Advice on e-bike kit/battery

Hi, I am looking at building my first e-bike and I am seeking some advice for my build. Basically looking to build a fast dual suspension electric bike that will get me to work and back without to much fuss and be able to used occasionally on dirt tracks on the weekend for XC. Round trip to work and back is about 15km's.

I have ridden a BH Emotion Cross, with a 350W hub, limited at the top end to comply with Australian laws of being a pedalec. Ideally something 4-5 times more powerful.

The bike I am looking to use is a 2005 Scott MC30 dual suspension bike. There should be enough room for batteries in the frame.

My requirements are as follows:

- 20-30km range with low to moderate pedalling
- 50-60 km/h top speed
- mostly flat riding in Melbourne with the occasional small hill
- I weigh about 80kg

Currently I am looking at the following options:

- Crystalyte HS3548 or HT3548 hub, not sure which one or to get a sensor or sensor less hub
- 26in wheel, more efficent but may overheat the hub with 72v, or 20inch or 24inch wheel, more power and the hub should run cooler but lower top speed
- Cycle Analyst 3 to monitor the battery and limit the current to the hub if needed, as well as set min cut off voltage levels for the battery
- Battery, 72V 10ah Lipo made up of the following:

8 x Turnigy nano-tech 5000mah 5S 25~50C Lipo Packs, 4 groups made up of 2 packs wired in parallel and then the 4 packs wired in series.

- controller, I am not sure if I need a 30amp, 45amp or 65amp controller. I am currently looking at the 18 FET Low RDS MOSFET Overclocker Ready LYEN Controller which is tuned for a 72v system and can take up to 65amps.

Please let me know if there are other more appropriate hubs/type of battery/battery voltage/battery configurations and controllers that may be better suited.

Thanks

Dan.

You and every other ES'er thinking of buying LIPO batteries need to read the threads, like this one from Floont:
http://endless-sphere.com/forums/viewtopic.php?f=6&t=48388

Floont said:

RIP Monzilla...

The battery charger caught fire and burned the bike beyond recognition. It also burned my whole house down including my car and my truck.

I will never go back to ebiking again.

FA

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Floont said:

Do you think your disaster might have been avoided had you been using a different chemistry other than lipo?

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YES

Who did you buy your charger from? I am specifically curious about how you know that the charger was the exact cause of the fire, my guess would be that was what the fire department thinks, but maybe you saw it light on fire and start burning other things.

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It was an Alloy shell charger from BMSbattery.

What advice would you give to others beyond being aware of the dangers of cheap chargers and lipo for those who currently use ebikes and those looking to get into ebikes?

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Don't use LIpo and if you must balance them frequently. Avoid buying anything form BMSbattery

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Worth repeating: Don't use LIpo. Instead, explore the world of LiFePO4 chemistry batteries, the safest and most environmentally safe of the current breed of lithium-ion batteries.

I've used lipo for 2.5 years without a problem, BUT, I'm not stupid enough to leave it bulk charging in my garage unattended. Yes, don't use lipo if you are irresponsible. In fact. don't use an ebike period. All battery chemistries will catch fire and even explode under the right conditions, even lead.

Thanks for the warning on Lipo's, I have read the quite alot of posts about Lipo's, and plan to charge these in my BBQ located in my garage, and also make sure I am present when charging. Also looking at balancing them regularly.

If you're going to run 20s lipo, suggest you use a balance charger to charge it and only bulk charge when you don't have access to a balance charger. I run my pack as 24s2p but balance charge as 12s4p. Only takes a few seconds to do it.

Lipo takes care and diligence to operate without risk of burning the house down. Charging to just 4.1v does help some, giving you some more room at the top for a mistake. You might look into other means of charging than a dumb bulk charger.

But you cannot operate safely for long, if you have damaged a cell and don't know it happened. I still tend to recommend other battery types for daily commuter use. Every single day is a bit often for checking out your lipo packs status.

55 kph is quite possible with 72v 20 amps. So you don't really need a huge amps controller. That makes a 72v 15 ah limn pack an option.

Geez what a bunch of anti LIPO FUD!

NOT TRUE!!!

LIPO is very safe. I have been using LIPO for many years (since 2005) for powering many devices. Can you have a fire? Sure you can! Is LIPO as dangerous as gasoline which you probably have several gallons of right now! NO WAY!!! LIPO is ridiculously reliable and safe. I walk away from charging LIPO all the time and have been doing so for years and years. I charge in my living room, in my den...where ever with zero fear of it EVER exploding. I never use a charging bag or even worry about charging on the wood or carpeted floor. What nonsense!

2 things to keep in mind that is true for all lithium chemistries.
1. Don't discharge to hard
2. Don't over charge

Just avoid stupid stuff no matter the chemistry and you are just fine.

LIPO does not "just explode". Right now in my spare bedroom where I do all my electronics and EV stuff is probably 40 10Ah or 16Ah LIPO packs. ALL of them are put together into either 16S, 20S or 32S packs. I charge them on my bench, in the EV's they power...whatever and wherever with ZERO concern of explosion or fire. Complete nonsense and fear mongering!!!

One time EVER did I have a LIPO pack fire and it was NOT spectacular at all. I took an old LIPO pack charged it up and drove a nail through it. There was some fizzleling around the nail hole and some smoke. NO FIRE OR EXPLODING! I wanted to see the spectacular and sensational fires like you see on youtube. I was seriously disappointed!

Actual examples of stupid stuff done by me that did NOT result in exploding LIPO packs...

1. Built a 12S 8000mah LIPO pack, but didn't have a BMS for it yet and then dumbly connected up the wrong charger to it. 12S LIPO needs 49.2 volts so that all cells reach 4.1v each. That's safe and extends the life of the cells. I grabbed the wrong charger and it put out 54.6 volts. Stupid mistake all the way around and I didn't check the voltage output. I came back sometime later and realized my mistake. The 12S pack was pretty warm and several cells had bulged. All the cells were at 4.5-4.6 volts each. I took the pack out to the garage and left it sit for a couple of hours. It cooled down after a while and then I discharged them all back down to 4.1 volts each. I was so mad at myself for such a dumb mistake that lost me some capacity and bulged a couple of cells in that brand new LIPO pack. It did NOT catch fire, did NOT explode, did NOT in any way present a hazard despite massively abusing the LIPO pack with far too much voltage.

2. I used to fly heli's a lot. I was hot dogging around and smashed one at full speed into a brick wall. The heli exploded into plastic, aluminum and CF bits. It was a total loss!. Smack in the middle of that wreckage was a 6000mah LIPO pack. Back then I was much more concerned about LIPO fires so I approached carefully. I soon realized that despite the LIPO pack being bent and dented and mangled that it was NOT going to catch fire or explode. I pulled it from the wreckage, no real heat or warmth at all. I later flattened it back out since it did get bent pretty good in the wreck. I was soon using that pack in my other helis with ZERO ill effect.

3. I was stupid...admittedly so. I was not paying attention and was unsoldering an XT90 connector from a 16,000mah 4S LIPO pack that was fully charged. I accidentally bridged my soldering iron across the 2 solder connections on the XT90 and instantly welded them together. For several seconds...10 or so I tried to get the soldering iron tip unwelded and it was not coming off. In between time that LIPO pack was dealing with a DEAD SHORT. Who knows what the current draw was...LOTS AND LOTS...100 amps easily!!! Did the LIPO pack explode or catch fire? NOPE! It was getting warm and if left in a dead short situation would possibly have become dangerous. I cut one of the battery wires at the Xt90 and that ended that. I immediately resumed unsoldering the XT90. 10 minutes later the pack was cooled down again. An hour later it was integrated into a 20S pack with a BMS and went on an 82 volt charger soon after that. I'm still using that 20S pack 2 years later and still no fires or exploding LIPOs.

If this isn't proof positive that LIPO's are resilient and safe and reliable and not a threat to your safety, then I don't know what is. There just is no need for the safety factor of LIFE at all. If you are "worried" about LIPO, just go to LION. They are far less prone to problems than LIPO and frankly LIPO is very safe already. Tesla makes a ton of cars every year ALL running on LION. So far they have had exactly 1 spontaneous fire. Even in cases of totaled cars, the vast majority do not result in battery fires.

IMHO, don't waste your time or money on LIFE. If you are worried about a battery fire, then be sure to duck every time a jet flies over. Who knows...one might just drop an engine or wheel on you! And how often does that happen? That's about how likely you are to have a LIPO fire or explosion.

What nonsense. I'm more concerned about the several gallons of gas in my garage!

Reworded - Lipo CAN be safe, yes!.

It is just like any other Lithium Ion based battery out there, whether it be prismatic pouches, or what I like to call Ziplock bag style, or metal can. It is how you charge and discharge the battery, it is how you take care of your battery, it is how you balance your battery, it is how you store your battery when you are not using it, it also depends on if you buy high quality products or generics.

Do you have high quality LiPo or some generic wonder off the web from some basement?

icecube57 mentioned that when he was buying LiPo from Hobbyking he found that atleast 10% if not 15% were duds and needed to be returned.

ElectricGod said:

.

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markz said:

Reworded - Lipo CAN be safe, yes!.

It is just like any other Lithium Ion based battery out there, whether it be prismatic pouches, or what I like to call Ziplock bag style, or metal can. It is how you charge and discharge the battery, it is how you take care of your battery, it is how you balance your battery, it is how you store your battery when you are not using it, it also depends on if you buy high quality products or generics.

Do you have high quality LiPo or some generic wonder off the web from some basement?

icecube57 mentioned that when he was buying LiPo from Hobbyking he found that atleast 10% if not 15% were duds and needed to be returned.

ElectricGod said:

.

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Reworded...LIPO IS safe...lots safer than the gas in your garage! Just spend 5 minutes looking at car fires. Admittedly, there are far more ICE cars driving around than electric ones. Still, look at the percentages. Of ICE cars, how many gas or oil related fires happen? Show me a single electric car that runs on LIFE. They all use LION. Now how about battery related fires in them. Lets even include the hybrid cars jsut to give this as much possible opportunity as is possible. LOL...gas and oil related car fires make lithium battery related fires look like a puff of smoke! I'm just NOT worried about battery fires...it is such a low risk.

In my examples, that first one where I over charged the 12S pack badly, that was cheap LIPO's I found on ebay. they were intended for some Chinese GPS. I got them super cheap. They were .5C, 8000mah cells and I was using them at 2C all the time. They worked fine at 2C with no over heating or bulging. They didn't have a very long life since they were such low grade LIPO cells. They were worse than multistar packs by a lot. I expect to get a couple of years use out of multistar packs. These cheapo cells were petering out after 8 or 9 months of regular use. That means daily use for 10+ miles and charging every other day on a stand-up scooter. The overcharged pack after I replaced the 2 or 3 bulged cells did die quicker than the other 3 12S packs I had made out of the same cells. These cells were so cheap. It seemed like a great idea at the time, but they were seriously low grade LIPOs and I was using them well above their ratings. They were going to lose capacity far faster than they would in their designed for use. Still, they never had a problem running well over their C rating, never over heated, never exploded, never caught fire...even the ones that were badly over charged. I had made 4 packs of 12S or 48 cells. Later on, I pulled those 12S packs apart and tested all the cells looking for good ones that had decent capacity still. Quite a few were useless...less than 1000mah and some had finally bulged. Quite a few were still running around 6-8000mah. In between time I had purchased quite a few more of them. I reused those cells to make a 20S pack which got used in the same EV for another year...along with new 20S packs made from more of these same cells. I've since retired all of them from active EV use since nearly all the cells are pretty well used up. 3 years later, I still have a 16S pack made out of them that I use on my bench. I have a bunch more of those cells sitting in a box that are still usable for some bench project since they still have 4 or 5000mah of capacity. Those uber cheap, crappy LIPOs never caught fire, never exploded. They just worked day in and day out without risk. I charged that scooter in my living room. It ran for well over a year exclusively on cheapo LIPO cells from ebay! That 16S pack, I charge on my desk in my spare bedroom.

Multistar packs can vary to be sure. I've bought 10,000mah packs and gotten some that test at 9,000 and others that test at 11,000. I'm looking for "close enough". Less than 10,000mah go back, but that has happened only once. I know they are not spectacular LIPO packs. I also have Graphenes from HK that are 10,000mah. I get better results than the multistar packs at having consistent capacity. I'm currently running 3 EV's on either multistar or graphene LIPOs from HK. They are all running great. One set of packs (10,000mah multistar) at 20S have about 4000 miles on them. I'm seeing a small decrease in capacity, but that's all. They run 2-4C all the time. Another set of 10 16,000mah packs set up as dual 20S are about 2 years old and running strong. They have far fewer miles on them, but they see 2-4C all the time.

I'm guessing here becasue I'd have to go look at the EV's and what's sitting on a shelf. I think this is close to accurate.

20 10,000mah multistar packs
10 16,000mah multistar packs
8 10,000mah graphene packs
250 cheap 8000mah LIPO cells from ebay
2 12,000mah multistar packs
10-15 "other" LIPO packs of various capacities

Surely with that many high capacity LIPO packs, if I was going to have a problem, I would have a LOOOONG time ago. IMHO, LIPO is pretty darn safe. I have no fear of any of those packs spontaneously exploding or catching fire while in use or while charging or while sitting there on a shelf.

I'm flat out NOT afraid of LIPO in any way. They just are NOT dangerous.

arkmundi said:

You and every other ES'er thinking of buying LIPO batteries need to read the threads, like this one from Floont:
https://endless-sphere.com/forums/viewtopic.php?f=6&t=48388

Floont said:

RIP Monzilla...

The battery charger caught fire and burned the bike beyond recognition. It also burned my whole house down including my car and my truck.

I will never go back to ebiking again.

FA

Click to expand...

Floont said:

Do you think your disaster might have been avoided had you been using a different chemistry other than lipo?

Click to expand...

YES

Who did you buy your charger from? I am specifically curious about how you know that the charger was the exact cause of the fire, my guess would be that was what the fire department thinks, but maybe you saw it light on fire and start burning other things.

Click to expand...

It was an Alloy shell charger from BMSbattery.

What advice would you give to others beyond being aware of the dangers of cheap chargers and lipo for those who currently use ebikes and those looking to get into ebikes?

Click to expand...

Don't use LIpo and if you must balance them frequently. Avoid buying anything form BMSbattery

Click to expand...

Worth repeating: Don't use LIpo. Instead, explore the world of LiFePO4 chemistry batteries, the safest and most environmentally safe of the current breed of lithium-ion batteries.

Click to expand...

This is the rare exception and while this is a bad story, what was the real cause for his house fire? Was it conclusive that LIPO's or his charger were at fault? What really happened? His opinion is valid, but I'd want a fire marshall to to say the LIPO's spontaneously exploded and burned his house down. Who knows, his charger may have been doing what I did by accident...massively overcharge his LIPO's. Is that the fault of LIPOs? I don't think so! Maybe he had a bad cell that was way under capacity and he wasn't balancing and didn't know it. That one cell charged to full well in advance of the rest of the pack and then promptly OVER charged. There's just not enough information here to make LIPO into something evil. IF he had a BMS, was it working? If he was using a balance charger of some kind, was it working? Lots of questions and far too much FUD and not enough factual information.

ElectricGod said:

Reworded...LIPO IS safe...

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Nothing IS safe!
Nothing at all.

LiPo has the same chance to explode and squirt out large flames the same as a Li-Ion Prismatic (aka Zip Lock bag style)
LiPo needs to be handled correctly the same as Li-Ion.
One could argue, and correctly so, that LiPo needs to be handled safer then Li-Ion. And for a new person, the factor for errors and fireworks is greater, then LiFePO4 or LiMn.

markz said:

ElectricGod said:

Reworded...LIPO IS safe...

Click to expand...

Nothing IS safe!
Nothing at all.

LiPo has the same chance to explode and squirt out large flames the same as a Li-Ion Prismatic (aka Zip Lock bag style)
LiPo needs to be handled correctly the same as Li-Ion.
One could argue, and correctly so, that LiPo needs to be handled safer then Li-Ion. And for a new person, the factor for errors and fireworks is greater, then LiFePO4 or LiMn.

Click to expand...

I 100% agree that LIFE is VERY low risk. It's pretty darn hard to get it to go wrong in any way that includes fire. Not impossible, but not easily done either. And in that regard LIFE is way safer than LIPO. LIPO can be punctured and cause it to flame out. It can be over charged and cause the cells to burst open and flame out. LIPO can be discharged too heavily, over heat, bulge, split and catch fire. These are all true...and LIFE will be hard pressed to fail in any way like that. LION pouch cells also will have these kinds of issues. LION can cells, once the seals melt down and air can get in can catch fire. Or if gaseous pressures inside the cell exceed the seal limits, pop off the top of the cell and then combustion can happen. These are real possibilities for LION and LIPO. It's just that they are very rare. When you consider how many individual LIPO and LION cells exist everywhere on the planet vs the number of LIPO/LION battery fires...well the reliability and safety factor is pretty good. A few cell phone batteries and a couple hoverboard fires to not make the entire lithium product line dangerous.

I'd say any lithium cell...LIFE, LION, LIPO, LTO...whatever...all need to be handled correctly. Avoid stupid things and you will save yourself and the battery. A LIFE pack sitting at 300 volts will kill you just as fast as a LION pack at 300 volts. Treat any high power device with respect.

You are right..."safe"...is bandied about like it's an absolute. I look at "safe" as a level of risk. IS my level of risk increasing significantly from X or is it staying essentially the same with or without its existence? I've been keeping gas cans in my garage as long as I can remember. I've also started a few fires on wet wood with it and had it go WHOOSH! Like anything that has some level of risk in it...be aware and deal with it appropriately. Some folks look at gas next to open flames as a "low risk" and others look at it as a "high risk". We readily accept the risk of driving a gas car and getting killed driving down the road every day. LIPO does not present 1/100th the risk of driving a car! We each draw our own line in the sand and live within those self imposed risk levels. I look at LIPO as providing very little risk to me or my house...and that is what I mean by "safe". My risk of death or fire has not increased in any significant amount that I can determine or measure. If LIPOs brought a significant increase in risk by actually exploding at random all the time...well that may be different. IMHO...my level of risk has not changed...aka LIPO is safe. Far safer than driving to work which I do every day pretty much without incident. However, just about every day there are accidents on the road. I'd still consider driving to be a fairly low risk. I'm 51 and still not dead from a car wreck or gas fire despite driving all the time.

I didn't think about it previously, but I have had the opportunity to scavenge laptop battery packs. I have hundreds of used 18650 cells. I recycle the ones that are too used up to be useful and keep the ones that can be used still. I pretty much run everything battery powered I have on used 18650's. They have become very handy to me in so many ways. The fact that I have a plastic bin sitting on the floor in my spare bedroom does not concern me at all despite there being something like 400 18650s in it. They get used or not and I never think twice about them. For about the last month, I've been going through my 18650's and capacity testing them again. It's been a long time! Anything less than 1200mah gets recycled. I've found probably 40 that are too weak and probably 40 more that are at 1200mah. They are all sitting in open zip log bags, just jumbled together. The chance of a fire or short is virtually zero.

Even Lead Acid Batteries can explode!

markz said:

Even Lead Acid Batteries can explode!

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Even my heart can explode. LOL...life=risk. I think I'll endanger my life by driving home in my explosive gas powered car! EEK!

Water can explode!

Apparently nothing can explode too. AKA the big bang. I guess everything in the entire universe is just one giant bomb waiting to explode.

Haha! Jeepers I didn’t realize how freaked out I needed to be. It freaks me out how little I was freaked out!