Sunday, June 12, 2011

HPV-22/HPV-22B Solar Controllers

Newer LD with factory-installed solar panels are equipped with the HPV-22B controller. It is quite similar to the previously used HPV-22 controller, but with one important added feature: it has a switch to set the charge level depending on whether you are dry-camping or hooked to shore power. The HPV-22B in shore power mode limits the charge to 13.2V. The power converter is set to 13.6V. . . . If you flip the HPV-22B to Dry Camp mode, or if you only have an HPV-22 with no shore power mode and bright sunshine, it will bring the system up to 14.6 or so. That probably explains why folks have to add water to the batteries frequently if they do not have an HPV-22B.

Actually, there is a solution for HPV-22(non-B) owners. You can do the same thing that the "B" models do with their switch. If you are replacing a lot of water in the batteries, and concerned about the 14+ readings the HPV is giving, you might want to follow the advice of Dave Reuter of AM Solar:

'The best solution to your issue is to purchase a new HPV-22B so that you can switch the charging mode to a 13.2 float voltage ("shore power"). The other option is to change dip switch (located in the upper left hand quadrant of the circuit board) # 2 to from "norm" to "low". This will change the charging set point to 13.2V just as the "dry camp/shore power" switch does. Obviously, this is not real convenient as it requires that you remove the 4 face plate screws and pull the controller out of the wall to access the dip switch block. By the way, the Bulk/Taper set point voltage setting for the HPV-22 is 14.3V.'

If you remove the unit from the wall, you'll immediately see the row of dip switches on the upper left of the back panel; flip the #2 switch, and reinstall. You should see battery water use drop dramatically.

It is super easy to upgrade to HPV-22B. The boxes are identical and can be swapped in, in about 10 minutes. You can order an HPV-22B from AM Solar, and they may give you credit for the HPV-22 after you return it to them.

Given that the non-B model has the dip switch arrangement, you could probably modify the original by adding a toggle switch to it. It wouldn't be quite as clean as a real 22B, but it should work the same.

Contributor: Jon, Dave

12 Jun 2011