Daisy Chain UPS's?

[jonnyGURU]

In my minds eye, this doesn't seem like a good idea.

One of our guys wants to plug one 650VA into another 650VA to lengthen his battery time.

He's thinking that one battery could run off the other and then, once the one plugged into the mains dies, the second battery that the equipment is plugged into would power everything by itself until it dies; effectively doubling his battery life.

This seems to simplistic to me.

There's a reason why this WOULDN'T work, right?

 

[Zxcs]

I can't really think of why it wouldn't. It would probably also help keeping sensitive stuff up during brownouts (because if one cuts out the other runs off battery). Seems like a pretty good idea to me, however it may not double his battery live (somewhere like 1.9 times) since the 2nd may drain extra power to boost it's battery a little.

 

[Nobody]

Being in Tampa, I infer he is looking to do this as a short term fix for Hurricane based outages?

If so you can probably get away with it for awhile, but I would suggest speaking to the manufacturer of the UPS's to see if there is any change in the Sine patterns or other power changes that could kill this.

 

[jonnyGURU]

Hurricane? No. Actually this customer is in Boston.

I screwed up in an email and typed "two 100VA's. One for each of two modules" instead of "two 1000VA's."

The guy didn't lnow any better and actually looked for 100VA batteries. When he couldn't find them, he went with the smallest he could find. When I told him that I meant 1000 and not 100, he figured he could just plug one into the other.

 

[davidhammock200]

It probably won't work as the "stepped" output wave of the first UPS
will probably be seen a "dirty" by the second UPS, causing it to go on battery.

But hey, try it & see.

 

[Ice Czar]

http://www.dansdata.com/diyups.htm

"The charge circuitry in really classy commercial UPSes may do these periodic topping charges"

its doubtful those "classy units" would automatically know whats attached to em as well
some UPSs are expandable others are more problematic without testing and research

 

[jonnyGURU]

I told him to go back to the office and pick up two 1000VA's. One for each of two modules. I'm just not taking any chances with daisy chained UPS's.

 

[[Spectre]]

FWIW there are UPS's that you can "daisy chain" extra batteries with.....but if I have Ice Czar correct no way in hell on those POS's

 

[gee]

You can daisy chain UPSes.

But what's the point? just buy a larger one with twice the battery size. And it's not like you need that much runtime anyway - when your power goes out, you're rushing to shut your stuff down anyway...

 

[[Spectre]]

you're rushing to shut your stuff down anyway...

You are? *Currently no power, running on batteries in a closet, during a tornado*

 

[davidhammock200]

You are? *Currently no power, running on batteries in a closet, during a tornado*

Hey, please be safe!

 

[[Spectre]]

Hey, please be safe!

You lucky east coast floridian.....you miss this hurricane and we get the tornados it spawns



We will try. I only have another 16 minutes before the batteries go and I have to switch. I am suprised the router and cable modem are still up.

 

[Ice Czar]

personally Id say screw the computer and be using the UPS for the AC

you guys stay safe

 

[[Spectre]]

personally Id say screw the computer and be using the UPS for the AC

you guys stay safe

Well we survived for now. We are supposed to be in for this all night though

I switched to the laptop......but if it happens again I am just going to pull out the cot and sleep there and say screw it.

 

[davidhammock200]

personally Id say screw the computer and be using the UPS for the AC

you guys stay safe

Last year after Frances, we lost power for 10-days &
everyday I would take a 60lb+ APC Back Up Pro 1100 to the office & charge it up,
so we could have about 6-hours of fans at night!

What fun!!!!!!!!!!!!!!!!!

Glad you guys are safe!
Dave

 

[macrospect]

Jeez, at what poing to you go and buy a generator