# Used Battery Questions - SLA

#### kcarring

Joined Jan 22, 2011
38

http://youtu.be/nmgFm222hK0

Here is the battery datasheet:

http://datasheet.octopart.com/HR1234WF2-CSB-datasheet-88144.pdf

I recently acquired 3 UPS battery packs, each having (8) CSB HR1234WF2 batteries. So, 24 total.

Their history is basically unknown, I got them from the recycler - free - I decided to take them home because their series voltages read 52v, 52, and 53v. Given they are supposed to go to 13.5v, a bank charge would 54v.

I am lead to believe the previous owner was a large company, ALL of their computers, UPS's, servers, and data equipment arrived, all at once, on the same day - so I think they were doing a large upgrade to pretyt much everything.

I started reading up on the batteries and tried some tests. In one bank, all batteries read 13.04v, and who knows how long they've been sitting. I did a quick 3 watt LED array test.

Then I thought I'd test one a bit further, so I plugged in 12-17 watt TV to a single HR1234WF2, the tv fired up and I watched the voltage decline to about 12.65v, and then it levelled off. I ran the TV a few minutes, and then let the battery stand for a few hours. When I cam back the battery pretty much bounced back, 13.02v.

If the batteries are rated at 34 watts, 12v and it says that a maximum discharge would be 34 watts, for 15 min.... what is a good test for the whole bank of 8? I have three of these banks but even a single bank test would be good.

Also, given these stats:

Cells Per Unit 6
Voltage Per Unit 12
Capacity 34W @ 15minute-rate to 1.67V per cell
Weight Approx. 2.62kg(5.8 lbs)
Maximum Discharge Current 130A(5sec)
Float Charging Voltage 13.5 to 13.8 VDC
Recommended Maximum Charging 3.4A
Current Limit
Equalization and Cycle Service 14.4 to 15.0 VDC/unit Average

Questions:

1. What would be a good load testing method for these both singular and as a bank?

2. Will a normal battery charger (12v) suffice for these?

3. Will my solar panels with MPPT charger work ok?

4. What exactly do they mean by float voltage and cycle/equalization voltage?

5. One datasheet I read (though not the one I linked to, oddly...) has one part that concerns me. It goes over the discharging scenarios: 15m 30m 60m and 90m and gives data for each. Then, it said below in an asterisk comment * discharge over 90 minutes is not recommended. It may have something to do with the F2 part of the model designation, because I did not find this on the NON-F2 version (HR1234W). So - Would I be better off to use these banks only situations where the load quickly discharges the entire capacity, or could I use them more sparingly for light / solar, for example?

In any event if the batteries end up being garbage, the metal cases will suit another project

Thanks for any input!

#### strantor

Joined Oct 3, 2010
6,690
I get those type of batteries all the time at work; they come from the fire detectors system and they're all over. company policy is that they have to be changed out once per month, so I check the battery disposal regularly. Usually if the voltage is >12V when I find them, I consider them good. If I find them <12, I charge them up and if they hold a charge for a few day I consider them "probably good". if they don't hold a charge, I put them back in the battery disposal, and that's my test procedure. So according to my standards, all your batteries are good. as far as your other questions, wait for someone smarter than me.

#### kcarring

Joined Jan 22, 2011
38

What I find odd, is...

In the HR1234F2, all discharge information is based on VERY fast discharging, and one datasheet even said * discharge over periods greater than 90 minutes not recommended.
Note how the datasheet says NOTHING about amp hours, only rates in watts over time.

Now,... I have, on hand another battery, that looks VERY similar, the VISION CP1290.
It's datasheet:

http://acdc.com.tr/tr/pdf/cp1290-vision-aku.pdf

gives a typical amphour rating and C20 discharge rate of 20 hours.

Are these batteries I acquired no good for running low loads over 8-10 hour periods?

It's odd to me.

#### kcarring

Joined Jan 22, 2011
38
In a nutshell, I'd like to know (and yes I have been reading the manufacturers explanations and they do tend to agree with this) if these batteries are specifically rated, the way they are, because their intentions are that the end user will use them during a fast rate of discharge. And if so, given the maximum rating for any one single battery is 90 mins... is it unwise to have this battery plugging along putting out mA, instead of amps? They specifically do not give an amp hour rating, like so many other batteries do (other SLA's). Are they not really a deep cycle battery, and more like CCA battery? I could see that, given that the banks are 4 batteries in series x 2 parallel banks. Possibly their sole intention (really) is to "dump current", to then invert to 110v, where a watt takes (roughly) twice the current? Give servers enough time to save files shutdown, or switch to generator power? That's my thinking. The batteries do seem quite good. They power one amp loads and recover... (individually) and seem to be charging over 13.35v (and climbing - first charge is tonight). I'd just like to group them according so they are "worked hard", if that's what they are intended for.

Thanks

#### SgtWookie

Joined Jul 17, 2007
22,230
They are CSB brand (China Storage Batteries); the company datasheet is here:
http://www.csb-battery.com/upfiles/dow01300946263.pdf

In case they move files around again, the link to HR prefix battery spec sheets is here:

Note that the first item in the list is the HR series general information brochure:
http://www.csb-battery.com/upfiles/dow01232502782.pdf

As the brochure says, the HR series initials literally mean "High Rate" of discharge. However, they mention things like street lighting in the brochure, so go figure on that one.

Since you paid nothing for these batteries, are you terribly concerned on how long they will last?

I got a few "freebie" batteries that were in UPS's; several were bad from the start, and I got about 6 months' use from one of them. It seems like your batteries are in pretty good condition at the moment, but unless you can find the manufacturing date, it'll be kind of difficult to determine how long they might have left.

As you can see from the spec sheets, discharging them deeply will greatly shorten their life in duty cycles.

#### Smoke_Maker

Joined Sep 24, 2007
126
Questions:

1. What would be a good load testing method for these both singular and as a bank?

2. Will a normal battery charger (12v) suffice for these?

3. Will my solar panels with MPPT charger work ok?

4. What exactly do they mean by float voltage and cycle/equalization voltage?

You should test the batteries one at a time to see how much usable capacity the batteries have left. You will have to figure out what the data sheet is saying (I looked at it ) What you want to do is discharge the battery at the specified rate and see how much time it takes to get to 1.65V per cell and compare it to the data sheet. That will tell you how close to junk there are. It looks like that these batteries are not a true deep cycle battery but a hybrid like the marine battery dual purpose, if you look at the cycle life graph on the data sheet they may be well suited for a solar panel.

For 2, 3, 4, your MPPT should be better suited for the batteries than most chargers, Charge at high amps until you reach 2.33 volts per cell, then change to constant voltage of 2.466 volts per cell until the current stops dropping for over a one hour period of time, then move to float voltage.

During maintenance you want to test the batteries to see if they need equalizing, test and record each battery's voltage and when you have more than .10 volts between the highest and lowest battery you need to equalize the string.

#### SgtWookie

Joined Jul 17, 2007
22,230
Just an interpretation of the charge/float recommendations:

Float: 13.65v @ 25°C, adjust at a 3mV per cell per -1°C offset from 25°, or 18mV per -1°C offset
Charge: to 14.7v @ 0.025pa = 34W * 0.025 = 0.85A (can also be used for periodic equalization)
Max charge rate: 0.1PA = 34W *0.1 = 3.4A (I would stay under 3A.)

Basically, the faster you charge the batteries, the greater the chemical reaction, which causes internal heating, which shortens the life. However, these are AGM batteries which tolerate fast charge rates better than flooded cell batteries.

#### #12

Joined Nov 30, 2010
18,224
I'm reading absolute maximum capacity is 2.00 amp hours. You can use that any way you want, as in, 90 minutes means nothing if you're only trying to run a wrist watch off these batteries. However, using the whole 2 amp hours per discharge/charge cycle would reduce the number of survivable cycles to 200.

I would also bring to your attention the idea that C20 means 20 hours to charge or 1/20th of the usable current per hour. You seemed a bit uncertain in post #3. C20 is by definition a 20 hour measurement.

Smoke Maker sees 2.43 amp-hours.

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