Battery and auxiliary items

1ThOFA87 · 28 July 2009, 23:57

Has anyone on this forum been able to use a battery to power items such as gps, fish finders, lights and baitwells? I'd seen a battery box that's advertised as a "power station" at Cabelas. I guess it allows you to plug items into the box after inserting the battery but the reviews weren't particularly great. Does anybody know anything about this or any other methods of powering aux items?

If you use a battery, where do you mount it? Does it need to be far away from the gas tank? Can it go in a cooler (does it need ventilation)?

Poly · 29 July 2009, 07:43

Do you want to charge the battery from your engine or do you simply wish to run all your electronics and charge it when you get home? I assume if you don't have a battery at the moment that your engine is manual start (pull cord). Do you have power out from the engine (e.g. a "lighting circuit").

If the plan is to go out for a day and recharge when you get home, then how long will you go out for?

Traditional lights put a big drain on batteries. LED's would allow you to use a much smaller battery - but are expensive to buy.

I don't know anything about bait wells - but imagine that they could drain a battery quite quickly.

Most people like their batteries in a ventilated area away from their fuel tanks. Sparks would happen when connecting/disconnecting batteries or if there is a fault - and fuel tanks should also be in well ventilated areas (fuel is heavier than air - so vents need to be at the bottom of any box).

Batteries only really need properly ventilated when they are charging (hydrogen is lighter than air so needs vents at top of box).

If it is any help I have a "Jump Start Pack" (sold in car accessory shops for when you leave your lights on etc). Which I have hard wired into my boat. The engine charges it up. It starts the engine, runs lights, bildge pump etc. It has a 12V cigarette lighter type socket so I can charge my h/held radio, phone etc if required. I went this way as it was already in a box, it came with a mains (240V) trickle charger, it had an "isolator" switch built in etc. All for less than the cost of the cheapest battery I could buy! But it is a fairly small (21Ah) battery so is only suitable for small engines, and needs the engine to charge it [I also have proper manual start on the engine - so if electric start fails it is not an emergency]. It is not properly waterproof but lives inside a locker on my boat and has been fine for 3 years (despite getting wet in a big stuff that partially filled the locker!)

jyasaki · 29 July 2009, 15:38

As Polwart says, you'll need a surprisingly large battery if you're going to a) power stuff for long periods of time, and b) depend on them for safety.

You should see if your motor has a charging circuit, in which case it would be a simple matter to connect a battery which would be charged as you run the motor. In that case, a smallish car battery should be fine.

If it doesn't have a charging circuit, well, I'd guess that a baitwell would be out, as that little water pump would suck current pretty quick.

jky

1ThOFA87 · 29 July 2009, 23:13

This is great advice guys. thanks! So how do I know if I have a charging circuit. I brought my 20 year old 25 hp mercury from a boat shop a few years ago and have no manual. What does one look like?

thornbackflound · 30 July 2009, 09:06

Quote:

Originally Posted by 1ThOFA87

This is great advice guys. thanks! So how do I know if I have a charging circuit. I brought my 20 year old 25 hp mercury from a boat shop a few years ago and have no manual. What does one look like?

you may be able to down load a manual ,,,,,,,,,have you tried googling MERCURY,,,,,,,,,I do beleive marinar had something to do with mercury ,the earlier models or the otherway round ,not sure i will find out for you

m chappelow · 30 July 2009, 09:46

with some older engines there is 2 wires from the wiring loom just hanging there ,they are for charging the battery ,only problem is you will need to get a rectifier,to go between the battery , even one from an old 12 volt motorcycle will do , if you just connect the wires to say a bulb it will just get brighter untill it burns out as you increase revs ,,though some engines have recifiers built in ,

jwalker · 30 July 2009, 18:55

Quote:

Originally Posted by 1ThOFA87

This is great advice guys. thanks! So how do I know if I have a charging circuit. I brought my 20 year old 25 hp mercury from a boat shop a few years ago and have no manual. What does one look like?

At that age, you may find your engine is actually a Yamaha Origin engine rebadged. If it is a Yamaha motor and if it doesn't have a voltage regulator (which most don't) there will be two unconnected wires, both green, coming from under the area of the flywheel. If they exist, they are coming from the charging/lighting coils (Not to be confused with the ignition charge coils.). They give out AC current which can be rectified and used to run navigation lights or charge a battery. From memory, I think the open circuit voltage is about 18v but it will drop substantially when a load is connected. If you wish to run electronic equipment you must not connect it without having either a voltage regulator connected to the green wires or a battery connected to them - preferably both a regulator and a battery for proper current and voltage regulation.

Try This thread from 2003.

m chappelow · 30 July 2009, 19:46

Quote:

Originally Posted by jwalker

At that age, you may find your engine is actually a Yamaha Origin engine rebadged. If it is a Yamaha motor and if it doesn't have a voltage regulator (which most don't) there will be two unconnected wires, both green, coming from under the area of the flywheel. If they exist, they are coming from the charging/lighting coils (Not to be confused with the ignition charge coils.). They give out AC current which can be rectified and used to run navigation lights or charge a battery. From memory, I think the open circuit voltage is about 18v but it will drop substantially when a load is connected. If you wish to run electronic equipment you must not connect it without having either a voltage regulator connected to the green wires or a battery connected to them - preferably both a regulator and a battery for proper current and voltage regulation.

Try This thread from 2003.

once towed a boat back in ,this young lad no experience had bought a speedboat with no electrics ,so he fitted lights radio ect ,wired up engine straight to a battery ,,,no rectifier ,,,and 20 mins later boom went the battery .acid everywhere ,,,,his tart wasent to impressed when her clothes started to disintergrate later on.

Sharkbyte · 30 July 2009, 21:01

I doubt very much whether a charging circuit is of any use on SIB if you have a 'reasonable' sized battery fitted.

Our Mariner does not have one and we happily run GPS, VHF (both never turned off)sounder and raw water livewell all day / night long on a 50Ah battery. It usually comes home with 12v remaining.

There's a little trick to saving volts when running a big livewell. Fit a pulse width modulator (fancy type of speed controller) in line with the transom pump.

No need to have it running full chat, so turn it down.

Ours is fitted on the console.

Unlike a regular speed controller, it loses naff all due to resistance, thus saving your battery. The added bonus is that it retains 100% torque to the motor when running slow, and doesn't wreck the brushes.

Wayne

Poly · 30 July 2009, 21:33

Quote:

Originally Posted by Sharkbyte

I doubt very much whether a charging circuit is of any use on SIB if you have a 'reasonable' sized battery fitted.

not sure what you mean by that or what you would consider reasonable. IIRC my 20 HP engine's "charging" output is rated a 7 A. (I would guess it probably does less at tickover/trolling speed). Since you have a 50 Ah battery I'll assure that is "reasonable". In reality it will only usefully give 25 Ah of power.

Your VHF and GPS are probably drawing 1-2 Amps (except when VHF transmitting). I guess the bait pump uses a similar power to a bilge pump so is drawing another couple of amps.

So the net draw is probably similar to the net input at trolling speed, and the battery should remain charged throughout. On the other hand your 50 Amp battery - with no "topping up" will probably give a maximum of 6 hrs operation until its output reached inadequate levels and by being continually "deep cycled" will not last very long.

Sharkbyte · 30 July 2009, 21:34

Sorry, forgot to mention that they only cost a tenner or so.

Sharkbyte · 30 July 2009, 22:21

Hi Polwart

I suspect the figures that you are quoting are not accurate. If our battery had run out of steam after only 6 hours, I'd either have bought a regulator for the motor or a bigger battery.

Without hunting for my manuals, I have had a quick search on the net for power consumptions of my electronics.

VHF quoted as 0.5A, GPS 0.8A at max power.

Presuming 1.3A and the 25 AH figure you quoted, this should give give me at least 19 hours operation for those two.

The sounder uses 0.8A at max power, very unlikely in a shallow North Sea, and is switched off except when motoring.

I suspect the pump uses a fraction of what you think. When testing the efficiency of the PWM, I had it pumping water for over 24 hours on a 7Ah alarm battery before I got tired of hearing running water outside and switched it off.

Having checked, the battery we are now using is a Leisure 685L. It seems that this is not 50AH but 85 and costs / weighs in at about the same as a 50. That said, we had quite happily been using Halfords 50A batteries in our boats up until we replaced them at the start of the summer. The old ones lasted for over 3 seasons before noticeably tailing off.

Poly · 30 July 2009, 22:29

The pump was a total guess - since I have never really looked at one, and obviously you have taken steps to reduce its consumption. But I think I understand what you are suggesting - that a big battery may be fine without charging.

prairie tuber · 31 July 2009, 03:28

Worth a look - very efficient batteries for their size & weight that can be deep cycled.

http://www.odysseybattery.com/battspecs.html

1ThOFA87 · 31 July 2009, 13:34

Quote:

Originally Posted by m chappelow

once towed a boat back in ,this young lad no experience had bought a speedboat with no electrics ,so he fitted lights radio ect ,wired up engine straight to a battery ,,,no rectifier ,,,and 20 mins later boom went the battery .acid everywhere ,,,,his tart wasent to impressed when her clothes started to disintergrate later on.

That's one way to get her clothes off...

1ThOFA87 · 31 July 2009, 13:42

Quote:

Originally Posted by Polwart

not sure what you mean by that or what you would consider reasonable. IIRC my 20 HP engine's "charging" output is rated a 7 A. (I would guess it probably does less at tickover/trolling speed). Since you have a 50 Ah battery I'll assure that is "reasonable". In reality it will only usefully give 25 Ah of power.

Your VHF and GPS are probably drawing 1-2 Amps (except when VHF transmitting). I guess the bait pump uses a similar power to a bilge pump so is drawing another couple of amps.

So the net draw is probably similar to the net input at trolling speed, and the battery should remain charged throughout. On the other hand your 50 Amp battery - with no "topping up" will probably give a maximum of 6 hrs operation until its output reached inadequate levels and by being continually "deep cycled" will not last very long.

All of this sounds too complicated for me. I'll probably just keep things as is and be safe. Maybe get a portable Hummingbird and forgo the lights. I don't usually go out at night anyway. M Chap's story is really scary! thanks for all of the great advice though!!!