DC pump

[George]

Has anyone found a durable, low wattage, 12V water pump?

[Rob Torcellini]

Most DC pumps have brushes in them and will usually be worn out in about 3-4 months.  There are some "brushless" DC pumps that you can get for under $100, but they are typically an AC pump with a small inverter built into the power cord.

[George]

Rob, which pump are you using?

thanks

[Rob Torcellini]

I've switch my off-grid system over to using a modified square wave inverter to run my pumps.  I'm sacrificing a bit of power to run the inverter, but it gives me a far better selection of pumps to use.

[Mark Hall]

You must have battery backup for nighttime use or do you use grid power at night?

Rob Torcellini said:

I've switch my off-grid system over to using a modified square wave inverter to run my pumps.  I'm sacrificing a bit of power to run the inverter, but it gives me a far better selection of pumps to use.

[Rob Torcellini]

It's completely off grid (painfully expensive to do!)  http://youtu.be/r3J4iROu1t4  I'll be speaking about it at the conference this September.

[George]

Thanks Rob.  I'm giving up on DC and going back to inverter.  

[Scott Roberts]

I'm running two brushless dc pumps in my system right now.  Low power draw, but I can't comment on long term reliability yet. 

[Rob Torcellini]

how many gal/min?

Scott Roberts said:

I'm running two brushless dc pumps in my system right now.  Low power draw, but I can't comment on long term reliability yet. 

[Johan Prins]

I haven't thought of DC pumps yet, but since I plan to run my pumps partially off-grid, maybe I should. For heating purposes you can get brushless DC pumps from Laing, Germany, but maybe 450liters/hour max isn't quite enough.

http://www.lowara.com/heating-air-conditioning-and-hot-water-circul...

Scott Roberts said:

I'm running two brushless dc pumps in my system right now.  Low power draw, but I can't comment on long term reliability yet. 

[Glenn]

Johnson CM10P7-1 Series Mag Drive Centrifugal Circulating Pumps are a good choice for 12 or 24 volt DC

Depending on model specs. they run from around 240 to 400 GPH.

The drawback is that they are NOT submersible but are in-line only. That isn't really too bad but most AP systems are designed around submersible. The Mag drive DC pumps Are all pretty limited to around 400 GPH or less but only draw around 60 watts where the brush type draws much more, is louder, and wears quicker.

[Johan Prins]

Thanks - I'll look at these Johnson pumps. The Laing D5 does only 119 GPH if I convert 450 liters / h correctly.

In the spec sheet, the Johnson pumps don't mention if the motors are brushless as on the Laing pumps.. anyone who knows more?

Just got my air pump and heater killed by a nearby lightning strike - "lucky" I have no fish in the tank yet, everything else in the house was apparently protected by the surge protector in the PC's UPS, or the almost full cable roller between the aquaponics and the house played inductor

Time to put a big surge arrestor one in the main panel, and a dedicated one in a panel for the hydroponics (it's hanging on 30ft of cable outside in the garden)

Glenn said:

Johnson CM10P7-1 Series Mag Drive Centrifugal Circulating Pumps are a good choice for 12 or 24 volt DC

Depending on model specs. they run from around 240 to 400 GPH.

The drawback is that they are NOT submersible but are in-line only. That isn't really too bad but most AP systems are designed around submersible. The Mag drive DC pumps Are all pretty limited to around 400 GPH or less but only draw around 60 watts where the brush type draws much more, is louder, and wears quicker.