MMC> I've already read Tom's reply, he did very good.

all who have responded have given me some excellent information... much of
it fits right in with my "theories" on how to go about doing
this... i like the idea of using automotive lights to limit current and
test the load... i can get them easily enough...

i'm chopping most all of your message because i don't have anything to ask
about in it... the information is welcome and does tell me that i've been
on the right track all along... however, i may come back to it again in the
future...

oh yes, the 11Ah ones are gelcell batteries...

[chomp]

 ml>> orange ones) and melted the insulation on the wire between the
 ml>> battery pack and the UPS due to the load... i'm just now looking
 ml>> at it and it appears to be 18ga stranded ;-(  i'm thinking that i
 ml>> need something more substantial... like 12ga or 10ga... the
 ml>> problem is being able to connect "stay-cons" to the wire to
 ml>> connect to the battery terminals...

 MMC> Ouch!  "Heavy duty" usually means the rubber insulation is
 MMC> thicker and can be dragged around a little without wearing
 MMC> through!

yeah, that's what i figured later...

 MMC> Agree, 18ga is way too small.  I use 4ga, but only
 MMC> because that's what I had around.  :-)

when i was in telephone school, i "harvested" some "ground
wire" that was being removed... they were just going to toss it until
i asked about it... i've been considering using it for ground plane for my
telco stuff... i've plenty of it so i went out the other day and cut me two
11 inch pieces to use as "buss bars"... i'm going to just solder
the connector wires to these and then use the same type wire that the UPS
i'm connecting this conglomeration to uses... i don't know what guage this
"ground wire" is but it is 1/4th inch in diameter...

 MMC> 12ga wire is rated for 15 Amps, and that would probably be
 MMC> good enough, but those cells can easily put out 100A if
 MMC> shorted, and you are paralleling a bunch of them.  I would
 MMC> recommend 8 gauge, and in any case, nothing smaller than 10
 MMC> gauge.

 MMC> As far as the connectors, my "standard" UPS uses 14 gauge wire
 MMC> to connect to 7AH batteries.  In your case, I would get
 MMC> connectors that will crimp to 12 gauge wire for the 11AH
 MMC> batteries, and use 12 gauge for each of the 11AH batteries.
 MMC> Use 10 gauge for connecting the 25AH batteries, then clamp or
 MMC> bolt all the (+) ends to a piece of 8 gauge wire for
 MMC> connecting to the UPS.  Same for all the (-) ends.

yup, that's what i'm planing to do... the stuff i used before was
"looped" thru the sta-con which are for 14-16 guage wire... since
i was having to put in two wires, well... i'm probably going to end up
getting solderable ones and soldering them onto the wires...

 MMC> There's nothing more unsettling than having the lights go out,
 MMC> then smelling wire burning!

that's exactly what happened! after about 10 minutes, i smelled it... two
computers, one monitor and several wallwarts on that load... it didn't take
me long to shut them down... i could hear things changing pitch as i
relieved the load...

 MMC> You also have to consider the increased load on the UPS's
 MMC> internal charger when the power comes back on.  All those
 MMC> batteries will likely cook the UPS while trying to re-charge.

this brings me to my next set of questions...

i've been looking at this and thinking about how to prevent problems with
the charging system in the UPS'... my current thoughts are to use some
diodes of sufficient size to allow the batteries to supply power but not
accept the charge from the UPS... instead, i'd use a charger for the
batteries... maybe even one per battery... i'm going to try an ascii
drawing...

       ===== + buss bar ======Z----+-----------
      /                             \ +        \
  ups                                battery    charger
      \                             / -        /
       ===== - buss bar ======-----+-----------

Z is a diode... but which one? and i only need one on the positive side,
right? the above is only showing one battery connected but i'd do all of
them in similar circuts and parallel them all in...

i think i like the motorcycle charger idea or the walmart wallwart
charger... i just need to find one that will do the desired charging
amps...

those 6-pack batteries are made of individual cells measuring 6 inches
tall, 2.5 inches diameter and they are all connected in series with metal
bars... looks like something already assembled and purchasable as a unit...
they are something that the phone company uses in some of their stuff...
the cells, themselves, are labeled as follows...

     Gates
 Energy Products

     Cyclon

   SEALED LEAD
   RECHARGABLE
     BATTERY

and on the other side,

     2 VOLT
     25.0 AH
     BC CELL

i found a sticker i hadn't noticed before on the plastic casing holding
them all together...

  0820-2016/12v-25AH/2297W

if that W number at the end is wattage, whoa! >

i located a site, www.powerfactorinc.com, that gives me some performance
stuff on the individual cells... they appear to call the packs that i have
"monobloc 12v" but only show 4v and 6v on the page... anyway,
each cell weighs 59 oz and their table shows the following for these
cells...

              Performance
    Constant current discharge/amps
(Constant power discharge/watts per cell)

15min    60min    90min    5hr     10hr
54.3     19.3     14.0     4.85    2.55

i'm guessing that these numbers are pretty good but i don't know exactly
what they are representing, ATM...

my biggest problem is going to be determining what charger to use on these packs...

the other "thing" is... i've currently got 7 UPS' handling ~12
machines, monitors and associated wallwarts... i know that i won't be able
to get 4 days uptime with this stuff without a lot more batteries and thus
$$$$ spent... possibly it'd be better to take a look at doing this with
marine batteries with the same attention to adding them in but charging
externally as we've talked about...

geez, i've reached 150 lines... guess i need to stop for now...

all information is really really appreciated...

)\/(ark