Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Jixter
 
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Default Uninterruptible Power Supply questions

Hi!

I have a 700VA UPS that has dead batteries... I'm about to purchase
replacement batteries but got to thinking..
The batteries this UPS takes are 6v 12aH and there are 2 of them running in
series = ~12v together (13+ realistically)

I can replace the 2 batteries running in series, but was thinking about
extending the runtime of the UPS by running 4 batteries.. (2 sets of 2
running in parallel)
Or should I just get 2 larger 6v batteries with more aH rating instead? Of
course they might have to be outside the UPS instead.
Or I could get 1x12v sealed lead acid battery instead.

I realize that a larger battery might not charge well or properly on this
UPS.

How might this affect the UPS circuitry and invertor?
I'm only trying to extend the run time and not the capacity of the UPS.

IBM Office Pro 700 (I've actually got the older serial port model)
http://www.tripplite.com/products/pr...productID=2801

Anyone have any feedback/thoughts on this?

TIA


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Gerard Bok
 
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Default Uninterruptible Power Supply questions

On Sun, 22 Jan 2006 07:15:01 GMT, "Jixter"
wrote:

I have a 700VA UPS that has dead batteries... I'm about to purchase
replacement batteries but got to thinking..
The batteries this UPS takes are 6v 12aH and there are 2 of them running in
series = ~12v together (13+ realistically)

I can replace the 2 batteries running in series, but was thinking about
extending the runtime of the UPS by running 4 batteries.. (2 sets of 2
running in parallel)


NEVER EVER connect batteries in parallel!

Or should I just get 2 larger 6v batteries with more aH rating instead? Of
course they might have to be outside the UPS instead.
Or I could get 1x12v sealed lead acid battery instead.

I realize that a larger battery might not charge well or properly on this
UPS.


And you must keep in mind, that some cheaper devices are
constructed in such a (lousy) way, that the components used will
only survive for the backup time provided by the batteries.

(Double the capacity, your UPS will run longer, parts may reach a
higher temperature and fail.)

--
Kind regards,
Gerard Bok
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Michael Ware
 
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Default Uninterruptible Power Supply questions

Because.....?

"Gerard Bok" wrote in message
...

NEVER EVER connect batteries in parallel!


Kind regards,
Gerard Bok



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Gerard Bok
 
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Default Uninterruptible Power Supply questions

On Sun, 22 Jan 2006 14:03:10 GMT, "Michael Ware"
wrote:

Because.....?

"Gerard Bok" wrote in message
...

NEVER EVER connect batteries in parallel!


Because no two batteries have exactly the same voltage.
But they do have a very low internal resistance (well, inititally
at keast. Connect them in parallel and both the internal
resistance and the temperature rise sharply ;-)

The resulting current is delta U/R or a small voltage over a very
low resistance. Which will still yield a huge current!

--
Kind regards,
Gerard Bok
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JazzMan
 
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Default Uninterruptible Power Supply questions

Gerard Bok wrote:


Probably wise to add, that batteries may explode when connected
in parallel.



So all those 24V truck systems out there are rolling death bombs?

LOL!

JazzMan
--
************************************************** ********
Please reply to jsavage"at"airmail.net.
Curse those darned bulk e-mailers!
************************************************** ********
"Rats and roaches live by competition under the laws of
supply and demand. It is the privilege of human beings to
live under the laws of justice and mercy." - Wendell Berry
************************************************** ********
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Gerard Bok
 
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Default Uninterruptible Power Supply questions

On Sun, 22 Jan 2006 10:01:40 -0600, JazzMan
wrote:

Gerard Bok wrote:


Probably wise to add, that batteries may explode when connected
in parallel.



So all those 24V truck systems out there are rolling death bombs?


Well, around here, some are.
But for a totally different reason :-)

It seems that you are right though.
I am totally amazed that trucks in deed seem to run their
batteries in parallel. And even more by the fact that several
references claim that available power equals the power of both
batteries simply added together.

Learning every day, I guess :-)

--
Kind regards,
Gerard Bok
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Ken Weitzel
 
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Default Uninterruptible Power Supply questions



JazzMan wrote:
Gerard Bok wrote:


Probably wise to add, that batteries may explode when connected
in parallel.




So all those 24V truck systems out there are rolling death bombs?

LOL!

JazzMan


Hi...

Huh? Any I've ever seen have been two 12's in series, not in
parallel

Take care.

Ken

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JazzMan
 
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Default Uninterruptible Power Supply questions

Ken Weitzel wrote:

JazzMan wrote:
Gerard Bok wrote:


Probably wise to add, that batteries may explode when connected
in parallel.




So all those 24V truck systems out there are rolling death bombs?

LOL!

JazzMan


Hi...

Huh? Any I've ever seen have been two 12's in series, not in
parallel

Take care.

Ken



The big trucks use parallel/series arrangements to get
the needed voltage and current requirements.

JazzMan
--
************************************************** ********
Please reply to jsavage"at"airmail.net.
Curse those darned bulk e-mailers!
************************************************** ********
"Rats and roaches live by competition under the laws of
supply and demand. It is the privilege of human beings to
live under the laws of justice and mercy." - Wendell Berry
************************************************** ********
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James Sweet
 
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Default Uninterruptible Power Supply questions

Michael Ware wrote:
Because.....?

"Gerard Bok" wrote in message
...

NEVER EVER connect batteries in parallel!





Because in theory one battery will always have a higher voltage and be
trying to charge the other. In practice I've done it with small gel
cells and had no problems, but I wouldn't do it as a permanent installation.


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James Sweet
 
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Default Uninterruptible Power Supply questions

JazzMan wrote:
Gerard Bok wrote:


Probably wise to add, that batteries may explode when connected
in parallel.




So all those 24V truck systems out there are rolling death bombs?

LOL!

JazzMan



That would be a series system right? Two 12V batteries in series is
perfectly acceptable, two in parallel is not.

Dual battery systems use diode based isolators to keep one battery from
interacting with the other, I suppose you could use something like that
with a UPS.
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Bennett Price
 
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Default Uninterruptible Power Supply questions

I've tried much the same with an APC Smart UPS with puzzling results.
When I ran it as a dumb UPS, with no monitoring software, I got twice
the run time, as you would expect. When I ran the paralleled batteries
along with APC's Powerchute software I could not extend the run time,
(despite lots of recalibration). It was as if Powerchute knew the
maximum capacity of two batteries and would not recognize/accept/deal
with 4, (despite the fact that it monitors battery voltage, seemingly as
an indicator of when to shut down a system).

I've no idea whether this is relevant to your UPS.

I think the problems warned of here in running them series/parallel are
misplaced. To quote from GE's "The Sealed Lead Battery Handbook" 1979,
page 91:

"With sealed lead batteries there are no major problems with parallel
connections."

Gerard Bok wrote:
On Sun, 22 Jan 2006 07:15:01 GMT, "Jixter"
wrote:


I have a 700VA UPS that has dead batteries... I'm about to purchase
replacement batteries but got to thinking..
The batteries this UPS takes are 6v 12aH and there are 2 of them running in
series = ~12v together (13+ realistically)

I can replace the 2 batteries running in series, but was thinking about
extending the runtime of the UPS by running 4 batteries.. (2 sets of 2
running in parallel)



NEVER EVER connect batteries in parallel!


Or should I just get 2 larger 6v batteries with more aH rating instead? Of
course they might have to be outside the UPS instead.
Or I could get 1x12v sealed lead acid battery instead.

I realize that a larger battery might not charge well or properly on this
UPS.



And you must keep in mind, that some cheaper devices are
constructed in such a (lousy) way, that the components used will
only survive for the backup time provided by the batteries.

(Double the capacity, your UPS will run longer, parts may reach a
higher temperature and fail.)

  #13   Report Post  
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Jixter
 
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Default Uninterruptible Power Supply questions

Thanks for the responses so far...

Yes extending the runtime may be bad for the components and surely they are
only designed to last so long. You can buy an invertor for a boat or camper
and that is rated to run for longer periods of time. The invertor in the UPS
is huge! I think as long as I'm well under the 700VA peak output I'll be
okay to extend it a bit.

Yes hooking up batteries in parallel does sound a bit scary to me... I think
parallel is the wrong description.. 2 in parallel and in series with another
identical set. See figure 3 in the link below.

Maybe this is only good for 6 volt batteries? I'm sure I've heard of 24volt
truck systems too.

Here's a link to some of the DIY projects I read earlier..
http://www.backwoodshome.com/articles2/yago88.html

Here is a link talking about some higher end UPSes that can accept addon
batteries.
http://www.lashen.com/vendors/trippl...tery_packs.asp
Maybe there is a DIY project out there that you can perform.

It looks like in this example though 24v and 36v systems are used though.

I don't think I'm willing to go this far for a home UPS, I just thought
maybe this would be an opportunity to buy a larger capacity battery
replacement instead of the identical replacement ones and have the same run
time. The way I figure it.. I'm replacing 2x6volt 12ah batteries.. with
1x12volt and higher aH rating.. Unless someone here can say for sure that 2
in series provides a larger capacity of run time.. That's what I'm trying to
figure out. There must have been a reason the UPS mfg went with 2 6volts
instead..

There are people that have built their own DIY UPS too --
http://www.dansdata.com/diyups.htm

I should also note that performing this with a car battery or deep cycle
marine battery is possible but dangerous because of the hydrogen released
from the battery. Should not be in a sealed room like a bedroom etc...

"Bennett Price" wrote in message
. com...
I've tried much the same with an APC Smart UPS with puzzling results.
When I ran it as a dumb UPS, with no monitoring software, I got twice the
run time, as you would expect. When I ran the paralleled batteries along
with APC's Powerchute software I could not extend the run time, (despite
lots of recalibration). It was as if Powerchute knew the maximum capacity
of two batteries and would not recognize/accept/deal with 4, (despite the
fact that it monitors battery voltage, seemingly as an indicator of when
to shut down a system).

I've no idea whether this is relevant to your UPS.

I think the problems warned of here in running them series/parallel are
misplaced. To quote from GE's "The Sealed Lead Battery Handbook" 1979,
page 91:

"With sealed lead batteries there are no major problems with parallel
connections."

Gerard Bok wrote:
On Sun, 22 Jan 2006 07:15:01 GMT, "Jixter"
wrote:


I have a 700VA UPS that has dead batteries... I'm about to purchase
replacement batteries but got to thinking..
The batteries this UPS takes are 6v 12aH and there are 2 of them running
in series = ~12v together (13+ realistically)

I can replace the 2 batteries running in series, but was thinking about
extending the runtime of the UPS by running 4 batteries.. (2 sets of 2
running in parallel)



NEVER EVER connect batteries in parallel!


Or should I just get 2 larger 6v batteries with more aH rating instead?
Of course they might have to be outside the UPS instead.
Or I could get 1x12v sealed lead acid battery instead.

I realize that a larger battery might not charge well or properly on this
UPS.



And you must keep in mind, that some cheaper devices are
constructed in such a (lousy) way, that the components used will
only survive for the backup time provided by the batteries.

(Double the capacity, your UPS will run longer, parts may reach a
higher temperature and fail.)



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none
 
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Default Uninterruptible Power Supply questions

On Sun, 22 Jan 2006 13:59:43 GMT, (Gerard Bok) wrote:

On Sun, 22 Jan 2006 07:15:01 GMT, "Jixter"
wrote:

I have a 700VA UPS that has dead batteries... I'm about to purchase
replacement batteries but got to thinking..
The batteries this UPS takes are 6v 12aH and there are 2 of them running in
series = ~12v together (13+ realistically)

I can replace the 2 batteries running in series, but was thinking about
extending the runtime of the UPS by running 4 batteries.. (2 sets of 2
running in parallel)


NEVER EVER connect batteries in parallel!

Or should I just get 2 larger 6v batteries with more aH rating instead? Of
course they might have to be outside the UPS instead.
Or I could get 1x12v sealed lead acid battery instead.

I realize that a larger battery might not charge well or properly on this
UPS.


And you must keep in mind, that some cheaper devices are
constructed in such a (lousy) way, that the components used will
only survive for the backup time provided by the batteries.

(Double the capacity, your UPS will run longer, parts may reach a
higher temperature and fail.)


Just get two larger AH capacity batteries. If the UPS is set up in
such a way as not to recognize the larger capacity try running a
bypass around the logic function circuitry and just let the "brain"
act as a charge regulator.( I refurbished an old UPS for a friend
awhile back and we modded it by using two sealed wet cell batteries(
ones designed for use on four wheelers and such.)
The batteries did have to go external but it gave him about four-fold
the run time and the wet cells are much more durable.
You could of course just use sealed lead acids of greater capacity,
the main advantage of course being that they'll last more cycles since
you won't discharge them as deeply during each AC off cycle.
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Mark
 
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Default Uninterruptible Power Supply questions

if you are OK with using external batteries ,

a car battery is probably your best deal...

just be SURE to properly fuse it in case something fail or the wires
short.... ....


Mark



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Tom Del Rosso
 
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Default Uninterruptible Power Supply questions

"James Sweet" wrote in message
news:G9RAf.1956$zh2.313@trnddc01...

That would be a series system right? Two 12V batteries in series is
perfectly acceptable, two in parallel is not.

Dual battery systems use diode based isolators to keep one battery from
interacting with the other, I suppose you could use something like that
with a UPS.


That's perfectly reasonable, but isn't a large cell internally equivalent
to small cells of the same voltage in parallel?

--

Reply in group, but if emailing add another
underscore and remove the last word.


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Caesar Valenti
 
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Default Uninterruptible Power Supply questions

I use an APC 1200 UPS and have it connected to two external car
(actually marine/starter) batteries. This is a 24v system. This has
worked reasonably well for me but for the past 7 years, but I have used
batteries that require water....and when I forgot to refill them, they
would dry out. I am now using a maintenence-free battery, and will see
how long it lasts.

Also, I originally used a deep cycle battery but I think a regular
starting battery would be better. We seldom have blackouts so the
battery would almost always be at max charge. This is what normal car
batteries are designed for. Of course, your situation may be different.

If I were you, I would just get a large car battery and try it....they
only cost $35-45 at Costco. I can't imagine a UPS failing because it
was only designed to run for a few minutes.....but who knows. I have
run my UPS for well over 10 hours straight with no problems...but it has
a cooling fan that kicks in.
cv





Mark wrote:

if you are OK with using external batteries ,

a car battery is probably your best deal...

just be SURE to properly fuse it in case something fail or the wires
short.... ....


Mark



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