UPS Questions

[edy]

Hi folks,

I have a UPS Cyberpower LCD 1500AVR. Link here:

http://www.cyberpowersystems.com/products/ups-systems/intelligent-lcd-ups/CP1500AVRLCD.html

It started cycling on and off every second, looks like the batteries are failing as it is about 5 years old. I opened it up and it has 2 SLA batteries.... both 12 V, type is HR-1234W... connected in SERIES. I quickly tested the main leads (which should be 24 V) with a paperclip and got ZERO SPARKS. 

When I tried that across each individual battery, one battery was sparking nicely while the other was completely DEAD. So it looks like one battery is completely resisting the flow of even the other battery (otherwise I would have expected even some current flow from the good battery if at least the DEAD battery was conducting).
 
Is this common with 2 battery supplies connected in series? Does one battery get killed while the other one survives? Is it good enough to buy 1 battery to replace the dead one, or should I get 2 exact same batteries? Does it matter whether I get a 12 V / 8.5A or 12 V / 10A or 12 V/7 A?

I didn't have my meter on me, so I will have to do some more testing. Thanks for your suggestions. How do I measure the internal resistance of the dead battery without blowing up my meter? Last time I tried this my meter fuse blew.  Thanks!

[edpalmer42]

Typically, when two batteries are in series, they drift apart as they age.  One battery will become undercharged while the other (weaker) one will become overcharged and eventually dry out.  Lithium ion batteries typically monitor this and prevent it from happening since Lithium batteries can fail in very nasty ways.  Large lead acid systems are monitored to prevent this and extend the life of the entire string, but it's rarely done with small ones.

5 years is a good run for a pair of UPS batteries.  There's really no point in trying to make any measurements on them.  Replace them both.  If you only replace the dead one, the other one will probably fail within a few months.  Before it fails, it could start to degrade the new one.  Replace them with two new batteries that have similar specs, size, and terminal arrangement as the original ones.

Ed

[tautech]

+1

If you install smaller capacity SLA's the charge circuit may exceed their max charge rate.
Replace like for like or higher A/Hr rating.
Check charging/float voltage does not exceed the SLA  Vmax when new batteries are installed and charged. Tweak if necessary. 

[edy]

Thank for the advice! I noticed the cost for batteries can be quite high, as local suppliers sell these for about $30-40 each. A pair of batteries with tax is close to $100, almost the cost of the UPS. Does anyone have a suggestion for a Canadian supplier or store in the Toronto area? Or is it cheaper to order online? Shipping would likely be very expensive though due to the weight, and I'm not sure how easy it is to get these sent up from the USA. I've seen a few online stores selling these for $10-15 but I imagine once it gets through shipping and customs and duties the price will creep up again.

[tautech]

You may find that some replacement SLA's are of better quality than those originally fitted.
Do some homework to identify the better brands.

[johansen]

batterysharks dot com is cheap. dunno if they ship to canada.
you can also use flooded lead acid, and they will probably last longer for the simple reason that you can add water.

most ups' boil the battery away slowly because they hold the battery at a specific float voltage, rather than floating them at a constant float current, after calculating the self discharge rate.

[Melkor]

When you compare Ah ratings note that they are dependent on the discharge current (because of the internal resistance of the battery).
If you see a single Ah figure most likely is at a slow discharge rate like in 20 hours or so. For use in an UPS you are more interested in a 10 minutes discharge performance so you have to dig around a bit for the specs.

[Bud]

Does anyone have a suggestion for a Canadian supplier or store in the Toronto area?

Sayal, they have multiple locations across GTA. Just bite the bullet and buy what you need and save your time.

[edy]

Thanks, I buy stuff from Sayal all the time as they are 5 minutes from me, never thought of looking there because I didn't know they carry SLA's too. Will check them out!

[edy]

Here are the original batteries in the unit... 2 of them:

http://www.bb-battery.ru/upload/iblock/468/HR1234W.pdf


One of the batteries is UPSIDE DOWN on top of the other one (so that the terminals of both batteries are close to each other to be able to run wires through them in series). But I noticed on the spec-sheet that you can use the battery in any orientation "(excluding used inverted)"??

Does that mean you can't use them upside down? The top battery would have been upside down in the unit as far as I know, the way the batteries are installed in there.

Here is the replacement battery available at Sayal (Power Patrol SLA1075):

http://www.batteriesasap.com/in12v7f1basl.html

I can't get much of a datasheet, unlike the BB HR1234W which has the manual above with specs. The dimensions are pretty much the same so everything should fit.

[johansen]

you wouldn't want to use them upside down because water will condense out on the inside of the case and when overcharging the battery, you will get liquid blown out the rubber cap, hidden underneath the plastic caps.

those batteries are absorbed glass mat, meaning the fiberglass is 90% saturated in 1.3 S.G sulphuric acid.

you can try adding water if you want. i would use flooded cells to replace them.

[edy]

Hi,
Everywhere I looked they recommend not charging them upside down. This UPS unit uses 2 batteries sitting on top of each other and inserted vertically into the unit but one is upside down on top of the other one.

I think when I get my replacements I will leave the batteries out of the UPS if the wires are long enough. However the case has a fan.... How important is it to have the batteries inside the UPS case? Will they suffer more not having that fan, being outside, or being inside but stuck closely together and with one upside down?

[Strada916]

I found an apc powerchute 1500 at local recycle centre. Ripped the sla's out made a longer cable come out from its hidey hole and reconnected small car batteries. It's been working for over 3 years. Replenished the water once in that time. Cheaper too.

[Legion]

I'm in the GTA near Sayal and have the same UPS, so I'm interested to hear what you find. I'll have to deal with the same thing eventually.

[centon1]

Does anyone have a suggestion for a Canadian supplier or store in the Toronto area?

MagnaCharge in Mississauga.

[edy]

Sayal has power patrol SLA1075, cost me $24 each with tax came out to about $62-64? I am connecting them outside the case.

How much would car batteries cost? Wouldn't it be better to use Marine deep discharge? Do they usually have amp hour ratings on marine/car batteries or do you need to go digging for specs?

[SeanB]

Just bought a lead crystal deep cycle SLA battery, and will put it in the UPS in place of the dying car battery that is currently there. It was $170 at Deltec, and came with a 3 year warranty. 65Ah will probably be a lot more than the existing 36Ah one in there now, and will hopefully survive the deep discharge cycles better. Heavy battery to carry.

[edy]

I've attached some pictures showing the tower configuration of the UPS and how the old batteries were connected with one upside down, on a plastic adapter that  allows the wiring to go through.

The new batteries are outside the case but there is a fan on the case probably to handle the power supply, which I don't think will matter.

[edy]

I opened up the top of the old batteries and noted 6 holes covered with rubber seals. The good battery looked fine. The "dead" battery had what looked like leakage and one of the rubber seals was bloated... when I lifted it off I heard some gas escape.

I assume this was the upside down battery. Is this battery recoverable if I add water to the cell? How much would I add? Is it worth toying around with or will I explode something and better just to chuck it?

[SeanB]

It is dead, take for recycling and get around $2 back. Just note that in many cheap UPS units the batteries are indirectly connected to the incoming mains via some diodes or such, and float at around half mains voltage. Thus the batteries and the connections need to be in an insulated box so the exposed metal is not accessible.

I have tried refilling them with 5ml of water per cell, and while it is moderately successful it only works on a battery that is not dead, the dead stay dead, and if it has bloated and the case is showing signs of crazing then definitely do not do it. You might get around 20% of capacity back, but the effect is short lived and dies fast.

[johansen]

you need a whole lot more than 5ml of water. fill it up until the fiberglass is saturated.

[SeanB]

I did, but sulphated till dead and dry still stays dead, even with a 30V wake up call. At best I got a slight recovery, but often the plates were either cracked or had shed all material by then.

I just take them and recycle, and buy new.

[Bud]

I opened up the top of the old batteries ...

I had a point when I said buy what you need and save your time...

[johansen]

so not to change the subject but i pulled a transformer out of a very similar UPS last week.

i took a better look at the "line interactive" transformer inside those things.. they used aluminum for the 15vac winding.