Who makes the best high output 72v battery pack?

[OCD Garage]

I just had a failure of my 72v 24ah pack from Grin, it's about 26 months old and won't charge above 82.4v, shuts down at 71v. I assume it has a couple bad cells in one of the groups. It was rated at 50amp output continuous, I ran an 80amp controller limited to 45amps with a Cycle Analyst. Who is making packs with a good life span? About 7 years ago I bought an Aliexpress battery from a company no longer around and it still has range and function like new...

 

[99t4]

To answer your OP title question, sorry I can only give a nonanswer. Most vendors seem not to be able to consistently produce similar spec products from one season to the next. i.e. the vendor who was selling a good product last season is now selling a junky version of that this season. And theoretically vice versa. However, those (individuals) who repurpose used EV battery modules report good longevity, performance, and quality.

Really, this very question gets posed about once or twice a month here. I have yet to see a reliable definitive answer.

Let's return to your situation. What exactly shuts down at 71V? Could it be the charger? How are you measuring? What did it used to do differently (when it was working good for you)? When and what changed? Grin battery should last longer than 26 months, unless it was defective or misused or mistreated.

 

[99t4]

Just now found this very recent post by ES forum member amberwolf, appropriate to your question:

Battery cutting out

Hi My battery cut out the other day, unplugged and would go for a while until not very much power would cut it out again. Battery was charged before the ride and showed full voltage on the display after cutting out multiple times. One cell showed very little voltage, everything was...

endless-sphere.com

 

[OCD Garage]

Thank you for your reply:
As a vendor for Grin, I'm not posting to complain about the quality of their products, I'm just surprised because I've bought/sold alot of their goods and have found them 100% after spending $kkks there. I am surprised that any product from them would run into issues so soon when my Aliexpress 'Herculesi' pack performs like new after 8 years with people telling me it will burn down my house. I have not cut the pack open to properly diagnose, but my past experiences tell me there is a group with high resistance, not charging/discharging like the rest, so the BMS is doing it's job shutting it down prematurely to protect me. Ping used to have a reputation for building great packs but I hear he is no longer around. There seems to be a lot of obviously risky units on the market with sub-standard cells and no where near enough nickel strips to do the job safely. I know EM3EV produces good packs but no longer does 72v. My grin pack was not abused, crashed, or frozen and the controllers used were limited via Cycle Analyst to 45amps when the BMS is rated for 50 continuous.

 

[eMark]

I just had a failure of my 72v 24ah pack from Grin, it's about 26 months old and won't charge above 82.4v, shuts down at 71v.

Because it's from Grin they should be willing to offer suggestions for helping you troubleshoot (with minimal effort) to first locate fault. That's the way i'd phrase the query to Grin ... "troubleshoot with minimal effort to first locate problem"

Don't mention anything about the other battery. If anything compliment them on how well you liked its performance. As far as you know there was never any abuse ... if anything treated it with TLC ... thank them for any help they can offer.

 

[neptronix]

It's rare for us to hear reports of a Grin battery failing.

The unfortunate thing is that em3ev has dwindling variety, and also like grin, only seems to sell packs with high energy, low power.

There's certainly a market hole for high power / large capacity batteries that is not getting filled. However, with UL regulations becoming more common place, it's unlikely that many vendors will sell them due to the cost of certifying each pack.

You may want to consider making your own batteries, which keeps getting easier as time goes on.

PS you may have some months left on your warranty if this page is correct:
Warranty - About Us.)

 

[OCD Garage]

Neptronix:
I agree with you and told them the same in my email to tech support. As stated I have sold $kkks worth of their products and this is the first failure I've experienced on any product purchased there. The pack's decline seemed fairly rapid, perhaps I had not gotten the it down to 71v before, but now it seems to drop more quickly than the first episode. I have not yet received an answer to my query, and did not want to open it before talking to them. I started the thread to see what other battery vendors are out there, not to complain about this rare occurrence from an otherwise industry leader.

 

[neptronix]

No problem, Ok to be honest with us about Grin products here
I would bet you have a parallel group that went bad. I'm hoping you hear back from them.

If you were to build a pack with 21700 molicel P42's and NESE packs.. 6P 20S..

Before shipping and taxes:
$582 for the cells
$289.6 for the NESE modules
Other bits: let's say $100
BMS: let's say $100

You're in $1076.6 + shipping/tax + 1-2 hrs of your own labor assembling the pack. No tab welding required.

Nice because it could actually be serviced on the road. Swap out the bad parallel module and keep rolling. More reliable than any battery you could buy today for that reason

 

[neptronix]

On this note..

I also find the ebike parts market is a lot less diverse lately.. it's sort of like ebikes.ca versus the alibaba/ebay/amazon vendors, a couple little western vendors with limited range of goods, and that's it. Even Luna has been dropping out of the DIY market.

Maybe the DIY market is a lot smaller because you can get a prebuilt for under $2000 these days. It used to be that prebuilts cost and arm/leg and DIY was cheaper + better. Now DIY is about the same price but better.

At the same time in DIY land we've only really seen innovation in the mid drive segment. Outside of Grin technologies, most sellers haven't changed their hub motor lineup in a decade.

 

[OCD Garage]

Neptronix;
I'm very happy with hub motors as I have imported them directly from QS motors for quite a while, their products seem very robust. Mid drives generally take less amperage to run and so require a smaller battery but the simplicity of hub motors makes them attractive to me. I totally agree with what you are saying about Grin.ca vs virtually everything else. I thought there may have been a manufacturer I haven't heard about that popped up in the last couple years. I see some of the Chinese packs now using rectangular cells that require very few connections which seems like a good way to go. Perhaps these are what you are referring to. Thanks for your input, it's appreciated.

 

[MorbidlyObeseKoala]

I dont have personal experience with either of the companies but they have a lot of recommendations on DIY Facebook groups and Youtube for what that's worth.

Amorge Power has pretty solid satisfaction ratings and can seemingly customize to whatever your heart desires. The teardown videos show substantial busbars and wire/connector ratings seem to be appropriately oversized.

The business is in China, I don't know what warranty or customer service is like after the sale if present at all.

Electro & Co (youtube personality and minibike testers) uses Eon Lithium for their packs. Those also seem well built from the videos and use ANT BMS for all of their builds.

 

[OCD Garage]

Thanks for the info M.O.C. Unfortunately Grin aren't selling anything larger than a 72v 16ah, this is the first of many packs from them I've had an issue with. I'll look into your suggestions as I'm sure there are new vendors popping up all the time and it's been at least 2 years since my knowledge base would be considered up to date.

 

[thebeachtoday]

No problem, Ok to be honest with us about Grin products here
I would bet you have a parallel group that went bad. I'm hoping you hear back from them.

If you were to build a pack with 21700 molicel P42's and NESE packs.. 6P 20S..

Before shipping and taxes:
$582 for the cells
$289.6 for the NESE modules
Other bits: let's say $100
BMS: let's say $100

You're in $1076.6 + shipping/tax + 1-2 hrs of your own labor assembling the pack. No tab welding required.

Nice because it could actually be serviced on the road. Swap out the bad parallel module and keep rolling. More reliable than any battery you could buy today for that reason

Don't mean to go off topic, but thought others might want to know... Have you assembled with the NESE modules? What your experience? I used the Vruzend product, and the were so damn bad that I didn't even email the vendor. Felt like I was doing QA for them. Broken plastic, bad contacts, had to use loctite, which defeats the purpose of the product. Anyways, let me know your experience. Love the idea, but have bad experience with their competitor

 

[neptronix]

Don't mean to go off topic, but thought others might want to know... Have you assembled with the NESE modules? What your experience? I used the Vruzend product, and the were so damn bad that I didn't even email the vendor. Felt like I was doing QA for them. Broken plastic, bad contacts, had to use loctite, which defeats the purpose of the product. Anyways, let me know your experience. Love the idea, but have bad experience with their competitor

I haven't but i'm considering it given that 5.3-5.8ah 21700s exist as of this year..

You are not alone in noticing the vruzend is sketchy, i've only heard good things about the NESE modules so far. Have not tried them.

 

[Chalo]

I just had a failure of my 72v 24ah pack from Grin, it's about 26 months old and won't charge above 82.4v, shuts down at 71v. I assume it has a couple bad cells in one of the groups. It was rated at 50amp output continuous, I ran an 80amp controller limited to 45amps with a Cycle Analyst. Who is making packs with a good life span?

If you charged it up to 84V every time and let it sit at full voltage, and discharged it down to cutoff every time, then you got what you asked for.

Charge to 81.0V, stop and recharge before it gets down to 66V, and you and your battery will be happy with each other. If you want to discharge at 45A, use a pack with at least that many amp-hours. It's not hard to get good longevity out of a pack, but abusing it won't be on the menu.

 

[999zip999]

72v battery of quality is hard to find !
I had a custom-made battery from bicycle motor works a Samsung 40t 30amp cell 20s 6p. So got the battery and wouldn't fully charge. Send it back. He replaced a parallel set. But only got 19ah out of a 24ah pack. They stopped answering phone calls. A year and a half later I had to open the pack just to find he put that set of six parallel cells in with a soldering iron in Solder wick it looked terrible. And 1,200usd later.
What a mess. Made in the USA
So now I'm just going to make on myself with a spot welder. As I have made three packs 72 volt but we're all bolt together.
And have a N.E.S.E kit 14s 8p of BAK 18650 20 amp cell this brand of cell is bigger in circumference and would only fit in his kit if I took off all the rappers all 115 cells so all in parallel so ok. Something you'd only find out if you did it yourself or here on ES he told me if I 3D printed I just have to enlarge it somehow, it's sitting on the bench and I need to put it to use.

 

[999zip999]

I want to know more about a 72 volt grin pack how mucth did it cost you ? how many ah ? and what sells did they use ? and what BMS ?

 

[DogDipstick]

The best? DIy.

.... yall never heard of " Amorge"? IDK if it has been mentioned ( the ebike battery building co) ... I know a few have bought p42b packs from Amorge.

...however they ( most all retail) will still last quarter as long, put out half the power, and degrade over time, not have good resale ( value) unlike the DIY packs i built and sold. bahahah. I'll put 2x the power and 4x the lifespan in the same footprint as the best retail.


Lol.

 

[Teeman]

Eon Power Brick 72v 24ah High Power Universal Battery | Eon Lithium They will Build any Battery you may want. Fast turn around.

 

[OCD Garage]

I want to know more about a 72 volt grin pack how mucth did it cost you ? how many ah ? and what sells did they use ? and what BMS ?

When Grin was doing their sailboat conversions they ordered a bunch of these packs which retailed for $1400. They were described as having Panasonic cells (don't remember the model), 24ah and capable of 50amps continuous output, I don't know any more about the BMS than that as I haven't opened the pack yet. I'm surprised, it only lasted 26 months as it's the only thing I've purchased from Grin that failed (in my eyes). I suspect a group went bad. It still performs well with lots of power, unfortunately it just shuts down at 71 volts thus reducing my range.

I always try to work within design specs, so had my controller limited to 45amps with a Cycle Analyst, never ran it below 70v, never let is sit outside to freeze, get wet or other 'known abusive behaviors'. It sat unused with 3/4 charge for about 3 months and showed the problem when I started using it again. I have cheap Chinese packs that are 7-8 years old that are still going strong. There must be a certain amount of luck involved with lithium packs from any manufacturer/vendor I suppose.

 

[999zip999]

What do they say at Grin ?
Teeman 1,700usd that's a lot of money.
300 amp that's 50amp per 21700 cell . What 21700 cell is going to handle that ? And live .

 

[Teeman]

What do they say at Grin ?
Teeman 1,700usd that's a lot of money.
300 amp that's 50amp per 21700 cell . What 21700 cell is going to handle that ? And live .

Hey if can't run with the big dogs stay on the porch. Hey zippy ,That battery is just a Example of what they can build for you. Whatever cells you want they will use in building you a battery. Do you get in now?

 

[999zip999]

Their battery ratings seem to be on the high side for a battery to last very many cycles in my opinion.
Okay nice see what you want me, please turn around I have 3 - 72 volt batteries just one that I'm using so I'm not going to be buying anymore even though I want to and the next battery I do have I will be building it myself thank you for the support.

 

[Teeman]

Who makes the best high output 72v battery pack? I give him what I thought was what he asked for. 999zip999 I wish you the best of luck,with your battery building. Thanks for your input.

 

[999zip999]

I repeat what 21700 do 50 amps as advertised just 6p.
It says 300 amp pack ?
Who wrote that for him they mave have copied it from a Chinese website.
Cuz I want a 20s 2p 100 amp pack oh yeah with Bluetooth and USB. With 27100 cells