Lithium Batteries

[ChrisOlson]

I'm happy (off grid), but I'm willing to be even happier. You're probably correct that there isn't enough profit to be made on us off-gridders, but if the battery lives up to its hype and is reasonably priced more on-grid folks will use these batteries for standby or even cut the cord and go off-grid.

I was told that the Aquion battery is going to be "competitive" with lead-acid as far as price/kWh of storage. But with better cycle life, fewer toxic materials in it, and ability to discharge to 100% DoD with no damage to the battery and less voltage "sag" during discharge as compared to lead-acid.

The downside for off-gridders is that at our locations it's kind of like forklift batteries - most of us don't have a way to move one into the power room. And that is why we have 5000-series Rolls batteries that only weigh 350 lbs each instead of a forklift battery. Two strong men can get a Rolls batteries out of the back of the truck and onto a wheel cart to get them into the power room. When we designed our power room we did not design it to be able to take a wall down and get a big battery like that inside.

Big batteries like that might be nice. But if all you can do when it arrives on a truck is sit under the shade tree drinking a beer and look at it going, "that is sure is a nice battery" it doesn't do you much good.

[mapmaker]

Personally I don't think there is enough profit to be made on us off-gridders, and existing technology is plentiful enough to keep us happy.

I'm happy (off grid), but I'm willing to be even happier. You're probably correct that there isn't enough profit to be made on us off-gridders, but if the battery lives up to its hype and is reasonably priced more on-grid folks will use these batteries for standby or even cut the cord and go off-grid.

--mapmaker

[PNjunction]

Sure hope Siemens likes them. It's all about selling to on-grid, actually THE grid providers. Wonder if Hawaii is going to use them for grid-stabilization. I'm sure they are pushing their Varentec system to go along with it. Those are the major customers.

Personally I don't think there is enough profit to be made on us off-gridders, and existing technology is plentiful enough to keep us happy. Just putting the shoe on the corporate foot here.

[ChrisOlson]

But until it actually reaches market, it reminds me of any-day-now "vaporware" of the past

The Aquion battery has reached market and they are in full production. But they are currently only selling to commercial customers and not us off-gridders yet. I talked to their sales dept on the phone about a year ago and they said that in mid-2014 they should have a dealer base set up so private individuals who want a battery for off-grid use can get one.

Their M100 battery module is a pallet mounted 2,800 lb 19.2 kWh battery. It has twelve S10 48V battery stacks in it in parallel. They are far beyond "vaporware".

[PNjunction]

B&D 20v Li-NMC 1.5ah discharge test

Under test is a new-old stock LBXR20 30Wh 1.5Ah li-nmc B&D battery pack from 2012, using the BDCF20 led light as a discharge load.

The pack is rated to last about 11 hours with one of these led lights. It held up fine and approximates the list of SOC voltages presented earlier. I took a measurement once an hour, and the light is very convenient if one wants to choose a storage SOC, especially at the end of a season. The pack was brought to full charge in order to insure that the batteries were well balanced.

Voltages were measured with a Fluke 87V, which would be a minimum of accuracy needed considering the wide variation in soc over a mere 2.5 volt range or so.

Hours / total voltage / cell voltage

0 / 20.7 / 4.14
1 / 20.4 / 4.08
2 / 20.1 / 4.04
3 / 20.0 / 4.00
4 / 19.8 / 3.96
5 / 19.5 / 3.90
6 / 19.3 / 3.86
7 / 19.0 / 3.80 <----- many manufacturers charge and store here for retail longevity. Definitely full-charge before first use!
8 / 18.75 / 3.75
9 / 18.47 / 3.694
10 / 18.27 / 3.654
11 / 18.13 / 3.626 <---- approaching lvc, and led's just starting to dim a bit.

I didn't go any further since I didn't want to drop below 3.6v per cell, and test to see if the pack electronics would actually trigger an lvc - it *may* depend upon a powertool to do so. I wasn't going to sacrifice this battery to find out.

Ordinarily this pack takes 3-5 hours to charge from the oem adapter. However I have read reports of it taking 8-11 hours, which unless the battery is damaged, the customer may have taken the pack down to the lvc, and the charger is doing the *right thing* of only charging at .01C or less until it reaches 3.6V, and then continues on with a full current charge. I'd have to rip my adapter apart to test this, but nah.

This light was chosen mainly to do controlled discharging, and of course to utilize batteries I already have on hand. However it would foolish to choose this entire setup just for the light alone. Li-ion's raison-d'etre is the ability to deliver huge amounts of power in a small lightweight package without suffering large voltage drops, perfect for powertools, EV, starting, marine house banks, RC, or what have you. For small fractional-C applications like this led light, it doesn't quite make sense unless there are additional considerations.

[PNjunction]

I respect Prof Jay Whitacre, and hope things turn out in the hands of Bill Gates, Vinod Khosla et al.

But until it actually reaches market, it reminds me of any-day-now "vaporware" of the past. AND, it means *nothing* to me if it is only available to oem's with proprietary black box charging - or at least until the NDA's expire, and one can actually get hold of some REAL charge specs. I don't need a micro-grid storage application - lets put it into a powertool and see how it survives.

The greatest hope is that it will provide competetion to what's already out there, and bring prices DOWN across the board. If not, there is no reason not to stick with lead / Pb where it fits the application, or continue to use existing Li-ion technologies.

Speaking of things you can get your hands on TODAY, over the shelf and online, with known characteristics and charging details available to the public at large, are my test results of the battery brought to us by Prof Jeff Dahn of Dalhousie ...

[ChrisOlson]

They aren't the universal battery power-pill for all needs. I still use lead for my fixed installation because it makes sense financially, and weight is not really an issue.

For stationary applications there's a company (Aquion) making a battery with salt water for an electrolyte. But the batteries are very big and are supposed have something like 20x the cycle life of lead-acid, and can be discharged to 0% SOC with no damage to the battery. They have some testing batteries in the field now and a battery that stores about the same energy as a Rolls 12CS that weighs 300 lbs weighs a half ton and fits on a pallet that you can move with a forklift. But the upfront cost is about the same as the Rolls battery.

I called this company about a year ago and tried to get in on their beta testing program, but was told I couldn't get a bank until mid-2014 sometime when they get a dealer network set up for them. But one of my off-grid friends that works at MidNite Solar has one of those beta salt-water battery banks and so far it works pretty good for him.

http://www.aquionenergy.com/energy-storage-technology

[PNjunction]

They make perfect sense in applications where high power-density to weight ratio is desired, as long as one can overcome the upfront costs, and charge properly.

Misinformation is rampant, which is not helped at all by the pie-in-the-sky marketers, battery abusers who do not apply the right charging techniques, let alone even know that there is an entire sub-class of li-ion (LiCo02, LiFeP04, LiNMC, etc etc, each with their own characteristics).

They aren't the universal battery power-pill for all needs. I still use lead for my fixed installation because it makes sense financially, and weight is not really an issue. But yeah, for boating, racing, EV, RC, powertools, powersports $$$ - sure.

I'm doing the discharge tests with the led light and will post some info in a day or so...

[ChrisOlson]

Chris - I could just brain you for getting me into this. I knew I would go too far.

Sorry. LOL!

At least I learned a lot about lithium batteries. I've always heard they're supposed to be pretty good compared to lead-acid. But taking care of them is a bit different. There's more and more people switching from lead-acid to lithium packs for the house batteries in sailing yachts. Those that have them swear they are much better than lead-acid.

[PNjunction]

I'm pretty sure that the B&D batteries contain smart charging circuitry consisting of an lvc, hvc, and individual cell balancing after looking at their patent:

https://www.google.com/patents/WO2006041751A2?cl=en

While they don't reveal specific voltages, the patent seems clear enough, although to save brain cells, perhaps only read the claims and not the summary.

The lvc appears to be smart, taking into account individual cell voltages and comparing it to an average stack voltage before throwing the sleep trigger.

What isn't clear until I reread it a hundred times, is if there is an allowable cell voltage-delta to trigger the bad battery flag and stop the charge, or if it will spend an inordinate amount of time trying to charge and balance a pack that is unrealistically out of balance due to major degradation of one or more cells.

In addition, I'm still not sure of any maintenance mode, where cell balancing might occur well after the initial balance charge is finished, and cells may drop out of balance say after only 12 hours due to unforeseen circumstances in a static state.

Chris - I could just brain you for getting me into this. I knew I would go too far.

[PNjunction]

Hey, B&D makes a LED light that uses that same battery? I might have to get one of those the next time we go into Duluth. I always can use a nice worklight.

Yep, it's pretty handy:

http://www.blackanddecker.com/power-tools/BDCF20.aspx

But be VERY careful! If you forget about it like I did last night, it will silently take you down to the LVC, something we want to avoid. In fact, the light can do worse damage to the pack by doing it slowly, unlike accidentally letting the high-current powertool do it. Basically, TIME spent at either the very high voltage or extreme low voltage is the multiplicaton factor for damage.

I'm going to time out the soc's from a full charge next time I stay awake!

[PNjunction]

PN sounds like you have some electronic background. I have a few circuit schematics for a constant discharge current load that can be tailored to about any voltage range one want. Great tool to measure battery capacity. Let me kno wif you are interested. Pretty simple really just a could of transistors and power resistor with a OP amp voltage reference.

Sure I'd love to see that. Honestly though, I'm not much of a builder any more (sadly). I've got a West-Mountain-Radio CBA-IV analyzer when I need to get down and dirty. Still, it might inspire a trip to mouser etc!

[ChrisOlson]

Hey, B&D makes a LED light that uses that same battery? I might have to get one of those the next time we go into Duluth. I always can use a nice worklight.

[Sunking]

Funny - I got the same treatment when I tried to put an Optima Blue-top on the bottom shelf.

The LED light, model BDCF20 arrived today. Makes sense to have a work light, or otherwise be able to put the batteries to use as light when necessary. I like it a lot, but I'll save the beamshots and other flashlight review material for Candlepowerforums. Does not come with a battery, figuring you'll use what you already have.

The best part is that this will serve as a controlled discharger, so I can take it down to whatever soc level I want when I feel the need. Later I'll put a timer on it, and get some data. Sure is a lot quieter way to discharge.

PN sounds like you have some electronic background. I have a few circuit schematics for a constant discharge current load that can be tailored to about any voltage range one want. Great tool to measure battery capacity. Let me kno wif you are interested. Pretty simple really just a could of transistors and power resistor with a OP amp voltage reference.

[PNjunction]

Funny - I got the same treatment when I tried to put an Optima Blue-top on the bottom shelf.

The LED light, model BDCF20 arrived today. Makes sense to have a work light, or otherwise be able to put the batteries to use as light when necessary. I like it a lot, but I'll save the beamshots and other flashlight review material for Candlepowerforums. Does not come with a battery, figuring you'll use what you already have.

The best part is that this will serve as a controlled discharger, so I can take it down to whatever soc level I want when I feel the need. Later I'll put a timer on it, and get some data. Sure is a lot quieter way to discharge.