Let me start with the short story. I'll add details if needed.
You'll need a SPDT (single-pole, double-throw) center-off toggle switch that can handle at least 6 Amps. Here are some Radio Shack part numbers that will work.
275-711 is 20A at 12V ; center off $2.69
275-325 is 10A at 125V; center off $3.29
275-654 is 6A at 250V; center off $3.49
The black battery wire needs to go to the shield of the charging jack and to both of the motors (negative side). The red wire needs to go to the center pin of the charging jack and the center terminal of the toggle switch. You'll want to cut one of the traces on the electronics board that leads to the charging jack (either one). This will take all of the existing electronics out of the loop.
Now you bring a wire from either of the side terminals of the toggle switch to one motor (positive side) and from the other side terminal of the toggle switch to the other motor (positive side) - the existing wires from the positive side of the motors should be removed first.
That's it. Push the switch one way for low pressure-high volume, and push it the other way for high pressure-low volume. Center position is off. I like to cut the toggle switch down a bit so it's not likely to get bumped when you toss the pump in your car. I also like to add a pressure gauge so I can monitor as it pumps.
I've been using a mid-2006 pump (after replacement of an earlier model due to impeller failure) and it's been working great. I think I've had it since August 2006 and have probably pumped up 10 kites/week on average since I got it. So it's doing pretty well
As mentioned I try not to move the pump at all when it's operating to avoid damaging the impeller, and I try to keep any sand from getting into it.
QUESTION: sometimes the battery seems to have enough juice for 3 kites, sometimes it barely fills one kite. (I normally leave my struts inflated on the bigger kites so I am only pumping the LE most of the time) The question is: what could be the cause of erratic battery charge, AND what can/should be done to maintain battery?
Hard to say why the charge is erratic, but it sounds like the battery might be on its last legs if it can only pump 1 to 3 kites (although that obviously depends on the size of kite).
Some important battery tips: these pumps use a sealed lead-acid battery (I believe it comes with a gel-cell). These batteries do not like a deep discharge. Unfortunately, this application is somewhat designed for deep discharge. The best thing to do is charge it frequently. Don't let it get very low. The lower you take that battery, the fewer charges you're going to get out of it.
Also, be sure to charge it with a proper lead-acid charge cycle. You don't want to let a gel-cell continue to trickle-charge for a long period. That will shorten the battery life considerably. The charger that comes with the pump is good that way. It will charge until the battery is full and then stop. But some folks seem to use a simple Radio Shack 12V walwart to charge it. Not a great idea.
Also, if you charge it from your cigarette lighter you might find you don't get a good charge - at least that's what most of us have found at 3rd Ave.
The good news is that those batteries have gotten pretty cheap. I've seen good 7 amp-hour gel-cells for $15 - $20.
vman wrote:Hi Spork
any idea how I can mod my 240v ac balloon pump to 12v?
I'm not familiar with your pump. I suspect it may be running on 12V internally, in which case you can bypass the power supply and run it directly on 12V. Otherwise you'll need a 240V inverter. Can you tell me more about this pump?
This one is listed as "not available" but would do the job. Google for more like this:
Well I just had a friend ask me to do the switch mod on her pump. So I finally got around to doing a better job of documenting the process. I have it as an MS Word doc with lots of pictures. I tried to attach it, but it's too big (about 2 megs). PM me if you'd like me to email a copy.