Monster (build thread, Lots of pics, Bike Porn included)

[Drunkskunk]

That is a pretty good Idea. I'm working on a revision of the Jeremy Harris Power switch. I think some kind of auto-off feature could be added. Maybe a motion sensor and a timer.

There is a drain down resistor in most controllers, which is one good reason not to leave a battery connected when they are powered off. But Caps leak. They don't block DC 100%. more like 99.9999%. I've had several that discharge several watts a day through the caps.

 

[Hyena]

I killed a brand new battery recently too in very similar circumstances - new bike I built for the wife, took her for a test ride then bought it back and got distracted and left it powered on. 2 weeks later I went to take it out and "uh oh" , 6 new tightly taped 6S bricks looking nice and puffed and reading 1v/cell
I normall use Lipo LVC buzzers, they're a good good cheap and easy insurance policy. If you forget and leave the bike on (or power is otherwise draining) you'll know soon enough from a few rooms away when the beepers start shreiking at you

 

[louis raaijmakers]

ahh that sucks.

is still got 1 question why does every one here on the forum use lipo battery`s?
they only take 300 times there charge i heard. and they don´t have an bms. so charging is a bit difficult without the balance leads.
becouse putting them in parallel isn´t the best option. and you need an powerfull charging station. and cycle analyst for the lvc.

if some one can explane my why every one with and awsome bike of 1000 of dollars is using cheap lipo? only becouse of the low voltage sag? :?

thanks.

louis raaijmakers

 

[Drunkskunk]

is still got 1 question why does every one here on the forum use lipo battery`s?

Easy. Performance. Nothing else packs as much usable power into as small and light of a package as Lipo. These are a high performance cells. They aren't meant to be practicle or long lived. Think of Lipo like Racing fuel for a high performance bike.

I think (hope) most people who build and ride ebikes don't use Lipo. Its simply too dangerous, expensive, and labor intinsive for 99% of the ebikes in the world. But this forum is where most of the Alphas in the Ebike world end up. Those who are either driving the industry, or those who are pushing the limits of the technology. So on this forum, you'll probably find more than a few running high performance rigs that need a high performance battery.

Don't think of us as Normal.

 

[Rix]

Well put DS, yes, I think the folks on most of the threads here are driven by performance over anything else and lipos are at the top in terms of C rate. Yah, running lipos comes at the price of paying a little more attention during bulk charging and not discharging below 20% SOC. I got into Lipos from Hyena's kit on my dads bike. He has 220 cycles on his pack and its going strong. Of course only discharging less than 3C, his packs voltage sag on 12s is only one volt WOT hot off the charger. Yah, I will be building a 20s Lipo for my Bomber pretty soon, if not this season, for sure this coming winter. My lifepo4 is getting tired and voltage is starting to sag alot under WOT.

 

[louis raaijmakers]

yes i know the have good preformance and are "cheap".
but you need to pay attention when charging them up and you need to have and expensive charging station to charge them quickly.
and you need an bms or cycle analyst to mange the battery.

so aren't you cheaper when you buy an lifepo4 battery 20 ah 72v? (786 dollars shipped A123 to europe)
yes i know these are alot heavyer but they have an cycle life of +- 1200 cycle's if punished hard. and it won't burn your house down.
doesn't it pay back?

thanks

 

[Allex]

The main problem of Lifepo4 is weight.
If I take my bomber battery, 72V18Ah the wight is around 13kg
I can almost have double performance with li-ion or lipo= 82V and 28Ah with the same weight and size.
The second problem is that you cannot find real a123 round cell snow. Those chinese are fake, not a real a123.
And if you take a pouch pack of a123 from cell_man they are to big for my frame to fit.

If you really need a safe and reliable battery with easy charging solution. I really recommend you to look at 18650 li-ion batterys.
They are as safe as lifepo4 and the weight and performance is almost as good as lipos.
Mr cell_man can build a custom pack for you, complete with BMS and a charger: http://em3ev.com/store/

 

[Drunkskunk]

yes i know the have good preformance and are "cheap".
but you need to pay attention when charging them up and you need to have and expensive charging station to charge them quickly.
and you need an bms or cycle analyst to mange the battery.

so aren't you cheaper when you buy an lifepo4 battery 20 ah 72v? (786 dollars shipped A123 to europe)
yes i know these are alot heavyer but they have an cycle life of +- 1200 cycle's if punished hard. and it won't burn your house down.
doesn't it pay back?

thanks

I don't know who said Lipo were cheap. They aren't. I have over $1,000 worth of charging equipment dedicated to just this bike's battery, just to start. And my 1337 Watt hours worth of Lipo (slightly less than the Lifepo4 you mentioned) Will cost me $800 with delivery) Plus the short life of the cells means they get replaced far more often than other chemestries, likely double or trippling the cell cost. Then I need various kinds of monitering equipment to make sure the cells are in good shape, and the cost in man hours to sit with the bike while it charges is also a factor. No, Lipo aren't cheap.

LiFePO4 wouldn't fit in the frame, and those chinese knockoff a123 LiFePO4 would fry nearly instantly trying to provide 10,000 watts for this bike.

Its all about performance. I could not get this kind of power and range out of another chemestry. Rockets need rocket fuel.

 

[Hyena]

Cocaine isn't cheap and doesn't last long either, but you don't hear people complaining they'd rather sniff glue

 

[Rix]

Cocaine isn't cheap and doesn't last long either, but you don't hear people complaining they'd rather sniff glue

Exactly!

 

[louis raaijmakers]

oke oke
thanks for the reply's

 

[Drunkskunk]

Just an update. Stairs.
Yesterday I had little time and had to run a quick errand. The Ebike is faster across town than my car so I grabbed it and headed out. Unfortunatly, I had to pass by the stadium on the way, and it has a nice flight of staires, just sitting there tempting me.
I had attempted this flight before, and failed when I lost taction half way up. But this time I was trying a new Fatback Sterling 4.25 tire. Let me tell you, this is a great tire! The bike clawed it's way up the flight of stairs from a standstill at the bottom with hardly a complaint, untill I hit the very last step. on the last step I managed to pinch flat the thing, even running the tire at max inflation, 25 pounds. it cut right through the extra thick motorcycle tube I was using and blew slime everywhere. That was a long walk of shame to get the bike home. Fat tires don't roll like a normal tire when flat.

The idea of using a motorcycle tire doesn't sound so bad at the moment.

 

[Rix]

The idea of using a motorcycle tire doesn't sound so bad at the moment.

Let me know which rim you want to run, if its a 17x1.4, 18x1.4 or 18x1.85, or 19x1.4, I got all the spoke lenght formulas worked out for the 54xx rim.

Rick

 

[dan974]

I know the mx tyre is the key but I have very less pinches since I took the time to adjust my rear suspension (little sag/+20psi than recommended/rebound adjusted just before getting a donkey kick, 3/4 open) and appropriated tyre pressure

Were you topping the rear suspension ? As it wasn't on a jump ? As you re seem pretty tall, have you got the right spring ?

 

[Drunkskunk]

@Rix. Thanks!

@dan974. I'm not topping out on this suspension at all. it's a long travel suspension that isn't even working hard to cope with stairs.
I think the last step got me because the rest of the way up the back wheel was in contact with 2 steps, distributing the weight. on the last step, it had to take the full weight of the bike on just the edge of 1 step and as the bike pressed down, it contacted the rim before anything else could support it. Unfortunately, I was at max pressure for the tire, 25lbs. These Vee rubber based tires don't take pressure as well as the Innova based tires, although they generally have better tread patterns.

 

[John in CR]

The idea of using a motorcycle tire doesn't sound so bad at the moment.

Let me know which rim you want to run, if its a 17x1.4, 18x1.4 or 18x1.85, or 19x1.4, I got all the spoke lenght formulas worked out for the 54xx rim.

Rick

That bike needs 21's if the motor can tolerate it.

 

[Drunkskunk]

That bike needs 21's if the motor can tolerate it.

Good point. I'm using 21" motorcycle tubes already.

 

[100volts+]

Drunkskunk,
How wide are your dropouts? You've probably answered this question, but this thread is already over 200 posts long.

 

[Rix]

DS, you should really consider a 19x1.4 or 1.85 mc rim running the Shinko SR241 3.50x19 tire. That tire is close to 4 inches wide, OD around 26". Pinch flatting problem solve at 24PSI.

Rick

 

[John in CR]

That bike needs 21's if the motor can tolerate it.

Good point. I'm using 21" motorcycle tubes already.

My 21's are a street/light trail tread and came out to an OD of 26.75" . I think they'll do on the rocky trails we have here, since I won't be riding in mud.

 

[Drunkskunk]

@100volts+ 135mm. I went narrow to keep the chain line simple.

@Rix and John. Ouch. I'm running a ~30" OD right now. Smaller might not be a good thing.

 

[Rix]

@100volts+ 135mm. I went narrow to keep the chain line simple.

@Rix and John. Ouch. I'm running a ~30" OD right now. Smaller might not be a good thing.

If you went with a 21x1.6 MC rim, you could run a 2.75 or 3.00 x21 SR241 with an OD of 27-28". Getting closer there.

Rick

 

[Allex]

NIce frame design, but what is the purpose of its enormous size? Smaller tyres will get you a more agile performance.

 

[Rix]

For DS, its not about agile handeling, he just wants to roll over everything that we would actually steer around :lol:

 

[Drunkskunk]

Hondas are just obstacles.