Bosch 36V fatpacks opened up

[TPA]

must cut open the red plastic. No easy chore.

There used to be pics of that exact procedure on page 1 of this thread, but they must have expired.

Maybe John in CR still has them on his computer, might be worth PMing him.

 

[TPA]

If you did the following as an example:

Parallel 3 (or any number you choose) intact packs, then cut open one pack and make a 3s6p pack out of those cells, then series the small pack with the larger one, you would achieve the same goal without all that extra work.

However, you would need a second charger for the small pack.

 

[jkirkeboe]

If you did the following as an example:

Parallel 3 (or any number you choose) intact packs, then cut open one pack and make a 3s6p pack out of those cells, then series the small pack with the larger one, you would achieve the same goal without all that extra work.

However, you would need a second charger for the small pack.

The problem is that I can't fit a big enough battery in the triangle-shaped frame bag without custom-building the pack. I have to stack the cells single (so 65mm deep) in a triangular shape. Probably start at 3 cells in the bottom, then 4,5,6 and so forth, until reaching 117 cells (13s9p) in the 13th row. Battery should then be 234mm tall, 270mm wide at the top and 65mm deep before protection sheets and duct tape. 40 grams per cell is 4.7kg for the 48.1V ~10Ah pack.

 

[icecube57]

You have to cut the packs open. Also to get the taps off you need a sharp razor blade and pliers. Be carful the spot welds are damn good. While ripping a stubborn weld I ruptured the bottom of the cell. There is a pencil lead sized hole in the bottom of it. I was trying to make a 6p 4s booster pack. I didnt do my math right and came up 4 cells short lol.

 

[pwbset]

The problem is that I can't fit a big enough battery in the triangle-shaped frame bag without custom-building the pack.

I was having similar issues, but said screw aesthetics and built "strap packs". They work awesome really except that my tab welds were awful (under powered welder) and kept vibrating off in my main pack (I ride off road a lot). I've since sold my raw konions and am going to get 6 fatpacks in 2s3p and build a strap pack with those. It'll be bomber. Frame bags are nice, but as you said you can't get more than around 112 cells in a traditional frame. I can promise you though that you're creating headaches for yourself and should really figure out a way to keep the packs in tact. Makes life SOOOOOO much easier (as John in CR has tried to teach me over and over with little success... sorry John... I'm a believer now I swear! :wink: ).

Here are this season's failures and successes with the whole battery building thing:

http://endless-sphere.com/forums/viewtopic.php?f=6&t=9691#p157096

 

[stiffi]

I second, (or third?) keeping the packs together.

I know nothing, absolutely nothing about battery chemistry and electrical work, and yet I was able to build myself a decent battery out of 4 packs. Thanks to the good folks here, who literally had to teach me what a spade connector was, I was able to create a wiring harness without much difficulty. Plus the connectors into the exterior + and - contacts, add some duct tape and you're done.

I do kind of regret not having more room, as those plastic cases are kind of unwieldy, but, I'm quite sure I'd have blown myself up if I tried to open them up.

Of course, as predicted, I'm missing my 48 volts, running at 36 now. I'm trying to decide if I want to buy 2 more packs, a controller and and create 2 72 volt packs in series :wink:

That is more money, but the setup is pretty easy.

 

[pwbset]

Of course, as predicted, I'm missing my 48 volts, running at 36 now. I'm trying to decide if I want to buy 2 more packs, a controller and and create 2 72 volt packs in series

I tell ya... the single best decision I've made so far was getting a 24v-72v controller (with 19v LVC & 100v volt fets/caps etc. etc.). I have, literally, run my ebike on everything from 22v on up to 88v and half a dozen in between it seems and all on the same controller.

My next batt pack with be a bunch of fatpacks in 2s at 82v "hot". It's all about the watts in my opinion.. I know that I commute using 1.8-2kw sustained no matter what.. would much, much rather get there @ high volts and 25-30A as opposed to like 32-35v under sag and 60A+.

Go series my man! The EV grin will become permanent I promise!

 

[aaronski]

the single best decision I've made so far was getting a 24v-72v controller (with 19v LVC & 100v volt fets/caps etc. etc.). I have, literally, run my ebike on everything from 22v on up to 88v and half a dozen in between it seems and all on the same controller.

What controller are you using? This sounds like *exactly* what I need.

 

[64ragtop]

the single best decision I've made so far was getting a 24v-72v controller (with 19v LVC & 100v volt fets/caps etc. etc.). I have, literally, run my ebike on everything from 22v on up to 88v and half a dozen in between it seems and all on the same controller.

What controller are you using? This sounds like *exactly* what I need.

Yeah, me three!!!

The only "challenge" I see with that is the lack of a low voltage cut-off - but isn't that what volt meters are for

ATB

BC

 

[jkirkeboe]

Well, I just ordered everything. Thanks for all the help here!

6 Bosch fatpacks from eBay (Toolsteal)
Tenergy 13S Li-ion charger from All-battery
Ezee rear kit with pedal sensor, 9-speed frewheel, left side half-throttle and Cycle Analyst from ebikes.ca

It's my understandig that the Cycle Analyst will do both LVC and current limiting.

I'm looking forward to putting all this together 8)

 

[pwbset]

What controller are you using? This sounds like *exactly* what I need.

I got the 24-72v 20A pedal first from ebikes.ca.. part number C7220PF on this page:

http://ebikes.ca/store/store_controllers.php

It's pretty pricey really, but it's got the 4110 fets and 100v caps and a 19v LVC and I soldered the shunt and routinely have put 60A sustained through it with 100A bursts and never seen a problem. 2kw sustained @ 30-35A for 15min every morning doesn't even get the thing warm. A great controller. I like pedal first 'cause then I don't have to worry about hall sensors, which blow, and I also consider it a safety feature when friends (and kids!) check out the bike and twist the throttle saying, "what does this do?" :lol: No need to worry about kill-switches or anything like that. Nice and simple. It activates around 5mph, which, unless you have physical issues, is so easy to get to even on steep slopes. Stand on a pedal half a revolution and vroom off you go.

Can't recommend this controller enough. Love it!! If you don't mind not having a warranty Justin can customize for higher sustained current settings like 30A or even 50A.

 

[docnjoj]

My first serious test of 4 // fatpacks went fine 2.9 Ah used in about 8 miles. Around 120 Wh hours. Sounds good, right. Well when I connected the charger (Bosch) with Alligator clips to the // pack, it turns green but no charging seems to be taking place (0.01 amp) When I try to connect the middle "sensor" wire it flashes red. These have been left overnight and are room temp. What is going on? Do I actually have to take the whole assembly apart and charge each fatpack separately? Please help!!!!!??????
otherDoc

 

[Russell]

My first serious test of 4 // fatpacks went fine 2.9 Ah used in about 8 miles. Around 120 Wh hours. Sounds good, right. Well when I connected the charger (Bosch) with Alligator clips to the // pack, it turns green but no charging seems to be taking place (0.01 amp) When I try to connect the middle "sensor" wire it flashes red. These have been left overnight and are room temp. What is going on? Do I actually have to take the whole assembly apart and charge each fatpack separately? Please help!!!!!??????
otherDoc

I use a cheap-o $24 charger on my 3-pack (tops removed) and never have a problem charging them even from a full discharge. Could it be the 4 packs are pegging some kind of current limit on the Bosch charger and putting it into a protection mode, it was after all designed to charge one at a time? Do you have another 36V charger of any kind to try?

-R

 

[docnjoj]

Thanks Russell. I do have a couple of 36 volt SLA chargers to try. I also wonder if I didn't draw down the packs low enuff (38.7 volts) to allow the charger to kick in? Is there a point at which it refuses to charge cause the voltage is too high? Seems wierd>
otherDoc

 

[stiffi]

Thanks Russell. I do have a couple of 36 volt SLA chargers to try. I also wonder if I didn't draw down the packs low enuff (38.7 volts) to allow the charger to kick in? Is there a point at which it refuses to charge cause the voltage is too high? Seems wierd>
otherDoc

Good chance, they are not drawn down long enough for the charger to "kick in". This happened to me my first ride. I didn't use a voltmeter, but my first ride, after creating my pack, I took the bike 3 houses down the street away, just to make sure I had connected everything right. When I put the charger on...nothing. I posted about this in my earlier posts in this thread.

When I went out for my first 12 plus mile rided, and came back, the charger kicked right in and charged for several hours. I am not using the bosch charger though. I have a separate lithium charger from ecitypower that I connected directly to the positive and negatve on the last pack.

 

[docnjoj]

Thanks stiffi. I am putting about 1hours worth of charge from my 36 Volt SLA charger and then will shut it down. I want to have near a full charge but NOT go to 42 volts like the SLA runs. Good old electric timer should keep me aware (I hope!) We will take a longer ride today (maybe 12 miles) and see if Dr Bosch will charge afterward! Thanks again! I may stick some diodes inline to cut down the SLA fierceness. It has no pots to adjust.
otherDoc

 

[Russell]

Thanks Russell. I do have a couple of 36 volt SLA chargers to try. I also wonder if I didn't draw down the packs low enuff (38.7 volts) to allow the charger to kick in? Is there a point at which it refuses to charge cause the voltage is too high? Seems wierd>
otherDoc

Possible but since you drew 2.9Ah out of a theorectical 8.8Ah pack I would doubt it especially if you used the Bosch charger in the first place. That said, yes a charger will not "kick in" if the current draw is below a certain threshold voltage/current. I believe the Bosch charger charges to 40.5V so the pack needs to be perhaps around 40.0V for the charger to start working, but as I said 2.9Ah drain should easily take the voltage down below the threshold.

I would suggest connecting up a voltmeter to check the voltage and if it's below 40.0V then hook up the 36V SLA charger and monitor the pack voltage closely. The SLA charger if left unattended will run the voltage of the battery up to over 44V so just charge the pack with it long enough to bring it close to 40.0V then try the Bosch charger again.

-R

 

[Russell]

Thanks stiffi. I am putting about 1hours worth of charge from my 36 Volt SLA charger and then will shut it down. I want to have near a full charge but NOT go to 42 volts like the SLA runs. Good old electric timer should keep me aware (I hope!) We will take a longer ride today (maybe 12 miles) and see if Dr Bosch will charge afterward! Thanks again! I may stick some diodes inline to cut down the SLA fierceness. It has no pots to adjust.
otherDoc

Yeah like that (posting time delay)

-R

 

[docnjoj]

Time warp! Well waddya know. I actually looked at the 2 sla chargers with my eyes open this time and saw the pots. I was able to adjust down to 40.6 which seems about right. I am now checking voltage every 10 minutes on the Whattmeter and will stop at 40 for this run. Tales from the dark side will continue later after we ride! Thanks again Russell and Stiffi!
otherDoc

 

[John in CR]

Doc,

You should be able to use the Bosch charger to charge all at once with no problem. Are the boards still on the packs? I tried alligator clipping to the charger which didn't work either. Probably something to do with that center prong being metal on one side and plastic on the other. Mine crank up just for top off charges, so it's not that the voltage was too high to charge.

John

 

[docnjoj]

Thanks John in CR. I am not sure either regarding that middle pin. It should just refuse to charge if the packs are too hot as it seems to connect to that thermister/thermocouple. All my packs are in pristine state, but I am approaching your point of view! For 50 bucks apiece, I could afford to shred them into cell sets in the red plastic stuff! I'll give it a 5-6 amp ride and see if Master Bosch turns on for a charge afterwards. Thanks again for the help!
otherDoc

 

[docnjoj]

It just dawned on me that the center post of the Bosch charger is shielded on the negative side. Could that just be short protection, since it is not shielded on the side nearest the + terminal????? And does this help us?????????
otherDoc

 

[John in CR]

It just dawned on me that the center post of the Bosch charger is shielded on the negative side. Could that just be short protection, since it is not shielded on the side nearest the + terminal????? And does this help us?????????
otherDoc

It's dark, so I couldn't see very well, but looking at the exposed boards from packs slid onto my chargers, it looks to me like the clip for the center is made up of 2 electrically separated pieces of metal unlike the + and - slots where the 2 sides of the slot are 1 piece of metal to grab both sides of the post. Bosch is apparently trying to stop you from doing what you're attempting. The only reason I can think of is that since the posts are males on the charger, a metal tool couldn't accidentally create a short for a charger plugged into the wall. If you can clip only to the side that's supposed to mate with the metal side of the center post, maybe that would get it running.

I don't know how your packs are organized. Can't you slide one pack onto the charger, while maintaining only a +/- connection to all of the other packs, so you can charge all at once?

John

 

[Rifle]

Just went over this a few pages ago myself, but to repeat: the middle connector of the charger can only touch the side of the middle connection on the battery that is closest to the positive terminal. The red flashing light is what you get when the charger's middle connection is connected to both sides of the battery's middle connection.

 

[docnjoj]

Easy enuff to just glue a piece of plastic on the middle clip negative side and see what happens? I am using my SLA set to 40.5 to charge all 4 in // now. Later!
otherDoc