Can i increase size of ups battery?


  #1  
Old 04-15-14, 09:01 PM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
Can i increase size of ups battery?

actually i have a home ups. It has 7.5 amp/hr 12 v battery and provides 8 min backup for desktop or at least 45 min for laptop. Now i want to increase the battery size to use it as a power supply. (electricity goes for 13 hrs a day in Nepal) i have a solar panel that charges big 80 amp 12 v battery (tubular and deep cycle). Can i charge it on solar and connect to ups so i can use my laptop for a 3-4 hrs? as laptop wont use high power.. how much time can it run on a single charge? and will there be any problem?

please help! urgent!!
 
  #2  
Old 04-15-14, 09:06 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,639
Received 3,897 Upvotes on 3,494 Posts
You can run a UPS on any amperage 12v battery. If the unit was designed with a 7.5Ah battery then the biggest you could charge with the UPS is around 10Ah.

You can certainly use your 80Ah battery to run the UPS and then charge on your solar system. You should get 3-4 hours on your laptop based on condition of the battery.
 
  #3  
Old 04-15-14, 10:06 PM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thank you pjmax for clear answer and fast reply
 
  #4  
Old 04-15-14, 10:06 PM
J
Banned. Rule And/Or Policy Violation
Join Date: Jan 2010
Location: KS
Posts: 1,655
Upvotes: 0
Received 1 Upvote on 1 Post
Why not simply buy a DC car adapter for your laptop and run it directly off the battery? Itll last a lot longer that way than it will using the UPS to step up the voltage then step it back down with the 120v laptop charger..
 
  #5  
Old 04-15-14, 10:11 PM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
@Jersey matt..the fact is that i live in nepal..and it is very hard to get anything except what you can buy directly. and there are are very limited shops that sell car accessories..might be one or two

thnx for suggestion...i will look for it in market.
 
  #6  
Old 04-15-14, 11:20 PM
J
Banned. Rule And/Or Policy Violation
Join Date: Jan 2010
Location: KS
Posts: 1,655
Upvotes: 0
Received 1 Upvote on 1 Post
It would be something you buy at a place that sells computer accessories, not car accessories... Does Amazon not ship there?
 
  #7  
Old 04-16-14, 12:03 AM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
@Jersey matt..i didn't know that it is found in computer accesSories not in car accessories..thank you..i will look for it.

nope no amazon no ebay nothing...you need to go to market to see it. online shopping is narly not available...
 
  #8  
Old 04-16-14, 07:17 AM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 27,520
Received 2,116 Upvotes on 1,895 Posts
Do you want to charge the batter off of AC when the power is on or charge by solar?

Easiest is if you let the UPS charge the battery when the power is on. One limit is the charge rate of the UPS. It will charge the battery but most UPS are designed to charge their small battery over an 8 hour period.

You did not say how much solar power you have available but that will determine how much charging you can do in a day and will determine how long you can run your computer.

I hacked a computer UPS. Removed it's small sealed lead battery and added wiring to reach a sealed telecom backup battery and it works perfectly. When AC power is on the UPS charges or maintains the big battery. Then when the power goes out it provides AC power. How long it lasts depends on the size of the battery and how much current your computer draws.
 
  #9  
Old 04-16-14, 07:31 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,505
Upvotes: 0
Received 274 Upvotes on 250 Posts
Theoretically you can substitute any larger battery of the same kind (e.g. lithium ion) although it will take longer for the UPS' built in charger to charge that battery.

Caveats: (1) The voltage applied to the battery as measured has to be more than the battery's output voltage at the start of charging but not more than the charging voltage given to the original battery. (2) If the charging circuits do not have a protection subcircuit, the increased charging current the larger battery draws can burn out the charging circuits.
 
  #10  
Old 04-16-14, 07:59 AM
Justin Smith's Avatar
Member
Join Date: Dec 2010
Location: Cressona, Pa, USA
Posts: 2,272
Upvotes: 0
Received 1 Upvote on 1 Post
What I did for my setup was I put a deep cycle battery in place of the UPS battery, and connected an external battery charger. I use my setup in my truck to run my sound system, mini fridge, and battery chargers so I don't have to be connected to grid power or have the generator running, but I think it'll work for you. Another option is getting an inverter/charger, I know they're available in the USA, but I'm not sure about your country.
 
  #11  
Old 04-16-14, 10:02 PM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
@pilot dane..the solar charges 80 amp battery and it works..

so is it best to keep a switch between big battery and ups' battery?

big battery will be charged by solar panel. when power goes out i will switch on big battery(+on + and - on - parallel connection with small battery).

if i dont put switch and then ups tries to charge solar battery too. so problem arise there as like overheating or damage of circuit or not?
 
  #12  
Old 04-16-14, 10:45 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,639
Received 3,897 Upvotes on 3,494 Posts
You don't want the UPS charging your big battery. It wasn't designed for that kind of load and will overheat.

If you use your UPS on the small battery and it gets low..... and then you connect the big battery. The UPS and the small battery will both discharge the big battery.

An ideal solution would be to switch from one to the other.
 
  #13  
Old 04-16-14, 11:09 PM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
@Pjmax i plan to keep a switch between big battery and ups battery. the switch will be always off so no current flows to big battery from ups circuit hence the battery will charge from solar power only and avoiding risk of overheating ups circuit.

when electricity goes off then I'll switch on the big battery.

is it necessary to separate small one and connect only big one? since small battery is also already fully charged. I think it will add movie juice...
 
  #14  
Old 04-16-14, 11:20 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,639
Received 3,897 Upvotes on 3,494 Posts
If you connect them when they are both charged it should be ok.
 
  #15  
Old 04-16-14, 11:40 PM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
It is better to switch to next battery if ups battery is already used and just connect in parallel if it is fully charged
 
  #16  
Old 04-17-14, 05:47 AM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 27,520
Received 2,116 Upvotes on 1,895 Posts
You said the size of your battery, 80 amps, but that has nothing to do with your solar cells and how much current they produce. A 5 watt solar panel and a 200 watt solar panel will both charge a 80 amp battery. The 5 watt one will take several days while the 200 watt might do it one period of daylight.

If you have a small solar panel and a big battery and want to use your computer every night you might be taking more power out of the batter at night than you put in during the day. Eventually the battery will go dead. In that case you probably want an AC powered battery charger. But, you don't want to have both a AC battery charger and solar panel connected to the battery at the same time without some form of isolation.
 
  #17  
Old 04-17-14, 06:19 AM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
for me changing is not a problem. all I want to do is to convert dc to ac so I can use my laptop. the thing is the big battery will be charged and I want to connect it to ups internal battery when electricity goes off.


Can any problem arise if I join 80 amp battery which was designed to have 7 amp battery so i can charge my laptop when power goes out
 
  #18  
Old 04-17-14, 06:22 AM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
Sorry that is charging not changing
 
  #19  
Old 04-17-14, 12:24 PM
J
Banned. Rule And/Or Policy Violation
Join Date: Jan 2010
Location: KS
Posts: 1,655
Upvotes: 0
Received 1 Upvote on 1 Post
Originally Posted by PJmax
You don't want the UPS charging your big battery. It wasn't designed for that kind of load and will overheat.

If you use your UPS on the small battery and it gets low..... and then you connect the big battery. The UPS and the small battery will both discharge the big battery.

An ideal solution would be to switch from one to the other.
The size of the battery is moot. It doesn't matter whether it's 7Ah or 200Ah. It doesn't 'load down' the charger, the battery simply takes what the UPS gives at the rate it gives. It'll just take exponentially longer to charge a larger-than-design battery. It's no different than using a 1.5A motorcycle charger to charge a battery on a big rig. It'll fully charge it, but it'll just take several days to do so - and it won't damage the charger.

The problem with having the UPS charge the large battery in this case is that a standard consumer-grade UPS requires 12-18 hours to recharge its OWN battery after it's been fully discharged (this on purpose to increase longevity of the batteries - the slower the charge rate the more charge cycles you can get out of them). So in the OP's case where they only have power for 13 hours a day, it'll barely have time to recharge its own battery, never mind something 10x bigger in that timeframe. It's got nothing to do with damaging or overheating the charger in the UPS.
 
  #20  
Old 04-17-14, 09:54 PM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thumbs up

Ok..roger that..Thnx @jerseymatt..Ups charger will take weeks..hehe
 
  #21  
Old 04-18-14, 06:10 AM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 27,520
Received 2,116 Upvotes on 1,895 Posts
That's where the size of your solar array becomes important. A small panel will take very long to charge a large battery and your computer may use more in a day than a small panel can provide.
 
  #22  
Old 04-19-14, 04:23 AM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
yep pilot dane
Thank you everyone.It is working.

I am sorry that I can't say how long it gives backup because I Need to go to school(I stay at hostel during school)and I haven't fully charged solar battery yet..after some weeks I will share the result with you amazing guys who cleared my confusions..thank you very much!
 
  #23  
Old 09-18-14, 07:50 PM
A
Banned. Rule And/Or Policy Violation
Thread Starter
Join Date: Apr 2012
Posts: 29
Upvotes: 0
Received 0 Upvotes on 0 Posts
battery provides about 3-4 hr even for desktop. I haven't yet finished it's charge. so i think it can provide upto 5 hr..but i am facing new problem....http://www.doityourself.com/forum/el...ml#post2325612
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: