Bosch 36V fatpacks opened up

[Russell]

Russell, are you still charging your pack to 41.5 volts? I just got my charger today (same seller as you) and the voltage is adjusted to 41.5. I just want to make sure it isn't too high.

The pot on my charger is really touchy. I set it a few times but it seemed to vary, not much mind you but it bugged me. After setting it and reinstalling the screws for the last time it seems to charge the pack consistently between 41.20 and 41.30 so I left it there. For longer life perhaps 41.0V should be the target but I drain mine almost fully each time I ride so longevity is probably not in the cards for my 3-pack.

BTW, did your charger come with the correct ac plug?

-R

 

[EVTodd]

Russell, are you still charging your pack to 41.5 volts? I just got my charger today (same seller as you) and the voltage is adjusted to 41.5. I just want to make sure it isn't too high.

The pot on my charger is really touchy. I set it a few times but it seemed to vary, not much mind you but it bugged me. After setting it and reinstalling the screws for the last time it seems to charge the pack consistently between 41.20 and 41.30 so I left it there. For longer life perhaps 41.0V should be the target but I drain mine almost fully each time I ride so longevity is probably not in the cards for my 3-pack.

BTW, did your charger come with the correct ac plug?

-R

I'll play with the pot a bit. I may just keep it around 41 volts for now.

I did indeed get the correct ac plug. I actually had to send him a picture of it since he didn't quite know which plug was used in the US. There is a bit of a communication barrier with that seller but he went out of his way for the sale. He even shipped it priority. All for only $24 total.

 

[TPA]

which one did you get for $24.....link?

 

[EVTodd]

which one did you get for $24.....link?

I purchased it directly from the company but this is the Ebay link for the same charger: http://cgi.ebay.com/ebaymotors/E-Bi...9071665QQptZMotorcyclesQ5fPartsQ5fAccessories

 

[ToughRowToHoe]

I purchased it directly from the company but this is the Ebay link for the same charger: http://cgi.ebay.com/ebaymotors/E-Bike-3 ... 18Q7c301Q3

Would it be relatively safe to leave 3 fat packs on this charger overnight with no supervision? I plan to leave the packs together so there would be no BMS. I'm assuming I don't have to fear the charger itself. I'd aim at 40.5 volts.

 

[Russell]

Would it be relatively safe to leave 3 fat packs on this charger overnight with no supervision? I plan to leave the packs together so there would be no BMS. I'm assuming I don't have to fear the charger itself. I'd aim at 40.5 volts.

It'll cause no harm since once the pack reaches the voltage of the charger there is no current flow. Aside from forgetting to turn it off there of course is no reason to leave the pack on the charger since there is no BMS and no balancing going on.

-R

 

[ToughRowToHoe]

Thank you Russell.

On a seperate note, somebody asked earlier in this thread for the dimensions of the packs before disassembly. I don't think there was a reply and I really haven't seen the dimensions listed anywhere else. I'm trying to figure out if three of them would fit into this handlebar bag?

http://www.niagaracycle.com/product_info.php?products_id=1261

Of course, I only have a volume size for the bag; 323 cubic inches.

 

[ToughRowToHoe]

I had checked several seller sites, Ebay auctions, this forum and the Bosch site without finding the dimensions.

Anyhow, I did find the following Ebay listing with the dimensions:

http://cgi.ebay.com/36V-2.2Ah-Battery-Fit-Bosch-BAT836-D-70771-Li-ion-New_W0QQitemZ260398407949QQcmdZViewItemQQimsxZ20090423?IMSfp=TL090423144003r28039

97.92 x 72.77 x 156.99 millimeters or 3.86 x 2.86 x 6.18 inches for about 70 cubic inches in volume each. Thanks.

 

[e-noob]

any idea what kind of Amps 6 of these in parallel could handle?(me r stoopid)

 

[Russell]

any idea what kind of Amps 6 of these in parallel could handle?(me r stoopid)

I've used a 22A controller on my 3-pack (~6Ah) with no problems so you could run double that with six. Obviously though the more current you draw the more they'll sag and of course make sure your wiring is up to the task.

-R

 

[pwbset]

any idea what kind of Amps 6 of these in parallel could handle?(me r stoopid)

Page 3 of this thread... already answered:

http://endless-sphere.com/forums/viewtopic.php?f=14&t=7569&start=30#p133193

6p = 60A continuous without heat issues and 100+A burst very easily. You shouldn't have power issues.

 

[e-noob]

Ty much.. missed that somehow.. Doc's explaination was quite good.

 

[John in CR]

60A for 6 packs in parallel is low by at least half. 6p packs is 12p of the VT cells. I ran 6 packs in parallel on my e-moto for a while with a 200A controller, and they never ran warm despite the 20%+ grade hill climb leaving my house. With the max recommended current of a VT cell of 22A, that's a max current of 264A.

John

 

[Russell]

60A for 6 packs in parallel is low by at least half. 6p packs is 12p of the VT cells. I ran 6 packs in parallel on my e-moto for a while with a 200A controller, and they never ran warm despite the 20%+ grade hill climb leaving my house. With the max recommended current of a VT cell of 22A, that's a max current of 264A.

John

Yeah the Fatpacks are tough little buggers so I think the real limiting factor to how much current they can deliver is how much sag you're willing to put up with. When drawing 22A from my 3-pack the voltage drops about 3 volts which is about the most I want to see. I think therefore someone should keep the current draw to 3-4C when using these packs.

-R

 

[pwbset]

60A for 6 packs in parallel is low by at least half. 6p packs is 12p of the VT cells. I ran 6 packs in parallel on my e-moto for a while with a 200A controller, and they never ran warm despite the 20%+ grade hill climb leaving my house.

That's good to know John. I was assuming 10A/pack ~5C/cell in a 12p/6pack setup sustained would be a nice conservative estimate for no heat build up based on Doc's info, but it's nice to hear you're not having heat issues. The VT cells I was testing with my old CBA at 10C got extremely warm... like do not touch warm, but I don't know how "used" they were when I got them so I think they were older and had lower capacity/higher IR at that point. The V cells I was testing got about the same temp @ 6-7C if I recall. Personally I'm targeting 4-5C tops with my new batt packs so I can at least get a couple hundred cycles out of them.

 

[DahonElectric]

Russell,

I read your blogs about the Bafang motor that you bought I presume from Rayben Motors?!? I'm looking to buy the very same motor from Rayben too simply for the price. I want to ride my bike like a bike and the hub must freewheel if I'm not using it and only need the assist if I want to. Can this motor do it?

I have a nice electric bike already, but I live in a bike theft capital of the world and unfortunately, the times I left my Dahon MuSL out there even for less than an hour with a set of nice locks (both NY Lock and Chain), people STILL WANT to steal it. So if I have to park my bike in some shady places where I can't keep my eyes on it, I want to use my old commuter which is good but relatively inexpensive and outfit that with the Rayben 250w motor. My question is, will a 700c tire fit the 28" rim? And how is it for durability? How long will it last and how does it do in rainy weather? I plan to use all stock as I figure that even if it is stolen, I'm not out a lot compared to my other nicer bikes in my stable.

Your thoughts on this would be greatly appreciated!

Thanks,

David.

 

[e-noob]

so, do these things really only last 300-500 cycles?. . .

 

[Russell]

Russell,

I read your blogs about the Bafang motor that you bought I presume from Rayben Motors?!? I'm looking to buy the very same motor from Rayben too simply for the price. I want to ride my bike like a bike and the hub must freewheel if I'm not using it and only need the assist if I want to. Can this motor do it?

I have a nice electric bike already, but I live in a bike theft capital of the world and unfortunately, the times I left my Dahon MuSL out there even for less than an hour with a set of nice locks (both NY Lock and Chain), people STILL WANT to steal it. So if I have to park my bike in some shady places where I can't keep my eyes on it, I want to use my old commuter which is good but relatively inexpensive and outfit that with the Rayben 250w motor. My question is, will a 700c tire fit the 28" rim? And how is it for durability? How long will it last and how does it do in rainy weather? I plan to use all stock as I figure that even if it is stolen, I'm not out a lot compared to my other nicer bikes in my stable.

Your thoughts on this would be greatly appreciated!

Thanks,

David.

You can see my initial review here: http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=8001

The motor was on this bike for 909 miles:
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=8579

I recently moved the motor to this bike: http://www.endless-sphere.com/forums/viewtopic.php?f=4&t=10458

The rim supplied in the Rayben kit is a 635mm 28" rim and NOT a 622mm 700C rim, so yeah you have to lace it to a new rim.

-R

 

[Russell]

so, do these things really only last 300-500 cycles?. . .

I'll get back to you in a few years. I now have about 28 cycles on my 3-pack.

-R

 

[EVTodd]

I would be happy with 500 cycles. I get more than 20 miles per charge with my 3 fatpacks so figuring conservatively that would be 10000 miles. It's cheaper than gas!

 

[John in CR]

I believe that 300-500 cycles is for their designed use with power tools, and with an ebike (especially larger capacity packs) our usage is far less demanding. Think about it with a powertool the consumer uses essentially maximum power and 100% discharge that the charging system allows on every cycle, but our usage is FAR more conservative, which is directly related lithium batt life.

On an added note, I'm certain that my konions will get me through the next 2 years, and I'm also certain that 2 years from now batteries for our needs will be smaller, much cheaper, and have realistic cycle lives that are at minimum what vendors are claiming for LiFePo4 now. That's why I totally support an approach that uses cheap packs now to get you through a relatively short period before extreme quality becomes affordable enough to power cars.

John

 

[e-noob]

we need a micro-version of one of these:
[youtube]efCelx7qe_M[/youtube]
Imo...

(too bad it will magically "disappear", like all the rest)

 

[set]

I've skimmed through all 12 pages and didn't see anyone putting these packs in series. Would it matter if a fatpack is 36V 20AH or 72V 10AH? I guess my question is, would there be any advantage in setting up a 72V pack? I understand more power from less amps but that would really matter for low C-rated batteries such as ping/cammy/sla. These cells can already discharge at 5c 10c burst(right?) so in theory, a 36V 20AH would have more range than a 72V 10AH pack while having enough power when needed. I'm looking to build 2 sets of 3 fatpacks and put them in panniers. Choosing between series and parallel is my next step. Would 36V be enough to run an x5 motor? I wouldn't want to downgrade since i normally get 25-30(peak) amps drawn from my 48V 20AH cammy pack and I ride 25-30 mph all the way. I guess the controller would limit the speed and amps. If I decide to set up a 72V 10AH pack, how much range am I looking at?

The ebikes.ca simulator is not giving me the speed I want no matter what amps I put it.

@iconoclast,

How are you getting 35mph @ with these fatpacks? What controller are you using?

 

[pwbset]

Would 36V be enough to run an x5 motor?

I running on a single fatpack right now and my 504 is topping out around 22mph... granted that's under pretty heavy sag like 32-34v, but I guess my point is that you may not quite hit your speed goal on "36v" (maybe just barely on a fresh 42v charge and light sag with enough parallel). Having said that I can't even imagine running a 5 series @ 72v on a mountain bike and it's giving me a new appreciation how nuts people like DocBass and Steveo are. :wink: :lol:

 

[set]

So I just purchased 4 fatpacks for $49.49 each for a total of $197.96 . I have to wait for my live.com cashback. They changed the site to "bing.com" but I'm guessing it works the same way. My cashback was $15.84 @ 8%. Subtotal would be $182.12!

4 fatpacks in parallels x2 then in series for 72V 8.8AH sounds like fun. Now to get a controller to match. What controllers are you guys using to match your fatpacks?