Re: [Paddlewise] Electric bilge pumps

From: Michael Daly <michaeldaly_at_rogers.com>
Date: Fri, 15 Aug 2003 18:10:08 -0400
On 14 Aug 2003 at 21:41, Dee Lutz wrote:

> Anybody have good luck with these and have a brand to recommend? 

When I investigated mine, I found that the Attwood pumps were 
consistently rated in terms of capacity and power requirements, 
while other brands tended to be overrated by their manufacturers.

The Atwood 650 (or 625 - whichever  - can't remember the exact size) 
actually take slightly less power than the smaller 450.  The 650's 
the one I chose, as it has the best performance for the amount of 
power reqd.  At full load pumping out the kayak with a good pile of 
water, I've measured the current draw at 0.9A, slightly below its 
rating.

There are a couple of other good pumps out there, but they weren't 
available locally.  IIRC Whale makes one.  There's also a new one I 
heard of that wasn't available when I purchased mine.  Web searching 
on bilge pumps will find info - look for the reviews in the boating 
magazines.

Mine isn't one with internal batteries - I put a battery pack in the 
rear compartment and wired thru the bulkhead (lots of 3M 5200 to seal 
the hole).  

Battery options include NiCd, NiMH and SLA (Seal lead acid).  I'd 
recommend NiMH or SLA (specifically AGM type).  Since NiMH can be 
considerably discharged repeatedly and safely, you can go with a 
lower overall capacity than with AGM.  For example, 1Ah NiMH would be 
roughly equivalent to 2-2.5 Ah of AGM since you can only discharge 
the AGM about 50% repeatedly and up to 80% occasionally. NiMH can 
handle 90-95% discharge without a problem.  Calculate the cost of 12 -
1.2V NiMH plus charger versus 1 - 12V AGM + charger and see what you 
prefer.  NiMH will no doubt be lighter - 12 AA size can easily be 
found with a net 1.6Ah capacity or greater.  Note that you want 12 
batteries, not ten, since 12V nominal for a boat is usually about 
13.5-14V.

Locally (i.e. Canadian $) 12 AA at 1.8Ah would be $48 and the charger 
about $50-60.  The 2.5Ah AGM would be about $35-40 and the charger 
about $26.  I bought my 5Ah AGM at a surplus store for $6.  YMMV

Mike

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Received on Fri Aug 15 2003 - 15:04:06 PDT

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