Leaving the battery outside the UPS.

[Anonymous user]

Does leaving the battery outside the UPS increase its lifetime?

Well, the battery compartment of my UPS reaches almost 40C in the summer, since the enviroment temperature can reach 30 to 35C (I'm from Brazil and don't have air conditioning where my computer is) and I've been reading some stuff on lead acid batteries and its variations used on UPSes like the Gell Cell or AGM valve regulated types and all the documentation I've read states that at 40 degrees the battery wouldn't go past a year. but it can reach 5 years at about 20 to 25C. Since for half of the year (Spring/Summer) the avarage temperatures inside my house is about 28C during the day and for the other half of the year (Fall/Winter) 20C, I assume leaving the battery outside the UPS would make it last at least a year or two more than inside the unit where the temperature will never fall bellow 30C and most likely be at 35-40 degrees during most of the year.

I know UPSes come calibrated for charging the batteries at a specifc temperature as per the battery manufactures specifications. When the temperature is cool, the floating/charging should be a bit higher, when the battery is warm the voltage should be a bit lower, they do this so the battery lifetime is a bit longer, but on cheap UPSes, the charging and floating voltage is fixed at a specific number and the user can't do anything about it, more expensive units, like those from the Smart-UPS series charge the batteries according to the enviroment temperature...

I'm currently leaving the battery outside the UPS. I made a 15cm long extension for the original +/- wires and plugged it to them so I can leave the battery outside the unit. I know APC won't support it, I just wanna know what you guys think about it. Leaving the battery outside will give me a significant longer life despite the charging/floating voltage being calibrated for higher temperatures? What you guys think about it?

Thanks!

New information:

I decided to measure the temperature again. The temperature inside my house now, where the computer is, is at 25C, it's summer, 10pm and a rainny night. Well, I decided to measure the temperature differently this time. I put the tip of temperature probe at the top of the battery against the plastic wall of the UPS and closed the lid.To my surprise, the temperature there reached 43C! Wow! it only means to me If a leave the battery there, every two years I'm gonna have to replace it! The air temperature under the battery is at 35C, which I think is also very high.

Message was edited by: rau

[BillP]

Yeah, the numbers and specs we get from the manufacturers are usually on the safe side. That isn't to say it 'will' last longer with a higher ambient temp, but normally they are pretty sturdy.

Good luck!

[BillP]

You may want to try and get a mini fan that only draws a couple of watts to have blow on the battery. It won't make a drastic change, but the airflow and modicum of cooling should help keep its temps down a bit especially when discharging or or charging.

[Anonymous user]

That would be a good idea, but since it's a small UPS, I don't know how I would do this without cutting anything. That's the unit I'm talking about:

http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=BE600-BR

I think it gets too hot because it is also a step-down transformer, it trims the voltage from 220V to 110V. I don't know why APC doesn't make small 220V only units in Brazil like they do in Europe. Many states in Brazil is 220V Phase+Neutral.

Thanks for replying anyway.

[BillP]

Well if you need one that has 230v out you could use something like:

http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SC620I&total_watts=25

As for the fan, you could get many that are USB, just use a USB port on the computer, and string it down to the fan if all of your outlets are taken. Even a really small USB fan could help take the edge off of those temps and keep the battery a bit happier.

[BillP]

Well actually I meant this as an enhancement if you are going to leave it outside the UPS. The airflow is going to help it push away the generous amounts of heat it will generate when discharging or charging, and help it from potentially swelling up. If you let it just sit with no real relative air flow, it will die allot quicker.

[Anonymous user]

I don't actually need it now, I was just wondering why no 230V out version of the back-ups line is available here, but anyways, I tried to find the Smart-UPS SC here and couldn't find anywhere. It's listed on the APC brazilian website, like many other products, but you can't find them. And it also ain't got USB connection, only serial.

Well, to place a fan in a way it can blow air inside the battery compartment or through it, I would have to cut a hole on the upper side of the UPS, and that's something I would never do, I'd rather leave the battery outside it. It's a three month old UPS, so cutting anything is out of question. I could leave the UPS sideways, with the battery compartment lid open, but I don't think it's a good idea since the transformer inside the unit is very heavy, so I don't know if placing the unit sideways is a good idea.

Thanks for the idea anyway!

[BillP]

Glad to help, and good luck!

[Anonymous user]

Oh, I get it now! 🙂

But the amount of heat generated by the UPS make the battery much hotter than leaving it outside the unit without air flow while charging/descharging. I made a test here and left the battery discharging for as long as it could keep my computer working and the amount of heat in the battery itself is negligible comparting to how hot the battery gets inside its compartment and the lid closed without even not being charged/discharged. But your idea is good since I can get at least a few extra months of life from the battery.

[Anonymous user · Accepted solution]

A guy on a brazilian computer forum told be that he has the same UPS I do and that he bought it in 2003 and due to heavy battery usage, because of bad power where he used to live, the battery lasted 2 years and a half. He moved to another house and told me the battery he replaced in the beginning of 2006 is still keeping his computer on for 15 minutes, which is really good for a three year old battery. He has also told me that his wife's computer has the same UPS model that was bought in 2005 and the battery is still good after three and a half years . Then I asked him about the enviroment temperature where he lives and apart from the winter being a little bit colder than where I live, he's from the south of Brazil, the summer temperatures there is almost the same as here. Oh, and the room where his computer and his wife's are, there is no air conditioner as well.

I decided to put the battery back in the UPS again and see how long its gonna last. If it lasts at least for three years it's okay, if not, when I replace it, I'm gonna leave it outside the UPS again.

Judging by the battery manufacturer specs, my battery wouldn't last much longer than a year. That's why I my concern.