LiFePo4 Motorcycle batteries, Ballistic EVO2 vs BatterySpace

[wavezz2k]

A simple question, that I've not seen significant mention and have searched a couple boards. There was a short set of posts on the Shorai, but not much detail, nor integrated on the road e-bike performance.

Help Please, Shorai and Ballistic EVO2 motorcycle LiFeP04 batteries ???

What am I missing in this picture... Anyone put a Ballistic EVO2 12v battery on a bench and tested the current draw, or have depth of discharge data? Battery is being made by zillions, stuck in motocycles with standard lead charging circuit, the balance BMS charger as 'optional'. Rave reviews by motorcycle owners. Robust case. Factory, no question, 3 yr warranty. 8 cell configuration stated to be 15ah lead equivalent. Turns over a Harley starter motor no prob, 10x or more, considerable more draw than my little 800 watt MTB. Motorcycle replacement at 1.6 lb per 8 cell config, 12v . Gameplan . daily charge w/regular Pb charger, cap volts slightly lower than LiFePo max, watch discharge depth with cycle analyst, discharge current limited by size of controller, jettison the on board BMS, then once a month balance trim the cells. Keep DoD within the 30% low to 85% max for cycle life. If I toast the battery, send it back. just a thought, but find no data.. $135 per 15ah 12v.
Don't want a Ping nor Cyclone softpack nor any other taped up funky china thing, yes, heard they are great.
I need a 10ah 48-52v pack for my ~800 watt bike, as joe working engineer have a bit of power experience ( Lockheed Martin power center, built 5kw PV w/65kw deka rack, all electrnx rack MPPT & inverters for off grid full size home, plus $100k PGE hookup w/ transformers, inter-tie, etx). Don't have the time for buying cells from china Aliababa style, doing custom BMS & mount racks, where do these folks find the time ... my kudos to them, cool stuff.

Alternate Batteryspace pack perhaps :
http://www.batteryspace.com/LiFePO4-38120P-Battery-51.2V-10Ah-512-Wh-60A-rate-with-PCM.aspx
Any experience to share on either EVO2 or the BatterySpace built up packs would be very much appreciated. Many thanks. wavezz, in santa cruz.


>>>>

Dimensions (Metric): 114MM (L) x 61MM (W) x 112MM (H)
Dimensions (Standard): 4.5" (L) x 2.5" (W) x 4.25" (H)
Negative Terminal Location: Right
Weight: 768 grams (1.7 lb)
Voltage (Charged): 13.6V
Amperage: 15 Pb-eq A/H
Pulse Cranking Amps: 275 CCA
Operating Environment: -18°C (0°F) to 60°C (140°F)
Typical Applications: 1000cc and under multi-cylinder motorcycles and 550cc and under singles cylinder dirt bikes, scooters, and ATV’s.

The 8 Cell EVO2 is our most popular battery by a large margin simply because it fits the most vehicles in the powersports world. The 8 Cell EVO2 will work with everything from 450cc MX bikes to 1000cc multi-cylinder motorcycles. This battery is robust, impact resistant, water resistant, and has more starting punch than 90% of all the powersports lead-acid batteries available. Most motorcycles in this range use an OEM battery that weighs up to 11lbs. The 8 Cell EVO2 batteries weigh 1.7lbs. That is a weight savings of more than 9lbs for less than $160! If your powersports vehicle has modified motor, additional electrical accessories, or operates in extreme conditions then we would recommend upgrading to the 12 Cell EVO2 for added durability. There is no special charger required, but periodic balance charging the 8 Cell EVO2 with our Ballistic Performance Components BMS charger will greatly extend the life of the battery.

Up to 80% smaller than the stock battery
Up to 10lbs Lighter than the stock battery
Service life of over twice a lead acid in similar conditions
Industry leading 3 year warranty
Designed, developed, and assembled in the USA
Completely “dry” technology so batteries can be mounted in any direction
Non-toxic, recyclable, and can be air shipped
Applications for powersports vehicles from 50cc - 2300cc
Tested extensively by professional race teams
Impact and water resistant
Works with the original equipment charging system
No trickle charger required, loses only 10% of charge over a year of static use

 

[Jeremy Harris]

Welcome to ES.

These starter batteries are just fairly low capacity LiFePO4 cells packaged in a plastic box, and aren't anything particularly special. They don't have a BMS built in, so to get the life claimed by the manufacturer you're supposed to balance charge them with their "BMS charger", which in reality is just an off-the-shelf RC LiPo charger.

You're paying a lot extra for having these cells in a plastic box, especially as there's no indication of the true specs or cell type (most probably they use one of the better Chinese/Taiwanese made LiFePO4 cells). The spec is misleading, as they quote "20 Pb equivalent Ah" for their 13.6 V, 12 cell pack, for example, which could mean anything, but probably equates to somewhere around 6 to 8 Ah true capacity at most. A typical small ebike pack of around 15 Ah and 48 V would cost a heck of a lot if made from these packs, well over $1000, plus it would still need a BMS in my view, plus a charger.

You can buy a complete 48 V, 15 Ah Ping pack, with BMS and charger, for around half that price, albeit with a lower peak C rate, or you could get the same sort of C rate by making up a pack from RC LiCoO2 packs for around $300 or so.

 

[wavezz2k]

Jeremy, thnx for your nice reply.

Here's along the lines of a stress test, as I was looking for -
http://www.youtube.com/watch?v=7SflmGhblRY&feature=fvwrel
The 'equivalent' AH rating is rather misleading, you are correct. Comparable rated is likely on the order of a half to 60%.

 

[Jeremy Harris]

Jeremy, thnx for your nice reply.

Here's along the lines of a stress test, as I was looking for -
http://www.youtube.com/watch?v=7SflmGhblRY&feature=fvwrel
The 'equivalent' AH rating is rather misleading, you are correct. Comparable rated is likely on the order of a half to 60%.

Worth noting that the charge/discharge pattern for use in an ebike or other EV is massively different from that for a vehicle starter battery. A starter battery doesn't need a good cycle life, for example, because it never really gets cycled by more than a few percent. Starter batteries are only required to deliver a high current for a couple of seconds, then get charged back up, whereas an ebike or other EV battery needs to deliver a lower current but continuously for an hour or more, then get charged from a very much lower state of charge. This usually means that starter batteries are a poor choice for ebikes or EVs.

For example, these motorcycle starter batteries can get away without using cell level protection or balancing for a fair time because they never get discharged to any significant degree. Put them in an ebike and they will almost certainly need to be balance charged at the very least, as they will probably drift out of balance when subjected to repeated deep discharge cycles (for which they aren't designed).

Also, a "stress test" for use in an ebike or EV would be very different to the series of short, high current, tests in that video. Testing for EV use would be subjecting the battery to a sustained continuous current, perhaps between 1C and 5 C, and measuring the terminal voltage and cell temperature.

 

[dogman dan]

Interesting to see the headway cells can be bought at batteryspace nowdays. I've always found the prices highish there, but shipping is always fast, not from china I mean.

Being an engineer, you must be smart enough to handle RC lipo batteries safely. Have you looked at hobby king 4s hardcase packs? I won't be the only one to chime in and suggest HK.

And because the world is just waiting for me to say it agian, you might be happier than you think with a ping. Putting it in a tough box is pretty easy.

 

[liveforphysics]

Jeremy, thnx for your nice reply.

Here's along the lines of a stress test, as I was looking for -
http://www.youtube.com/watch?v=7SflmGhblRY&feature=fvwrel
The 'equivalent' AH rating is rather misleading, you are correct. Comparable rated is likely on the order of a half to 60%.

I've opened one up.
They are simply 2p4s of A123 26650 cells.

That makes a 4.6Ah ~13v battery.