Lithium batt/bms/charger combo suggestions? - new to board

[scoot-e]

First post - appreciate all the topics/posts I've read and researched over the past 12 months here!

Questions about lithium battery wholesalers/retailers specifically with additional focus on matching bms/charger.

Project
Mini seated lightweight electric kick scooter with removable seat (think better Razor e300) with 8" sensored brushless hub rear motor, 44.4vnom/50.4vmax 10ah lithium based battery, matching or slightly oversized bms and 3a charger with goal of charging in less than 4hr to 100% and possibly longer/overnight balancing. Climb moderate hills for several minute stretches pulling max 30a peak, goes up to 25mph, 15 mi safe distance including moderate hill riding.

Prototype
I started using 8 packs of Turnigy 3s 20c 5ah lipos at $27+shipping = approx $230 USD
(http://www.hobbyking.com/hobbyking/store/__15006__Turnigy_5000mAh_3S_20C_Lipo_Pack_USA_Warehouse_.html)
They sent 2 packs with some dead cells on arrival and since I used paypal and bought from USA store they weren't too much of a hassle to get them to send 2 replacements relatively quickly since I made a fairly large order. Within a month or two of testing and regular riding in the 12s2p config (2 larger combos of 4 packs of 3s in series and then paralleled together to form the 10ah) I lost a couple more cells. When they work, the speed, distance, hills were all great and met my specs but the reliability is poor. I'd say these are the cheapest and easiest solution and the bottom of the checklist and I'm now looking to upgrade from my 50w balance charger also from HobbyKing and the individual 8 packs of balance charging one by one, to a custom made commercial pack with built in bms most likely and a 3a (dumb) charger/power supply. I'm considering only a 3a charger just because I don't want to over tax the batts on charging in order to hopefully help the cycle life as well as I don't see a major improvement from a 2hr charge to a 3.5hr charge if one is commuting or not using all day long anyway. As long as I can get under 4hrs for full charge and overnight for balance charge I'm happy.
Due to the low quality of the HK lipos, I'd like to avoid them, although when they work, they meet my needs, but I'm just concerned about quality here and if I were to make/sell a few scoots to my friends in SF or LA asking about them for their commutes, I'd be more concerned about fire/meltdown possiblities with these volatile and low quality lipos in addition to dead cells (most likely compared to fire I know but if there is a safer or even slightly safer but similar technology for not drastically more money then I'm open to it)

Checklist
First I searched for the top of the line based on forum posts, ebay/amazon searches and the grapevine. Seemed like this was the top company and although it's pedigree is mixed as to who owns it, bankruptcy, current operation etc, they seem to be reliable, current sellers and USA based and meet all the specs I require although they are at the top of the list in terms of price/cost:

http://www.buya123batteries.com/ANR26650_Lithium_Ion_Cylindrical_Cell_p/300475-306.htm
http://www.a123systems.com/lithium-battery.htm

They claim 70a continuous peak discharge and 120a max discharge which is far beyond my needs but knowing the ebike world overkill is better when possible.

So, first I'm curious if a few people can give their feedback on these in terms of real world use, quality control (dead cells on arrival or high quality only?), how the capacity seems to last for distance in rides, whether the discharge amps are real, and any other feedback.
The cost as I see it are:
13 cells at 3.3v nominal (to equal my 44.4v nom approx)
2.5ah each x 4 (to equal my 10ah total)
=52 cells at $9.25 each (if you buy a minimum of 10 - further discounts for more than a hundred, etc)
= $481 raw cost
plus shipping ($50?
plus case/wiring/soldering - does anyone know a custom builder that can build to my dimensions? (no more than 2" tall, no more than 7.5" wide, no more than 15" long?) to fit in my scooter frame without the deck being too tall off the ground for standup riding.
plus bms & charger - maybe another $50 each for a 30a continuous and 50a max bms and 3a charger.

Next, I searched the forums again and came up with the following technologies and list of sellers. If the a123's are top price at let's say, $600-$700ish (including bms/charger) customized into a wired pack and shipped, and $230 for the Turnigy batts (or if I really wanted bargain basement, I could go for the 4s grey hardcase Turnigy lipos on HK for $175 shipped and save another $50 but I'm already circumspect about the blue Turnigy quality as it is...http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=18631) plus another $100 for bms/charger at total of $350 rounded up packed and shipped, then I'm hoping to find something in the $400-$600 or less range for quality, reliability, power, distance, weight, size, and price.

Here are the options I've found and I'd really like feedback from actual buyers/users/sellers on this list or others you guys actually have experience with. Yes, there are a million ebay or online alibaba fly by night companies but nobody has the time money or patience to deal with sorting them all out and I'm sure this forum has enough knowledge by now for others to at least recommend a few quality dealers. I know lithium won't last forever, in fact if with regular use I mean at least several miles riding a variety of flat & hills every week for a period of 2 years is doable without significant loss until the 2 year mark to meet my 25mph 15mi range with moderate hills benchmark for the 44.4v 10ah batt combo or thereabouts then I welcome it.

I'm not recommending and do not have any dog in this hunt, nor do I represent or shill for any company but I am very interested in not wasting money or reinventing the wheel if someone can give me a lead on a few quality suppliers. Parsing the posts is difficult but this is what I have found so far. Also, if the bottom line is anything under $400 shipped is just crap and I'm seriously taking my chances on a bad cell at any moment vs over $600 to even approach quality, then so be it but I'm hoping there is a compromise in there somewhere:

migueralliart posted this post recently from which I'm paraphrasing the data:
(http://endless-sphere.com/forums/viewtopic.php?f=14&t=48074)

Ebay seller ID supowerbattery111
supowerbattery@gmail.com
http://myworld.ebay.com/supowerbattery1 ... 7675.l2559
Samsung INR18650-20R (3.7v nom and 2ah p/cell)
( at $7 cost roughly each with soldering/tabs pack building included plus shipping and bms & charger costs additional probably from 3rd party)

"If you have a 10AH pack made out of these cells you'd have a 5P configuration which is capable of 100amps surge"
This is more than enough to cover my 30a surge for hill riding and fast starts from dead stop.
The price is a bit high but you do get quality spot welds and excellent communication.
390$ is a good price for 8ah 15s li- ion"

neptronix wrote:
"Looks like these are fairly happy at 2C continuous. 3-4C bursts are ok, but saggy.These look like they'd perform very well along the 1-3C range. Definitely an upgrade from standard issue 1-2C rated lifepo4."

So, if I wanted several minutes of continuous 30a draw and I had the 5p config at 2c I could easily reach my goals no prob. Regular riding drops to 10-15a discharge draw for average ride so is even further under the limit)


Circuit wrote:

Re: Samsung INR18650-20R .. yes these cells can punch

"$7 for 2Ah cell is $3.5/Ah, which is 3 times more expensive than other quality cells... A bit too much."

to which Migueralliart replied:
"Its not cost per AH but capability of a high discharge on a known and safe chemistry. Everyone loves lipo but don't want a fireball. Everyone loves lifepo4 but don't like the size. To me this is the answer that bridges the gap. Even thou you say its 3.5$ /ah the Panasonic's are more than 4$/ah. No one said this is the cheapest but for the diy the seller gives you a headstart with all the spot welding."...

If $3.5/ah is too much and "3 times more than other quality cells" - could someone recommend these other quality cell suppliers?...


--------------------------

So, that's where I am with batteries/chemistries and suppliers.

Re the BMS I am leaning towards this company for inexpensive (have to buy 2 pcs but they start cheap and shipping is inexpensive) at 40a continuous discharge (more than my 30a required but I figure they always exagerate their specs in China and won't hurt to have overkill):

Approx cost $38 each plus shipping (about $20 I believe from latest quote)
http://www.bestekpower.com/444v12spcmbmspcbforli-ionli-polymerbatterypack/PCB-D166.html

Question:

So, I realize that lipos or 3.7v nom batteries can have full charge at 4.2v and the bms from many companies list 4.25, 4.28, 4.35 as the peak for balance charge and that there are reasons around this and that most cells won't actually get that high when balancing and I have actually overcharged a few prysmatic turnigy HK lipo packs to 4.35v with no noticeable puffing or problem cells over time in my own experience by accident, but I'm hoping to use my Cycle Analyst and controller settings to keep the discharge from LVC (low voltage cutoff) at any less than 3.5-3.6v per cell simply because it will allow for a buffer when riding and will hopefully also maintain the cycle life better. Ideally, if I knew anyone to build an inexpensive (if possible) but quality bms from scratch maybe even in combination with a custom designed controller for my specs I'd have the max charge be 4.15v as well for cycle life maintenance but I'm not an engineer and not really sure how much difference these things would make. However, I have noticed my cells hold up better, longer, with more capacity if I don't discharge below 3.5v or so on a regular basis. Thoughts are welcome here

RE Chargers/Dumb charger/power supply:

I was considering this 4a charger:
http://www.batterysupports.com/432v-44v-504v-4a-lithium-ion-lipo-battery-charger-12s-12x-36v-p-167.html

For approx $54 + shipping

There are similar chargers for less and around 3a which would work equally well.

Any thoughts on chargers/retailers?

Thanks all!
Dan

 

[dnmun]

can you tell us how you decided the packs had dead cells? what did HK require that you do in order to talk them into giving you free packs to replace these you decided were dead? did you charge them up and test capacity first?

 

[scoot-e]

Sure, first, I simply took my $5 digital volt meter and test the balance leads and there was not only a low voltage showing but zero volts displaying on a couple packs in one cell out of the three. Then I took my multimeter and opened the pack's plastic wrapping to get to the tabs and tested. Same result. Then tried to charge but wouldn't accept charge on the HK balance charger because the cell was broken.

In addition to dead on arrival cells, I also had cells that dropped down to 2v or so (just a couple, but enough to be annoying) after a couple rides and even with recharging them they seemed to be faulty and I had to remove them (at considerable time and effort of course.)

When I received my shipment of 8 packs I immediately emailed them. They first refused and said I had to take a picture, measure the cells, write the serial number or whatnot but before I could respond (and I was willing to do those things btw) a different supervisor wrote to tell me he would make a one time exception to the normal list of rules and just send two more packs out which I received with a few more days or so. The packs that went bad after a couple months I obviously just had to eat, but I was able to cannabalize a few packs to make a new one so they are working for now but not a sufficient or trustworthy long term solution and this same thing has happened several times to me and my friends as well as documented on this forum. I'm not saying don't buy from them, but HK is not a quality supplier for transportation vehicles, toy planes, sure...

 

[dnmun]

we should have a thread for any HK lipoly packs that arrive dead to see if there is some common factor associated with dead packs.

i have never had a bad HK pack and others said they had dead packs so if there was a way to collect all that info, lot numbers and dates to go with the failures sorta thing.

 

[scoot-e]

Perhaps, but I don't know many retail scooter/bike companies that use HK/Turnigy or related batteries in their products and any feedback from others here as to other options is greatly appreciated.

 

[scoot-e]

Contacted Supower regarding the following Price Quotes and Shipping Quotes below:

I wrote Supower that I am very interested in the Samsung 25R 2.5ah 20ah discharge p/cell for higher continuous amp discharge rides on hills, etc and liked the overall specs. (I also asked about 20R for reference but since they aren't much cheaper than 25R and would require more cells to equal the same 10AH that I use, I still am planning to go with the 25R but got the quote regardless for 20R too as well as the Panasonic cells they initially recommended until they realized it wouldn't work to meet my requirements after all, see below)

Want to pull 30-35amps for continuous hill riding so at 2.5ah per cell decided to go for at least 4p so I have 10ah or the ability to go up to 80a discharge (at 20a p/cell or 8c max) but at 3c continuous it's more like 30amps (7.5a max p/cell at 3c x 5p = 37.5a discharge) to safely ride longer on hills or applications that draw about 30-35a without overheating or lowering the overall lifecycle. I would never ride at 10c ever but 3c seems reasonable and even if I do a 5 min moderate hill ride I will most likely average very few overall minutes on anything other than light hills and flat sprints for most practical purposes but I want the ability to easily do moderate hills without worrying ever.)

My mini scooter runs great at 12s (44.4v nominal/50.4v max) so I was planning to chose either:
12s4p or 12s5p with a 3a charger and a 45a max rated BMS all from Supower including spot welding the tabs, wiring all up to the bms which is shrink wrapped inside.

This is the response from Supower:

They said:
"Yes, 20R / 25R could do 20A (8c) max continuing for one single cell, so the 12S4P pack could do 80A continuing, 12S5P could do 100A continuing at 20a/8c discharge."

"Here is the quotation for your reference:
44.4V 10Ah 12S4P (25R) $340.00
44.4V 12.5Ah 12S5P (25R) $395.00
44.4V 10Ah 12S5P (20R) $345.00
50.4V 4A Lithium Charger $50.00
50.4V 3A Lithium Charger $46.00

Not too bad for complete packs with bms & charger ($340 or $395 + $46 for 3a charger = approx $400-$450 all in)

They also "recommended" the Panasonic NCR18650PF 2.9ah cells but I am opposed for my specs because it is half the 20a discharge per cell of the Samsung at only 10a max discharge, (or about 3C rate per cell)
"Panasonic single cell could do 10A continuing, then the 12S4P could do 40A continuing."
W/Bms:
12S4P 44.4V 11.6Ah $368.00

However, they even confirmed the Samsung would be better for my purposes:
"If it needs to keep discharge at 35A, even if the battery pack could do 40A, but it almost reach the limitation of the battery, this will shorten battery life. It will be much easier for Samsung 25R / 20R with lower heat and will give a longer circle life."

Now comes the bad part:

SHIPPING to San Francisco, California...ouch!!

"As the complete battery pack is about 3kg, shipping cost is very expensive, to ship 1x 12S5P pack + 1x 3A charger cost $265.00 by TNT Express (which is another express carrier like UPS, Fedex etc) , this is the only way to ship such big battery pack, UPS / Fedex / DHL do not accept battery pack over 2kg. TNT Express take about 6-8 days deliver to door. And we will label a lower spec. on packing to make it easier to ship."

WOW - so the shipping is almost $300 and the battery/bms/charger is $400-$450...crazy, won't work for me unfortunately as I am not willing to pay nearly the entire cost in shipping as the battery pack and charger would cost...

They went on:

Just for your reference, shipping cost for sending 20x 12S5P pack by Express cost about $860.00, this may lower down the shipping per unit (about $43.00 for one pack). Or we could ship by air mail for 20pcs (or more), that will be lower cost than express, we could even ship by sea transportation for volume orders that will not have much restriction for Lithium battery.

But for sample order like 1~2pcs, its just the only way to ship..."
---

So much for Supower unless someone had a large order and wanted to chip in...the shipping is a killer at this point, doesn't matter for loose cells or whole packs, at least from their company - please let me know if anyone found reliable, quality, real Samsung 25R cells in relatively small quantities (60 -100 cells) without more than a $1 a cell shipping or $5 a cell raw price....

Will have a few other suppliers info back shortly to report as well

Thx!
Dan