Quote:
Originally Posted by barx1963
Thanks for the detailed explanation John.
I have never had an issue with the Digifire 7 actually cutting out as I always carry spare batteries and simply replace it when the low voltage light cuts in. Of course I am not running Go To so my power usage is lower.
Kendrick have an interesting discussion of the reasons why they implemented this feature on the their website ( see http://www.kendrickastro.com/lvc.html ) which makes the reasons clear. Whether this is valid, I am not qualified to argue having just about zero knowledge of electronics.
Obviously whether this feature is seen by the OP as a positive or negative point in their circumstances would have to be left to them.
Malcolm |
Hi Malcolm,
Someone mentioned to me a few years ago that the low voltage cut out was to preserve battery life, which I take on board. On the Dew Buster website they say it is to ensure people don't flatten there car battery. Both reasons are plausible. The low voltage cut out on the Kendrick is stated as 11.6 in the commentary on their website (11.5 was a good guess). On both the Dew Buster and Thousand Oaks controllers the low voltage cut out is set at 11.2 volts. The problem with the Kendrick Digifire 7 in my case (and anyone mounting the dew controller on the UCA with powered poles) is that I had a voltage drop of .3 volts from the battery to the top end of the scope. Consequently, the Digifire 7 was shutting down when my battery was still at an actual level of 11.9 volts, which is too high. I have disabled the low voltage cut out on the Thousand Oaks controller with the built in switch. This means I never have a problem with the unit shutting down and keeping the dew at bay. Notwithstanding this and what Kendrick says and all the battery experts might say, I still get over 3 years of life out of my 12V 24AH SLA battery. I have replaced 2 in my jump starter pack over the past 8 years. The replacement batteries are well under $50 posted from EBAY. That to me is the best option to ensure dew free observing nights and I don't need to lug more than one battery with me when I travel.
Cheers,
John B