A project that has been going on for at least half of April has been my semi-annual testing of various batteries around the house. Primarily, not the stuff I use regularly, but stand by batteries for after a hurricane or other extended power outage. As usual, some of them were fine and a couple others weren't. It's a topic I've written on many times.
The "problem child" this time around was pictured in a post from December 2015, and the battery has a label on it with the date 1/5/14 so it was nearly 2 years old in '15. That battery has been getting lower and lower in capacity for years and it's finally time to say good bye and send it off to the recycling center. A year ago that 35 Amp*Hour battery delivered 10 AH. Clearly not good, but a thought that has to be addressed is "how good does it have to be?" If I'm running things that don't take much current, and that can be used longer with the 10AH battery, why not keep it? Even or especially if it's a "backup to a backup."
This time around, that battery hasn't been able to deliver more than 3 AH. That's approaching practically worthless. It's also just over 10 years old now, so that's yet another sign that it's past time to set it out to pasture.
My battery farm contains three Lithium-Ion car jump starting batteries (like this but not this one) that were chosen because they have USB outputs that can charge a phone or run anything that uses USB power, and they also have 12V outputs. Next, I have that dead AGM battery, and two more sealed lead-acid batteries I recovered from my old UPS that died last October. Then there are a few Ryobi "One +" 18 V batteries primarily for the tools that take down (and put up) hurricane shutters and all, and finally a few 18650 cells that were bought as an experiment, for no particular application.
In the decade since I bought that AGM battery, a "new hotness" has made tremendous inroads in home use, coming down steeply in price and becoming more widely available. These are Lithium Iron Phosphate batteries, usually designated LiFePO4 (or LiFePO4) and called by a handful of other names. I've had tendency to call these Life-po, with the first syllable being the word "life" and the last is pronounced "po" with a long "o". I maybe the only person on Earth using that.
As class of batteries, LiFePO4 batteries have a substantial number of
advantages over lead acid and AGM (really just another type of lead acid - adsorbed glass
mat). This illustration taken from
a product listing on Amazon
is a good summary. The only thing lead-acid batteries might be better at is a
lower starting price.
Let me be go all disclaimer. This isn't any sort of endorsement of Eco-Worthy batteries or this specific one, but it's correct to the best of my knowledge and convenient to post here. I haven't bought this or any other LiFePO4 battery. Somewhere in the last year or two, I think I heard they were a good brand, but I have nothing to base that on.
An important point is that specification second from the bottom: Depth of
Discharge (DOD). The exact number for what a lead-acid battery can discharge
to depends on what kind it is; starting batteries are different from deep
cycle batteries, which are different from sealed lead-acid (SLA) or AGM.
Still, the best they do is to around 60% DOD - which says that 40% of the capacity is unusable. That says that if my 35AH AGM
battery was really delivering 35AH, I could discharge it to 14AH (40%) using
21AH, or perhaps 17.5 AH (50%) using the same. That 30AH LiFePO4 battery would give me much
more - even if I stopped using it at 90% discharged, that's 27AH. Instead of this pictured 30AH battery, I'd get the same amount of usable AH as the AGM gives with a LiFePO4 half that size.
Most (if not all) of the Life-PO batteries have a battery management system built in which I believe means none of my lead acid battery chargers will work with one. The cars still have lead acid starting batteries, so I'll keep one of those chargers around. Switching over to the new battery chemistry brings up all sorts of questions, so I'm digging for information. With pretty much 30 days to the start of what looks to be an active hurricane season, I need to get moving fast.
Thoughts, recommendations or sick jokes are welcome from those of you familiar with these things.
The only one I'm familiar with is the battery pack for the Futaba radio I use with my RC cars. It seems to pack a pretty good punch, because I've used it for a month or more between charges. Totally irrelevant to your intended use, but you asked....:-)
ReplyDeleteLook at Lithium Titanate lower voltage 2.3V than LiPO4 3.2V but can be abused at lot more both physically (crush with out fire) and electrically -100% discharge and won't damage it to badly if not immediately recharged. Charge rates up to 10C, 20,000+ cycles.
ReplyDeleteThe only readily available ones are the Yilong coke can size (35 -50 ah) and these are generally used ones from Chinese buses (they get a boost at most stops) with ~ 10k cycles on them -still leaves plenty of use.
I have tons of LiFePO4 batteries and I can tell you that the biggest thing you should worry about when buying them is how the particular company's BMS works. First, make sure the maximum current is high enough for your purpose. You might have to dig to find the spec, but it's all over the map. It sucks to buy a battery for a car and then find out the maximum draw is 50 amps.
ReplyDeleteSecondly, make sure how it behaves when the battery gets fully discharged. A cheap battery will "brick" and have to be taken apart and manually charged, bypassing the BMS. Most BMS's shut the battery off below a certain voltage (you might see a volt or two leakage) but they wake up when presented with a charging voltage. Just the other day I found my garden tractor BMS had shut off but I was a long way from a charger. I just touched the terminals to an ebike battery and it woke up enough to get it back to the shop where the charger was.
Finally, don't pay any attention to their built-in "capacity" or "charge state" indicators. Many use a complex algorithm involving voltage, current, and history, and they can get so confused that there's no correlation between reality and what they're telling you.
I took all my lead acid batteries to the recycler long ago. Like using horses to get around, they are too much to fiddle with.
"I took all my lead acid batteries to the recycler long ago."
DeleteI'm pretty much at that point now. Well beyond the date I should have, I know. The two SLA batteries from my old UPS are marked 9AH. When I salvaged them I got ~7AH. The tests so far, six months later are in the 6.5 range. The "smart charger" tells me they're five cells instead of six, so I have to charge them with an old Sears "stupid charger" to get the voltage high enough to charge on the other one. I could keep ranting but I won't.
I guess the brand name that has my highest perceived quality level is Bienno, and a casual look around shows a flood of Chinesium batteries. Any sense of who's good, or who to avoid?
The market is flooded with bad battery sellers. I've had bad luck with companies that sell expensive do-everything "house battery packs" that try to ape the Tesla Powerwalls. I bought two of those from different places and both have issues.
DeleteOn the other hand, I've had very good luck with a stack of discrete 12V batteries from Lossigy, available on Amazon in a variety of capacities. I have the 400AH ones.
As far as recommending against a company, it seems they take care of that themselves by going out of business quickly. Lossigy has been around for awhile now.
Check out the latest portable powerhouse from dji - 1024h 4000 recharge cycles, pure sinewave output, 70 minute recharge time, service live 10 years, 5 year warranty, currently on sale. https://store.dji.com/product/dji-power-1000?vid=156141
ReplyDeleteI find its easy to neglect battery maintenance. I am always after myself cause its long times between full diagnosis and inspection procedures, but thats a personal trait. Got a lot going and put stuff off sometimes.
ReplyDeleteBeen using a 12vdc fork truck battery, got it new, has a 1250amp @20hr rate, supposed to per factory specs have a 1200 lifecycle @80% depth of draw for a 6 hour running shift, its a honker, pretty heavy with a quarter inch steel case, weighs 785lbs.
Engineer at the manufacturer mentioned with lead-acid motive batteries, the overall single determining factor as to real world battery capacity was related to the weight of said battery, as that signified how much lead compounds and the heftiness of the grids, was in the battery, he said too everything else was mostly advertising, like tread patterns on tires, mostly there to sell the customers, or akin to types of fishing lures mostly to catch customers. Interesting analogy in any case.
We use it with a set if four high quality Kyrosea solar panels and 2000 watt twin PMA on a single shaft wind generator on a 40 ft tower, using a 8ft 5 blade prop. Built a hot water dump load, feeding a tankless hot water heater, its comprised of a 40gal insulated SST tank, the dump elements are 3, 12vdc 600 watt and 2, 750 watt heater elements, you have to have more than the max rated dump load wattage than the style of PMA we have, no auto wind brake, so the resistance load of the heater elements act as brakes, no free wheeling in high wind, the heater element are in a natural convection circuit, so if the mains power goes out we still get hot water, the pre heat water then becomes the main hot water, its all on a single circuit, the elements are outside the tank in a heater box which are plumbed into the cold in hot out lines. Complicated but simple in operation, but it works great.
Its the best money saver so far out of all the benefits of a stand alone battery off grid system. But the battery itself its claimed, if you maintain a 20% or less depth of draw, (meaning you leave 80% of capacity alone), not use it, because its a motive traction wet acid cell batt, the engineer predicted to expect 30 years of usable service, long as its charged correctly. After 10 years so far its held up fine, got one cell that reads a bit lower specific gravity but its still in the green zone on the hydrometer, at 70f corrected.
They are very strange devices, have personalities almost. Mine does anyways. I have read even now no one truly understands completely how wet acid lead batteries function and all their nuances. They know a lot but like heat treating steel there are things still not quite understood fully, they just know if this happens, you do this or that, that is the result kind of thing. I believe it after 10 years, cause this fork truck battery still does weird things i don't understand sometimes, like how at about 12.6, drawing down from a full kept charge of 14.2, this sudden drop to 12.4 volts happens, freaky cause thats like 25-30% drop in reserve amps, then it can go back to 12.6 again. On a 12vdc motive battery its like going from near 100% charge to 69% all of a sudden, where did all those nice fat amps just go? Really threw me off at first, think its just its "personality."
Its been a superb investment as first we always have some power thru 12vdc inverters which feed part of our home, we don't notice at first when we loose mains power sometimes, we have been saving between $50 to $125 per month on our mains bill for ten years. A ballpark figure of more than 10 grand in savings, its now paid itself off, parts wise, as we did all the fab and assembly work. Off grid i believe if you got the resources to deal with it that is, it is a far more wise investment than grid feed. Again, if your doing the work to install and operate and maintain one. Money in the bank for us so far, never looked back, and security, peace of mind also is a great aspect too.
Lots there but let me focus on one little thing.
DeleteHow do they make lead-acid batteries? They're the only battery where both cathode and anode electrodes are the same material, the lead. In every other electrochemical cell, they're dissimilar materials: I'm sure you've seen NiCad, or Nickle/Cadmium, for example. Zinc/carbon (the most common batteries in your local store), zinc/manganese dioxide ("alkaline" batteries) and silver/zinc are other common chemistries.
I think the way they do it is to build the cells, fill it with acid and hook it up to a charger in the desired polarity. I think of baby ducks imprinting on mamma duck. The cell "sees" the way the electrons flow and "thinks," "that's the way I'm supposed to be." (what's the duck-centric equivalent of being too anthropomorphic?)
Aside from that, it strikes me as horribly inefficient and waste of resources to build giant, heavy, and expensive battery to take 20% off the top. I suppose "if it works for you" is what it comes down to.
SiG, the cathode of a FLA battery is lead oxide, and the anode is plain lead. This is a good article on the chemistry:
Deletehttps://www.electricity-magnetism.org/electric-battery/composition-of-lead-acid-battery/
I hear you, but you priced out a 1250 amp hour LiFePO4, compare it too the type we bought? Delivered from Chicago to WV, total with tax and haz-mat was $1698,
DeleteI know with the large motive batteries most are fully recycled. Manufacturers take them back, or they auction whole yards of battery sets to scrappers. I know first hand they sell for exceedingly high dollars at auction. Have been told they reuse the lead compounds because thats the real expensive material in WLAC batteries. Was a coal mine welder before retirement, some mines everything is battery run, they have these rigs called a Mucker, its a very low profile scoop for cleaning out sections of coal ribs during and after a section is mined. Sometimes lot of water from spring lines run thru sections, gets messy. Muckers have very large batteries in them for double duty purposes, its whats called a Bonder Battery, electricians call them that, got massive coil resisters on them with a selector range of voltages/amps, pretty crude but effective, mostly they are for lights small tools and welding. You heat up or cook your dinner off the bonder boxes, the cabinet enclosure can get cherry red. Because its a perfect DC sine wave welding off them is beautiful, smooth as glass. no sparks or sputtering or spatter, you can weld in any position even overhead like your running 7014 flat rod. Almost no noise either, a tiny amount of hiss and hum. Thing with LiFePO4 they still have weaknesses that lead acid do not, which they will iron out eventually. Its not generally known these rare earth batteries require serious tonnage of raw earth and rock to extract the rare materials. Somebody is gonna come up with something like a neutrino box or zero point vacuum power source, and all that old tech is history, something you drop on a pad in your yard and it outlives you. Bet you inside ten-fifteen years it happens too. (just got to get rid of the satanic psychopaths and their global domination/genocide game controlling most all tech right now)