PLEASE help me pick from these 3 lifepo4 choices

[alpharalpha]

Getting ready to buy a 24v x 30ah lifepo4 battery setup, have a max budget of $400. And I've narrowed it down to one of these three (if someone knows a better option for the money...)

Sunthing28, made of eight 30ah pouch cells, he cannot disconnect bms but will charge before shipping which will take 2 months.

Hipower USA has 3.2v 30ah prismatic cells that have been sitting for a year on the shelf, marked down to $33 . Ships from USA and has 2 year warranty--though only if cell goes under 60%.

Vpower a123 26650 cells. I don't hear a lot of good things about Vpower, but he can disconnect the bms before shipping and claims they are not fake and have 100% capacity.

If I'm going to buy from China I need to make a decision asap so it's shipped before upcoming Chinese New Year.

This is such a hard decision. I hear decent things about sunthing but should I be concerned about a bms running on a pack for 2 months, or even having it charged before shipping?
Does sitting on a shelf for a year affect the Hipower prismatic cell. I've read that lifepo4 loses capacity over time even if not used.

I'm a bit overwhelmed.

Thanks.

 

[r3volved]

My Vpower has worked well...though upon tear down I've noticed poor manufacturing. Bms was not secured in its case and the board was just wobbling around. The cells are ok but after seeing some other company tear downs and diy stuff...I can tell the cell connections are pretty weak and not much stability covering them.
Though it's held charge and operated just fine for the over 1000km.

It's a bit heavy too and was tiring in my backpack. I've recently split the pack and secured to the bike.

If you go with them, I'd suggest you tear it down and rebuild it back up how you need.

 

[dogman dan]

Ok, you could get me to go with V power, if you gave it to me free. A123 cells? Are you serious? Prove it V power. If they are A123's why the low max discharge rate on the pack?

9 high power cells is pretty attractive. One for a spare if you need it. Then put a ping bms on it.

Sunthing fine, if you don't plan to do any riding till past easter. It will arrive badly disbalanced. When is Chinese new year? Forget ordering it a week before that.

 

[arkmundi]

A few recommendations:

• Listen to Dogman; he's usually right. We have a shared concern about any claim coming from China regarding the legit sourcing of A123 cells. A123 continues to clamp down on the "grey market" for its cells. Old cells pulled from recycled defective battery packs, while having the label, are unlikely to perform and so do not have the backing of the manufacturer.
• Take your time and don't rush things - either the decision or build.

 

[999zip999]

Those hipower cells look to be the best. One big 30ah cell with with easy termanation. No Victpower to many horror stories.

 

[r3volved]

My Vpower was NOT A123 cells
It was 16s5p 3.2v 3000mah 26650E cells like these:

I should have taken a picture... sorry
Epic fail

 

[Melbourne]

Ok, you could get me to go with V power, if you gave it to me free. A123 cells? Are you serious? Prove it V power. If they are A123's why the low max discharge rate on the pack?

9 high power cells is pretty attractive. One for a spare if you need it. Then put a ping bms on it.

Sunthing fine, if you don't plan to do any riding till past easter. It will arrive badly disbalanced. When is Chinese new year? Forget ordering it a week before that.

I think if you order from Sunthing now...it will be fine as it might be caught up in the Chinese new year. My sunthing arrived in 7 weeks and was balanced and still working perfectly. I did what was recommended by ES members... charged overnight, quick run around the block, charged overnight.

 

[alpharalpha]

So, Vpower is out. I wondered about the low discharge rate too, thought maybe it was a typo.

Chinese New Year begins Jan 31st. Sunthing says he will charge the pack before shipping but I hear the bms runs off only certain cells.

I'm waiting to hear back from Hipower about the warranty. Since they've been on the shelf for a year I want assurance of full capacity. I like the easy terminations too. This is simplest.

There is one other I had decided against but will put it out there; it's twelve a123 20ah pouches (which would make a 36v x 20ah pack instead of 24v x 30ah) This seller has removed the tabs and punched holes in them to install nut and bolt connection. He says they were only used once for an electric scooter build that he had some problems matching his electronics up to a parallel connection...and so went with 60ah cells. He's in Laguna Hills which I've been to, it's a pretty nice area for what that's worth. He would sell them for $335 shipped. He also says he can provide the voltages and internal resistance and will match them as close as he can with the cells he's got (he has more than the 12.)

 

[friendly1uk]

I wouldn't let him charge it before sending, It should be half charged for storage, just as he should be buying them in.

I calculated my bms would unbalance my pack so much over 6 months, that it would take a whole hour on the charger to correct it. basically one charge, because it amounts to nothing. If there really was an issue with running off just a few cells, they would run off them all instead. It is a safety device. I think some of the anti bms brigade are telling you stories. If you like, find out what bms it is and I will calculate it for you, as it won't be the exact same as mine. With 15Ah in the pack you may reach lvc some time after the batteries die of old age. This issue you hear of won't exist.


People are openly laughing at vpower and high-power are offering cells not a bms. Only sunthing is left, but tbh I have only seen one of there packs and it was not very good. Still, with your budget they are the winner.

 

[999zip999]

Removed the taps ? I think he got them from used pack they ripped them out for resale. The short tabs and nuts and bolts to short out ? No. The hypower 30 ah and a Ping as a signalab bms. Plus you need to learn how to build a battery so it will work. Also 36 volt min.

 

[dogman dan]

Except that 36v 30 ah will be too big to carry well.

I didn't say the sunthing battery would arrive damaged. Just in need of some time on the charger before it gets completely balanced.

Calculating the time it would take to single cell charge and balance, has nothing to do with how much charger time it might need, with 90% or more of the time spent discharging the high cells. It could take days to get the thing fully balanced, at 1 min per hour of charger on time. The rest, the bms discharging the high cells.

There are bms's that work on the whole pack, but typically bike battery bms's run on one or two cells. Here is the important thing, after the bms trips for lvc, the bms continues to draw on those two cells. This is why you don't want to store a bike battery with bms for 6 months, after discharging it partialy.

Shipping the sunthing battery for two months should do no harm, after it has been charged and balanced. It will merely need more than a few min on the charger to fully balance.

 

[999zip999]

What's the battery for ?

 

[alpharalpha]

It is for an electric bike: 24v 500w brush motor.

Sunthing says he charges to about 26-28v before shipping.

Hipower USA (sold thru electriccarparts) says I can return the batteries if not satisfied with a 20% restocking fee.

 

[dogman dan]

We'll help you with installing a bms on the highpower cells, if you get those.

But, do they have a 20 ah cell? If you don't live in a hilly place, 20 ah should be big enough for your bike, still give you some decent range, and be better for expansion to a 36v bike later.

I know you have a controller known for pulling an amp spike, but realistically, at 24v you will reach full speed very quick, and amps will drop to less than 20 fast.

 

[alpharalpha]

Hipower does have a 20ah cell so I could get 12 of those and make a 36v pack instead. One thing about these Hipower cells is that while they are rated 3C (18amps) the standard discharge amperage is 6.7 amps (1C) & they have a pulse discharge of 60amps. (The 30ah ones standard discharge are 10amps, 3c, 27amps, 90pulse.)

NOMINAL CAPACITY/Ah
20

NOMINAL VOLTAGE
3.2

CHARGE TYPE
CC/CV

MAX CHARGE VOLTAGE
3.65

DISCHARGE CUT-OFF VOLTAGE
2.5

STANDARD CHARGE AMPERAGE
6.7

QUICK CHARGE AMPERAGE
20

QUICK DISCHARGE AMPERAGE
40

STANDARD DISCHARGE AMPERAGE
6.7

MAX OPERATING DISCHARGE AMPERAGE
60

MAX PULSE AMPERAGE (20s)
3C or 60A

MAX PULSE AMPERAGE (10s)
10C or 200A

3C DISCHARGING CAPACITY (Ah)
18

INTERNAL RESISTANCE (mΩ)
1.5

VOLUME ENERGY DENSITY (Wh/L)
104

GRAVIMETRIC POWER DENSITY (Wh/Kg)
82.5

CHARGE WORKING TEMP (F)
32 to 113

DISCHARGE WORKING TEMP (F)
-4 to 140

CYCLE LIFE (80%)
2000

Metric

CHARGE WORKING TEMP (C)
0 to 45

DISCHARGE WORKING TEMP (C)
-20 to 60

ENERGY TYPE
20Ah 3.2V EV Lithium
LiFePO4 Prismatic Cell Battery

 

[999zip999]

We'll help you with installing a bms on the highpower cells, if you get those.

But, do they have a 20 ah cell? If you don't live in a hilly place, 20 ah should be big enough for your bike, still give you some decent range, and be better for expansion to a 36v bike later.

I know you have a controller known for pulling an amp spike, but realistically, at 24v you will reach full speed very quick, and amps will drop to less than 20 fast.

Just the hypower 20ah and get one extra.

 

[dogman dan]

Or get 9 cells, 8 plus a spare, in the 20 ah size. and then have money for the bms and charger you will need. If you get a 36v hubmotor kit later, you could add more cells to run that motor at 36v or 48v.

One reason I thought the smaller size would work has to do with the slow speed you will be going at 24v. Yes, you will have an amp spike, but you will reach the very slow top speed pretty fast. Likely you will pull about 200-300w most of the time, traveling well below 20 mph. That's a max of 12 amps continuous, on flatter ground. One c discharge rate of 20 ah is 20 amps. So all you got to do is keep your continuous below 20 amps. I don't know where you got 6.7 amps.

If you were to buy enough for 36v, then I would advise the use of a maximum 20 ah controller. Why? Because now you are capable of a top speed much higher and using more watts, and on hills you could pull more than 20 amps continuous easy. With a faster bike, it will matter more than you limit amps to 20.

Looking at it from a range point of view, 20 ah will take you more than 20 miles, at 15 mph or so. It's about 500wh. At 20 wh/mile, 25 miles.

 

[alpharalpha]

I got 6.7amps from Hipower's specs for the 20ah cell:

STANDARD DISCHARGE AMPERAGE
6.7

At 3C they are only 18ah but can burst up to 60amps.

Perhaps Hipower is not the way to go?

So you don't think I'll get up to 20mph using the 24v pack? Even on flat ground with a 700c rim?

If that's the case I'd get a 36v setup. I can get that from Sunthing as well.

 

[999zip999]

There's a lot more work to making a battery then just bolting cells togethere. lots. The hypower are better on paper, Sunthing is plug and play. But you may be using at it's limit.

 

[dogman dan]

That standard discharge looks like a typo to me. Thought perhaps you had done it, looking at standard charge instead.

3c in 20 ah is 60 amps. We know that doing that is a bad Idea. But 1c discharge should be ok, that's 20 amps.

The easiest way to go, remains the sunthing 30 ah. I was just trying to say, "did you need 30 ah if you went with the high power?" With that, more re configurable type of cell, I'd be looking ahead to a year from now when you want to run a 36v bike with hubmotor.

I can't tell you what you should do. But if you are completely happy with your current 24v ride, then a 30 ah from sunthing will give you lots of range, and a battery able to handle your steepest hills.

We have not had a lot of complaints about sunthing battery failures. But some on the charger he sends with it. You WILL want a spare charger no matter what you buy anyway.

 

[999zip999]

cheap can be to cheat get a good battery

 

[silviasol]

Those hipower cells look to be the best. One big 30ah cell with with easy termanation. No Victpower to many horror stories.

I have been shopping around for cells for my next upgrade and saw some stuff from victpower I liked. Are these horror stories just the a123 prismatic cells from last year or are there others?

 

[999zip999]

Vicpower is a battery company without a heart or soul. they will take your money and not get back to you. Its a one way street as soon as a your money goes to him they don't know you. I'm talking about there packs. Low quaity.

 

[alpharalpha]

If I'm understanding c ratings right then the cheaper batteries are a trade off of price vs longevity. The Hipower battery is 18amps at 3c, so pulling 12amps I'd be running it pretty hard. I really like the a123 batteries because they have such a high c rating, I am newbie so am not sure about this but if a123 20ah pouch is 20amps at 1 c then if my 24v pack would draw 12amps I'd be using closer to .05c which gives the longer lifespan (and supposedly a123 has longer calendar life.) I found another eBay seller with no tab pouches that they guarantee never used, good feedback 8 cells $240 shipped, I know nut and bolt short potential, but otherwise, seem like the best cell for the money. Then there is someone in usa with full tab ones but they are $340.
I'm suspicious of hipower but besides that; they have some 20ah cells on sale returns cycled 10 times still with warranty about $200 shipped. so pricing is going to be about the same for a123 or hipower. Of course putting together a a123 pack is going to be harder. Oh and china seller I think can get them here in 10 days so that's not an issue.
I'm going to make this purchase in the next couple of days, so any advise is greatly appreciated.

 

[999zip999]

China A123 cells from where full tab cells ?