Epic battery, or is it? Check out link

[unclejemima]

I've been suggested by a friend this is the "cats ass" of batterys...not sure it would be great for bike use, but he says its epic.

What do you guys think? (check out link)

http://elitepowersolutions.com/products/product_info.php?cPath=27_29&products_id=124

 

[dogman dan]

Epic, no. But some have liked these for running commuter type bikes, such as typical hubmotor kits. The container is good protection for the pack.

Thanks for the link, I was trying to find this place the other day and it wouldn't pop up on google. Couldn't even begin to remember the company name.

The larger size packages might be epic, I don't know. Your buddy may be talking about applications in larger EV's.

I was refering to the 12v 20 ah lifepo4 packs offered on this page of the site. here. http://elitepowersolutions.com/products/product_info.php?cPath=25&products_id=145

Those work as well as any 2c lifepo4, and at a good price.

 

[amberwolf]

The cells in these are what is referred to sometimes as "thundersag", as they don't do over 1C to maybe 2C very well without sagging in voltage. I haven't tested that theory with mine, which are 60Ah IIRC, but also haven't yet been used realistically on a bike yet (just a test here and there, becuase I only have 10, not enough for what I really want to run).

But at least a few ES members have used these types of cells for ebikes successfully.


They are fairly common in large-EV conversions, though lead-acid is probably still more common.

 

[Ypedal]

i think the blue cells are " CALB " or " CALEB " .. supposed to handle 2C .. gooooooooo.... nothing epic about that.

It does matter what setup you are working with tho....

what's your plan ? ( motor, controller, distance, weight, etc )

 

[neptronix]

not thundersags, these are a different brand.

It does say that they are GBS cells, guys

~100whr/kg means that they are gonna be as big/heavy as headways. These are not all that great for eBikes, but they weigh less / are smaller than SLA and NiMH/NiCAD.

 

[nechaus]

iv had thundersags,

They still are good batteries, and i never used a bms with them once lol
they were 20 ah cells, good for 2 c.. but they do sag alot

headways are better

 

[Chalo]

I like the look of these for a few reasons:

The packaging looks legitimate, way better than heat shrink tubing or duct tape.

Cost per claimed Wh is very reasonable.

Seller is in the continental USA.

Pack includes cell balancers and 3-1/2 hour charger.

The seller claims 2c continuous discharge and 10c burst. Is there any reason to doubt these numbers, especially the continuous rating? Because on the face of it, this pack seems like it might meet all the criteria I set forth in an earlier thread, which no previously suggested pack completely fulfilled:

- 48V nominal, at least 16Ah no-fooling-around actual capacity
- Plug it into the wall and it charges
- No fires, no self-destruction
- No diddling around with a multimeter regularly to see what went wrong this time
- No diddling around with a laptop regularly to see what went wrong this time
- Someone who'll take it back and give me a refund if it doesn't work
- Pack can sit as-is on a bike rack or inside bike luggage without damage
- Less than $1000 ready to ride, less than $2 per cycle

I have a 48V, 35A controller to work with. I have a hub motor that will happily gobble up every watt the controller can push out. Is this battery appropriate for the job?

Is there a catch?

Chalo

 

[nechaus]

The catch is the price.
Your better off with ping

 

[Chalo]

The catch is the price.
Your better off with ping

Duct tape "case", Chinese vendor and all? Did you look at my criteria?

I was advised that Ping packs would not have enough discharge capacity for a steady 35A. Is this true of Elite packs too?

Chalo

 

[dogman dan]

True that 20 ah size woudn't be good for 35 amps.

That's why I backed up and qualified what I was commenting on. Bear in mind a few things about the 20 ah 12v version in the plastic case. They will power a 20 amp controller, and that's about it. The price does not include a bms, or a charger. So the price for a ping is not that much more.

But in some situations, a rider may greatly prefer the plastic prismatic case for the cells to a Ping. Easier to replace a single cell etc. BTW, it's been about 4 years since ping sent out batteries wrapped in duct tape. But to this day, you better plan on building some kind of protective enclosure for a ping.

 

[Chalo]

True that 20 ah size woudn't be good for 35 amps.
(...)
Bear in mind a few things about the 20 ah 12v version in the plastic case. They will power a 20 amp controller, and that's about it.

So they say 2C continuous and 10C burst, but it's not really true. Correct? I guess that would be characteristic of battery manufacturers in this sector.

The price does not include a bms, or a charger. So the price for a ping is not that much more.

From http://elitepowersolutions.com/products/product_info.php?products_id=124:

"Package contains 16X GBS LFP20AHA cells, 16x EPS balancers and a matching charger. "

If this doesn't mean the balancers and charger are included, I'm not sure what it could mean. I had interpreted that to mean $730 plus shipping would get me all I needed to power my system.

Am I correct in assuming that generally, batteries that are balanced on charging don't need BMS for discharging at moderate (2C) rates? Should I be looking for something with a full function BMS board?

Chalo

 

[dogman dan]

I've come to the conclusion that you don't run a battery at or very near it's specified c rate. In general, the c rate is based on tests of a single cell, but you are running multiple cells. Odds are, your pack has at least some weaker that spec cells in it that may develop problems earlier than you'd prefer if you run at the full c rate.

So running at half the spec c rate, you get less sag, less chance of ruining cells early, and a more reliable pack.

It also depends on how you ride, where you ride, etc. If your typical riding style and terrain means your 35 amp controller never pulls more than 20 amps, it's really no different than a 20 amp controller right? But if you do no pedal starts on steep uphill grades enough, you might wear out your batteries early.

Likely you see a cycle life claim, say 2000 cycles perhaps? It's possible that cycle test is a single cell, at 1c or less.

One way to look at pulling max c rate from a battery. A car has a red line on it's tachometer you shouldn't exceed. How long do you expect the motor to last if you run it 1 rpm less than the red line habitually? Sure, the engine can run at high rpms, but it lasts a lot longer at half that. A battery is somewhat like that, it will be much more likely to last longer if you don't run it at it's max.

They do sell packages, so that price does include balancers and a charger. The link I provided was looking at just the battery. We had a guy here years ago that kept swearing how cheap this option was, and they were even cheaper then as well. But to make a true comparison to a ping, you had to add in the price of a charger and battery monitoring of some kind.

Comparing prices without shipping. Ping 36v 20 ah, with charger and bms, about 30 bucks cheaper than the EPS 36v 20 ah package with balancers and chargers. Shipping might even that back out, or even make the EPS deal cheaper. Pretty comparable batterys and similar prices. I couldn't say which one would last longer, or sag less. Both should have tolerable sag at 20 amps, and last years.

Again, this 20 ah size is quite adequate for 20-25 amp controllers. It may run ok on 35 amp controllers, but we have no real data to say for how long. We have the data to say you can expect quite a few cycles with the 25 amp controllers.

 

[Chalo]

One way to look at pulling max c rate from a battery. A car has a red line on it's tachometer you shouldn't exceed. How long do you expect the motor to last if you run it 1 rpm less than the red line habitually? Sure, the engine can run at high rpms, but it lasts a lot longer at half that. A battery is somewhat like that, it will be much more likely to last longer if you don't run it at it's max.

That makes sense to me. I guess I was interpreting their 10C peak discharge as "redline" and 2C continuous rating as, well, what it can deliver continuously and reliably. It sounds like the 10c part is fiction from any practical standpoint.

It looks like a 20Ah pouch cell pack from cellman is still my best bet for performance, but close to $1100 shipped for a naked soft pack, from a remote Chinese supplier, has kept me from pulling the trigger so far. I have eight criteria I'm trying to meet, and the cellman packs only fulfill five of them. The EPS pack appears to meet at least six of the eight, but falls down on important technical merits (same as Ping, which also loses another point for packaging).

It's amazing to me how different the battery situation is for e-bikes versus cordless drills, portable electronics, etc. The batteries for those other things meet spec, do the jobs they are supposed to do, and can be purchased locally almost anywhere in the same way as other retail items. The e-bike battery makes me feel like I'm trying to buy a brick of hashish in terms of price, technical specification, availability, realistic warranty, and credibility of the sellers.

Chalo

 

[dogman dan]

I would really love to have a 48v 20 ah cellman pouch cell pack too. Lotta money, but it would do a lot too. Likely have it made in two 10 ah sections for better carrying on a pannier bike.

It would be very interesting to buy one of those EPS batteries, and actually cycle test it by discharging it to 80% dod, using 10 second 10c discharges.

I almost killed a ping pack on the racetrack, doing 10 second 2c bursts. It was insanely out of balance in 12 laps. But discharged only about 40%.

It recovered somewhat, but never delivered 15 ah again. The pack was a week old.