> welded relay contacts. Evil. My UPS rarely has to engage, if it's also relay-oriented (likely) it hasn't had to survive a stress-test like that. I would call it consumer-grade crap, but it has done excellent work. In a truly evil power environment, I'd be tempted to deploy one of my two FerrUPS systems. They're definitely pro gear, but large, noisy, and inefficient. (I have a 3kVA and a 7kVA unit.) The smaller one was free, the larger I paid $200 for. The SmartUPS was $35. I also have a SmartUPS 3000XL that I've never used, which also was free. All were sans batteries, effectively.
I am amazed that I've gotten 16 years of service out of my batteries, and counting. (Well, only 12 out of one of them.) These are sealed AGM batteries, definitely more expensive than a regular deep-cycle battery. With what battery prices have done in recent years, I am NOT looking forward to their eventual replacement. > So, yes, I do have reason to suspect my SmartUPS 700 is not equally as good. If that photo is of your 700, it looks exactly like my 2000. I am surprised, but then all four of my larger UPSs are 48V units, not 24V. So there's at least _some_ difference in the charging circuitry. Mine had an external battery pack, styled like the UPS itself. (All four batteries dead when I got it, as expected. For the same price as the special small batteries that'd fit inside the cute case, I could buy 75AH big batteries that would not, but that would run my gear for hours if necessary. It wasn't much of a decision, given that I had plenty of space for the big batteries to hide in the basement of my computer cabinet.) > Wanting to have a maintaining operation going on, I decided to purchase a > BatteryMINDer OnBoard Battery Desulfator/Conditioner (OBD24). When I > first got it and connected it to the batteries connected to the SmartUPS > 700, the light on the OBD24 blinked like it is supposed to. After a while, > though, it stopped. I don't know if the threshold of the OBD24 changed or > if the SmartUPS 700 decided to lower its charging voltage, but if the > voltage across the two batteries is raised 50 - 100 mV, the OBD24 works. > That is why I am using the two 12117TCs. I thought about rigging up a DC > supply with a current limiting resistor to add a little current to the > battery string to raise the voltage above the threshold, but just have not > gotten around to doing it. This scenario is disturbing. You have THREE different battery chargers connected to each battery, and you're proposing a fourth. All three are 'smart', and could well be interfering with each other. The UPS, if it's at all like mine, periodically tests the batteries by putting them under load. (Frustratingly, it is unable to supply power UNLESS it thinks the batteries are good. So, in the event of battery failure it goes from UPS to NPS, rather than falling back to whatever duty cycle your utility can supply.) So: three guys in the front seat wrestling over the steering wheel. But, if it's working for you then you've gotten lucky. > P.S. The little voltmeter is not very accurate; I know that. My Fluke 77 > does not have as many digits as I would like to be able to really see > what is going on. The Fluke 87 has one more digit of precision. I have two of them, both used, both acquired at pawnshops for around $100 each. -- Jim _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
