venomous21 wrote:


To re-cap, I want to protect my ac adapter and laptop...which means taking my battery out of my laptop and plugging into a UPS but don't know if A) the adapter can provide all the juice and i'll damage the laptop. I would keep the battery in but again read that you shouldn't plug a laptop with battery into a battery backup UPS.

venomous21, I passed over the battery on battery action because it wasn't the point I felt needed making, but I left out some additional stuff I thought of but didn't have time to put in right then 🙂

First, I have used laptop's on an APC UPS, as well as power strips - which is also a "no-no", and I never fried anything. I tested performance, voltages, battery heat and charging on the UPS vs Wall socket, monitored the UPS / etc - and I couldn't detect any measurable difference between running on the UPS and the Wall socket.

I had the same need, protecting my electronics against way outback mountain power... it's rough stuff.

I got a 120+lb isolation transformer. It was normally used for large demo booth floor conference participation. It was contained in a beat up box/trolly - but inside the box it was a pristine giant isolation transformer and more than flattened out the power 🙂

That thing was a fixed installation solution after it was mounted in place in the lake cabin. For traveling I got the largest Triplett AC filtering as normal AC power allows - about $250 per socket - with 4/8 filtered outputs. Haven't looked for a while, but last I looked they were still available.

There are newer active power filtering systems that will likely solve your problem too, but be more expensive - or less - it has been a while since I looked.

What I am saying is, yes you can try running with the battery in your laptop plugged in to the UPS on a standard power strip and you should be ok. Watch temps of battery and charging cycle - length of time to charge from a set % just to make sure things are acting normally.

But, better would be to get a good power line conditioner and use that in front of the stuff you want to protect.

As an aside, that mountain power snuffed a Macintosh in 20 minutes before I got the isolation transformer, so I know what you are worried about.

My Convergent UNIX tower had really good power conditioning built in, and didn't mind the mountain power 🙂

I hope that helps!

And, always keep your battery in your laptop 😉

venomous21 wrote:
I would love to get a line conditioner or isolation transformer for the house but doubt the wife will approve the expense with a baby on the way.

This article is from 2004 but doubt much has changed with our grid since that time. http://www.geek.com/xyzcomputing/daisy-chain-your-ups-571188/

Tripplite said:
No, I would not recommend daisy-chaining your UPS units. When your UPS goes into battery mode, it outputs a modified sinewave, which will be interpreted by the second UPS as a power surge. The second UPS would then channel the current back into the first UPS. This is potentially hazardous and will result in damage to the first UPS and probably the second.

optiUPS said:

Yes, It is feasible and safe if your two UPS are sinewave machine (not stepwave or simulate sinewave).

APC Says:

4) “In most cases, daisy-chaining UPSs does not allow for extra run time. If you are using a UPS that outputs a step-approximated sine wave when on battery, as soon as the fist UPS goes on battery, the second UPS will also go on battery because it will see the step-approximated sine wave as distorted or bad power. Both units will discharge together, and will not provide any extra run-time to the load.”

Obviously, I'm not daisy chaining UPS (or care about extra runtime) but basically my laptop with battery acts as a UPS so it is similar. Also, my APC ups does use a step-approximated sine wave. As such, assuming this information is correct, I could possibly damage my laptop if I use it with battery plugged into a UPS battery outlet during a surge or power outage.

If I don't care about my laptop's battery life (since I rarely travel), will plugging my laptop's ac adapter (without battery in the laptop) into a UPS battery outlet protect my ac adapter & my laptop will function normally and not be damaged (as long as the UPS remains in tact)? I want to make sure my ac adapter can provide the necessary power with the laptop battery removed.

venomous21, the laptop battery system isn't a UPS. Don't confuse the issue, they are not comparable. There is no problem plugging your laptop in to a UPS.

And, it's completely unnecessary to take out your battery from the laptop. Your laptop on AC power will not run the current through the battery. The battery is not in the circuit to provide power to the laptop while on AC.

The laptop will switch over to the battery power when the power stops coming from the AC input.

If you run your laptop without it's battery (unnecessary in every way) while plugged in to the UPS, and you kick out the AC cord from the laptop, more common than you might imagine, your laptop will immediately cease to function and you will lose the data not saved in open applications, and you might get your disk contents corrupted because Windows didn't get a chance to save cached data - and if the power outage occurs during a disk write - also quite common - the last write will be corrupted.

Your chaining UPS sine wave analogy - makes no sense when applied to a laptop battery. The battery is only in circuit while there is no AC power coming in. The AC to DC power converter in the laptop is still running while on AC power so that is the only consideration.

The laptop while on battery is using Direct DC from the batter and converting to various DC voltages as need internally, it isn't converting battery DC to AC and then converting back to DC to use in the laptop 🙂

You can use your UPS, plug in your laptop, leave the battery in, and you have isolated your AC Adapter from the incoming AC house power.

I always buy 1 or 2 spare power adapters for my laptops, as you can't just drive down and buy one should it fail. I keep one at home, one at work, and one in my bag, then I am never left stranded with only 3 hours left of battery life before my laptop is a useless dead weight 🙂

I hope that clears it up for you 🙂

If not, you can contact the UPS maker directly and ask them. You can call, email, chat with the support for your UPS and ask the same question(s).