Bosch 36V fatpacks opened up

Would somebody be able to offer advice to a total noob?

I have a Go-Hub front hub (Crystalyte 408). Motor is 500 watt and my controller is 20 AMP. I've been running it at 48V with SLA.

I was hoping to build a pack from the Fatpacks, but I wanted to know how many I would need.

Also, how hard is it to create a parallel pack without removing all the cells. Are the all the wires needed, already inside the casings? Or do I need to have other wire availalable. Can this be done by a relative noob? I've crimped on connectors and dones some light soldering, but I'm very new to this hobby!

Thanks, in advance for your help.
 
Stiffi,

Sorry my pics at the beginning of the thread disappeared...hard drive crash. To keep things simple and maintain the structural integrity of the packs, I'd suggest going up to 72V and putting the packs in 2 series. That's super easy to do for even the noobiest of us. It would however require you to buy a new controller, but once you go to a higher voltage you never go back.

That said, if I recall correctly, once you get the packs all the way to the cells, I think you can cut the connecting tab to break it into 2p5s fairly easily. Then that in series with a full pack will give you a nominal voltage of 55V and 61-62v fresh off the charger. If your controller can handle that voltage, then that's an option, but charging will be an issue with the odd voltage as will LVC, so it is probably cheaper to spring for the new controller and charging with a pair of stock 36V chargers in series.

John
 
I'm pretty sure I can power my motor with 36 volts, even with the 20 AMP controller, as it has a LVC of 29. I know top speed might drop a little, but I'm more concerned with range anyway.

My biggest concern, however, is simplicity of installation. That's why I want to stick to a few packs in parallell.

I wanted to ask about charging. I did read this entire thread, but I'm unclear. Can the stock Bosch charger charge a pack of these packs in parallel all by itself? I think I understand that it doesn't charge them to full capacity, but will it work?

thanks again.
 
Stiffi,

Yes, it's easy to parallel them. Connect all of the parallel packs via just the positive and negative wires on each thru just one of the slot connectors that comes with a pack. Then you can use that connection to charge all at once with the stock Bosch 36V charger. Those chargers cut off at 40.5V .

Don't throw away the electronics boards that contain the slot connectors in case you want to use them in the future, because the chargers need them to function properly. I'm currently running 2 of the chargers in series for an 81V cutoff, and that requires two of the boards. I plan to use 4 chargers in a 2 parallel X 2 series arrangement to be able to charge twice as fast, and since I kept all my slot connectors I don't have to try to figure out any electronics, just simple connections give me a 500W+ charger.

John
 
@iconoclast,
How are you getting 35mph @ with these fatpacks? What controller are you using?
Click to expand...

Wavecrest Tidalforce, X model. Turbo mode. 6P fatpack.

Head down, elbows tucked in. Adrenaline. EV Grin. Bugs in teeth.
 
John in CR said:
Stiffi,

Yes, it's easy to parallel them. Connect all of the parallel packs via just the positive and negative wires on each thru just one of the slot connectors that comes with a pack. Then you can use that connection to charge all at once with the stock Bosch 36V charger. Those chargers cut off at 40.5V .

Don't throw away the electronics boards that contain the slot connectors in case you want to use them in the future, because the chargers need them to function properly. I'm currently running 2 of the chargers in series for an 81V cutoff, and that requires two of the boards. I plan to use 4 chargers in a 2 parallel X 2 series arrangement to be able to charge twice as fast, and since I kept all my slot connectors I don't have to try to figure out any electronics, just simple connections give me a 500W+ charger.

John
Click to expand...

John, is the slot connector insie the plastic housing? That is to say, do I have to remove that first? If so, what's the best plan of action? I'm guessing remove the wires from each board, and then keep the wires stickign outside the housing? Ideally, I'd like to keep the housing on, for protection inside my trunk when the whole pack is together.
 
Stiffy,

Yes you could do everything without even opening the packs up. If space savings along with a bit of weight are higher priority than preserving the warranty, then you can easily get rid of about 1/3rd of the volume by removing the end caps and the electronics board. The remainder still keeps the cells in a very strong plastic housing with only the ends to be covered. Too bad I lost those pics, or it would all make perfect sense.

Regarding number of packs, though one could run your bike, for the sake of minimizing cell stress (especially important since we operate them without the benefit of the forced ventilation through the pack that the power tools have) I wouldn't go with less then 3 packs in parallel. At less than $50 delivered I'd go with as many packs as you can fit and afford. Then you're virtually guaranteed at least 2 or 3 years of service, and by then superior batteries should be even cheaper. With an even number of packs you can upgrade to 72V with only the outlay of a new controller. The performance increase is not a subtle one, and after living at 48V you'll probably be unsatisfied at 36V anyway. A $400 upgrade now, 6 packs run 2p3s plus a 72V controller will broaden that EV grin after being accustomed to 48V of lead, though if you don't have disk brakes you'll want to spring for that too, since the speed at 72V requires good brakes.

John
 
stiffi said:
Don't you think 72V would blow my motor? It's a Crystalyte 408.
Click to expand...

No way... ran a 4011 at 84v nominal all last summer with no problems at all. Clytes can take pretty much anything you can throw at them. 4 series will happily eat up a couple kilowatts sustained for quite awhile.
 
stiffi said:
Don't you think 72V would blow my motor? It's a Crystalyte 408.
Click to expand...

I'm not sure anyone has reached a voltage limit for the brushless hub motors. It's high current you need to be careful about with the motor, especially as it's bogging down climbing hills, because at lower rpms the motors are much less efficient and turn much more of the electricity into heat. You do need to be more careful from a personal standpoint, but I think even 36V or 48V DC can be lethal with the high power batteries we run. Keep those 60A fuses intact that come with these Bosch packs as one safeguard, and please do be careful with wiring. I've been lucky and only blackened the ends of a thumb and fingers...these batteries really will create quite a plasma flash when shorted. I'm not trying to scare you, just instill some due care, because it's usually carelessness that bites us, and even the best and most experienced have snakebite stories.

I'm scared to death of electricity and practice over the top caution and still got scorched. If you ever swap multimeter plugs to measure current, switch them back immediately afterward, I forgot twice and it's a blinding, metal vaporizing flash if you go to measure voltage later without switching them back. All I messed up was the vaporized ends of multimeter probes and some skin. Others haven't fared so well, though it's typically the equipment that gets screwed, but we probably wouldn't even hear about someone killing themselves.

While I'm acting like an old lady about safety, do you have proper torque arms on your rig? Front or rear drive?

Sorry couldn't help myself,

John
 
Yeah, I'm kind of scared of wiring a pack together, which is why I keep asking how easy it is.

Is there anything I can do to shut down the packs while I'm trying to wire them together?

As for the motor, i'm running a front drive hub. I don't have a torque arm, but I have very tight steel dropouts that I check religiously. I've been fine running at 48 volts over the past year. I'm not sure I want to go any higher on voltage.

I read somewhere, it was probably here that "you should only go as fast as you are willing to slide on asphalt"
 
Steel or not bike dropouts aren't designed for any twisting torque, only to hold a regular bike axle on. Think of the pressure your motor pulls the bike, and multiply that force times the ratio of the wheel diameter to axle diameter (about 50:1). That's the force on your dropouts and nuts holding the axle on.

No, a battery can't be turned off. If you open the packs up, you're dealing with just 2 sufficiently long thick wires (1 pos and 1 neg for each pack), and all you do is splice those together to combine packs. It's really simple, and the wire is stiff enough to easily make sure the positive doesn't touch the negative wire of that pack. Worst case would probably just blow the fuse.

John
 
Thanks for the help.

I took the plunge and just ordered 3 packs and a charger from Amazon, along with some Anderson Power Poles, because that's what my motor's leads are. I've never tried powerpoles, before, so wish me luck.

If anybody is shopping go to Amazon. They have the packs for $49.00 and the charger for $39. If you have Prime, you can even get free shipping on the packs! So, I got the 3 packs and the charger for only $186!

So, I'm going to wire the 3 packs in parallel and see what I get on my stock GoHub and 20 Amp controller. I may in fact need more packs, but now that I know Amazon has them, it's easy to get more.

If you don't mind, John, can I check back in if I get overwhelmed opening up the packs?

thanks
 
Sure, in the meantime I'll try to find backups of those photos and get them posted. I processed 10 packs, so by the end I got it about as simple as possible given minimum size as a goal while retaining the tough shell that comes with the pack.

John
 
I decided to really test my "3p" fatpack konion VT battery pack this afternoon (10s6p)... I drew ~6.8ah out of it @ 28wh/mi before hitting my self-imposed 30v LVC cutoff.. that was charged to ~4.2v/cell. Went about 9mi and didn't pedal at all except for starting out. Lots of little steep hills. Had I pedaled I'm sure I could have stretched that to 20mi or so easily. Not bad for ~$135. I'm pretty convinced that these fatpacks are by far the best bang for the buck currently. And when you strip off the casing etc. they really compact down nicely... solder the +/- how you need them... keep the 60A fuse in place just 'cause and you've got serious ebike energy happening.
 
John in CR said:
Sure, in the meantime I'll try to find backups of those photos and get them posted. I processed 10 packs, so by the end I got it about as simple as possible given minimum size as a goal while retaining the tough shell that comes with the pack.

John
Click to expand...

What's the easiest way to connec the pack wires to each other? I'm thinking some simple twist connectors. Would soldering be better?
 
Hey Everybody,

Can somebody help me with a general question? When wiring batteries together, what is the best way? Can I just used some twist connectors? If not, what should I do, assuming I want to just permanently wire them together.

Thanks, for helping a novice.
 
stiffi said:
Hey Everybody,

Can somebody help me with a general question? When wiring batteries together, what is the best way? Can I just used some twist connectors? If not, what should I do, assuming I want to just permanently wire them together.

Thanks, for helping a novice.
Click to expand...

I don't know what I was thinking. I know, I have to wire each battery to the next's terminals. Then take the last wires and connect them to the motor. Unless, that sounds wrong to anybody, let me know.
 
stiffi said:
stiffi said:
Hey Everybody,

Can somebody help me with a general question? When wiring batteries together, what is the best way? Can I just used some twist connectors? If not, what should I do, assuming I want to just permanently wire them together.

Thanks, for helping a novice.
Click to expand...

I don't know what I was thinking. I know, I have to wire each battery to the next's terminals. Then take the last wires and connect them to the motor. Unless, that sounds wrong to anybody, let me know.
Click to expand...

Well, stiffi, the only thing you have said so far that is "wrong" is about the twist connectors. They are really for use on 110 volt wiring used on houses and will damage the finer gauge wires we use on 12, 24 and 36 volt e-bike and/or e-scooter projects. At least that's the way I was taught. I will say that I have seen some of the most GOD-AWFUL KLUGES of wiring for all practical purposes patched together with baling wire and spit that were working. They were also on the ragged edge of "working", and were at the same time possible safety hazards and putting the equipment at risk.
 
pwbset said:
:shock: :lol: I used household twist connectors for my first battery pack build (see photos 6 and 7) and pumped well over 30A through them, but having said that I'd definitely solder them if you can.
Click to expand...

I didn't say the household twist connectors wouldn't work, but I'll stand by what I DID say. I apologize to stiffi as well. I hadn't been keeping up with the usernames in this thread and thought I was helping a complete newbie, not someone who is well into their project. :oops:

Once upon a time, the Federal Communications Commission inspectors would write up citations to radio stations where the wiring was not done or maintained to what they called "good engineering practice". This generally meant built "battleship tough" to withstand the stresses of long term 24/7/365 operation. That's how I was trained and how I prefer to do my projects now. Not to say I don't take shortcuts now and then, but when I stick to the "old school" techniques I was taught, I don't have to walk home pushing my bike or scooter nearly as often. :lol: :lol: :lol:

ATB :mrgreen:

BC
 
64ragtop said:
pwbset said:
:shock: :lol: I used household twist connectors for my first battery pack build (see photos 6 and 7) and pumped well over 30A through them, but having said that I'd definitely solder them if you can.
Click to expand...

I didn't say the household twist connectors wouldn't work, but I'll stand by what I DID say. I apologize to stiffi as well. I hadn't been keeping up with the usernames in this thread and thought I was helping a complete newbie, not someone who is well into their project. :oops:

Once upon a time, the Federal Communications Commission inspectors would write up citations to radio stations where the wiring was not done or maintained to what they called "good engineering practice". This generally meant built "battleship tough" to withstand the stresses of long term 24/7/365 operation. That's how I was trained and how I prefer to do my projects now. Not to say I don't take shortcuts now and then, but when I stick to the "old school" techniques I was taught, I don't have to walk home pushing my bike or scooter nearly as often. :lol: :lol: :lol:

ATB :mrgreen:

BC
Click to expand...

You seem to have some experience about radio stations, but considering your only a 100w station, your twisted wires wont be noticed by the FCC..lol

:mrgreen: :mrgreen: :mrgreen: :mrgreen: :mrgreen: :mrgreen: :mrgreen:

Sorry, couldnt resist, the rf devil made me do it

Roy
 
pwbset said:
How many fatpacks did you end up with and what is your desired voltage? Are you trying to series to 74v or just parallel a bunch together @ 37v??
Click to expand...

I bought 3 fatpacks, and I just plan to parallel them together, for 37 volts.

thanks
 
I purchased 4 fatpacks. All are 35 volts but one was 7.4 volts. Defective? Bad?
 
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