The original Group 27 battery that came with our trailer didn't last a hoot. My dad gave me two Sam's Club GC2 that he had used as house batteries on his boat. He had used them for a couple of years before we got them. He swapped out the 8D house batteries on his boat for GC2 because a GC2 is about 1/3 of an 8D but when you're trying to load them on your boat, get them down the hatch and into the engine compartment, the 8D's were a literal pain in the back. He had to create rigging to remove the 8D's. The GC2's he could man handle. Plus on a cost basis, GC2's are about $80 each at Sam's versus about $400 for an 8D. It takes about three GC2 to store the same energy as one 8D. Keep in mind a GC2 is a 6V battery so you'll need two in series for 12V applications.
That's an amazing run with flooded lead-acid batteries... I end up replacing my pop-up's marine deep-cycle battery every 3 years or so, even when being careful to keep it charged when not in use. Maybe I need to find a better brand....
You're right about the fire risks of lithium-ion, J Williams. As material scientists like to say, "The chemistry is edgy." That's why I find it hard to believe they would use lithium-ion cells in these applications without including the battery pack cooling systems.
I, too, was amazed by the 70% figure, WilliamK. I knew that EV batteries are built with a buffer to prevent overcharging and undercharging, but it it still shocked me that 70% of the capacity would remain. Regarding modifications: When I asked if the cells-only would be used or if the pack with its entire cooling system would be used, GM said it wasn't sure. There are a lot of aspects to this which still need to be studied.
Hi Marty, The DCO's I'm familiar with (military installations), the battery drives the board directly so it is always "on-line" and the chargers provide just enough current to drive the load plus a little extra for occasional conditioning and maintenance. My understanding was these things were designed with thicker plates instead of greater surface ares for longer duration discharge at the expense of peak current like what is used in a starting battery for a vehicle. I was never at any one place long enough to experience the lifecycle replacement of the cells. I've long since left that environment so I'm not sure what's currently done in the exchanges.
You're definitely on the money regarding the cost per W-hr. Pb-acid beats Li-ion hands down, but not on weight where in a transportation environment lithium based batteries are more attractive from that point of view. Plus lead-acid batteries are much easier and efficient to recycle.
My choice for best-value distributed energy storage would be lead-acid even with its warts. (Electrolyte containment and proper venting are the two biggest bugaboos.)
Thank you for commenting on my post. Although the chemistry is the same, deep discharge batteries probably contain a greater amount of raw material per unit of capacity than flooded cells. The flooded batteries I am familiar with are kept in trickle mode all the time and are discharged only briefly in use and discharged deeply in testing. They also generate copius amounts of hydrogen which is a problem when installed indoors. Every design has its purpose. Lead acid chemistry is cheap and has a fairly good power density.
I have not had direct experience with the Pb-acid batteries in a telecom environment, but the pair of GC2 flooded batteries I use for house batteries for my travel trailer lasted for a decade of heavy use and a serious dose of benign neglect with a crappy OEM-spec charger. These things sit exposed on the tongue of my trailer year-round. We deep discharge them when we dry-camp and then cook the cells when we're hooked up to 'shore power'. We use our camper year-round in all climate conditions. Ideally we should've topped them off with distilled water but I'd say I only did that for the first couple of years then got lazy. My wife never checks the electrolyte, so if she's camping without me, those black blocks on the tongue are never even looked at.
I want to believe that the glass-encased cells would perform significantly better in a stationary application, controlled environment, proper charging and discharging, etc.
But I have to defer to those who live with these things day in and day out.
My experience with encased flooded lead acid batteries is that they last about 10 to 15 years max - not 20 as advertised. They are extremely heavy and require regular maintenance by trained techs. Cracked cases resulting in acid leaks are a nightmare.
I'd rather be using the glass-encased lead-acid cells they used in the DCO's for POTS. With proper care and feeding, those things will last decades. I have yet to hear of a lead-acid cell catching fire while in use. (We'll neglect the knuckleheads who don't know how to properly jump-start a vehicle and end up with a faceful of sulfuric acid.)
As for lithium-ion batteries, a very nice combat submersible for the Navy SEALs was destroyed due to a run-way Li-ion cell.
This looks like an attempt to justify a problem at the tax payer expense. First, the subsides given to bailout GM then to buy a technology in a car that isn't all that green. The resources to mine the Lithium, put it in a battery, and charge it is already a sham. Now it looks like the government is throwing dollars at something not to recycle it but to justify what to do with the old batteries when the answers required are not technical they're political. I do agree we should look into recycling the batteries but I am more inclined to let the free markets dictate those solutions.
Altair has released an update of its HyperWorks computer-aided engineering simulation suite that includes new features focusing on four key areas of product design: performance optimization, lightweight design, lead-time reduction, and new technologies.
At IMTS last week, Stratasys introduced two new multi-materials PolyJet 3D printers, plus a new UV-resistant material for its FDM production 3D printers. They can be used in making jigs and fixtures, as well as prototypes and small runs of production parts.
In a line of ultra-futuristic projects, DARPA is developing a brain microchip that will help heal the bodies and minds of soldiers. A final product is far off, but preliminary chips are already being tested.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.