battery is a simple job. Most regulators come with a schematic diagram showing the inputs and outputs along with any fuses needed.
I leave my panel connected all the time. I have not suffered a flat battery yet. I run a plotter, sounder/log, vhf, nav lights and internal lights and also charge the laptop and phone on occasions.
The engine will put charge into the battery, most will only output a few amps, if run for a decent period of time. I use my engine to get on and off the mooring and when its calm. I'd say the solar panel puts 95% of the charge into the batteries. Its served me well so far.

 

[Rigger Mortice]

I mainly use a solar panel to charge my batteries. 10 amp output per 100ah is a rough figure to work with.

I think you meant 10 watts output

 

[Zagato]

If your outboard has a charging/lighting coil then it will provide at least enough power to drive some basic navigation lights, so it should be able to power a GPS. However, if you don't give more information about what engine you have and exactly what equipment you want to drive, then people can only make guesses about how best to tackle it.

Thanks for the responses. Yes understand RM, I will call to find out what output the outboard has tomorrow and dig out the solar panels etc

thanks