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Small Cabin Forum / Off-Grid Living / 12 volt water pump
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# Posted: 21 Aug 2020 19:21

I had a friend ask to use my camp over the past week...turned out to be seven people for seven days...wowzeee.

As far as lights/fans, no issues...Loving the new Chevy Volt set up. Gobs of extra power for 30+ LED lights and 5 fans ( w.DC motors and LED lights) from a paltry 24 volt system.

Water was a different story. I have a 60 gallon pressure tank that I use as a reservoir and, well, pressure, and a 40 gallon propane fired hot water tank.

Typically fine when by myself but they needed to fire up the remote controlled genny to pump water from lake to blue tank 4 x a day and run the genny when doing dishes, ( shower yet).

Ok so I need a larger holding tank...understood...My original intent was to get a 325 gallon holding tank and mitigate the refill but I've been told that it will not solve the "recharging" of the pressure tank and it will lose pressure before you run out of I gain nothing by adding the reservoir.

Assuming this is true I'm considering getting rid of the blue tank and just install a 12 volt pump, Shurflo etc.

This would necessitate a 12 volt battery obviously as I've run 90' of line from the battery bank to the bldg.
So I can't tap off my battery bank.

So my question is assuming a rather heavy water use how long would the 12 volt battery last before it would need to be recharged.

Or even better, could I run a 110 Shurflow off my 4 kwh lithium battery bank

# Posted: 21 Aug 2020 20:51

So baring your water source your trying to change over your setup from generator power to 12v or 120v via a battery bank?

What's keeping you from running your current pump via your battery bank?

12v is not going to travel 90' very well with out spending big bucks on wire. They do make 120v surflow pumps. Either way your pressure tank should still be used. This allows the pump to run and stop while your still useing water. Without a pressure tank the pump can cycle very fast. Start up current can be alot so the less you start the pump the less power you use and the longer the pump will last.

You need to get a pump with enough GPM that it has more demand than your shower/faucet.

I believe amazon has a decent 5gpm pump for about $100, it may be 12v though. For your needs I suggest you get a 120v pump.

# Posted: 22 Aug 2020 00:27 - Edited by: ICC

I'm not sure I understand the problem the guests were having. Running out of stored water or????

It sounds like you have the inverter in the cabin and the battery pack 90 feet away, with cables bringing the battery voltage to the cabin. If so....

...There are DC to DC converters. Samlex is one brand, there are others. Samlex has some that can accept an input range, like from 20 to 30 or 30 to 60 VDC and put out 12 VDC or 24 VDC, depending on which model. Samlex has many. They are reliable. I have a couple in different uses. FWIW, they also make step up versions and same in and out voltage, that act as a regulator to maintain aa steady output from a wandering input. You have 24 VDC in the cabin, hook up a DC-DC converter to supply 12 VDC and hook a standard Shurflo up to the 12 volt output.

With a Shurflo one does not necessarily need a pressure tank. Their pumps are designed with a built in pressure switch and have no problem cycling on and off each time a valve is opened and closed. Almost every RV has a Shurflo or a Flojet or some Chinese or Indian copy. Shurflo does make a small pressure tank for those who must have one but they do not recommend them. The Shurflo in my bus RV is 15 years old, has seen a lot of use and still runs with no maintenance being needed. Some folks don't like hearing the pump run but I like it as if I hear it cycling and know I'm not running water myself, then their is a leak or a faucet not turned all the way off.

# Posted: 22 Aug 2020 05:42 - Edited by: rachelsdad

I probably didn't word the post well, sorry for the confusion.

What's keeping you from running your current pump via your battery bank? It's a big AC motor wouls kill battery bank

Yes, the issue is running out of stored water...which I had told them would happen and I explained how to use the remote on/off on the genny to recharge, (fill), the pressure tank...takes about 5 minutes, if that.

My 24 volt bank is inverted to 120 at bank and travels 90' at 120 to the breaker panel in the cabin. I have 4 1 kwh Chevy Volts. I have apprx 20 led lights that are rated at 4 watts each, (40 watt LED) and 5 fans w/DC motors that use 2 watts on low...which is MORE than adequate.

IF I were to go 12 volt I would add a seperate battery under the cabin, cables would be a few feet long.

I guess the question is does it make more sense to run a 120 pump.

This -45-psi-115vac-no-cord?variant=13250332491819&c1=GAW_SE_NW&source=PLA_USA_SS&cr2=smar t_shopping__-__all_products_112768&kw=6527_13343_0&cr6=pla&cr7=c&utm_campaign=gs-2020 -01-06&utm_source=google&utm_medium=smart_campaign&gclid=EAIaIQobChMIkeS4jcKu6wIViYrI Ch1W0wj1EAQYAiABEgJubPD_BwE

seems pretty efficient

# Posted: 22 Aug 2020 05:54 - Edited by: Brettny

I that that pump in 2.9gpm. It's a bit small. The gpm rating is with no head pressure. XHYXQ6T5FMB&dchild=1&keywords=shurflo+water+pump&qid=1598089958&sprefix=Surflow%2Caps %2C187&sr=8-10

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