Electric bilge pump users?

JohnAbercrombie

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I'd like to get feedback from paddlers who have set up electric pumps in their boats, since I think it might be possible DIY a working pumps system with a LiFePO4 battery at lower cost than the EK system.
After more research, I think that the LiFePO4 batteries are probably too heavy. It looks like a battery pack using 18650 lithium cells would be better.
Those are the cells in almost all the power tool lithium batteries.
The battery pack is definitely the tricky part of doing a DIY setup. Using a power tool battery and charger might be a simple solution. It's too bad that most lithium packs for power tools are 18 volts or higher. The M12 Milwaukee packs are only ones I've found.
BTW, battery packs are often specified by how many cells are in series and parrlel inside. So, starting with 18650 cells which are 4.2 volts max when fully charged, we'd need 3 in series to get 12.6 volts to run a bilge pump. If each cell is rated at 2.5 amp-hours (2500 mAh) a 3s2p pack with 3 pairs of cells in series would build a 12.6 volt 5mAh pack.
In theory a 2.5 amp hour pack should run a Rule 500 pump for more than an hour, so quite a few pumpouts of an average cockpit.
Things I've learned in the past little while:
Charging lithium batteries isn't the simple task that charging a lead acid or sealed lead acid is; there needs to be a battery management system (BMS) controller in the battery pack OR an 'intelligent' controller in the charger. Some power tools have a BMS in the tool to prevent over-discharging the battery.
 

DavidDeWitt

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I have used this NiMH battery successfully with a Rule 500 pump. Quite small and reasonably light

 

AndyM

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Disclaimer: I'm more of a - "if I can't fix it, it will break" kind of person.
For example, on long trips, I used a kayak with a rope skeg (as opposed to cable).
So I wouldn't use an electric pump.
However, they certainly would save you in a pinch.
And I certainly agree on the company (EK) being top notch.
An alternative might be a foot pump, don't know where (or if) they are available anymore.
I've had one instance in my paddling days when I could have used an electric pump:
A serious flip exiting Forster/Tuncurry bar (Coolongolook River, Australia). The sprayskirt imploded, so, after rolling back up I had a cockpit full of water - still in outgoing flow - against incoming surf. Luckily, I was able to paddle out of the turbulence (out of outgoing flow and outside of surf zone), then able to hand-pump out kayak.
Next town I got to, I ordered a foot pump (from NDK). I also picked up a spare hand pump to carry (realizing the reliance I had on the pump). I completed my trip before the foot pump arrived, so I never installed it.
 

Jasper

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An alternative might be a foot pump, don't know where (or if) they are available anymore.

Yep, still being made:

I've had a few foot pumps in a few kayaks and have been pretty happy with them, they empty the cockpit as fast as any electric pumps I've seen and it's just always there, no fussing with batteries and stuff.

I've had a battery operated attwood waterbuster when I was guiding/teaching. It was nice for emptying a clients hatches without interrupting the teaching process, but it lacked in durability.
 

SZihn

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Shoshoni Wyoming
A thought I have is to see about getting a good pump company to make one of these but with a great improvement in quality and power. If Anna (my wife) can get some time, I may pet her on the project. She's a design engineer and can get most of the sub-assemblies through her professional confections.


So it could be used like the manual bilge pumps and un-lashed from the deck bungees when needed, but it could be dropped in the cockpit and turned on so it would pump at the same time a person is doing their reentry.

The entry tube could be only 2-3 inches long and the exit tube should be made of pliable rubber or plastic, good to very cold temps. It needs to reach outside the cockpit on any boat, and at any practical angle, so I'd make it 3 feet long. If the buyer needs less he can cut off what he doesn't need. The housing and switch should be made like a scuba light. Such lights exist now and are good to deep water pressures and work fine.

The pump needs to move a lot of water fast. I am thinking of a battery pack using 6 nine-volt batteries to power a pump using 1" I.D. bores, and moving about 40 gallons a minute. Most the sub-assemblies are made now, but no one is putting them together in the way kayakers need. Batteries need to be kept fresh, but they don't go dead very fast if you don't use them a lot. You'd only use the pump at times when it's needed, and even keeping extra batteries in your kit is not a big deal. Just something you'd need to keep in mind.


With such a pump no modification to the kayak are needed at all, and no wiring to fuss with at all. When needed, slip it behind your back-band or seat back and turn it on. At 40 Gal Per Minutes most of the kayaks we use now would be down to "sponge depth" in 60 seconds or less. A very large cockpit that was as swamped as it can get would still be close to empty in less than 2 minutes.


I need to find out what it will cost to get all the sub-assemblies and I may end up machining a few of the caps and/or battery housing myself, but if such a pump can be made and sold for under $200 I am betting a LOT of kayakers would want one. If it existed now, I'd pay that much to get one.


If you capsize it's nearly always in rough water so hand pumping means you can't be using your paddle at the same time. A hand-free pump would be a very nice thing to have in such situations but the one I want to make needs no holes drilled, no wires run, no problems with the switch and no issuers with placement.
 

JohnAbercrombie

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I have used this NiMH battery successfully with a Rule 500 pump.
Thanks for that link, and that idea.
NiMH batteries have some real advantages over lithium ion batteries - fewer shipping restrictions, less complicated charging requirements, and cheaper, too.
Did you find that the NiMH battery held its charge well between uses? One problem I had with the SLA battery in my pump setup was developing a routine for checking and charging it.
 

JohnAbercrombie

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I need to find out what it will cost to get all the sub-assemblies and I may end up machining a few of the caps and/or battery housing myself, but if such a pump can be made and sold for under $200 I am betting a LOT of kayakers would want one. If it existed now, I'd pay that much to get one.


If you capsize it's nearly always in rough water so hand pumping means you can't be using your paddle at the same time. A hand-free pump would be a very nice thing to have in such situations but the one I want to make needs no holes drilled, no wires run, no problems with the switch and no issuers with placement.
:thumbsup::thumbsup:
Take that idea and run with it!
:)
 

JohnAbercrombie

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I've had a few foot pumps in a few kayaks and have been pretty happy with them, they empty the cockpit as fast as any electric pumps I've seen and it's just always there, no fussing with batteries and stuff.
Thanks for that info. My only experience with foot operated pumps was in the galley on my sailboat. Even filling a cooking pot with water seemed a fairly slow process, but that was probably because of the narrow bore spout on the sink fixture.
Do you remember what type of foot pump was in those boats?
On some of my kayaks there's not a lot of 'foot freedom', on others the rudder pedals restrict options. I guess a foot pump really needs a bulkhead footrest and a high deck?

I've had a battery operated attwood waterbuster when I was guiding/teaching. It was nice for emptying a clients hatches without interrupting the teaching process, but it lacked in durability.
I didn't know about those; thanks for that idea.
 
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JohnAbercrombie

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A serious flip exiting Forster/Tuncurry bar (Coolongolook River, Australia). The sprayskirt imploded, so, after rolling back up I had a cockpit full of water - still in outgoing flow - against incoming surf. Luckily, I was able to paddle out of the turbulence (out of outgoing flow and outside of surf zone), then able to hand-pump out kayak.
Thanks for posting that 'real world' example. Paddling a kayak with cockpit full of water - keeping it upright in rough conditions - is not an easy thing to do!
:thumbsup::thumbsup::thumbsup:
The only time I used my electric pump was in a 'rough water' clinic and my paddling partner was nearby in case my 'solo reentry' didn't work. By the time I got back in the boat there was about 8" (?) of water in the cockpit - a lot- and the boat felt quite unstable. It was nice to be able to concentrate on bracing and paddling while the pump emptied the water. BTW, it's necessary to open the sprayskirt (at the side?) to allow air to enter the cockpit when the pump has run for a while. I saw the skirt being pulled down and felt my drysuit legs inflating- I guess air was being pulled from the upper suit area because of the 'vacuum chamber' being created under deck. There are definitely some advantages to skirts with zipper openings whether using a manual or electric pump.
 
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CPS

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John, if you're pursuing Lithium batteries, consider looking into those used in model airplanes and the like. High energy density for lightness and space efficiency, and they are necessarily compatible with various chargers available. NiMH batteries are in my experience not as good at holding a charge when not used, and more subject to gradual voltage loss than LiPo. They are however much less delicate.
I have a 5000mah (I think, been a while since I've used it) LiPo that puts out 24(ish) volts. Weight and dimensions are similar to a stick of butter.

That said, I've seen both type of batteries 'discharge' when damaged, and both are fairly spectacular. Not something I would want to have happen at my feet in an enclosed cockpit. However, a reasonable amount of precaution and a hard case would likely be sufficient.
 

JKA

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I've seen both type of batteries 'discharge' when damaged, and both are fairly spectacular. Not something I would want to have happen at my feet in an enclosed cockpit.

I envisage a scenario: "Okay, so your kayak has exploded and is on fire and sinking! Manage the resulting mess. Oh, and you have no legs!"

:oops: ;)
 
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JohnAbercrombie

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John, if you're pursuing Lithium batteries, consider looking into those used in model airplanes and the like. High energy density for lightness and space efficiency, and they are necessarily compatible with various chargers available. NiMH batteries are in my experience not as good at holding a charge when not used, and more subject to gradual voltage loss than LiPo. They are however much less delicate.
I have a 5000mah (I think, been a while since I've used it) LiPo that puts out 24(ish) volts. Weight and dimensions are similar to a stick of butter.

That said, I've seen both type of batteries 'discharge' when damaged, and both are fairly spectacular. Not something I would want to have happen at my feet in an enclosed cockpit. However, a reasonable amount of precaution and a hard case would likely be sufficient.
Thanks for that info.
Right now I'm looking at Li-ion batteries, not Li-Po. Most of the power tool battery packs use Li-ion 18650 cells in series-parallel.

The battery for the Expedition Kayaks pump kit just arrived a few minutes ago. I'm going to do some charge/discharge tests on it and then I'll probably void the warranty and have a look at what's inside. :)
I'll post any interesting results here.

A bilge pump with its ~2 Amp draw is a 'kinder' load than some of the tools and model aircraft with higher current requirements.
In theory, the BMS board in the battery pack should prevent most problems.
The self-discharge when not being used is one of the biggest problems - in the event that I need the pump, I want that battery to have plenty of energy. That's one of the big advantages of lithium cells
 
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JohnAbercrombie

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I envisage a scenario: "Okay, so your kayak has exploded and is on fire and sinking! Manage the resulting mess. Oh, and you have no legs!"

:oops: ;)
I hope you aren't typing on a laptop/notebook computer. :)
Whenever I see folks doing that, I envisage the scenario: "Okay, your notebook computer battery has exploded and you have no hands or eyes. And...your house is burning down!!
:)
 

JohnAbercrombie

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Update on FPV-Power Battery 12v 7Ah.....
The battery for the Expedition Kayaks pump kit just arrived a few minutes ago. I'm going to do some charge/discharge tests on it and then I'll probably void the warranty and have a look at what's inside. :)
I'll post any interesting results here.
I unpacked the battery and charger, and read the instructions:
The FPV-Power instructions:
Charging with standard 2A Charger
1. Plug the supplied 2A charger into the wall and check that there is a green light on the charger.
2. Plug the battery into the charger. The light on the charger will turn red.
3. Once charging is completed, the light will turn green. You cannot over charge our batteries as there is an automatic cut-off.
Plugged the charger (a small 'wall wart' unit)- green LED on charger, connected the charger and battery - still green LED.
Funny.....perhaps the battery was shipped fully charged???
Check the battery voltage ... 11.2 volts - 50% charged...
Oh, well...plugged the battery and charger together again.
Checked back in 6 hours...battery voltage still 11.2 volts
Checked charger output....erratic 9-10 volts....
Emails off to Mariner-Sails (Canadian/US seller of battery) and FPV-Power.
I don't expect a reply till Monday (today is Saturday)..

Not a good sign.
I have electrical and electronic test equipment - what about 'innocent' buyers who put their trust in FPV-Power?

NB: I didn't break the seal ("Warranty Void") on the battery pack!! :)
 

JohnAbercrombie

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Update:
After forwarding my complaint to every email address I had that was associated with FPV-Power, I got a reply on August 25.
Summary:"Our Canadian distributor will test a new charger and battery and send them to you. Please return the defective unit using the prepaid UPS label."
Replacement was shipped on Aug 30 and arrived today. Charger works and battery pack is now charged to 12.6 volts (full charge for 3 Li-ion cells in series).
Inside the battery box is a shrink-wrapped bundle of six 18650 Li-ion cells with a BMS board.

On to the install - drilling holes in a boat...:eek:
 
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JohnAbercrombie

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Backflow preventers:
I did some 'quick and dirty' testing this morning to get an idea of pump flow rates.
Pumping in and out of a bucket:
Hand pumping with a Harmony pump: 7 US gallons/minute
Rule 500 pump with backflow preventer installed: 5 US gallons/minute
Rule 500 pump with Whale (larger) backflow preventer: 6 US gallons/minute
Rule 500 pump with no backflow preventer: 9 US gallons/minute
So the 'removable bung in the outlet' instead of a backflow preventer in the discharge line would be the option to choose if faster pumping was the goal. Removing that 'blabbermouth' preventer makes a big difference, and the larger Whale preventer beats the stock Rule pump version.
Food for thought, for me.
Keep in mind:
The advantage of the electric pump is not speed but the fact that the paddler can be bracing and paddling while the boat is being emptied.
And my hand pumping speed will reduce minute-by-minute, unlike the electric pump which as been pumping for 90 minutes in the back yard, using a Li-ion battery pack.
Also:
There's an old marine adage: "Not many pumps are as good as a scared man with a bucket!"
After Tzu Hang was pitchpoled W of Cape Horn, Beryl Smeeton yelled as she climbed back aboard: "I know where the buckets are!!"
 
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