PV orientation [RE-wrenches]

Fri Aug 23 15:25:28 PDT 2002

Windy is having some ISP vs. Topica problems, and could not post this, so asked me to post it.

Dave Nelson wrote:

>Allan and all,
>Here'smy 2 cents worth on the ETA pump system. We installed a livestock watering system, on a remote ranch, the beginning of June 2002. Upon initial startup the system worked correctly. Within a week the rancher called me and told me the pump was no longer producing water. When we went to the well site and completed the testing outlined in the manual we found the AC side of the controller had failed. I called Dankoff at the pump site and, after some discussion with the Dankoff crew, including Windy, a new controller was shipped out. A new controller was received and installed within two days. The ETA pump system has been working flawlessly since the new controller was installed. This ETA pumphas a very low serial number ...

Windy Dankoff's reply:

Etapump IS a new product, with over two years of field trials. However, some necessary improvements were made for this year's intro to the US market. Some potential weakness showed up, including the one that caused your first unit to fail. The last weaknesses was resolved shortly after your purchase. Also, factory testing has been expanded to simulate greater potential field extremes.

>This ETA pump ... was sized under the original sizing sheet. The pumps maximum output was sized for 5.3 gal. per minute, however I've never seen more than 4.5 gallons per minute, in full sun, with a tracker. To their credit the guys at Dankoff have revised their sizing sheet.

Yes, the German developer lacked full appreciation of the extent of loss factors that occur in the real world, including extreme cell temp and PV modules whose output may be less than NOMINAL specs, but within the specified % tolerance per warranty. Our new sizing table (Version 2, July 18) incorporates 28% total loss factor from nominal output rating of the PV. This reflects "worst case" situations including wire losses to the allowable max. Our problem now? -- Some dealers want higher numbers because we are too conservative!  -- However,I sleep better at night.

>There is only one quirk that really "toasted" me at the well site. The controller has a bizarre screw terminal angle that requires the screwdriver to be at such an angle as to almost be impossible to tighten the terminal screws ...

Understood -- The problem of tool interference was corrected in June.

>... that you can barely get the appropriately sized wire into.

The terminals are industrial (DIN) standard to take #6, but the case has limited access and bending space.

>The solution: when I installed the second controller I removed the control board from the control box (four screws), added 4 in. jumpers of the appropriate wire to the screw terminals, put the control board back in the control box, and wire nutted the system wires to the jumpers.

We have a more convenient fix that makes it easy to handle small pigtail wires in case your pump cable is >#10. It also adds pulling space, and makes it easy to get a meter on the output wires. We recommend a 6" square J-box immediately below the controller's output, connected with 1 1/4" conduit. This is part of a whole pole-mount assembly that we devised using common parts. Since I put details and photos of this in the manual (I think you just missed it), we stopped getting complaints like yours. Anyone can download the Etapump instruction manual from dankoffsolar.com.

I started this project with great enthusiasm and high hopes for Etapump. I maintain that attitude in light of our current results. The manufacturer has been extremely responsive and a pleasure to work with, and deserves enormous credit. Thanks all of you for your continuing interest.

Windy Dankoff

Michael Welch

------------------------
"I always wanted to be somebody, but I should have been more specific."
			Lily Tomlin

Michael Welch, michael.welch at homepower.com
     Home Power magazine
     www.homepower.com
     To reach me: 707-822-7884
     To reach Home Power: 800-707-6585

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