Newbie 12V Question

Submitted: Monday, Sep 11, 2017 at 20:52
ThreadID: 135583 Views:2851 Replies:3 FollowUps:4
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Hi! I'm sure this has been answered more or less in other threads, but I couldn't find exactly the answer. I apologise for that in advance.

I'm looking for a really basic solar setup to power a 12V pump to run the sink tap on the tailgate kitchen of my camper trailer. The tank is mounted under the trailer, and is currently tee'd to two hand-pump taps (one mounted on the outside of the trailer, and the other at the kitchen sink). I am replacing the kitchen sink one because it has never worked (plumbing had an air leak), and thought an electric pump would be a nicer option.

I don't really have any idea how practical this is, but googling suggests it can be done.

In my naivety, I thought about fitting one of those 12V / 4LPM diaphram pumps in the cavity beneath the sink (the pump would therefore be higher than the tank), to a tap of some sort, connecting the pump to a battery of some type, and connecting a basic 5W solar panel to the battery.

Can it be done that simply, or does it require switches, fuses, multiple-batteries, chargers etc? If a self-priming pump has 1.2m of prime, will it draw the water from the tank up to it? Does the length of the run from tank to pump have any impact?

As I mentioned, I'm trying for as basic a solution as possible.

Any advice / experience / or even specific products that would do the job would be greatly appreciated.

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Reply By: Tim F3 - Monday, Sep 11, 2017 at 21:15

Monday, Sep 11, 2017 at 21:15
You dont require solar to recharge batteries if you are only running a water pump intermittantly.

Just wire it to your battery with a fuse close to the battery..

5 watt solar wont do hardly anything.. I have 160 watt solar on my vehicle to support 60 litre fridge /freezer..

AnswerID: 613701

Reply By: Les - PK Ranger - Monday, Sep 11, 2017 at 22:03

Monday, Sep 11, 2017 at 22:03
Miko, do you have a 2nd battery in either the vehicle or camper ?
Do you run a 12v fridge (or freezer) ?

It might be worth just setting up a decent AGM battery of sufficient power, and enjoying the benefits of some led lighting above the kitchen, in the camper, vehicle camp lights, run a fridge > no more ice :) . . . and the water pump.
This is the pump I have > Boab water pump

A 2nd battery could be set up on the vehicle, but better to have on the camper so it is self sufficient for day trips out in the car away from camp.

If camping more than a couple of days you would need to set up a bit of solar to charge, and running the above items I mentioned, I get by with 100w or 150w folding solar blankets.
These ones from SCA are great value . . .
100w panel
150w panel

If you didn't want all the other stuff, then what about just a new more efficient hand pump for the kitchen sink duties ?
It wouldn't be getting that much use that it would be terribly inconvenient.
AnswerID: 613706

Follow Up By: miko1974 - Monday, Sep 11, 2017 at 22:29

Monday, Sep 11, 2017 at 22:29
Thanks for the reply, Les...

We have no additional battery in the vehicle. The LED lighting would be great but we've been managing without it. We have thought about a fridge but have decided against for the moment. So the pump and possibly the lights would be all we'd need in the near-term. Thanks for sending the pump and panel links.

Is it possible to set up a single battery to use as required and charge from the panels when not in use, sort of on-demand, without have to disconnect / reconnect (if that makes sense)?
FollowupID: 884211

Follow Up By: Les - PK Ranger - Monday, Sep 11, 2017 at 22:54

Monday, Sep 11, 2017 at 22:54
Neither a pump or led lighting really needs full blown, are you camping for only weekends ?
Or longer periods touring ?
If just weekends, the pump and leds could be run from a small 12v battery charged at home, and maybe not even need charging in the field.
You can run leds (eg small strips) from 6v, and I think even a 9v duracell battery would do it !!
Though I've only used 12v, but pretty sure they runn off about anything like mentioned.

With 12v, you still need to fuse for safety, but this can all be done on the trailer after input connection.

It wouldn't be easy setting up solar panels to charge 2nd battery while driving, although you could go to a flexible thin apanel and attach to trailer top perhaps if there was asuitable flat place to mount.

Probably easier to set up something in between what I originally suggested, maybe have a small enough AGM in the engine bay and charge via VSR.
Set up in a battery box perhaps, anderson plug connection, so it can be easily disconnected, velcro strap retainer released, lifted out and taken to the camper.

At the camper, just plug into anderson plug, through a fuse block to accessories.
You could say go for smaller AGM battery maybe about 80w, that would even handle a decent 40lt or so fridge overnight.
Otherwise you could start with a small 2nd hand normal wet acid battery if you wanted.
That would run a pump and lighting fine.

Set up this way, if touring you could just have it charging when driving, if camped up put the solar out and hook up to battery.

You need to assess just how you intend using for the short and mid term, because setting something up for led and a water pump is still going to cost maybe 80% of what a larger setup will, and then later if getting fridge / other you will need to upgrade a heap of stuff too, battery to hold power needs, larger solar to put power in during daylight to meet needs.

Think about setting up to meet current needs and perhaps mid term needs.
If budget is an issue, just go for cheap battery, charge at home, use to run pump / led strip(s), buy one of those folding solar panels (all integral with controller) and set it up to charge battery at camp.

Others might like to add to suggestions above, I'm just thinking what could be done, but don't know exact circumstances of your current and future needs and camping habits etc.
Time out will have a big bearing on the above options as mentioned.
FollowupID: 884215

Follow Up By: Bob Y. - Qld - Tuesday, Sep 12, 2017 at 05:40

Tuesday, Sep 12, 2017 at 05:40
Have a look at the Whitworths website here.

They have a large selection of pumps, both hand & 12v to choose from, as well as giving you an idea of what's available. They also stock LED lights & solar panels. Their mail service is excellent too!


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FollowupID: 884218

Reply By: Rangiephil - Tuesday, Sep 12, 2017 at 16:27

Tuesday, Sep 12, 2017 at 16:27
If you have a Breha manual pump (which is the most common), you can connect the electric pump through it with a momentary switch.

You then have the best of both worlds where if the battery goes flat you can still get water.
I don't understand your comment on the manual pump as if your plumbing is faulty then you have to fix that before fitting an electric pump.
The Breha is very simple and new washer kits are available if the pump is the problem.
Regards Philip A
AnswerID: 613719

Follow Up By: Zippo - Tuesday, Sep 12, 2017 at 18:07

Tuesday, Sep 12, 2017 at 18:07
Gawd, that takes me back. We had a Kombi camper in the 80's with one of those hand pumps. Too often you had dirty/greasy hands and trying to wash them (one pumping, one under the water flow) was bordering on ridiculous, and wasted water too.

I fitted an in-line pump just as you suggested, operated by a thigh-level momentary push switch at the front edge of the under-sink cupboard. Worked a treat.
FollowupID: 884234

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