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| Hey EVMetro....I found some used industrial batteries.; Opinions Please, Any good for a Solar Project?? | |
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| Tweet Topic Started: May 28 2015, 11:18 AM (983 Views) | |
| Rondawg | May 28 2015, 11:18 AM Post #1 |
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I had to make a run to a salvage yard today and ran across some Batteries that sparked my interest. The story goes that a contractor for cell towers dropped a bunch of them off there. Supposedly they are replaced per a time schedule and they are perfectly good. They want $30 each but I could prolly get 2 for $50. Do ya think it's a good deal? Ever heard of this brand?? Would the power ratings on the sticker be good for a Solar Project?? ![]() ![]()
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| evmetro | May 28 2015, 11:33 AM Post #2 |
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It is pretty hard to tell how much life is left in them, but if they are still good, that could be a pretty nice deal. A typical starter battery for a Metro has about 50 to 60 AH, and these are advertised at 98 AH The AH storage will go down as the battery ages, so it is hard to tell what is left in them. If they were only used for backup, they may still have some life left in them. Kinda sounds like a roll of the dice. |
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| Rondawg | May 28 2015, 11:39 AM Post #3 |
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It's hard to tell from the photos but they are quite large. Darn things are 80 lbs! |
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| Rondawg | May 28 2015, 12:30 PM Post #4 |
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Are you saying that per the label, when new, these batteries had about the same "AH" (whatever that means) as the battery under the hood of my Metro which is about 1/3 the size?? |
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| Freeman | May 28 2015, 12:43 PM Post #5 |
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The Family Man
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More like 1.5x the strength of the metro battery. AH is amp hours, but 60 AH could be 20 amps for 3 hours or 10 amps for 6 hours from my understanding. So the amp rating on these could be MUCH lower than what your metro battery is putting out, thus lasting longer. (I think?) EV definitely would know more than I do. |
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| evmetro | May 28 2015, 04:55 PM Post #6 |
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Yea, the amp hours is how many hours it will last at 1 amp. In your metro, you don't really care about this, since your alternator keeps it charged. What you need in your metro is several hundred amps for a short time to start it up. Your metro battery probably is rated for 550 to 650 cranking amps, but it won't do it for long. For solar, you will be interested in running an amp or two all night, so ah is important. The 98 ah rating on these batteries that you are looking at is like a gas tank with 98 units of fuel. Unlike the Metro gas tank, the battery's fuel storage gets smaller and smaller as time and or use ticks by. They may only have 20 ah of storage left by now. If you really want to know how much energy storage is left on these batteries, hook up something that draws 1 amp, and see how long it takes to run it down. I doubt it will be the four days that it is rated for, but at least you could see how much is left in them now... |
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| Rondawg | May 28 2015, 09:29 PM Post #7 |
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This my sound dumb but what makes a battery like this wear out/deteriorate over time? There are no moving parts. Other than overcharging em and boiling out all the acid. What about replacing the acid, would that help assure better performance? As these batteries are charged, trillions & trillions of electrons are somehow stored in there somewhere. Are these electrons trapped in the acid or in the lead? I'm actually thinking of geting 4 of them for $100 and that would be the 1st step in the solar generator project. |
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| evmetro | May 28 2015, 11:09 PM Post #8 |
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Mother nature always comes calling. She eventually claims our car batteries, our cars, and ourselves. We do what we can to slow this process down, and in the case of batteries, this would be keeping them at the optimum temperature and charging them correctly. They can only be charged and discharged about 300 to 500 times before they are done for anyway. There is probably no way to know how many times the batteries that you are looking at have been charged, or how they have been maintained, which is why I call it a roll of the dice. Worse case is that they are at the end of their life, and you are left with 40 bucks worth of cores, best case, you get two more years out of them. |
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| scratchpaddy | May 29 2015, 12:37 AM Post #9 |
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Not so fast
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There are no mechanical parts, true, but the electricity comes from a chemical reaction. The reaction the batteries are built for is reversible by applying a charge instead of a load on the battery, but over time, other reactions occur that cause the electrodes and electrolyte to break down into inert compounds. Those compounds don't hold any charge, plus they resist any charge going into or out of the battery (higher internal resistance). The battery loses capacity, and using what capacity that remains becomes less efficient. You didn't ask, but you've probably heard of capacitors. Capacitors also store charge, but they do it directly, holding electrons captive between charged plates. They don't use any chemical reactions, so they can store and release charge far faster and more efficiently than any battery, and they don't really wear out. However, they can't hold nearly as much energy as a chemical battery. There are these experimental electric buses in Shanghai that use capacitors instead of batteries. Their range is only a few miles, but they can be fully recharged in seconds. Each bus stop is a charging station. It's fully charged in the time it takes for people to get on and off. |
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| Ephemeral Glade | May 29 2015, 02:17 PM Post #10 |
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Here is a link to a pretty good site for battery related 101. http://batteryuniversity.com/ |
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| Highwayman | May 30 2015, 02:49 PM Post #11 |
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For solar or back up battery systems; batterys are rated in hours rather than cranking amps. Deep cycle battery capacity is specified at a 20 hour rate. That means a battery with a 100 Ah rate will operate at a discharge rate of 5 amps for 20 hours ( 5A * 20h= 100 Ah). If a battery is operated at a higher discharge rate, it will produce less than the rated capacity. Such as a 100 Ah battery discharged at 10 amp rate will only produce appx. 93 Ah. If it is discharged at a 1 hour rate (100A), it will only produce appx 60 Ah of capacity. It destroys a deep cycle battery to fully discharge it so a rule of thumb is to have twice the capacity you will need so you never totally discharge them. If one of the batterys goes bad on a cell or repeater system they replace all the batteries as different age batteries dont work well together and cause melt down. If you bring your cheapy volt ohm meter with you and set it to DC volts, the batterys should read 12 to 13 or 14 volts. One of those batterys will test at 2.2 volts or more low. That will be the bad one. Our batterys on our system at work to back up our server has each battery that size at 2.2 volts each then are connected together till they equal 48 volts and are charged at 52 volts. As your batterys in the picture are 12 volt batterys they were likely tied together to equal 48 volts. They look like Sealed lead acid rather than Absorbed glass mat. AGM are the best but most expensive. Deep cycle batteries are nothing like automotive batterys in design or treatment. If you go to wall mart and look at their batterys you will see that the ones for motorhome and trolling motors are rated in appx 95 hours rather than 500 cranking amps. The deep cycles dont have much warranty if any. A automotive battery wont last long as a solar battery as they require immediate recharge when depleted and is why your 120 volt converter shuts down at 11 volts. (to avoid damaging your battery). By the way, your automotive alternator is a AC generator. The diodes couse the ac to become DC power because a diode is a one way electrical valve. Causuing the ac to become dc as it cant return to its source. In a nut shell; If you bypass the regulator and diodes, you have a speed regulated ac generator. At idle the alternator puts out appx. 38 volts. As you slowly increase speed you can stop and hold the voltage when your ac volt meter says 120 volts.if you keep increasing speed it might say 220 volts. Amps times volts equals watts.... 100 amp alternator times 120 volts equals 12 thousand watts. If increased to 220 volts = 24 thousand watts from your car alternator. That is why you can arcweld with a car alternator. Problem is the frequency is in excess of 400hz which is mostly used in aerospace applications. Will run resistive loads but not inductive loads. Your car alternator will run any motor with brushes such as Skil saws, jigsaws, electric chainsaws, vacuum cleaners, light bulbs, electric bathroom heater but wont run the fan because the fan is inductive and requires 60 hz to operate. This is the stuff one is forced to learn if they desire to survive off grid. P.S. Those batterys in the picture have pressure valves in them to try to keep the electrolyte in them. DONT put one of these in a automobile as they require less than 15 amps preferrably less than 10 amps or they will boil or melt down or explode if charged at a high amp rate such as a automobile alterator does when you first start the car and the belts squeal for a few seconds. Edited by Highwayman, May 30 2015, 02:59 PM.
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| myredvert | May 30 2015, 04:34 PM Post #12 |
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myredvert
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So if the belt is tightened properly and doesn't squeal, it won't explode?
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| Stubby79 | May 31 2015, 12:27 PM Post #13 |
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From the specifications pages for these cells (http://www.nrsga.com/wp-content/uploads/2014/05/VE-Range-Summary.pdf) "Charging current: PowerSafe VE can be safely recharged at high current rates." They can also sustain 630 amps discharge for 2 minutes. More than enough for starting. You'd want to be more careful with a gel cell, but these are AGM. They can handle high currents, and higher charge voltages than a gel could. Not so sure if they will appreciate the heat of an engine bay. Not that I suggest using one as a starting battery anyway, but you could if you really wanted to. and 80lbs is a bit heavy for a geo battery! PS: Haven't read all the replies, but I'd think these would make a great battery bank for a solar setup. They've probably lived 99% of their lives on a float charge, only being discharged occasionally when the power goes out. They're non-spillable(safer), no-maintenance, efficient (for lead acid, anyway), and can hold their charge for a long time between charges(low self-discharge). I'd grab my battery tester and snatch as many up as I could in your shoes. Edited by Stubby79, May 31 2015, 12:31 PM.
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| Highwayman | May 31 2015, 02:09 PM Post #14 |
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My mention of the squealing belts was my poor way of saying the alternator is putting out a high amount of amps the instant the car starts to quickly replace what was removed to start it. After a minute or so the alternator reduces the amperage till it is putting out only what you are actually using once the battery is topped off. The battery voltage is actually what determines how much amps to put out and how many volts. If you charge your battery occasionally especially in the winter with a plug in charger; you will notice your headlights are brighter and the car starts easier. That is because the slightly higher battery voltage allows the alternator to produce slightly higher volts. By the way; those AGM or SLA batterys cost over 250 dollars each when new. A core charge for one is 10 dollars so you would only be actually paying 15 dollars each. I would grab all the good ones you can get. The AGM batteries our communication guys swapped out recently had been in use the 28 years I had been looking at them below my laboratory. They installed a new bank of batteries but left the old ones hooked up thinking they would increase capacity. A few days later I had to call them to let them know the whole building smelled like sulfur gas. That is when they found out they shouldnt mix old batterys with new; so they removed the old set and sent them to scrap. |
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| Highwayman | May 31 2015, 02:34 PM Post #15 |
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My statement about charging at low amps is from my battery technology part of when I attended the college of southern idahos Automotive technology and diesel truck classes. The rule of thumb to prevent damage to the battery is to not exceed a charge rate of 10 % of the amp capacity of the battery. That is why other than jump chargers at mechanic shops; most chargers are rated 6 to 12 amps. If you multiply the amps in the battery by hooking 10 batterys together; you would have a 12 volt battery with 920 hours in it. So you could concieveay charge that array at a 95 amp rate. You could also hook them together positive to negative then you would have a 120 to 140 volt battery but it would only have 95 amp hrs in it. Same as increasing solar panels: you can increase volts or you can increase amps depending on how you wire them but not both. By the way; my portable 7 kw electric start backup generator came with a 16 hr AGM battery and works fine but it likely only charges at a couple of amps rate. Good luck I would love to have those batterys at that price.
Edited by Highwayman, May 31 2015, 02:35 PM.
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