Endurance testing of overbatteried UPSes?

[eccerr0r]

Have anyone done some endurance experiments with UPSes with larger than specified batteries attached?

Meaning, if a UPS was designed with a 7Ah battery, how hot does it get if you ran it twice as long with a 14Ah battery pack, would it survive? What about 70Ah?

I wonder what the typical overdesign UPSes have; likely not much. Perhaps at lower utilization, say ¼ the rated load, the UPS will have no problem powering the load indefinitely?

I wish I had a long wave infrared camera to check out hot spots...

[Per Hansson]

Re: Endurance testing of overbatteried UPSes?

If it has a fan it will be no problem, lots here have done such mods in the past.

[petehall347]

Re: Endurance testing of overbatteried UPSes?

should be fine with a fan . i have done it lots of times and ran them for hours .
even with fan some seem to have a timer and switch off after a certain time like 20 minutes or whatever its set to .

[eccerr0r]

Re: Endurance testing of overbatteried UPSes?

Yeah definitely a lot of people have done it, but I wonder of any failures... and how hard they're being used...

Any difference between the high frequency models and the low frequency models?

As I picked up one of my UPSes, I was wondering why it was so light, not because there was no battery in it, but it appears to be one of those high frequency switching PSUs versus line frequency switchers. While not a problem in itself, there could be some correlations...

[kc8adu]

Re: Endurance testing of overbatteried UPSes?

i have a bunch in use on a solar bank.
the rules are.
1. old metal apc or best power. old rack mount metal heavy units of other brands can be good too.

2. added fan that comes on in inverter mode.
3. extra heatsink on charge regulator.
4. replace all caps(they are bad from age and heat)
i get 6 month to 1 year take out d31 truck batts and they do fine on my modded ups units.
most of my neighbors have these setups too.
only failure so far was a direct lightning strike on the service entrance.
this wiped out everything in the house and their insurance had to replace everything including the breaker panel and some wiring.
some more rules to heed.
if it has a plastic case its most likely junk.
if the heatsinks are just little blocks its junk.it has a firmware timer too.

[eccerr0r]

Re: Endurance testing of overbatteried UPSes?

Ah... that's something... how prevalent are the timers? That will be annoying, so they actually time out even if you have a very light load?

I suspect the plastic denotes lightweight high frequency inverters. I haven't seen any line frequency inverters with plastic cases due to the extreme weight of those transformers...

I have a Best Power 1KVA standalone UPS (metal, low frequency, has AVR) which I despise now due to it requiring 18V. Thought that I could get more than a year out of a set of batteries, but it ate them. The 12V ones I have unfortunately is only 300VA (metal, low frequency), 550VA (plastic, high frequency) ... how long they'd survive a bigger battery I don't know...

[kc8adu]

Re: Endurance testing of overbatteried UPSes?

Ah... that's something... how prevalent are the timers? That will be annoying, so they actually time out even if you have a very light load?

I suspect the plastic denotes lightweight high frequency inverters. I haven't seen any line frequency inverters with plastic cases due to the extreme weight of those transformers...

I have a Best Power 1KVA standalone UPS (metal, low frequency, has AVR) which I despise now due to it requiring 18V. Thought that I could get more than a year out of a set of batteries, but it ate them. The 12V ones I have unfortunately is only 300VA (metal, low frequency), 550VA (plastic, high frequency) ... how long they'd survive a bigger battery I don't know...

18v= 3 golf cart batteries.
super runtime.

[eccerr0r]

Re: Endurance testing of overbatteried UPSes?

Where to get good ones cheaply (and multiply by three) is the question!

[ktmmotocross]

Re: Endurance testing of overbatteried UPSes?

do not recommend it.
battery charging current is capacity/10
44Ah= charging current 4,4A

charger unit will overheat
low charging current is bad for battery, because u charge it much longer and its life is reduced
if u overpower it, some ups start get missing power from batteries and slowly kills them

as ups must be to work everytime, this is not a good way

[eccerr0r]

Re: Endurance testing of overbatteried UPSes?

we know there are potential issues, alas, some UPS ... if not a LOT of UPS ... are overdesigned, and that's the query here: what's the chances of getting an overdesigned unit. The batteries are the limiting factor in runtime.

Yes ideally the batteries are recharged as fast as possible without boilover, but leaving them discharged is worse. You also have to consider the depth of discharge too - if the larger pack discharges a smaller percentage, the pack will last longer, so that too needs to be part of the equation.

What do you mean by overpower with batteries, the UPS should not be get any energy from the battery pack unless line power is down. It doesn't matter what the size of the pack is.

[ktmmotocross]

Re: Endurance testing of overbatteried UPSes?

we know there are potential issues, alas, some UPS ... if not a LOT of UPS ... are overdesigned, and that's the query here: what's the chances of getting an overdesigned unit. The batteries are the limiting factor in runtime.

Yes ideally the batteries are recharged as fast as possible without boilover, but leaving them discharged is worse. You also have to consider the depth of discharge too - if the larger pack discharges a smaller percentage, the pack will last longer, so that too needs to be part of the equation.

What do you mean by overpower with batteries, the UPS should not be get any energy from the battery pack unless line power is down. It doesn't matter what the size of the pack is.

i mean overpower like u have 1000W and u get 1100W from it. some ups like IMCO get power from batteries when overpowered

[eccerr0r]

Re: Endurance testing of overbatteried UPSes?

That seems like a bug or questionable feature - it should warn if you use more power than the batteries are capable of on their own. At least my 1000VA UPS does warn if one is using near full capacity. If it was caused by poor wiring, that's another issue altogether.

In any case, running full power isn't exactly conducive to getting maximum battery life, that 1000VA UPS would run my machine for almost an hour on its stock batteries because I was nowhere near 1KW, but it'd be nice to get a few hours of runtime.