Converting Dry Battery UPS to Wet Battery UPS

Discussion in 'General Electronics Chat' started by pakilahori81, Apr 17, 2010.

  1. pakilahori81

    Thread Starter New Member

    Apr 14, 2010
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    Hi All,

    I want to convert my dry battery ups to charge wet battery. Please give me any suggestion how I can do this.

    I replaced dry battery about twice but it did't gives any backup (Even of a second).

    I can post ups circuit snapshots if you required to assist.

    Thanks
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    A mod will be along presently to move this thread to a better area.

    OK, so what is your dry battery? Part numbers are good, so are pictures.
     
  3. pakilahori81

    Thread Starter New Member

    Apr 14, 2010
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    Thanks Bill for your reply.

    It's not of APC or other international brand ups. It's a local company product.

    Battery is made by CSB. GP1272 12V 7.2Ah

    Thanks
     
  4. SgtWookie

    Expert

    Jul 17, 2007
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    The CSB GP1272 is not a "dry cell", it is a SLA (sealed lead-acid) battery.

    Manufacturer's page for the GP1272:
    http://www.csb-battery.com/english/01_product/02_detail.php?fid=5&pid=11

    You will need to compare that cell's specifications to the battery you will be replacing it with.
    [eta]
    It is common for SLA batteries to have higher float and charge voltages than lead-acid batteries.
    You need a deep-cycle type battery. An automotive-type battery will have a very short service life. They are not designed to be used in deep-cycle applications.

    Note that SLA batteries are safe for indoor use. More traditional lead-acid batteries (like automotive and marine batteries) are NOT safe for indoor use, due to the presence of explosive gases.

    If your UPS provides no backup power at all, then either you are overloading the output, or the UPS is defective.

    Don't try to power a motor (such as a refrigerator, washing machine, vacuum cleaner, etc) from a UPS, as the initial inrush current will be many times the rated power of the device.
     
    Last edited: Apr 17, 2010
  5. retched

    AAC Fanatic!

    Dec 5, 2009
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    Are you getting measureable output on the outlets of the UPS? If you have a lamp plugged in and you un-plug the UPS from the wall, does the lamp stay lit?
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    Lamps are also a problem, as they will have a very high inrush current until the filament comes up to temperature. It's one thing if the lamp is already hot and the power fails; the UPS should be able to continue the existing current flow if it's within the UPS VA rating. However, attempting a "cold start" on a lamp or motor will probably fail.
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    I find I have to replace my UPS battery every 2 years give or take. It uses a SLA battery. This is considered normal maintenance for a UPS.
     
  8. pakilahori81

    Thread Starter New Member

    Apr 14, 2010
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    Thanks for all of you guyz for your replies.....

    But my concern is to convert that UPS to charge wet battery.

    Can I directly use it's Live and Negative to charge battery or need any modification ?

    My UPS detail is :
    Alfa 5303
    Input : 220/50 Hz
    Output : 220/50 Hz
    Capacity : 500VA

    [​IMG][​IMG][​IMG][​IMG]
    I have also attached images. Please help me to convert it. Thanks
     
  9. retched

    AAC Fanatic!

    Dec 5, 2009
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    Is the battery a 12v battery? If so, you can replace it with a regular lead-acid battery. It will charge it.

    The problem is not in charging the battery. The problem is in USING the battery once you have it charged. If you try to start powering more devices, the UPS cant handle too much more current. The parts will heat up and blow.

    If you just want more run time out of it, just switch the battery to your "wet cell". You will want to add a high flow vent fan to the case to ensure it stays cool. These UPS systems are not designed to run for an hour. They are built to get you time to turn the computer off without loosing any work. So if you run it longer than intended, you NEED to cool it.
     
  10. pakilahori81

    Thread Starter New Member

    Apr 14, 2010
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    Yes it's 12V and 7.8 Ah
     
  11. retched

    AAC Fanatic!

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    Make sure the fan is blowing on the heatsink, and there is enough holes for the air to escape.

    You may end up damaging your UPS if you run it to hard or too long.
     
  12. pakilahori81

    Thread Starter New Member

    Apr 14, 2010
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    Before I only used it just to shutdown my system or to run a light of 15watt light. What I come to know from your post is that I did't need to make any modification yo UPS circuit to charge Wet battery (Car Battery). Actually know I want to use it to lid lights of 15Watt.
     
  13. retched

    AAC Fanatic!

    Dec 5, 2009
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    you could. If you are going to run it for extended times, You will want to add a fan. A simple computer fan will do. And it can run off the 12v battery.
     
  14. pakilahori81

    Thread Starter New Member

    Apr 14, 2010
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    What if I add fans at both sides of UPS and use it for computer. will it work or not ?
     
  15. retched

    AAC Fanatic!

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    It will work. But you want to check it every five min to see how hot it gets.. it may be ok.. just check to be sure.
     
  16. pakilahori81

    Thread Starter New Member

    Apr 14, 2010
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    Thanks. 1st I will try it old car battery, and will inform you if it comes successfull.
     
  17. retched

    AAC Fanatic!

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    Ok. The fuses on the UPS should keep you safe if anything goes nuts.
     
  18. SgtWookie

    Expert

    Jul 17, 2007
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    If the old car battery is still good, it won't be after a few cycles.

    You must not use the car battery indoors, as you may have a build-up of explosive gases.
     
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