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migr
join:2008-01-04

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Re: Home UPS powered by car battery

ok 1st point, how long does it take to get to 0 min, about 30 sec and it doesnt make a difference weather it thinks it has no external batteries or 12 external batteries.

i ran the calibration but it gets to 25% bat in secconds so it doesnt really get a chance. it just believes they are dead when they are not

the batteries, well i am running 2 banks of 12v batteries. the 1st bank is a set of 2 12v gel cell deep cycle batteries designed to hold up a local pay tv network for hours. they are usually mounted up power polls and linked to an inverter for years at a time. the seccond set is a set of 2 x 12v truck batteries. these are absolutetely huge. not really designed for deep cycle but have like 175 amp hours so will certainly help the up time and are tested to be fine.
migr

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sorry m8, i wasnt having a go at you. just trying to clarify the sizes so others didnt think i was useing tiny wire. my apoligies if you thought otherwise

SmokChsr
Who let the magic smoke out?
Premium Member
join:2006-03-17
Saint Augustine, FL

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said by migr:

i ran the calibration but it gets to 25% bat in secconds so it doesnt really get a chance. it just believes they are dead when they are not
In this case I would have to soy something is flaky with the UPS. The only judge of battery that the UPS has is normally voltage. With this new information I would tend to think that the threshold voltage is set improperly. I don't suppose there is any way that the UPS was actually designed to run on 24V using 2 batteries in series is there and now you are running 12V? That of course would tend to try to overcharge the battery.
migr
join:2008-01-04

1 edit

migr

Member

no i am running 24v m8, i have 2 x banks of 2 batteries, so in total i have 4 batteries so i have 2 x bats of the same sort making up 24v then i have another 2 x 12v bats making up another 24v then i parallel the 2 banks of 24v. the origional bats were just the same but on a smaller scale and without the 2nd bank.
The unit was designed to run with 24v and thats what i have provided it with but just with larger capasity batteries.

SmokChsr
Who let the magic smoke out?
Premium Member
join:2006-03-17
Saint Augustine, FL

SmokChsr

Premium Member

In that case.. It looks like the UPS battery sense circuit has a problem.
ericrazar
join:2007-11-04
Orlando, FL

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ok migr. I just read you response and it seems your UPS has an issue. Is the unit fairly new model? The apc smart UPS ones I used were built in 1999 and another in 2000. The only other thing I would ask is if you had the original dual 12v 12amp hour batteries in the unit would it work correctly at both low and high loads. I also had a newer apc 1500 model used the the DUAL 125 amp hour batteries for a test setup at my job to hold an environmental chamber up during a possible power outage. The chamber in heat mode would cycle up to 6 amps @120 for several seconds each minute and 1 amp the rest of the time. I ran a check with that setup for almost an hour before I know about the reprogramming advantage with hyperterm. So it sounds like your UPS has an issue unless it works correctly with the original batteries or you have a defect in your harness hookup that causes too much drop at higher loads making the ups think the battery is dead.
migr
join:2008-01-04

migr

Member

the unit is 9 years old, as are the origional batteries that i took out of it so those bats are no good for anything. the cables from the batteries to the unit are top notch, its the same cabling we use to run -48vdc perminently in telephone exchanges all over australia. this cable is capable of carrying a constaint -48v @90a and the terminations are the same that i use in the exchange also. the problem is with the unit its self. i updated the unit so that it now believes new batteries were installed a couple of days ago instead of 9 years ago likt it was when i 1st aquired the unit. i think its a lost cause. atm i am running it in dumb mode. if the power goes down it will hold my rack for 8 hours and thats all that matters, but it would be nice to be able to monitor the battery status via the serial port the way it was intended.
ericrazar
join:2007-11-04
Orlando, FL

1 recommendation

ericrazar

Member

ok migr. I just discovered something about one of my SU1000 that made one read much lower minute run time than the other. It has to do with the battery constant. With hyperterm after you type Y and get SM back type 0 (zero not letter O). You should get back A0 if you dont then the battery constant is screwed up. On one of my units it read 55 which gave me 20 min estimated run time on the other (A0 one) it gave 45 min. This was when both had 000 external battery packs. Raising the battery pack to 001 for the 55 unit made it work to 45 min also. I suspect your constant must be really low so that adding battery packs in hyperterm doesnt help. I also found you cant readjust the battery constant it in hyperterm. I did find you can fix it with APCFIX.exe .

»apc-fix.com/page.php?id=22

Go to the download link on that page bottom and extract the RAR file. Shut down your hyperterm or powerchute software. Run APCFIX and choose com port. Go to options in upper left hand corner and click both the battery constant auto fix and the hex code detection on. I had to close the program then and restart it then pick com port again then it automatically would fix my "0" battery constant from 55 to A0. Then when you add battery packs (with hyperterm) it should work right again and give you proper minutes with your external batteries and with powerchute running. It is good this issue came up because I have a somewhat similar problem with a apc3000 that has short run time too even with modest loads and good batteries. You made me go back and look harder for a better solution. BTW For a 24 volt system each external apc pack equals ~36 amp hr capacity. So 5 packs equals ~180 amp hr and 10 packs ~360amphr This would help you to get the run time minutes roughly "right" when equating to your external battery setup. In your case I would adjust the battery count till your estimated run minutes equals 480 or more or so at the 44% load. It seems wet cells require you to "lie" to the UPS and say you have more batteries than actaul amphour amount. I ended up with 5 external batt setting myself for my 125amp marine batt pack.

The

www.apcupsd.com

website PDF manual has most of the info on the codes.

GOOD luck !!!!
public
join:2002-01-19
Santa Clara, CA

public

Member

said by ericrazar:

It is good this issue came up because I have a somewhat similar problem with a apc3000 that has short run time too even with modest loads and good batteries. You made me go back and look harder for a better solution.
SU3000 should never be used with the internal microscopic batteries at heavy load unless you like seeing flames.

Wet cell batteries used by telcos have lower terminal voltage than the sealed agm types for which the ups is preset. Hence some of your problems.

If you use apc ups's get one of the smart slot management cards and do not waste time with serial ports or terminal emulators.
ericrazar
join:2007-11-04
Orlando, FL

ericrazar

Member

PUBLIC :
MY SU3000 is the 5 U rack mount type with 4 x 20 amp hr gel cells. I would get only 10-15 minutes with a less than 500 watt load with old or newer OEM style gel cells. My 2200 with the same new batteries at work would last ~25 min with a 800W load. See the discrepancy? Now that I realize the battery constant issue I expect it should be a non issue once I fix the constant back to factory. At the time I put the unit aside thinking it was defective in some way. AS you see from all my earlier posts the issue is the APC UPS's use a coulomb counter feature that measures the actual amp/hours that flowed to and from the battery to determine minutes remaining. This is just like the battery circuit in a laptop. The battery terminal voltage is only part of the story. What actually happens is as the battery ages and it get discharged during an outage or during a "cal" it modifies that battery constant as the usable amphr capacity goes down. What is bad is APC doesn't seem to have a convenient way to reset that to factory other than what I found. My APC 1000 with the wet cells give excellent run time (12 hrs at 160watts) if the external batteries modules and battery constant are set correctly. While I agree that the wet flooded cells don't quite have the low internal impedance and surface charge voltage the GEL type have it is obvious the real problems are the constants and not the chemistry.
migr
join:2008-01-04

3 edits

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that was it m8, you are a genius. that apcfix worked out perfectly. now with 44% load it said 570min run time, so 9 hrs. i am reducing that to around 6 external battery packs now to reduce the run time, it was on 8 for that 570min run time. i think around 5-6 hrs is more than enough, when it gets that low it will shut down the server which is what i wanted.

I cant thank you enough for that usfull hint m8. u solved my problems anyways

EDIT: i ended up reducing it to 4 extrrnal batteries giving me a total of 6.2hrs estimated run time
more than adiquit, in most power cuts it will just remain running till the power comes back on, infact, i cant remember ever having a power cut last longer than that.

Thanx again m8
ericrazar
join:2007-11-04
Orlando, FL

1 edit

ericrazar

Member

the real genius is the guy who wrote the apcfix.exe . I am just an observant engineer lucky enough to find it. I found a tech at APC website say they ship out a "hardware key" that goes on the rs232 port to reprogram the unit to the A0 constant. The apcfix guy did it without all that. Also note that other size model smart ups that the default battery constant is different but the apcfix appears to know each of the right values.

Update:
It appears besides the apcfix there is a way to do it though hyperterm. Check warning in link. You need to know what the default value is for your particular model APC UPS.

»www.rm.com/Support/Techn ··· rrer=rss

KAI
@telecom.by

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APCFiX Home page: »apc-fix.com/page.php?al=apcfix
zoltan48
join:2008-02-22
9301

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I broke my new UPS. I converted a couple of old 400VA UPS's to 96Ah deep cycle batteries giving more that 6 hours running one PC. Here in South Africa we are having serious "power shedding" problems. Having our power off for more than 2 hours daily. This lead me to buy a MECER 2000VA UPS. Opening it I realized I will need 3 batteries in series, giving 36V. I hooked up 3 96Ah batteries in series. I mounted a socket on the outside of the UPS so that I can disconnect the extra battery bank, using the UPS separately. This means it was two different capacity 36V battery banks in parallel, but still supplying 36V. I tested it, It started up with the AC connected, then I tripped the AC. There was a loud noise, sounded like arcing and I could see sparks through the vent. I can't think what went wrong. Please, any advice would be appreciated.

SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA

SparkChaser

Premium Member

Which one did you buy, one of these? »www.mecer.co.za/content/ ··· y/24/90/
zoltan48
join:2008-02-22
9301

zoltan48

Member

Yes I bought the "ME-2000-BK (2000VA): 1080W"

I did not mention that I did not had any load on the UPS when I tripped the AC, don't know if that could have made the difference.

SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA

SparkChaser

Premium Member

said by zoltan48:

Yes I bought the "ME-2000-BK (2000VA): 1080W"

I did not mention that I did not had any load on the UPS when I tripped the AC, don't know if that could have made the difference.
The reason I asked was, for the 2000 it says 8 batteries. It doesn't say what configuration.

I never heard of Mecer. It appears to be a SA company. I wonder if these are re-branded from another manufacturer. There isn't too much info on the Mecer site. Did you operate it without the second bank before it went up on smoke?
zoltan48
join:2008-02-22
9301

zoltan48

Member

"ME-2000RBK, ME-3000RBK: 8 batteries" and further down "ME-2000-BK: 12V/9 Ah x 2pcs" which is incorrect for mine has 3 batteries. Yes it worked fine with its own batteries.

CajunWon
join:2005-12-30
Cary, NC

CajunWon

Member

I'm no EE
3 issues come to mind:
1)a wire became crossed.
2)the auxiliary battery pack was connected in series with the internal battery pack, providing more than the rated volts.
3)not reading the mfg information, perhaps it requires less than 36v to begin with. Did you measure the volts supplied by the oem battery bank?
zoltan48
join:2008-02-22
9301

zoltan48

Member

Yes I measured the voltage when I opened
it, it was 39 Volts with disregard-able low
load. That should be normal for one battery
is +/- 13V fully charged. Before I connected
the auxiliary battery pack, I measured it as
well, it was 40V. After I connected the two battery packs, I measured It again, and it was somewhere between 39V and 40V, which is expected. This should make that the auxiliary battery pack charge the internal battery pack with one Volt difference. Everything was
connected and was working well while it was
on AC, which makes me dare to say it roles
out wires crossing(If I understand it right,
wires shorting). Except if wires could
connect that it created a higher voltage,
which I doubt, because I used proper
insulated crimping connectors. I opened it
afterwards, and there was no sign of
something that shorted. It did smell like
something that shorted, my guess was that it
could be the relays, maybe they sparked
inside, making a bright enough light, being
visible from outside the relay and the Ups
box itself. There is three 40A fuses, on the UPS board which did not fuse. It was the first thing I checked.

SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA

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I've been unable to find any info on the Mecer unit except that one page. So, there is little to go on. They claim everything is protected. I guess you found one vulnerable point.

What kind of load did you have on the unit at the time of the switch to batteries? What gage wire did you use to connect them? This thing can draw quite a bit of current.

I'm not a fan of parallel batteries but it's done all the time, so, what do I know. It's certainly better if you use all of the same type and capacity to minimize any circulating currents.

You may have just done something that the circuit was not prepared for. Anytime you go beyond the supplied part you run that risk.

aurgathor
join:2002-12-01
Lynnwood, WA

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said by migr:

i was wondering if there was a way to change the nominal voltage it expects to see from the batteries.
Find the place where it senses the voltage, and "lift up" that sensor connection somehow, either putting in a small 1.2V - 1.5V battery in serial, or through some resistors and a higher voltage external source. I'd try a small battery first.
ericrazar
join:2007-11-04
Orlando, FL

ericrazar to zoltan48

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I would look at the circuit board again on both sides to be sure you didn't vaporize the copper traces going to the battery wires or some other hidden fuse. It sounds like you did the wiring correctly otherwise based on the charging voltage measured before/after the parallel hook up. Of course if you had a short occur due to wire heating and terminals moving and shorting that could have happened too I guess. if you read earlier post what i did with my apc 1000 setup with the marine batteries i used heavy wire up to the batteries and transition down to the 8-10 gage wires inside the unit with ring terminals. I read you have an external rear connector so that is convenient but should still use heavy gage wire and transition to a wire size that the connector uses.