Battery Space 20AH Prismatic LiFePO4 tests

[dnmun]

use compression on these too.

 

[imorton]

use compression on these too.

Maybe I'm missing something here, but aren't these GBS cells made out of a hard case, so how would compression help?

 

[dnmun]

you have to put them in compression to keep them from swelling up. this is common knowledge.

 

[imorton]

you have to put them in compression to keep them from swelling up. this is common knowledge.

I don't want to disagree, but I am not so sure about the compression, as the 12 V 20 ah pack that they sell doesn't seem to be under kind of compression?

 

[RLT]

Well, Ian, Remember that I have yet to try any of these in a 'real world' application yet. If you buy now, You will become a beta tester too

But yeah, I always order spares... As a person who expects the entire system to collapse at any moment, I like to have backups; None of the JIT supply lines for me, if I can help it...
And when dealing with Chinese made stuff it is good to order extras... Back in the old days when I was one of the first few to buy Headways, one arrived completely dead, and a couple of others were substandard.

 

[RLT]

As to compression, I'd say that this is a: 'maybe'... It sure wouldn't hurt.' The plastic cases ARE pretty rigid. If you drop one on your foot it is your foot that will suffer, not the battery. I'd say they are more structurally sound than a typical car battery, due to the relatively thick ridges on the sides...
But I did notice that one of my new batch of cells is very slightly swelled. I didn't measure it, maybe 1 -1.5 millimeter of swell at the center on each side. Squeeze them as hard as I can by hand and I can feel a very slight amount of give. right in the center, but not close to the edges.

I'd say, without actually testing; Compress them if you can, but if you can't, don't worry about it too much.

 

[imorton]

As to compression, I'd say that this is a: 'maybe'... It sure wouldn't hurt.' The plastic cases ARE pretty rigid. If you drop one on your foot it is your foot that will suffer, not the battery. I'd say they are more structurally sound than a typical car battery, due to the relatively thick ridges on the sides...
But I did notice that one of my new batch of cells is very slightly swelled. I didn't measure it, maybe 1 -1.5 millimeter of swell at the center on each side. Squeeze them as hard as I can by hand and I can feel a very slight amount of give. right in the center, but not close to the edges.

I'd say, without actually testing; Compress them if you can, but if you can't, don't worry about it too much.

I'm curious about the 12v 20Ah packs that they sell. I wonder if I put 4 x 12v 20ah modules how to compress them. It looks like all the 28 cells that you got are up to spec and seem to be testing well. So I guess if one or two cells puffed after 3-5 years, you could swap it out for a $35 cell within 10 minutes. That's what appears interesting to me.

I just bought a Sun-Thing28 pack for $400 with integrated BMS, and a 5 amp charger. Now if one of those LifePo4 pouches swells/puffs, I don't have a spare nor the experience to extract a LifePo4 and do open heart surgery….

I wonder what to use to compress them and how to do a 16s pack.

IAN.

 

[RLT]

....... It looks like all the 28 cells that you got are up to spec and seem to be testing well.

I've only actually tested about 1/4th of them so far... and so far so good, although one was a bit under 20AH@ 10A... 19.7 if I remember correctly... It will likely pick up a bit after a few recharges... Most of them seem to gain a bit.

I wonder if I put 4 x 12v 20ah modules how to compress them

Guess it depends on how much space you have, how much of a craftsman you are and how much money you want to spend.

Gotta be several suitable methods... Dogman's method might be a good starting place, and not overly expensive or requiring expensive fabricating machinery or major skills.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=53488&p=796136&hilit=LiPo+compression+pack+build#p795944

So I guess if one or two cells puffed after 3-5 years, you could swap it out for a $35 cell within 10 minutes. That's what appears interesting to me.

Yep. The packs I've built with cylindrical cells, it usually seems that the cells that go bad are in the center, where you have to take the whole dang thing apart to replace one or two bad cells.... I haven't had to mess with pouch cell packs yet, and with any luck, never will

 

[Punx0r]

There are a few different batteries available with similar design of plastic cases and they do suffer from swelling and compression is recommended, although they are physically much larger and so less rigid. It's common to see pallet banding applied to the channels in the cases to provide support. You may or may not need compression depending on how you treat them and how they react to repeated cycling.

 

[imorton]

There are a few different batteries available with similar design of plastic cases and they do suffer from swelling and compression is recommended, although they are physically much larger and so less rigid. It's common to see pallet banding applied to the channels in the cases to provide support. You may or may not need compression depending on how you treat them and how they react to repeated cycling.

Thanks for the info, so it appears that "compression" will have to be incorporated into my battery design/installation..

 

[IBScootn]

check out this site to see how GBS bands four cells together:
http://elitepowersolutions.com/products/product_info.php?cPath=25&products_id=92

 

[arkmundi]

You may or may not need compression depending on how you treat them and how they react to repeated cycling.

In your opinion. Respectfully, I believe all pouch cells are begging for some rigid encasement that will hold the pack in compression. Its a battery pack life extending move. The swelling & cell degradation may not show up until closer to the end of the cells usable life and that's when compression will be more necessary.

Thanks for the info, so it appears that "compression" will have to be incorporated into my battery design/installation..

Yes, but not for these cells. Its looking like they've been constructed with adequate compression, from this early testing. By the way, a big thanks for the early adopters, testers & posters.

 

[arkmundi]

check out this site to see how GBS bands four cells together:
http://elitepowersolutions.com/products/product_info.php?cPath=25&products_id=92

Thanks for the product reference. I've been looking for this product a while: http://elitepowersolutions.com/products/product_info.php?cPath=47&products_id=212
A portable energy system based on advanced Lithium Ion Battery Technology

- Over 1KWh of energy storage
- 500W true sine wave inverter
- Two 120V AC outlets
- Two 5V DC USB ports
- East wheeled design
- Recharages in less than 6 hours
- 1 year warranty
- Weight: 64 lbs
- Dimensions: 17 15/16" X 13 1/8" X 16 3/4"

The idea is a range extender for when I want to go eBike camping for a few days. I've considered a lot of different approaches, from simply more batteries to building my own such with AC inverters and so forth. I purchased a Duracell Powerpack 600 with some hope. But that product sucked bad. What I want is a big battery pack that I can plug my charger into when needed on the road, but also my laptop computer for connectivity, my cellphone for charging, camp lights, etc, etc. I even have a high efficiency DC powered refrigerator and a new fangled magnetic induction stove. The equivalent of an RV packed into a small light weight bike cargo trailer.

I'm glad someone is making the rather exact Li-ion portable battery I need - 1 kwh, ~83 amp-hours. That's enough for a full day's travel, camp side dinner, lights, etc. Only thing I don't like is its 6 hour charge time.

 

[Punx0r]

You may or may not need compression depending on how you treat them and how they react to repeated cycling.

In your opinion. Respectfully, I believe all pouch cells are begging for some rigid encasement that will hold the pack in compression. Its a battery pack life extending move. The swelling & cell degradation may not show up until closer to the end of the cells usable life and that's when compression will be more necessary.

I absolutely agree - well put. I added the caveat because I didn't know anywhere near enough about the batteries the OP is using to state conclusively he must use compression or suffer obvious problems. As you say, the thickness of their casings combined with their small size alone may apply adequate compression.

 

[dnmun]

no it doesn't. why do you think i made it a point to warn you guys you need compression these plastic cases....?????????????

 

[Punx0r]

I'd like to say because of the rigorous testing you've conducted on them, but I suspect that is not the case.

Supplemental compression may be necessary, or merely helpful, or not necessary. As I do not know for sure I expressed this uncertainty rather than speculate and state my opinion as fact. If someone has better information on these cells and can state their compression requirements authoritatively, then that's great. In lieu of such information I offer my caveated warning for the OP's consideration.

 

[John in CR]

check out this site to see how GBS bands four cells together:
http://elitepowersolutions.com/products/product_info.php?cPath=25&products_id=92

Thanks for the product reference. I've been looking for this product a while: http://elitepowersolutions.com/products/product_info.php?cPath=47&products_id=212

- Over 1KWh of energy storage
- 500W true sine wave inverter
- Two 120V AC outlets
- Two 5V DC USB ports
- East wheeled design
- Recharages in less than 6 hours
- 1 year warranty
- Weight: 64 lbs
- Dimensions: 17 15/16" X 13 1/8" X 16 3/4"

The idea is a range extender for when I want to go eBike camping for a few days. I've considered a lot of different approaches, from simply more batteries to building my own such with AC inverters and so forth. I purchased a Duracell Powerpack 600 with some hope. But that product sucked bad. What I want is a big battery pack that I can plug my charger into when needed on the road, but also my laptop computer for connectivity, my cellphone for charging, camp lights, etc, etc. I even have a high efficiency DC powered refrigerator and a new fangled magnetic induction stove. The equivalent of an RV packed into a small light weight bike cargo trailer.

I'm glad someone is making the rather exact Li-ion portable battery I need - 1 kwh, ~83 amp-hours. That's enough for a full day's travel, camp side dinner, lights, etc. Only thing I don't like is its 6 hour charge time.

Arkmundi,

I'm finding it difficult to wrap my head around the idea that an active 2 year veteran would even consider such a poor solution. This is a product for someone without an EV, knows little about lithium, and has money to burn. Where do I start?

weight- 64lb for 1kwh of battery, a 200w charger and a low power inverter. I'll be extremely generous and allocate 4kg of the 29kg total to charger, inverter, and box. That's a whopping 40wh/kg of capacity...about on par with lead.

price- $1795 . With shipping that's well over $1.80/wh of capacity. I paid less than $0.30/wh including shipping for my latest purchase of batteries as good or better than those contained in the box, and with quite simple packaging they'll come in at 120wh/kg.

At 1/6th the price and 1/3 the weight and far less bulk, that leave plenty of room to DIY something far better. It would be a simple matter to set your own up with series parallel switching to series connect 3 modules to connect to your ebike battery while riding for extreme range, and then switch disconnect that and put them in parallel for camping, that is only if you're married to the low voltage. I say just use a nice size DC/DC converter. Let's say you go with double the capacity, 2kwh, that leaves plenty of budget for a DIY solar charger more powerful than that box's wall charger and a far more powerful wall charger. For less weight and money plus a relatively minor amount of sweat equity you get double the capacity that also can directly tie to your bike, and solar power that makes unlimited camping time possible unless you get unlucky in terms of sun.

If you need assistance, I'd gladly help put a package together for you.

John

 

[arkmundi]

For less weight and money plus a relatively minor amount of sweat equity you get double the capacity that also can directly tie to your bike, and solar power that makes unlimited camping time possible unless you get unlucky in terms of sun. If you need assistance, I'd gladly help put a package together for you.

John

Hey, thanks for that offer. Maybe. Perhaps I'll re-evaluate. Yea, I've got a window of opportunity for return. The primary question is how many 36V 20ah pack charges can I get out of it. I want to do testing and the only way is to buy one. If its not up to my expectations, I'll return it for a full refund, and eat the li-ion shipping charges back, but worth it. I want two 80%DOD charges of my A123 20ah packs. I sent Rick the specs of my batteries and the charger - he said yes, I should get two. So I've effectively doubled my capacity. 80ah I believe will get me my 70 miles per day.

There's more to the equation, of having those 120 AC plugs, for laptop & Bose speakers, so cargo trailer converts to "sound bike" and the BikeBloc is asking for them.

I thought about building up my own, like my two A123 pack builds. Let's say I did. I want LiFePO4 chemistry and a good 2000+ charge/discharge cycles. I can get that in A123 and would probably use the AMP20 prismatic 20ah cells. I need a full carton of 20 cells or 4S5P to be equivalent, at $1400 per. Then add in nice packaging for portability, a good AC inverter, built in charger, LV & HV BMS, the AC outlets, USB outlets, etc. I'm getting up there to close the same price.

I like the spec and the price on this P-Box from Elite. We'll see if its up to snuff.

 

[John in CR]

For something unlikely to see a high number of cycles AND doesn't need the high power density the way over-priced A123AMP20's would be a waste. Compare that to 2 Nissan Leaf modules at 500wh each for about $100ea plus shipping. It would give you a slightly higher nominal voltage than the BOX, but electronics should work fine. That would only weigh 16.5 plus some weight to box and compress. Bolt on connections including the balance taps make it about as effortless as DIY gets. Why try to get AC just to convert it back to DC for charging? Get 5 modules giving you 10s or 37V nominal. Assuming you have 12s of A123's on the bike for your 36V pack, then they'll be happy at the 42V top of charge for 10s Leaf cells. 5 Modules will weigh 41lbs, well under The BOX, and then you've got 2.5kwh of extra capacity that will parallel directly to your bike pack and can be charged using the same charger.

If you plan to leave the big pack at the camp site it can be charging with solar panels or a plug in charger or just sitting there, and when you return and want to charge the small pack your "charger" between the big bank and the bike pack would be simply a positive and negative wire with a properly sized resistor to slow the current somewhat. Due to the relatively small difference in voltages between the big batt bank and the bike pack, especially as the Leafs sag a bit and the A123's have reverse sag, this would be far more efficient charging than The BOX. Plus you can do rapid charges which the A123's can handle without issue and The Box can't deliver.

Ebike lights that take 36V without issue can be your campsite lighting, and to the extent you really need 12V just use DC/DC converters to supply it, but I'd try to avoid it. Just use an ice chest, but if you need more cooling for a longer stay, how about a high power Peltier?...no very efficient but with 2.5X more capacity and more efficient bike charging you'd come out way ahead.

If you don't recharge with solar, then the simple charge would provide a lower and lower TOC voltage for the bike pack, but run an RC charger off of the DC/DC converter and fully charge the bike and balance it too if you like. Solar charging is too good to pass up and even do it on the trip there since you have a trailer, so it's a no-brainer unless your area simply doesn't have any sun.

FWIW, you asked about the number of bike pack charges the BOX could deliver, and the answer is only 1 full charge of a fully depleted 36V20ah bike pack. The losses in multiple conversions may mean you can't even get one full charge. The big 2.5kwh pack would only support 3, and that's why I say bring hundreds of watts of solar power camping with you. Then with decent sun you can stay as long as you have food and water, and ride your ebike daily.

I say big pack, but it would be smaller, lighter, and you keep hundreds in your pocket even after including the solar power.

 

[arkmundi]

Hey John, thanks. You're right. I reserve the right, however, as an ordinary human, to think and act stupid. I had some time ago posted on a thread, in consideration of touring, that what made the most sense was to buy more battery. Rather than any other range extender. I've considered small gas generators (like the Honda 1000 watt), small diesel motors connected to an alternator, solar PV, etc. I consider and come back again and again to the just more battery solution. I have a light weight solar panel and a Genasun Solar Boost Charge Controller to go from 12V Solar to 36V battery. Couldn't get it to work, put on the back burner. You'd think I'd get tired of wasting money. Anyway.....

 

[John in CR]

Nothing to be embarrassed about at all. Failures are part of learning when out there at the edge. You should see my stockpile of stuff, especially from early on when I was buying big heavy brushed motors and the like. I knew pretty close to 0 about anything electric at the time. Even with all the waste $ it's still by far the cheapest hobby I've ever had, somewhere hovering near $0 net even with my hoarding, since the car rarely moves saving thousands a year on gas for the last 6 years.

Solar is becoming easy, practical, easily portable and cheap. Forget a genny. Then all you need is food, water, and a secure campsite, so you can go off exploring the wilderness on your ebike every day for extended periods. Traveling very light would be interesting in optimum weather with the right bike and a couple of square meters of fold up and store solar that doubles as part of your shelter. Then just keep going deeper and deeper into the wilderness or extended touring, and all you have to do is schedule extended relaxing stops during peak sun. Dogman lives in the desert but has been shooting down this approach for years, but I know absolutely it will work great. If I could get away from daily family duties for a while I'd love to prove it and just go. It sounds like you are planning exactly that, at least for weekend jaunts, so do it.

 

[arkmundi]

I haven't given up on solar, just not for now. My momentary intent is to head down to NYC for the http://peoplesclimate.org/bikebloc/ happening September 21st. I'll take the https://en.wikipedia.org/wiki/East_Coast_Greenway down, something I've been wanting to do for a while. Its a learning exercise. If I like it and loose my fear of longer distances, then I'll do more of that, maybe over time perhaps covering the entire length of the trail, see America the Beautiful before dementia sets in.... haha.

FYI, I've returned the Elite power supply (before its been delivered, by arrangement with UPS), and opted instead for a https://www.batteryspace.com/LiFePO4-Prismatic-Battery-Package-36V-10C-Rate-With-LED-Balancing.aspx 36V 40ah full pack, for 1.4 kwh of power, which will weigh about 40 lbs. I'm assuming ~1ah/mile and needing ~70 hrs/day for my NYC trip. Thanks again for the sanity check.

 

[arkmundi]

moved to on the road solar charging ... please respond there. thnks.

 

[RLT]

Maybe the Endless Sphere community would be better served if this were split off into a separate thread?

 

[RLT]

I have finally finished the initial testing the rest of the batch of these batteries.
I'll try to get a summary of the results posted tonight.