Wanted: Pinout for Minuteman Alliance A425 UPS proprietary serial cable . . .

Not really - it is a 425VA UPS (about 275 W). Here's the DB-9 pin outs.

This is a 10 year old UPS and no doubt the batteries are gone by now. I'd scrap it and buy a 350VA APC UPS next time it is on sale at Staples for $30.

Travis, Hey thanks for the reply! Yeah, I checked out the link you gave, and it defiantly states it is a

275-watt output unit. But I don't get it. What is the 425-VA rating if not power in watts?

Oh, and thanks for the 'Staples' tip. I will defiantly stop in and check that out! By the way, you have also given the APC units rating in units of "VA". So, does this mean that it will be less than 275-watts output?

- Stan Shankman

VA means volt-ampere.

It's basically an AC power term which takes into account phase and inductive loads. It's not my area of knowledge, so perhaps someone could elaborate.

Dave

Yes, the 350VA UPS is 200W. Of course they also make bigger sizes, for more $$$. For most applications where you have a home PC and just need 'ride through' capability for those intermittent power glitches, the

350VA system is fine.

awtb

Sorry, I should probably have added 'reactive loads' as well.

Dave

I still don't understand.

Isn't one VA equal to one watt? A watt is a volt-amp.

How can a unit be both 425 VA and 275 Watt?

No, a VA is not equal to a watt. To understand this you need to understand the differences between measurements of power for DC and AC. Try reading my post and following the link.

Dave

Dave D,

Hey, I did finally read that power-factor FAQ sheet you so nicely pointed me to, and yes, it did answer all of my questions.

So, thanks for that!

I also had the thought of just using a car (or deep cycle) battery with my unit but upon further reading, discovered that I might have problems that way with completely dead battery charging. This is so, presumably, because a dead battery presents a larger load to the existing charger. So I'm wondering if anyone can speak about that issue.

I have been checking around on eBay and Craigslist for used UPS units, and it seems reasonable to expect I might find a good used rig that way.

Also, for your information, I have found a few web sites that do sell replacement batteries at what appears to be very good prices. - Half (or better) of what one would expect to pay locally! So if anyone needs a battery, you should check around on the web. I know I was pleasantly surprised to find these reasonable prices. (Prices very widely, so keep checking for the least costly ones.) I have also noticed that enterprising individuals are buying lots of old UPS units and then replacing the batteries with these new cheap replacements and then selling the refurbished units on eBay - again, at what seems like very reasonable prices. - That may not be a bad way to go.

Thanks for the help,

- Stan Shankman K7SJB

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my

Glad it helped :-)

I was going to try that myself a few years ago- I wanted to replace the existing batteries with car batteries. I think I reached the same conclusion as you did.

Dave

Yea; don't worry about it. I put 50AH batteries on my 900VA SmartUPS that had ?6-8? AH originally. Yes, it charges slowly. It may take a few days.

But the charger puts out what it can, and the resistance of a discharged

6AH string is not much different than a discharged 50AH string.

And it was nice having a UPS that lasted ~24 hours under light loads...

But forget the car batteries; use deep-cycle ones.

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