Using a car battery with an APC UPS

[k-fox]

Hey folks. I recently wired my SmartUPS 1400 to two Optima Yellow Tops.


(Not shown is the 60A fuse between them for great justice)

Unfortunately, despite three run-time calibrations and the three (yes three) actual power outages today alone, the UPS still believes that at full capacity there are only four minutes of runtime. These batteries are brand new, shrink wrapped, off the shelf. The proprietor of the ricing store where I bought them told me someone from Optima comes and replaces the ones sitting on the shelf with fully charged batteries every three months.

According to apctest from the apcupsd package when the UPS is running on the batteries the voltage drops from 28.01 to just over 25 very quickly, as does the battery level percentage. Sure enough, after four minutes I'm looking at one blinking light on the front panel gauge - but 20 minutes later the thing is still running about a 20% load.

Here's some sample output of apctest while the batteries "recover" from the last outage:

Batt level percent: 060.0
Batt voltage: 28.01
UPS Load: 035.8
Line freq: 60.00
Runtime left: 0002

The odd thing is the battery voltage is 28.01 when the capacity is at 100%

It's also 28.01 when the capacity is at 40% - on the way up. At 40% on the way down it's closer to 25.

Is it possible my UPS has gone screwy? One of my colleagues has modded half a dozen UPSes like this and I did a fair share of googling before attempting it myself - this seems to be a straightforward plug-and-play operation for everyone else.

I'm trying to avoid running out and buying a stand-alone car battery charger and load tester. If anyone has any insight as to what these symptoms could be indicating I'd really appreciate it.

Thanks!

[NeoPTLD]

Originally Posted by k-fox

Unfortunately, despite three run-time calibrations and the three (yes three) actual power outages today alone, the UPS still believes that at full capacity there are only four minutes of runtime.

Observe the minimum battery voltage at the circuit board side as it switches onto battery. How many volts per pack does this come to? APC UPS monitors battery internal resistance through observing dips (dv/dt)

Also, the load vs run time is not a proportional relationship. Even if you set the unit's calibration parameters to brand new batteries, it would use the assumed battery characteristics to estimate run time.
Internal parameters are used to best guess the battery's rate of discharge vs capacity and this is not something you can alter on an APC firmware.

So, if runtime at 50% is 30min, at 100%, it will be something like 5min.

You can try changing the current transformer or shunt to a different ratio, so that unit thinks actual load is less than the real load, but that could have adverse consequences too.

[philipma1957]

try two wires for each connection. your wires look like 12 or 10 gauge. 2 at each connection will help lower resistance.


I had a tripplite with 4 golf cart batts wired to 48 volts.

when i went to 8 batts I had to increase gauge from 2 to 0 to get proper

charge

[ianj1]

I run an APC1000 XL - an extended runtime unit that is designed for a longer active operational cycle - both in charging batteries and running the inverter.

Running in Europe (Finland) at 230v, 50Hz

It has no internal battery - just Anderson connectors on the back

I run 4 regular 12v, 95 Ah car batteries in 2 strings of 2 (24v) and power a single PC and 5-6 monitors (yes i did say 5-6) , network switch, CFL desk light, etc. Normal operation loads the UPS to about 50%, but on power saving the monitors shut down and the setup drops to about 25% UPS load (I have to leave the PC on as its acting as a server and must be up all the time)

We have regular brown outs locally - some nights in the year its like Christmas tree lights flashing, but we do lose it for 3-5 hours several times a year. The batteries are only 6 months old, purchased new as a set together - and on my last discharge test i got bored waiting for them to discharge after about 8-10 hours, i stopped before the charge level dropped low enough to threaten the battery condition. The down side is the time taken to recharge the batteries - 15 hours+ at last check

I also have a generator (we lost power for 5 days last Christmas) and just acquiring a hefty 24v truck battery charger to boost the battery pack up (disconnected of course) to 70-80% in 5 or 6 hours instead of 14+ so we don't need to run the generator all day if/when it happens again. In that case we would ensure we had real good ventilation.

We had to disable the alerts with PowerChute as the alarm still fire off non stop after about 10 minutes even though the UPS itself still registers 95%+ charge left

Not given any problems yet - works like a charm

Just a last note - when watching battery voltages they were dropping fairly linearly and there was reasonable correlation between indicated charge level remaining from the UPS on PowerChute and my guesstimate based on measured power consumption during the test. The voltages dropped maybe 2-3v (from 27.9v at main power, fully charged) immediately on initial load - then didn't budge for a few hours and dropped steadily after that. I pulled the test at something near 20% remaining capacity

[ianj1]

Originally Posted by ianj1

I run an APC1000 XL - an extended runtime unit that is designed for a longer active operational cycle - both in charging batteries and running the inverter.

As a quick experiment i just did a quick discharge/recharge test
I pulled the main power at 20:32 until 21:10 - about 40 minutes
The UPS fans kicked in and dropped the UPS temp by 12+ degrees immediately and stayed on until the battery was recharged which took about 60-70 mins to reach initial voltage, after which the charging current clearly tailed off over a short period

Ambient temp was 20-25 C (its -5c outside - i opened the window for a while and the cold flooded in and dropped to the floor where the UPS was - hence some of the temp variation) Once charged the UPS cooling fans switch off and the UPS internals stabilise around 36c

The power usage drawn from the UPS was was about 350-360w and the power used BY the UPS when recharging was around 550w - so about 190-200w additional when recharging batteries - that tallies with the recharge time noted

Remember this is 2x2 x 12v, 95Ah regular sealed lead acid car starter batteries so about 190Ah at 24v - or thereabouts

After 40 mins on UPS powerchute software showed about 90% remaining charge

Time		Input   Battery   UPS      UPS
		Voltage Voltage  Load%   Temp C
22:50:05	228.8	   27.87	53.0	34.2 
22:35:05	230.1	   27.87	59.2	27.9
22:20:05	227.5	   27.87	55.6	22.5 topping off charge
22:05:05	227.5	   27.47	51.4	27.0
21:50:05	224.9	   27.06	52.0	26.1
21:45:13	227.5	   27.06	52.0	25.6
21:40:13	226.2	   27.06	51.4	25.2
21:35:13	224.9	   27.06	52.0	24.7
21:30:13	226.2	   26.93	51.4	24.3
21:25:13	230.1	   26.93	51.4	22.9
21:20:13	228.8	   26.93	51.4	21.1
21:15:13	227.5	   26.66	51.4	19.8
21:15:00	227.5	   26.66	51.4	19.8
21:14:00	227.5	   26.66	51.4	19.8
21:13:00	227.5	   26.52	51.4	20.2
21:12:00	227.5	   26.39	51.4	20.2
21:11:00	226.2	   26.12	51.4	20.7
21:10:00	227.5	   24.90	49.9	20.7 reconnected power
21:09:00	0.0	   24.90	51.4	20.7
21:05:35	0.0	   24.90	55.6	21.6
21:00:35	0.0	   24.90	49.9	22.5
20:55:35	0.0	   24.90	50.4	23.8
20:50:35	0.0	   24.90	50.4	25.6
20:47:43	0.0	   24.90	50.4	27.0
20:32:43	0.0	   24.77	51.4	36.9 disconnected power
20:17:43	231.4	   27.87	57.2	37.3
20:02:43	228.8	   27.87	53.0	37.3
19:47:43	230.1	   27.87	53.0	37.3
19:32:43	228.8	   27.87	53.0	36.9
19:17:43	228.8	   27.87	53.0	36.9

[Infiltratr]

Hi There!!

This is a fantastic tread!

I am in the same boat. I have an APC 1500 that is currently running fine on internal batteries, however I want to get much more runtime out of it!

At the moment, I get about 2 hours runtime out it, which is fine, but I really want to run them on battery for about 6 hours (the longer the better actually).

What I want is for the UPS to run on mains for 18 hours a day and ups for 6 hours a day, every day. Its not about backup power for me - but giving me time to let the generator cool down every day (my mains is generator powered because of where its located).

Would the Optima Yellow tops be the ones to use for this???

[Googer]

Originally Posted by Infiltratr

Hi There!!

This is a fantastic tread!

I am in the same boat. I have an APC 1500 that is currently running fine on internal batteries, however I want to get much more runtime out of it!

At the moment, I get about 2 hours runtime out it, which is fine, but I really want to run them on battery for about 6 hours (the longer the better actually).

What I want is for the UPS to run on mains for 18 hours a day and ups for 6 hours a day, every day. Its not about backup power for me - but giving me time to let the generator cool down every day (my mains is generator powered because of where its located).

Would the Optima Yellow tops be the ones to use for this???

If you have one of their commercial smart UPS, APC makes a battery pack that should plug in to the back of your 1500 and each pack can be daisy chained.

Cable for the pack. Pack URL will be posted when I know the model of your UPS.
http://www.apc.com/products/resource...e_sku=SMX039-2

Possiblity one:
http://www.apc.com/resource/include/...ase_sku=br24bp

Possiblity two:
http://www.apc.com/resource/include/...sku=SU48R3XLBP

Possiblity three:
http://www.officedepot.com/a/product...ction-_-162530

[Googer]

Originally Posted by Red Squirrel

I have an old UPS exactly like this one:



The battery on it is bad. Got the UPS used, was basically being thrown out, or I could keep it, so figured why not. It lasted me a few months then started beeping non stop and the battery light flashes.

It's over 100 bucks to replace the battery so it's not really worth it when I can get a new UPS for that price, but at same time I kind of don't like throwing out something that will work fine with a replacement part.

Would it be safe to hook up a car battery to it? Any special type of car battery I should use? A car battery is cheaper and will probably provide more juice. I'm guessing a deep cycle batter is probably the best idea. I heard of people doing this before but with lot of modifications.

You can get a newer unit with the same v/a capacity, but a newer low end unit will out put square wave AC vs the Smart UPS line is a true Sine Wave unit. The smart line is also much more robustly made than typical home units.The difference can really affect certain types of electronics.

[ianj1]

Originally Posted by Infiltratr

Hi There!!
I am in the same boat. I have an APC 1500 that is currently running fine on internal batteries, however I want to get much more runtime out of it!

At the moment, I get about 2 hours runtime out it, which is fine, but I really want to run them on battery for about 6 hours (the longer the better actually).

Be careful about using the regular APC 1500 - The XL version has uprated components to the charger AND inverter, allowing it to run long duty cycles - i don't think a regular APC 1500 would last for long on long cycles - also watch out for the noise - when the UPS is on the cooling fans kick in - you will need to move it out of earshot. Last think is to make sure you disable the low battery alarm - or you will go insane after 15 mins - i made up a special cable and used powerchute to disable the alarm permanantly

[Googer]

Originally Posted by ianj1

Be careful about using the regular APC 1500 - The XL version has uprated components to the charger AND inverter, allowing it to run long duty cycles - i don't think a regular APC 1500 would last for long on long cycles - also watch out for the noise - when the UPS is on the cooling fans kick in - you will need to move it out of earshot. Last think is to make sure you disable the low battery alarm - or you will go insane after 15 mins - i made up a special cable and used powerchute to disable the alarm permanantly

If it's one of those cheap back-ups models, the internal compoents are very low grade compared to the basic units of the Smart-ups line.

[Red Squirrel]

My current setup still working nicely, though I've only been through one large power outage since (about 5 hours), I even have it setup so I can monitor the battery voltages so I can shut down stuff.



Thats done with arduino, and a monitoring program I've been working on. I found all the existing solutions either too complicated to setup, or lacking of features.

Once I build a proper battery shelf I want to also buy my own cable crimper and raw cable/ends to make my own cables so I can space the batteries the way I want. Right now I'm restricted by the short cables so I can't build a shelf with say, 4 batteries on top of 4 more as the cables are too short to space the batteries that way. My goal is to have about 12 hour reserve. Gives me enough time to figure out an alternate power solution (such as generator) if shit hits the fan. I can't afford to let my main server go down as it's very old hardware and every single time I've shut it down I ended up having to replace parts to get it back up.


Eventually I want to get a 48vdc setup with more capacity so I can put my office workstation on it as well as my entertainment system. If power goes out and I'm in the middle of watching a movie or something, no problem.

[smico]

Hi everybody.

I found this forum yesterday, and I was very impressed with knowledge of the group. You guys are working on the project that I have planned to do for some time...

I bought APC SmartUPS 1500 with dead battery, and 6 AGM 96Ah batteries that I will get tomorrow.

Sorry if I post already referenced links, but there are many excellent videos on the subject on youtube from user knurlgnar24 www.youtube.com/user/knurlgnar24

Also user Tesla500 has some very good videos on subject how to simply improve the APC UPS: www.youtube.com/watch?v=KJj3H00idh0

If you find videos useful, please subscribe to the users. I think that they get paid by number of subscribers, and this is well deserved.


Red Squirrel,

Is that Open Source project with Arduino, or you are doing it for yourself?
Do you measure temperature of the batteries?

Thanks
smico