Water Pressure

[JuniorBirdMan]

For a long time I've wished there was a little more flow in the shower when boondocking and using battery power to run the pump. While researching possible replacement pumps I ran across this little tidbit: "Voltage at the pump should be no less than 11 volts while running." Interesting. I ran right out and tested mine: 9.0 volts across the terminals while running with a battery bank showing 12.9 volts. Oops!

 

Apparently the three switches (master and two rockers) along with their relatively long wire runs and somewhat small gauge wire (not to mention the age of my Ollie, 6 years) all contributed to this excessive voltage drop. Fortunately, the fix was simple and cost less than 10 bucks.

 

First, a trip to the local auto parts store for a 12v relay, sometimes called a horn relay, rated at 30 amps or more ($7.00). Then, about 10-11 feet of 10-gauge wire and a few connectors. The old "hot" wire to the pump is used as the control and the new wire runs directly from the battery to the power terminal on the relay. Oh, yeah, an inline 10-amp fuse added to the red lead on the pump itself since this mod bypasses the panel protection.

 

The difference is amazing! Over 12 volts at the pump and a shower as good as when using the city water connection. I wish I had learned this years ago!

[ScubaRx]

Very good.

[mountainborn]

Great article Aubrey ! Any chance you might have photo's or part numbers ?

[bugeyedriver]

Aubrey,

 

Did your lights flicker a bit as the water pump was just about to turn off? If so, do they still flicker after your mod?

 

Pedro & his sidekick, Oscario

[JuniorBirdMan]

Larry: I tried to post a photo of the relay I picked up at Autozone for $6.99 but I keep getting the following error message: "Sorry, the board attachment quota has been reached".

Any 4-terminal relay rated at 30 amps or above (this one happens to be rated at 44 amps) will do. Photos would not be very helpful but I'll sketch out the schematic soon and try to post it here.

 

Pete: I never noticed any lights flickering but I'm not surprised because so much power is routed through the switch panel. Lights, pump, accessories, etc. This mod will probably eliminate that issue since only a small amount of current from the switch panel is being used to control the relay and the larger current is coming directly from the batteries.

[SeaDawg]

That's a great mod, Aubrey. So, with the addition of the relay, the water pump is still activated from both swtches--the outsid shower switch and the indoor switch by the sink?

 

I got the same message when trying to upload photos directly. I went back to using my photobucket account, making photos a two step process. I think small photos may still be able to upload directly. Not sure.

Sherry

[JuniorBirdMan]

Hi, Sherry. Actually all three switches, the two rocker switches AND the master switch on the panel at the entrance, still function as before. The difference is transparent; the relay merely allows the power to the pump itself to come directly from the battery via a larger gauge (and much shorter) wire.

[bugeyedriver]

Very illuminating, Tom.

[JuniorBirdMan]

The schematic, with no artistic talent whatsoever:

 

 

Horn relay terminals are all numbered the same (30,85,86,87) no matter the brand. The 10-amp fuse assumes your particular pump draws no more than 6-7 amps; the data placard on the pump should indicate the draw.

 

I found a convenient place to connect the new hot wire: there's an 'always hot' terminal under my inverter that worked perfectly.

[mountainborn]

Tom & Pete, you guys are just baaaad !

[DavePhelps]

This is a great mod. Has anyone notified the Oliver team about it so that it could be included into the standard wiring schedule?

The higher water pressure would be a great convenience, especially for speed of filling the water tank in areas with no direct hookups. The pump motor should last much longer as well if operating at the correct voltage.

Thanks for sharing.

 

Dave

[bugeyedriver]

I mentioned how effective it was to Robert Partee, in sales. Hopefully it does become standard practice.

[dstr8]

FWIW: Almost all our travels, with former off-road worthy trailers, was in "boon docking" fashion. In other words we were generally away from unlimited flow of water in between tank fill ups; sometimes a week or more at a time. So water conservation was key.

 

In addition to an inline pressure accumulator I used a kitchen style sprayer for our shower head. I timed the off-the shelf sprayer, sourced from Home Depot, at 3gpm. I was able to increase the pressure of the shower system substantially by placing a penny into the base of the sprayer that functioned as a flow restrictor. I think I drilled a 3/32" diameter hole in the penny...but worst case it will only take you a few cents to experiment .

 

Now we have a relatively high pressure shower system that flows at only .75gpm thereby allowing good shower water conservation for the times we don't have an unlimited water resource while in the outback. And the sprayer, with its simple on/off trigger allows military style showering...without too much sacrifice.

 

Just an FWIW/FYI.

[SeaDawg]

That was an ingenious solution to your problem, dstr8.

 

Our 2008 Oliver has a Scandvik faucet/shower with the cutoff. I don't know what the flow rate is, but I doubt it's much more than 1.75 gpm, and probably much less. Maybe I'll measure it one of these days.

We've used flow restrictors in a number of our home showers and faucets. Home Depot, Lowe's etc. carry inexpensive NeoPearl kits that fit most showers and faucets, but not all. I've ordered others online. Residential shower heads today usually are stamped or labeled with the gpm, which is really helpful in choosing a shower that fits your conservation style. I don't know if that process has carried over to the rv and marine world, however.

Years ago, I added a cutoff to the kitchen sink. It's a little gizmo that replaces the aerator, with a long pin attached. To operate the kitchen sink, I turn on the water, but have to touch the pin to actually get water flow. Beats trying to turn off a slippery faucet knob with soapy hands. I got ours at Home Depot in Asheville, but I don't think they carry them anymore. I bought replacements at an rv show. I think I posted a photo years ago. I'll look for it and add a link.

 

Here you go: http://www.instant-off.com/

Sherry