Solar panel to keep up with auto bilge pump

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I have a friend who keeps a wooden folkboat on a swinging mooring. Like most wooden boats it leaks a bit. It is fitted with an automatic bilge pump and he has on one occasion come back to find water over the cabin sole and a flat domestic battery.

I reckon the simple answer is a flexible solar panel just crocodile clipped to the battery when he is away from the boat for any length of time.

Any problems with this, how big a panel would the team recommend and cheapest source please.

- W
 
I am not going to camp on my friend's boat for a fortnight noting when the pump comes on, so we need some approximations here.

Can we assume for this calculation that without any input a 100AH battery will go flat (sufficiently flat to not run the pump) in 10 days?

- W
 
A 30watt solar panel should be enough, but I'd go for a solid one not a flexible one.

Try

http://www.aireandsun.co.uk/

for advice and excellent delivery.

(You might just need a regulator to stop the battery overcharging, with a 30 w panel.)
 
Other poster are right, but I've had a 5w panel connected to a pump for 3 years without problems other than a faulty switch. This had to cope with an open deck of approx 9' x 11' so had to pump a fair amount of rainwater!
Panel was vertical and faced south, which would make a difference...
 
Instead of an electric pump why not one of those wave-driven ones? Quite a few chandlers have them and cost-wise probably about the same as a decent solar panel. I think that's what I would use if I had Border Maid on a mooring.
 
[ QUOTE ]
Can we assume for this calculation that without any input a 100AH battery will go flat (sufficiently flat to not run the pump) in 10 days?


[/ QUOTE ] Based on that assumption I would agree with Sarabande's suggestion of 30 watts. But it is an assumption apparently without basis.
 
The other way to look at it is to calculate (roughly) how much water was in the boat when it did flood, and over what time period it took to get that much water in. That, at least should give you an idea of how long a pump will be on for, for a given gph rate.

Calculations are all very well, of course......
 
On my previous boat (1938 gaffer, complete with a permanent leak) I had the smallest Rule auto bilge pump and an 11w flexible solar panel, connected to a 55 Ah battery. It was in the water from April to Oct most seasons and I never had a flat battery - the bilge pump was the sort that would switch on every 2 minutes and carry on running all the time there was water to pump out. I suppose a float switch type would be more economical provided the bilges weren't filling up too quickly.
 
When I fitted automatic pumps on my previous boat I also fitted am electro-mechanical 12 volt counter across the pump so I could see how many times the pump had switched on during the time I was away.

The on time would be fairly constant so the amount of water pumped in each cycle could be accurately estimated so the power could be estimated quit accurately.

It can also be estimated as to if the leak is getting greater by an increase in pump cycles over a constant time.

web0754.jpg
 
Can't help thinking that your friend has:
a. a big hole in his boat, or at any rate a very substantial leak; or
b. a battery which is well down on capacity; or
c. long periods between visits.
Pump on my boat is alleged to pump 500 gallons per hour and a 3 amp fuse is recommended.
So how much water was removed before the battery finally gave up? maybe the top priority is to reduce the amount of water coming in, and then think about a solar panel ...
 
[ QUOTE ]
I have a friend who keeps a wooden folkboat on a swinging mooring. Like most wooden boats it leaks a bit. It is fitted with an automatic bilge pump and he has on one occasion come back to find water over the cabin sole and a flat domestic battery.

I reckon the simple answer is a flexible solar panel - W

[/ QUOTE ]

The simple answer is a nice thick layer of grp over the hull and deck. Wood is good for decoration and for toothpicks, but not for boat hulls I reckon.
 
[ QUOTE ]
So how much water was removed before the battery finally gave up?

[/ QUOTE ] It's more a question of a float switch on a swinging mooring - water in the bilges sloshes around and so it comes on rather a lot even if it only has to pump a little water each time.

It's a wee boat and the saloon bilge isn't very deep, so we are not talking about the pump giving up because it had too much water to pump - it is much more a function of how many cycles it went through before the battery gave up.

I reckon 15A is probably plenty and won't need a regulator. Flexible because it is a wee boat and so that will be easier to stash - there isn't anywhere to fix a decent size solar panel on a folkboat and it isn't needed when the boat is in use.

Thanks to everyone, even if some of you did seem determined to make it more complicated than it really is. It's a budget boat and KISS is the watchword.

- W
 
[ QUOTE ]
The simple answer is a nice thick layer of grp over the hull and deck. Wood is good for decoration and for toothpicks, but not for boat hulls I reckon.

[/ QUOTE ] Yeah, right. No-one every did any serious sailing in a wooden boat.

Thank you so much for your helpful opinion - now awa and bile yer heid /forums/images/graemlins/smile.gif

- W
 
I've got a UniSolar 10w panel which sits on the lazarette and feeds 2 x 85AH deep cycle batteries. The boat electrics are all switched off except the Navtex and the auto bilge pump. Navtex is Furuno [fully dimmed < 8 mW] and the Rule 360 submersible pump with a homemade very very simple 'tank tender' type CMOS controller + pump which when operating draws 18 Watts - Bilge capacity as set is ~50 litres ( say 11 imp gallons or 13 USA gallons) ..... There's also a simple 6V Plastimo mechanical counter which counts the number of times the pump has clicked in. You can work out the 'AH' or whatever --- It's worked on my leaky boat for the past 8 years /forums/images/graemlins/smile.gif and the batteries remain fully float charged ... and the boat (CO26) hasn't sunk.

Cost (inc VAT): Rule 360 £12.00 then now ~ £16.00; CMOS controller and ancillaries: £6.00 ..... = Peanuts. AND IT a) WORKS and is b) maintenance free for say ~10 years.

Is Steve Birch around? This is something that he could make/ market and secure his/mine retirement /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif
 
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