Good source of used/blemished batteries

AntronX · April 2009

Hello solar fans! I have a small 340W 24V system with 100Ah of AGM storage. I found that I need more reserve capacity because often, my batteries are full too soon, and my system pretty much idles. And then there are times when I drain the batteries down to 80% DoD. I figured that with my usage patterns I will need to triple my Ah capacity. The problem is that it's too expensive at $1500 for good American made AGM batteries.

I found local battery distributor that offered to sell me their blemished batteries at a good price. They get huge pallets of them couple times a week and some batteries have terminals (dual terminal type) or handles broken. The distributor cannot sell them and sends them back to the factory, where they get recycled. So otherwise fine brand new battery gets wasted.

So, I wonder is this a good idea and what other good sources of bargain batteries can you guys recommend? I've read about some people getting used UPS system batteries for very cheap, where should I look to get something similar?

A little more about my system: 2x 170W Evergreens, FM-60, 24V 100Ah Fullriver AGM, 600W Exeltech P.S.W. inverter (bought from NAWS), 24V input ATX desktop 2.5Ghz AMD dual core computer sipping power at 52W idle, Phillips 25W F32T8 Alto lights, coffee maker, some Ham radio gear, some pro audio gear, all running on solar! 83 KWh DC generated so far since February.

icarus · April 2009

Re: Good source of used/blemished batteries

I would be curious to know how they are priced,, how they warrant them. If they were price in the range of scrap value it would probably be a pretty good deal.

Let us know more details.

Tony

niel · April 2009

Re: Good source of used/blemished batteries

if they are still good functional batteries then i would assume they could still warrant the performance of them and mixing of old/new or different types of batteries is not a good idea. if you go this route, please keep us updated on how well they perform.

AntronX · April 2009

Re: Good source of used/blemished batteries

Since the batteries would be heading to recycling plant, I doubt that the warranty will be offered. I will ask if I can exchange them if I get complete failure within few days. Batts are Odyssey PC 2150. They are $300 new 75 lbs AGM battries, I was thinking offering them $50 a piece as is. What do you guys think about how much I should pay?

I would have to make sure I get them in identical pairs of similar age for connecting them in series for 24V. But I think I should be able to parallel different age and capacity pairs together for larger overall capacity without serious problems. More powerful and younger pairs will suck up the charge at slightly higher current than older pairs, but eventually all should stay balanced i would think. Oh, and this is not mission critical off-grid middle of nowhere installation. We have grid power 99.9% of the year (south FL). But I find solar/R.E. power pretty fascinating, not as a treehugger, but as an idea of capturing and using clean energy that lands in my backyard for free.

BB. · April 2009

Re: Good source of used/blemished batteries

Antrox,

DapDan's first post here was an interesting link to a paper that describes how to rehabilitate old/abused AGM batteries by adding some distilled water and replacing the old caps (new catalyst to convert generated hydrogen/oxygen back to water).

In combination with your battery source--may be worth a try at ten cents on the dollar (New AGM caps are not cheap).

-Bill

baddawgz · April 2009

Re: Good source of used/blemished batteries

BB. wrote: »

Antrox,

DapDan's first post here was an interesting link to a paper that describes how to rehabilitate old/abused AGM batteries by adding some distilled water and replacing the old caps (new catalyst to convert generated hydrogen/oxygen back to water).

In combination with your battery source--may be worth a try at ten cents on the dollar (New AGM caps are not cheap).

-Bill

How about golf cart bats..there has to be a million of them in Florida..they usually have a lot of take outs that still have lots of life in them..they cost from scrap price to ??..I have had some last over two years...just load test, if they pass drain them, rinse them out, and replace with new bat acid..

BB. · April 2009

Re: Good source of used/blemished batteries

I think the "failure" modes of AGM, in many cases (basically, going "dry" because of overcharging and/or failed/worn-out catalyst allowing the cell(s) to vent), is different from flooded cell batteries (that have otherwise been kept properly watered).

On the other hand, if you get your money's worth from used golf cart batteries (and can properly dispose/recycle the acid and scrap batteries)--why not.

-Bill

icarus · April 2009

Re: Good source of used/blemished batteries

If they are going to the scrapper anyway,, what are they getting paid at the scrapper? Lets say it is $.50/lbs,,, offer $.60 and you are really out nothing,, as if they fail you can get the $.50 from the scrapper,, assuming lead prices stay stable. Also, in this case I wouldn't really care too much about mixing old and new/ bigger and smaller batteries in the same string. If you shorten the life of the string as a result,,,, so what,, if it comes at no real cost.

Let us know more details.

Tony

PS. It seems that there is a huge difference between "used" (unknown age condition) batteries, and new damaged batteries. If you can essentially get a new battery for scrap because it has a broken post, or a crack in the top of the case,, or something minor like that,, then it would seem that you are golden,, assuming the damage doesn't effect the performance. I wouldn't pay scrap prices for used batteries with an unknown history as the headache factor of moving and installing a bunch of batteries out weighs most potential benefit.

niel · April 2009

Re: Good source of used/blemished batteries

hey, if they are going to be scrapped anyway act like bill shatner and go lower. i'd offer $5 a battery with no warranty of performance.

AntronX · April 2009

Re: Good source of used/blemished batteries

Well, the deal is a no go. Called today and their sales manager said that the guy I spoke with first was wrong and they are required to send those damaged units back to factory. There are two more battery dealers I can call, but the outcome may be same.

Found one guy that sells used batteries and he's got whole container full of used AGM batteries from a large UPS. He wants $35 for 75Ah battery. I don't know what brand or model they are, and their age. Will find out tomorrow.

Dapdan · April 2009

Re: Good source of used/blemished batteries

Hey A,

I would encourage you to keep at it. When I started looking for used batteries I got hold of some old trojans from golf courses and they did not work out so well but i stayed the course. I soon found bigger and better as i keep asking around and searching. My first deal was when i bought some used hawker traction batteries from a submarine company and those were 3 years old at the time and got 24 of em'(2v wet cells at 640Ah) at $35 each. I was tracking those for about 1 year before they were decommissioned last Sep. In Mar this year i scored a better deal and got 12 used agm (900Ah) for free. I was tracking those for about 1/2 before i got them. I am using both banks and everything has been improving for the last 6 months. I am still on the look out for more cause you never know when those are going to fail on ya.8)

I would advise you to contact some middle management at your local telecom company and befriend them. Those guys will always come into contact with DC cells (that is how i landed my score on those 900Ah gnb agms). Contact guys from the electric company as well they need to use them on their switch gears. I have found that those cell are always in a better condition as compared to say forklift batteries since they operate under what they call " float service" and are generally not cycled hard like say forklift batteries.

Good Luck
Cheers...

Damani

AntronX · April 2009

Re: Good source of used/blemished batteries

Wow, 900Ah at 24V will take 14.4 days of perfect sun to charge from my system. Thanks for your advice. Will remember the telecom thing in case I will need such large batteries. So far I do not have space to put that kind of monsters anywhere. Maybe I should call local large UPS service companies and ask what they do with their used batteries.

westbranch · April 2009

Re: Good source of used/blemished batteries

those AGM's have a foot print of 2 feet X 3 feet roughly and should be laid on their side, so the second one just uses 'space'

each 12 v unit will weigh about a 1000 pounds so they need a very strong floor (or a basement concrete floor) to support them...
cheers
Eric

homerramirez · April 2009

Re: Good source of used/blemished batteries

were can I get some of those batteries ?

n3qik · April 2009

Re: Good source of used/blemished batteries

Just a warning to the OP and others, watch out for gel cells and some batteries used at the telco. They are for float stand-by use and have a very low cycle use life count.

The gel cell used in most UPS's are good for only 3-5 years in stand-by mode then they are toast.

Dapdan · April 2009

Re: Good source of used/blemished batteries

hey n3,

the telecom ppl down here use large agm. The brands is see are deka and gnb. The ones i got have a float life of 20 years. I know one manager from same company that has been running his house for a few year using similar cells to the one i got. If you get them for free it is a win win situation and the companies usually recycle them after 5-10yr usage.

Cheers...
Damani

dwh · May 2009

Re: Good source of used/blemished batteries

There's a place near me that (from what they've told me) gets returned batteries.

For instance, someone buys a new battery then decides it's not big enough and they return it and get a bigger one - if the one they returned has a scratch or other blem on it, it can't be sold as new, so Battery Power buys them.

I know they have Deka 105ah 12v batteries there for $150 - I've seen them. They tell me that the batteries they sell come with a new battery warranty.

YMMV.

Dunno if they ship...

Google for "battery power inc sylmar" and the first link is them - on Foothill Blvd.

AntronX · May 2009

Re: Good source of used/blemished batteries

Ok guys I think found gold! Found a pair of used 1.5 year old Lifeline GPL-8DL 255Ah 12V batteries. Just tested one and got above 91.4% of rated capacity. Ran it for 6 hours (untill 10.5V) at 30A and got 2070 Wh (2070Wh / 12V = 172.5 Ah). Got them for $100 each. Pretty happy so far

AntronX · May 2009

Re: Good source of used/blemished batteries

Got two more batteries today. So now I should have 24V 414Ah of actual storage capacity at 20hr rate. My idea is to never let these get fully charged when in use, so that charge controller never goes into absorption mode. This was an issue with my smaller 100Ah (advertised) batteries. How often should I put them on a charger and let them equalize?

Few pics attached:

mike95490 · May 2009

Re: Good source of used/blemished batteries

Those look like sealed batteries, and should NEVER be equalized. They should be fully changed at least every couple of days, AGM are sulphatation RESISTANT, and can still be damaged by incomplete charging on a regular basis.
(If I'm wrong, and they are flooded cell, dis-regard this)

AntronX · May 2009

Re: Good source of used/blemished batteries

Yes, they are sealed AGM. I did not know that they can be damaged by partial charges. I thought sulphation only occurs if batteries are left fully discharged for long time.

mike95490 · May 2009

Re: Good source of used/blemished batteries

sulphation is generally, irreversible. 1% today, 2% next month, then another 1%, pretty soon, 10% is gone. Resistant is not bullet proof. Each Mfg will have their own specs, and because of the speed, boiling (overcharge & venting) will kill an AGM faster than sulphation.
Maybe there is a more authoritative expert on AGM & sulphation ?

niel · May 2009

Re: Good source of used/blemished batteries

you need to search concorde's website and look up the charging requirements for those batteries. they will need to be fully charged and they may give instructions if you wish to try to eq them. err on the side of caution for eqing.

AntronX · May 2009

Re: Good source of used/blemished batteries

I tested third battery out of second pair and it also delivered above 93% of original capacity. I got them from DC Battery http://www.dcbattery.com/ in Miami, FL. Call and ask for Albert, he's got 6 more of these batteries. You need to come down there and load test them to make sure you get the good one.

Dapdan · May 2009

Re: Good source of used/blemished batteries

Hey antronx,

I am interested in your load testing regime. How exactly (details please) do you carry out your load testing on these cell to arrive at your perctentage. Do you use the constant current data for the particular battery inorder to qualify your results?

Cheers...
Damani

AntronX · May 2009

Re: Good source of used/blemished batteries

Dapdan wrote: »

Do you use the constant current data for the particular battery inorder to qualify your results?

Yes. I discharged the battery using Xantrex Prosine 2.0 12V inverter running creatively picked loads to give me 30A of load at the battery. So, this setup is more like constant power than strictly constant current. It ran for 362 minutes until 10.5V at 30A.

30A * (362/60) = 181Ah

According to Lifeline spec sheet, this battery when new should deliver 25A for 475 minutes until 10.5V.

25A * (475/60) = 198Ah

181Ah / 198Ah = 0.914 = 91.4%

Since I tested it at 30A, my result is lower than if I were to test it at 25A. That's why real percentage compared to factory test should be slightly higher than 91.4%. I wanted to do real 8 hour rate test (255 Ah / 8 h = 31.8 A ) Turns out the real real 8 hour test rate is 25A, because I was basing my Ah value on advertised "20 hr" rate. Interestingly, even at 8A spec sheet rate, they still fail to reach advertised 255Ah. 1670 minutes / 60 = 27.8 hours ! Way more than 20 hrs.

8A * (1670/60) = 223Ah

Lifeline's sales staff referred me to their engineer with my question, but he never picks up his phone...

From my AC kill-a-watt meter I got 1880 Wh, at 90% inverter efficiency (measured) that makes it 2070 Wh DC. Battery voltage average was (10.5 V + 12.5 V) / 2 = 11.5 V

2070 Wh / 11.5V = 180Ah

Close enough...

Dapdan · May 2009

Re: Good source of used/blemished batteries

A,

yes that is close enough. I have done a very similar test on my batteries. I am glad to see that someone has formulated a very similar test to mine.

the only difference is that i want to use a dc clamp meter to verify my discharge current at the batteries.

Cheers...
Damani

AntronX · November 2009

Re: Good source of used/blemished batteries

Well, it has been 6 months and those Lifeline AGMs are doing good. Today i got some extra freebies from UPS system at work. I got 15 C&D Technologies UPS12-270FR AGM batteries. They were replacing all of them due to few bad ones that caused whole system to fail. Battery date code is 12/06. I brought load tester and picked out ones that could hold voltage above 11V at 100-150A load. Most stayed at 11.5V under load, except few failed units. I know these are not designed for deep cycling, but they only cost me $10 in gas to transport them home. If they last 1 year, I will be happy. Has anyone else here used same battery?

Dapdan · November 2009

Re: Good source of used/blemished batteries

Oh damn,

That is a good deal. I have two of those UPS batteries that i got for free as well and they work great. I wish i could have gotten say about 6 or 8 more of them. Great find, mail some to me.

Cheers...
Damani

RCinFLA · November 2009

Re: Good source of used/blemished batteries

Used UPS AGM can be a reasonably good prospect. Most UPS rely on super heavy discharge rates. The system monitors effective internal impedance and flags any that don't meet the pretty tough criteria for the high discharge rate in the UPS.

Take a portable DVM with you and check to make sure they are at least 12.4 vdc. Also judge them on date code. Less then four years old are reasonable prospects.

AntronX · November 2009

Re: Good source of used/blemished batteries

RCinFLA wrote: »

Used UPS AGM can be a reasonably good prospect. Most UPS rely on super heavy discharge rates. The system monitors effective internal impedance and flags any that don't meet the pretty tough criteria for the high discharge rate in the UPS.

The UPS units there are pretty old, and do not have per battery monitoring. One of UPS units actually failed during routine self-test and took all it's loads with it. Batteries that I took home all can hold voltage above 11.5V under 150A load. They are at 12.7V open. I got them all wired in parallel and ready to be fully charged when it gets sunny again down here in FL.

Good source of used/blemished batteries

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