Bosch 36V fatpacks opened up

[Briankissel]

FYI the "BMS" isn't a bms at all. It only contains circuitry for the 3 segment led display and a thermo sensor. Both the power tool and charger engage the battery directly with no interference outside of a stock 60amp fuse.
BK

 

[ambroseliao]

Is it possible to use a Mean Well 48 V power supply trimmed down to it's lowest setting of ~41V to charge the Bosch Fat Packs? I have 6 BFPs wired in parallel now and want to add two more I have to create a 2S4P 72V 8.8AH pack. I've been reading this thread:

http://endless-sphere.com/forums/viewtopic.php?f=14&t=4125&start=375

But wanted the quick answer to whether this would work on the BFPs.

Thanks,
Ambrose

 

[John in CR]

Doc,

I've be running the 20s, 74v nominal for a year. Time for a change. Some are going to get the rough treatment of double Methods 100v100a controllers 24s. I'll probably use the Bosch packs and my other VT cells for that pack. My V cells are going to get the new Lyen high voltage treatment, which will be 34s or 36s. I still have two 10p34s packs from back when I was running 63v nominal, so my easy answer is 34s. I've got 2 of his max off the charger 150v controllers "in route to destination country" as I type.

The Double Methy bike should be "E-King of the red lights", and the Lyen driven bike will have multiple gears and will be low and sleek, so it should be both "E-King of the mountain roads" and "E-King of the Costa Rican autobahn" with a 60a or 80a setting. They'll all be frock powered, with the Lyen Special being out of wheel, and either should slaughter our favorite blue show bike from down under in any race longer than 50ft or so.

These bikes will help me determine how to put my secret weapon hubbie, the "big-ass outrunner", to best use and hopefully earn the title "Colussus Killer".

I need to hurry up and get these on the road before Luke, DocBass, and SteveO post numbers I don't want to attempt.

John

 

[John in CR]

Is it possible to use a Mean Well 48 V power supply trimmed down to it's lowest setting of ~41V to charge the Bosch Fat Packs? I have 6 BFPs wired in parallel now and want to add two more I have to create a 2S4P 72V 8.8AH pack. I've been reading this thread:

http://endless-sphere.com/forums/viewtopic.php?f=14&t=4125&start=375

But wanted the quick answer to whether this would work on the BFPs.

Thanks,
Ambrose

It will work, though I wouldn't. Bosch charges to 4.05/cell for a reason. Over-charging lithium cells is one of the surest ways to shorten their life. Better would be to go with the next lower voltage of Meanwell and charge to 40v or 40.5v regularly, and save higher top of charge voltages for special occasions that you want extra capacity. It's the "V" cells that come in Makita packs that withstand regular charging to 4.1v-4.2v regularly.

John

 

[ambroseliao]

Thanks John,

I wouldn't overcharge them. I want these to last a long time!

Thanks,
Ambrose

 

[docnjoj]

Here are the before and after photos of the switch from Ping/Fatpacks to all fatpacks. saves about 15 lbs and is the same voltage but about half the amp/hrs. More than enough for me. Now I can actually put stuff in the panniers. Now since it works I heed to make it look nice with orange paint for the Lexan and Orange Duck Tape for the packs. I can never escape Duck Tape!
otherDoc

Before


After

 

[veloman]

Anybody see these 2.6ah fatpacks made by Titan?

http://bigtimebattery.com/store/gdbos362.html?site=google_base

I wonder if they are equal in cycle life and such.

 

[yoyoman]

As I wrote a while back, my 2 fatpacks died after leaving them connected to my watts up meter during an off season. Now that it's bike season again, I thought it was time to try to revive them.

When I connected my 36V Soneil SLA charger thru a fuse and the watt's up meter to the battery, the LED of the charger stayed green and never went red. Does this mean that it wasn't charging? Assuming the charger is 3A, how long should I let it charge? I would like to revive them enough that I can put them on the Bosch charger to finish.

 

[amberwolf]

Does the WU show current flow to the battery? If not, then it's not charging.

The numbers the WU gives you can help troubleshoot some of it. What voltage does it show? The dead-pack voltage or the Soneil charging voltage? If the former, then the Soneil isn't outputting anything. If it starts to show the latter and then changes to the former quickly, the Soneil is probably detecting too low a voltage and thinks the "SLA" is dead or damaged, and doesn't want to charge it.

 

[dequinox]

Does anyone have a dead fatpack, or even just the plastic casing that includes the mating surface where the fatpack slides into the charger/tool? I was thinking of designing a multi-pack interface similar to one another fellow on here has built for the makitas that wouldn't require the use of an end-mill. Just an idea... but if you have one you'd ship to me for free (plus the cost of shipping) I would make the design available as open-source. It would be nice to be able to just swap these out

@docnjoj

Hey otherDoc how far does that set of 6 fatpacks get you? And how did you get 54 volts out of 36v packs?

 

[docnjoj]

Hey dequinox
I can get about 20 miles on the 8ah system. I have 4 fatpacks at 36 volts // in series with two fatpacks at 18 volts. I did surgery on those packs and wired them 5s by splitting the case and some jumper wires to a buss out at 18v. It took a bit of work and there are a bunch of pictures either in this thread or another when I wired them with my 36 volt Ping.
otherDoc

 

[dequinox]

Oh ok so you did split one up. I have a brushed controller with a 60v maximum so I was curious 20 miles is a good range for 8ah, mine would be a little less but I think the weight reduction (from 40lb of lead down to 4 fat packs) would be well worth it...besides that actually would still trump my current capacity. Now I only get about 6ah tops before the voltage sag on my 36v pack drops below the cutoff voltage for the controller, and thats out of 18ah batteries. Lead sux!

 

[docnjoj]

Yes dequinox. The higher voltage (54 nominal) seems to give better efficiency and range than using 36 volts. I guess I am on the throttle less time but whatever it works. By this logic 72 volts should be even more efficient
otherDoc

 

[docnjoj]

I have been searching for Fatpacks and I find they are either stupid expensive or very difficult to find. What is going on?
otherDoc

 

[John in CR]

I have been searching for Fatpacks and I find they are either stupid expensive or very difficult to find. What is going on?
otherDoc

Message DoctorBass. Forget the VT's and get yourself some super cheap V's. Turning them into packs is really no more difficult than your Fatpack surgery, and the 40% greater energy density is a big plus. I'll be taking my 10 Fatpack pack off very soon for its one year inspection and balance check, and I doubt it will go back on since a 10p20s V pack is physically smaller and packs a lot more range. The Fatties were really only a good deal when they were $50 or less including shipping.

John

 

[ambroseliao]

I have been searching for Fatpacks and I find they are either stupid expensive or very difficult to find. What is going on?
otherDoc

The Bosch Fat Pack 36V packs have reached their end of life and are becoming harder to find and more expensive to purchase.

Ambrose

 

[docnjoj]

Wah! Thanks John and Ambrose. Yes I can build packs but the Fatties were just so convenient. Oh well! Is Bosch planning to phase them out entirely?
otherDoc

 

[ambroseliao]

I agree with you about how convenient they are. I find the package to be rugged and well designed. There is a small chance that they may make more, but it's more than likely that they will sell out of their current stock and move on to the next design. You can always find them elsewhere if you're patient and handy.

Doctorbass here often has the cells used to make them available (Sony Konion 18650VT). I've bought some from him. I've also had luck on the 'Bay and also found the majority of them here on ES. They will be available for a while but I expect prices to remain high. The lowest prices have definitely come and gone.

Ambrose

 

[John in CR]

The good doctor typically has Makita packs with the V cells, which really are better for our use anyway due to the greater capacity. Turning them into a pack of good cells is really quite easy. I doubt the 10p20s V packs I've made were any more difficult than my compacted Bosch fatties that ended up 10p20s. At $50/ea incl shipping, the fatties were hard to beat. Why don't one of you guys try becoming a Bosch distributor? Plus they must be coming out with some pack solutions to go with their new e-bike drive system. We just need below $.50/wh, though I still prefer the $.30/wh of my last batch of Makitas, cheaper and more freedom of orientation on the bike, and of course, that 40% increase in capacity in the same space and weight is the final nail in that coffin.

 

[yoyoman]

Does the WU show current flow to the battery? If not, then it's not charging.

The numbers the WU gives you can help troubleshoot some of it. What voltage does it show? The dead-pack voltage or the Soneil charging voltage? If the former, then the Soneil isn't outputting anything. If it starts to show the latter and then changes to the former quickly, the Soneil is probably detecting too low a voltage and thinks the "SLA" is dead or damaged, and doesn't want to charge it.

I have a Soneil charger and a generic 36V SLA charger from a electric scooter. I'll try both and maybe make a video of the WU to have y'all decipher for me. Maybe the generic one is dumber and will let me charge even with a low voltage.

If it's better for reviving the packs, I also have a 48V charger from a Ping battery pack.

 

[docnjoj]

Miracle occured they are back on Ebay! Even at 75 bucks apiece shipped a bullet proof 10 ah 36 volt pack for 375 is not a bad deal. About the same +/- as Headways and a Signallab BMS. What say you?
otherDoc

 

[John in CR]

Miracle occured they are back on Ebay! Even at 75 bucks apiece shipped a bullet proof 10 ah 36 volt pack for 375 is not a bad deal. About the same +/- as Headways and a Signallab BMS. What say you?
otherDoc

Compared to my last DrBass pack of 74v15ah for $336 incl shipping plus some elbow grease, much of which I'd incur either route, you know my position.

If this 2-pack of Makita 18v is really 2 packs for $80, then it's a better deal. http://www.google.com/products/cata...og_result&ct=result&resnum=1&ved=0CBkQ8wIwAA#

EDIT: Sorry they do have a 2pack, but not at that price. I did see the Makita 18v3ah on sale a few months ago, which was a pretty good deal in the mid $40's.

Times are tough, where are the battery price wars? Under $50 w/ free shipping over a year ago should mean $30 incl shipping now. We need to get further up the line and get factory direct 2p10s Konion sticks for well under $.50/wh . That's still $2,77/cell, so I believe factory direct with only the tab welds and packaging (no electronics, just +/- leads) under $.25/wh is possible in sufficient volume. We need to find an ebike lover with a family relation high up in Sony's battery division or Makita.

What sucks it there's a Panasonic battery factory 2 miles from my house, but the only lithium batts they make are the little button cells and none of the quality traction packs Panasonic now makes.

 

[docnjoj]

Yep John you are right (as usual) Those Makitas have some extra ah but prolly not 3 to max DOD. The Bosch I rate at 2ah and the Makitas prolly 2.6 so there is some advantage but it's really close. The Makitas may be more readily availible since the lower power tools are coming into vogue like those little impact screw drivers. Hmmmm...............Lipos anyone? I may give them a try when my Fatpacks die. I just don't want my as* burned off! On the other hand I have ignited high power electric sailplanes with Nicads pulling 60C. In a contest of course. Oh well! Enough of former triumphs! :lol:
otherDoc

 

[docnjoj]

Yeah those Makitas look like 80 bucks apiece. That is not so great! Lipos anyone?
otherDoc

 

[webfootguy]

Times are tough, where are the battery price wars? Under $50 w/ free shipping over a year ago should mean $30 incl shipping now. We need to get further up the line and get factory direct 2p10s Konion sticks for well under $.50/wh . That's still $2,77/cell, so I believe factory direct with only the tab welds and packaging (no electronics, just +/- leads) under $.25/wh is possible in sufficient volume. We need to find an ebike lover with a family relation high up in Sony's battery division or Makita.

What sucks it there's a Panasonic battery factory 2 miles from my house, but the only lithium batts they make are the little button cells and none of the quality traction packs Panasonic now makes.

I recently when through a local custom battery builder to quote out getting Sony LiMn (konion) cells directly from the Factory (Sony). They were not interested in anything less than 50K to 100K cells. They also wanted to know the application before they would look at the business (risk adverse?). I would guess that any direct route has to be high volume (meaning a third party) to get fresh factory matched cells from the same lot. This cuts out just about all end users. The folks in Europe I know that use these cells go through a third party to get their raw cells (probably for the same reason) and had to carefully insist on matched cells from the same log/date code (their BMS solution only monitors TEMP and VOLTAGE of groups of cells, not per cell).

I think a problem with long term use of the tool packs for large groups of cells is the difficulty with getting "matched" cells. Over time, the mismatch (age or different IR due to batch differences) can become significant and becomes more likely in larger packs. This puts the burden squarely back on the Battery Monitoring System (BMS). The need for matched cells may be less important with some cells (like A123 M1 cells) which seem to not care about age and are somewhat abuse tolerant and seem to have higher quality control when they were built. Just my opinion.