DC-Switches -- Reboot upon fast voltage drop !
Posted: Tue Sep 26, 2017 3:02 pm
We've recently noticed switches reboot when grid power drops.
Batteries are connected in parallel to the switch, and upon loss of grid voltage drops from ~ 27-28v to 24-25v and results in a reboot of the switch.
The switch comes back seconds later, and works just fine on the lower voltage.
This happens also with 48v systems (where normal voltage is in the 55-56v area and drops to 48-50v upon loss of grid power).
I'm tempted to say this is due to recent firmware upgrades, as we had years of service without this problem, with the same switches...
Obviously, these occurrences are not common (thankfully grid power is pretty stable), so can't say with certainty what's going on.
We did had about 10 such cases in August alone, and none before, at least not that we've noticed (August did not had particularly many power failures).
This is probably also related to another observation:
We've recently purchased a number of these chargers (Mean-Well PB-1000-48):
http://download.siliconexpert.com/pdfs/ ... asheet.pdf
The reasoning was to have good chargers for our large sites, to prolong the life of our (costly) batteries.
These sites use 4x200AH AGM batteries in series.
We liked the reputable 8-stage charging intelligence of these chargers.
Sadly, the Netonix switches (tested only with WS-8-150-DC models), reboot occasionally when the charger is in it's 8-stage mode.
They work fine when the charger is in the 3-stage mode, which is the solution we're using for now, at the cost of losing the benefits of these costly chargers.
Attached is an image of the Netonix's voltage graph upon connection of the smart charger... The switch would reboot when the charger is in it's float/trickle stage, especially in the 5am time frames (being the coldest hour - the chargers are temperature compensated {we're in coastal California - so it's never very cold}).
I think all the above are symptoms of the same problem - which I'm guessing got introduced into recent firmware of the DC-DC converter.
Thanks,
Yahel.
Batteries are connected in parallel to the switch, and upon loss of grid voltage drops from ~ 27-28v to 24-25v and results in a reboot of the switch.
The switch comes back seconds later, and works just fine on the lower voltage.
This happens also with 48v systems (where normal voltage is in the 55-56v area and drops to 48-50v upon loss of grid power).
I'm tempted to say this is due to recent firmware upgrades, as we had years of service without this problem, with the same switches...
Obviously, these occurrences are not common (thankfully grid power is pretty stable), so can't say with certainty what's going on.
We did had about 10 such cases in August alone, and none before, at least not that we've noticed (August did not had particularly many power failures).
This is probably also related to another observation:
We've recently purchased a number of these chargers (Mean-Well PB-1000-48):
http://download.siliconexpert.com/pdfs/ ... asheet.pdf
The reasoning was to have good chargers for our large sites, to prolong the life of our (costly) batteries.
These sites use 4x200AH AGM batteries in series.
We liked the reputable 8-stage charging intelligence of these chargers.
Sadly, the Netonix switches (tested only with WS-8-150-DC models), reboot occasionally when the charger is in it's 8-stage mode.
They work fine when the charger is in the 3-stage mode, which is the solution we're using for now, at the cost of losing the benefits of these costly chargers.
Attached is an image of the Netonix's voltage graph upon connection of the smart charger... The switch would reboot when the charger is in it's float/trickle stage, especially in the 5am time frames (being the coldest hour - the chargers are temperature compensated {we're in coastal California - so it's never very cold}).
I think all the above are symptoms of the same problem - which I'm guessing got introduced into recent firmware of the DC-DC converter.
Thanks,
Yahel.