bullet-proof batteries?

[pithy]

Been a long while since I've been on ES. Hello everyone! A few years ago, with the help of people here, I put together and used daily a Townie with a Crystalyte 408 for commuting to work (with great success!): http://endless-sphere.com/forums/viewtopic.php?f=6&t=3995

Eventually, I needed something with a little more storage room than just panniers. So, a couple of years ago, using the awesome instructions on tomscargobikes.com I built this:

I moved my whole kit from the Townie to the cargo bike: 408, a Cycleanalyst and controller from ebikes.ca, and six 28-volt Milwaukee batteries (2s3p). The setup has been so great that I ended up drifting away from ES completely, since everything has "just worked" for a long time now (aside from a warranty replacement on the batteries a couple of years ago). The reason I'm now back on ES is because my batteries are finally showing their age, and so I need to start looking for a new bullet-proof option.

What currently are the best options for bullet-proof batteries? I've really enjoyed the simplicity and safety of the Milwaukees. Is there a better/cheaper option out there now?

Should I go with the DeWalt nanos this time instead? When I was last checking, lifepo4 was the rage and had high expectations for longevity, but hadn't been time-tested all that much yet. Anybody still using their DeWalt nano packs after thousands of charge cycles?

Or, since Ping has been selling (apparently) the same "2.5" batts for a long while now, maybe they're bullet-proof enough for my purposes?

I assume that any lipo is still not really an option for my type of setup, right?

Other than gently telling me I need to read through the last couple of years since I've been gone to try to catch up (which I'm just starting to attempt to do), does anyone have any comments/suggestions/tips for me? Directing me to especially useful threads/posts also appreciated.

 

[USAEBIKECO]

Cool setup!

 

[melodious]

What is that thing next to your little one?

 

[pithy]

Thanks, lester12483. This bike has served me well.

That "thing" is a lion. I hadn't realized til you pointed it out that it looks kinda odd in that photo because only the front bit is visible (and at a weird angle).

 

[biohazardman]

With bulletproof in mind I would say the a123 batts are just about as close as you will get. I have overcharged to 4.2V and over discharged to .8 and .6V per cell and only had to replace a few. The rest seem to be doing just fine some months and some years later. I ran the pack down and then left the controller on for the weekend for one fine over discharge job. Don't exactly know how I did the other but the batts got hot at dman's house after a long hard full speed ride and a few popped the caps up. Don't remember how I overcharged but I definitely was not watching very close. No fires no smoke no dead cells. So in all I have killed eight cells in 7K+ miles with all the abuse I have handed them in a 2P 20s configuration. Hard to beat that. No BMS and I seldom balance just bulk charge them in 20 minutes and I am on my way to run them down again. Sorry not many thousands of cycles yet but I would expect nearing my first thousand by now. Same range same speed as always.

 

[dogman dan]

Yeah, an A123 pack made from 20 ah pouches would be ideal. Talk to cellman at Emissions Free website. We trust him, and his first language is english which helps a lot.

A ping 20 ah pack would be very good as well, assuming your not planning any huge increases in motor power. They rock for 20-30 amps controllers. I got 3.5 years from my first ping, and after some horrible abuse, I am about to hit year 3 on my V2.5 ping. So you for sure expect 3 years or more from a good ping.

Any battery unfortunately, can develop one weak cell, or have a bms component go bad. So bulletproof? I can't say such a thing exists. Personally, I've learned to watch batteries closer than I did at first. I added some plugs to the ping that allow me to quickly and easily check each cells voltage at any moment by carrying a cellog 8 in my pocket. For monitoring the pack voltage, I carry a CA on most of my bikes, and plug in a cheap voltmeter if riding the bikes that don't have a CA.

 

[Ykick]

Bulletproof battery pack is a myth. Anytime you push large amount of current in & out there's risk. A123 pouch cells or Ping are probably what the doctor ordered but just don't fool yourself into believing it's totally safe and "bulletproof".

I like RC Lipo because it's relatively cheap and easy to charge fast which allows me to personally monitor both charge and discharge cycles. Plus, as DM noted it's also taught many of us more about assembling, balancing and maintaining high power battery packs than any of the obvious "plug & play" options.

 

[wineboyrider]

Ditto on what Dogman and Ykick said...

 

[docnjoj]

Let's not forget that DeWalt is no longer using A123 cells anymore, so the toolpack options are limited. I"m using old Pings but I just built a new A123 20 AH 12S battery from agniusms kits and cells from Victpower. Their cells are now a bit suspect due to short tab length and "reuse "of used cells but both JohninCR and OSNPower can supply new AMP 20 cells with full sized tabs. These are capable of 10C or 200 amps but I will only run them at 30 amps cause thats what I use.
You may want to search out agniusm and his kits as well as the other folks I mentioned. That is a great bike that you built and the kid looks cool too! these new batts and cells are much more reliable and powerful compared to the old toolpacks.
otherDoc

 

[Ypedal]

The 408 with 20~25 amp controller is a solid motor, quiet and smooth, i daily driver is a 409 in a 20" at 100v.

Unfortunately, nobody is yet offering what i would consider " bulletproof " battery packs.

The A123 cells, as good as they can be, are not new or perfect cells, they are ALL rejected and recycled cells... not to say you can not make a good pack from them regardless, but i hate the idea of buying used batteries.

so, to that end, i have completely switched all my bikes to lipo from HobbyKing.com

Smallest, lightest, less voltage sag, they com in 5ah increments, even 8ah cells if you fish around enough.

what kind of range do you need from this thing ? more than before, of same ? or less ?

 

[pithy]

Thanks for all of the input everyone.

Maybe instead of "bulletproof" I should say "super-stupid-simple-and-safe" or basic simple "plug and play"? Is there currently anything out there that's as safe and simple as cordless drill packs?

Ypedal's post reminds me that I should say more about what exactly I'm looking for. Currently, I'm only getting a few ah out of my 56V pack before needing to recharge. For most of the trips I do, that's barely OK. Bumping up to a useable 10ah or so would be fantastic; more than that isn't really needed at this point (as long as C-rate is high enough--at 1C, I'm guessing that a 10ah Ping pack wouldn't be enough for me; it would need to be 20ah or bigger). One option I've considered is just buying more Milwaukee packs, since they've worked so well. But I'm hoping there's a better option out there now that will get me more ah for the same or less money.

That reminds me of another question-- For my purposes, would it make more sense for me to go lower volts with higher amps? When I had this motor/pack on the Townie, I'd regularly zip along at up to 26 mph or so. On the cargo bike, it tops out at maybe 23 mph (limited to 15amps), and my regular cruising speed is most commonly only about 12-16 mph (this mild-steel contraption rides kinda like a '75 station wagon--a little too long, a lot too heavy... :lol: ). So, I don't go very fast, but I frequently need some good torque to go up hills, especially when I have a toddler and a bunch of groceries in the box. In this context, is it simply that Watts are Watts? Hypothetically (just to simplify the numbers), would 36V running at 30 amps be roughly the same for me as running 72V limited to 15amps, since functionally I'd probably never need to go faster than the top speed of the 36V pack, but either way I'd be maxing out with about 1080 watts going up a steep hill?

Also, is lipo now actually safe/easy enough for what I'm looking for?

Thanks!!

 

[Drunkskunk]

I've been riding a 408/4012 combo since I started in ebikes. I have a half dozen other motors as well, but it's still my favorite motor to ride. Nothing else runs as silent or smooth.

A Cell_Man 48v 15Ah or Ping pack would more than meet your needs, giving you 10Ah usable with a comfortable reserve, even as they lost capacity over time. Cell_Man's packs are a little better, but at a premium price compared to Ping. Both are trusted, and as far as a battery goes, they are as close to idot proof as things get in Ebikes.

There is No Safe Lipo.

There is realy no safe battery in the same way there is no safe gas can, or no safe loaded gun. You have to be carefull with them and respect the power within. They are safe if you are safe with them.

But back to Lipo. No. it isn't safe. It can burn when you do nothing wrong, or for no visable or apparent reason. It's Fun. Its the best way to get high power in a small package. It's cheap. It's light. It's easy to work with when you have the skills. It's rocket fuel for an ebike. But it's never safe.

As for your motor, the 408 isn't a torquey motor. It doesn't have the same torque or efficancy as a 9C or MXUS of the same speed, and in general, its a higher speed wind than you would want for a cargo bike.
If it's not overheating and it does the job, then nothing else will be as smooth and quiet. but if it's getting hot or falling short of your expectations, then you may want to look at a diffrent motor

 

[Ypedal]

that motor will gladly take 40 amps if you need more hill climbing power.. :wink: .. just needs a bigger controller.

 

[dnmun]

" Currently, I'm only getting a few ah out of my 56V pack before needing to recharge. For most of the trips I do, that's barely OK"

why not just repair the battery you have now? usually they fail on just one or two cells from the damage of being tied up in the tape or impact inside the battery box. fix the bad cells and it should work like new. i just repaired a totally dead 48V20Ah ping pack for someone without too much trouble. you could too.

 

[pithy]

Again, thanks everyone for input. It'll be after the New Year before I will be at the buying stage--right now just starting to do some research (and budgeting…). Y'all are a huge help!

I've started looking but haven't found it yet--is there a thread for discussion of Cell_Man packs so I can read up on them? Can some kind person point me in that direction?

Thanks for the info about lipo. That was my suspicion, but I hadn't looked into it for a while. I was hoping maybe something had changed.

@dnmun -- I don't know that a rebuild like that would do it. This "pack" is made from six unmodified cordless drill packs made with LiMn cells that have already had hundreds of charge cycles and a fairly steady slow decline in available power over a couple of years or so. But maybe I'm misunderstanding something, and I should try to open them up to see about putting some new cells in? I'm also not sure yet if I'm up to the task of soldering my own pack from loose cells…

No comments from anyone on the "watts are watts" issue? Maybe I should put it a different way… Would 30 Volts at 40 amps push me up a steeper hill than using 60 Volts at 20 amps? Or the same? Either way, it's 1200 Watts. I assume top speed on a level surface would easily go to the higher volts, but which setup would win going up a steep hill? Anyone have any input on this? Or is there already a thread somewhere about this question?

 

[miuan]

Get as much voltage as you need to reach your desired top speed. It's a linear relation of speed vs. volts, and you already know that. To maintain the climbing power or torque you have now, you have to proportionally raise the amp limit of the controller to get the same watts, as you already understood too. This will involve reprogramming, shunt modding, and/or replacing your current controller entirely to match the voltage span of your new battery.