Power supply for dinghy pump

[bromleybysea]

Having both dodgy knees and a dog I have decided to invest in an electric dinghy pump, the one I'm thinking of draws a max 25 amps. My battery box is rather inaccessible so I want to provide the pump with a plug, and socket connected to the boats supply. Should I take the lead from the batteries directly, or from the 1-2-off switch or main fuse which I think is rated at 80 amps? Not to sure as to the rating of the main supply from the 1-2-off switch to the main fuse though, it looks pretty hefty. Any advice as to the best options, and the type of plug and socket that would be suitable much appreciated.

 

[vyv_cox]

I have two Dri-plug sockets for this purpose, one in the cockpit and the other in the anchor locker. The supply runs off the main panel, which takes its power from the 1-2-both switch via heavy cables. The wiring to the sockets is protected by a 25 amp fuse.

 

[gregcope]

I have two Dri-plug sockets for this purpose, one in the cockpit and the other in the anchor locker. The supply runs off the main panel, which takes its power from the 1-2-both switch via heavy cables. The wiring to the sockets is protected by a 25 amp fuse.

Vyv,

What cable size did you use for those?

 

[vyv_cox]

Vyv,

What cable size did you use for those?

2.5 mm2 I think but it was a long time ago. 12 volt shop calculator suggests 4 mm2 but the inflator only runs for about a minute and all has been well for years now.

 

[myquest]

the one I'm thinking of draws a max 25 amps.

Do you mean 2.5 amps. A pump drawing 25 amps would be a bit excessive for a dinghy I would have thought.

 

[prv]

Do you mean 2.5 amps. A pump drawing 25 amps would be a bit excessive for a dinghy I would have thought.

No, he was right the first time. I have the same pump. It's a powerful little thing, you feel it kick in your hand as you press the button.

Wiring up a socket for mine is near the top of my job list. Because of the length of the cable run (I'm putting the socket in the anchor locker) I used my volt-drop spreadsheet and came up with 10mm² for the cables. I'm sure it would work with thinner ones and some drop, but presumably this would reduce its effectiveness.

Pete

 

[bromleybysea]

Definitely 25 amps. All the top- end pumps are that or more. That's why you can't just plug 'em in to your boats cigar type socket I reckon 2.5 amps would struggle to blow up a kids balloon!

 

[michael_w]

I spliced mine into the feed for the electric windlass. The plug and socket used was one from Marinco for an electric trolling motor.

 

[Rigger Mortice]

If it is the LVM inflator which has crocodile clips fitted then a couple of studs can be used instead of a plug and socket. Just wire the studs into the locker a few inches apart and clip on when needed.

 

[prv]

If it is the LVM inflator which has crocodile clips fitted then a couple of studs can be used instead of a plug and socket. Just wire the studs into the locker a few inches apart and clip on when needed.

And make sure never to have any loose metal items knocking around in the locker.

I think I'll stick with a plug and socket, thanks.

Pete

 

[Rigger Mortice]

And make sure never to have any loose metal items knocking around in the locker.

I think I'll stick with a plug and socket, thanks.

Pete

I've got a couple of studs like that (for a different purpose). Sensibly mounted they are absolutely fine. Cheap, robust and easy to use.

 

[RIBW]

Any advice as to the best options, and the type of plug and socket that would be suitable much appreciated.

Because we sometimes want to inflate a dinghy away from the boat we use (with a Bravo turbocharger -20A- pump) a portable 7Ah Sealed Lead Acid battery, in an insulated container.

http://www.maplin.co.uk/p/yuasa-12v-sealed-lead-acid-battery-7ah-1-pack-mg47b

It takes a few (too short a time to be bothered to measure) minutes to inflate a 2.5m Avon. Battery and pump fit in a small linen shopping bag and can be stowed any which way. We recharge slowly from a 12V socket or using a mains adaptor.

Yes, the battery costs but a Buccaneer mated pair doesn't come cheap (and I hate drilling holes in boats!)

Just a thought?

Bob

 

[Mudisox]

Because we sometimes want to inflate a dinghy away from the boat we use (with a Bravo turbocharger -20A- pump) a portable 7Ah Sealed Lead Acid battery, in an insulated container.

http://www.maplin.co.uk/p/yuasa-12v-sealed-lead-acid-battery-7ah-1-pack-mg47b


When I used to arrive by car with the dinghy in the boot, I used to just connect a suitable pipe to the exhaust pipe of the car and blow it up that way, simple and cheap just avoid topping up by mouth!

 

[Poignard]

I have a jump start pack on board for engine starting when the main battery is flat: This sort of thing:

http://www.clarketooling.co.uk/tools/info_760.html

I haven't tried it but I reckon it would be fine for powering a dinhy pump. Easily carried on deck and re-charged from a 230VAC shore supply or via an inverter

 

[Trundlebug]

Some way over the top solutions being suggested IMHO

I have a cordless dinghy pump which is charged from the cigar socket. Bought it at the boat & leisure show at the NEC a few years ago.
Like this http://www.camping-intl.com/details...=google_base&gclid=CMS85pXvqL4CFcLItAodj1cAgw
It inflates the dinghy really quickly - about 2-3 mins each side on a 2.6m dinghy.
The rechargeable battery last ages, I've only recharged it once in about 5 years and it's pumped up the dinghy fully from flat at the start of each season.

Powerful too - just 2-3 pumps with the footpump afterwards to get the final pressure.
Charges from a standard 12v power socket, no massive currents. Or the mains when available.
No wires to trip over or be too short!

Not sure why anyone would consider anything else to be a better solution!

 

[30boat]

There was an article on PBO years ago about a LVM inflator that was connected to a motorcycle battery all neatly enclosed in a wooden box with a handle.It didin't seem very hard to make and with a modern AGM battery there would be no worries about spillage.It was recharged by connecting to the boat's battery bank.

 

[RIBW]

Because we sometimes want to inflate a dinghy away from the boat
Bob

Perhaps I should have been more explicit about my specific application? We inflate buoyancy tubes to between 150 and 200mbar. If we use the spare dinghy (3m Avon), the airdeck has to be inflated 750mbar.
Cheers
Bob

 

[TSB240]

I have found the most convenient high capacity supply in the cockpit is via the existing Bulgin socket for our tiller pilot. In most cases these are wired directly back to the battery and are fused with a 30 amp fuse if I recall. I have found this is excellent for plugging in Anchor light, Dinghy Pump & Cockpit tent light. I also use it for connecting our solar panel when I am not using the Tiller Pilot.

 

[prv]

I have found the most convenient high capacity supply in the cockpit is via the existing Bulgin socket for our tiller pilot. In most cases these are wired directly back to the battery and are fused with a 30 amp fuse if I recall.

That's rather a generalisation! Surely they're wired however the person who installed the tillerpilot saw fit, which may or may not be according to the instructions and (since they're usually retrofitted by owners, of varying competence) may or may not be sane or safe. I certainly wouldn't plug a 25-amp load into a tillerpilot socket without checking on the wire size and fuse or breaker. The one on Kindred Spirit wouldn't have been up to it.

Pete

 

[TSB240]

That's rather a generalisation! Surely they're wired however the person who installed the tillerpilot saw fit, which may or may not be according to the instructions and (since they're usually retrofitted by owners, of varying competence) may or may not be sane or safe. I certainly wouldn't plug a 25-amp load into a tillerpilot socket without checking on the wire size and fuse or breaker. The one on Kindred Spirit wouldn't have been up to it.

Pete

Both of my boats are wired according to the manufacturers installation guidelines using 2.5 mm tri-rated cable which is rated up to 30 amps!

I may be wrong about the fuse size but the worst that could happen is the fuse would blow if it is rated at less than 30.

I agree some installers might skimp on cable size which is stupid given the minimal extra cost and benefit of a larger diameter cable.

I run an electrical controls business. One of the first things that gets my attention on any boat is the quality of crimped connections,wiring size, breaker and fuse sizing as an electrical fire is IMHO the worst hazard at sea.

I spent a useful stormy weekend last, tracing a cable that had been directly wired to the battery without a crimp, no fuse and bare wires exposed in the aft locker next to the Ob petrol tank!