Bosch 36V fatpacks opened up

[RealPeterPan]

How are you guys charging the Bosch 36v packs? I have two of them in parallel on my ebike now and they work AWESOME! But my intelligent SLA charger overcharges them to 43.3 volts.

Yeah, I just wondered about the same thing as most of us were pretty happy about the charging possibillity of LiFePo4s with regular SLA chargers.

EDIT:
Another thing is that there are quite a few different sources on ebay which are all having either different Ah's or even no describtion at all.

If I search for "Bosch Fatpack" i just find one supplier in the US who dont display the Ah's at all.
If I search for "Bosch 36" I find quite a few more but they have different labels then and are rated all different.

The worst thing is that we dont have professional suppliers here in europe at all so the shipping will be expensive enough for the packs.
I just dont wanna buy some old or reproduced crap for 500$.

Has anyone a serious source or can suggest one of the following:

http://cgi.ebay.de/2-Bosch-36V-Litheon-Batteries-FatPack-Battery-BAT836_W0QQitemZ310126200822QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item310126200822&_trksid=p4634.c0.m14.l1262

Tis one is from ebay germany: http://cgi.ebay.de/BOSCH-GBH-36-V-Li-Akku-2-6AH_W0QQitemZ220371278842QQcmdZViewItemQQptZElektrowerkzeug_Zubeh%C3%B6r?hash=item220371278842&_trksid=p3286.c0.m14&_trkparms=72%3A1232%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318
the describtion is quite logical and says 2,6ah but the label is not the same as the fatpacks.

where do you guys got your packs?

Kind regards

Sven Brinkhoff
--

[theyerb]

Sven, I got mine on ebay for $46 per battery from a seller in Florida. I'm sure either of those auctions would be legit. Here's a pic of me making the 2 Bosch packs into a parallel pack:

[webfootguy]

If I search for "Bosch Fatpack" i just find one supplier in the US who dont display the Ah's at all.
If I search for "Bosch 36" I find quite a few more but they have different labels then and are rated all different.

--

Steve, if you want to be sure you are getting the right model, search using the Bosch part number which is "BAT836".
I recommend using "bosch BAT836" as your ebay search string.
If they are advertising it as that, it is either the right part for a fraud listing.

Good luck!
--phil

[RealPeterPan]

Sven, I got mine on ebay for $46 per battery from a seller in Florida. I'm sure either of those auctions would be legit. Here's a pic of me making the 2 Bosch packs into a parallel pack:

I just found him and he already replied to my question if he would ship to europe.
Fair Play, very fast response.
Unfortunately not what i wanted to hear: he doesnt ship outside US.
Thats the biggest problem right now for the old world
Somehow we dont get the high power tool stuff here.
I have no clue why but its a pitty.
And some sellers know that they are the only source for us and ship but for incredible high shipping costs.
I´ve seen quotes like 50$ for each pack. No combined shiping. each aditional item 50 bucks extra.

Well well...

But thanks for the tip with the "BAT836".
I´ll keep looking.

Best regards
Sven Brinkhoff
--

[leamcorp]

I used to do this with my friend - He would buy something and send it to my address, then I will resend it as a "gift". This way he doesn't have to pay VAT once it get into EU.

If you have a friend or someone you could trust here that might be the best option.

[John in CR]

What we need is someone here on the forum with factory direct purchasing ability, with both European and N. American warehousing. I'm working on exactly that right now. I believe in big packs, and at the right price that becomes a reality for everyone with the side benefit being, based on educated speculation, that packs of these cells will have far greater cycle lives, than in their design use as power tool packs, because in large capacity formats the current draw is at a much lower C rate. Unfortunately, these types of negotiations seem to take forever, especially when you're dealing through a regional rep of a multinational company. Hopefully no short-sighted corporate bureaucrat gets in the way, because what I'm putting on the table is a no-lose scenario for Bosch, unless the packs are a loss item just to sell their tools, which I would find impossible to believe. I've even laid out an ad campaign that will help them establish markets such as here in Costa Rica, where lithium tool packs have yet to penetrate.

Sub $.25/wh high power packs are just on the horizon, I can smell them even if this Bosch thing falls through.

John

[dnmun]

43.3V is not overcharging a 12S pack(3.6V/cell). or is it 10S?

[RealPeterPan]

43.3V is not overcharging a 12S pack(3.6V/cell). or is it 10S?

The Fatpacks come in 10s2p.

I'm still trying to figure out what kind of charging is possible with the packs.

Regards
Sven
--

[lcyclist]

How are you guys charging the Bosch 36v packs? I have two of them in parallel on my ebike now and they work AWESOME! But my intelligent SLA charger overcharges them to 43.3 volts.

Hi,

I use a li-ion charger similar to this http://cgi.ebay.com/Universal-Smart-2-0 ... m153.l1262
Search in ebay for universal li-ion charger.

It charges my 3 parallel pack to 42V.

I used to use the bosch litheon fast charger. It charges it to 40.8V but it is too bulky.

[lcyclist]

How are the batteries running? What kind of distance and speed are you getting, and what voltage? thx- I'm planning on doing pretty much the exact same thing as you, and a bit of info could help in the planning

Hi,

I use 3 parallel packs (6AH) to run on my 1000W BMC motor with a BMC 36V 30A controller. My top speed with this configuration is 30 mph. On a 600W geared motor, my top speed is 28 mph.

My range is 20 to 24 miles (20 mph average speed) pedaling with the motor, in which I discharge my pack about to about half (3.6AH).

[Doctorbass]

How are the batteries running? What kind of distance and speed are you getting, and what voltage? thx- I'm planning on doing pretty much the exact same thing as you, and a bit of info could help in the planning

Every of the 1.3Ah cells inside give around 3.75Wh max of energy. at 35km/h you usually need 15Wh/km no pedal...

so with 4 of these cells tou go 1KM

one fatkpack have 20 cells so thst's 5km no pedal at 35km/h

Doc

[Doctorbass]

These cells are the 18650VT and have 1.3Ah 3.7V nominal and 4.1-4.2V max charge

Charging them to 4.3 will decrease their life by a factor of 3 according to the Sony spec sheet so pay attention guys..

the recommanded voltahe for charge is 4.1V and not 4.2V.. charging to 4.2V will just a bit reduce the charge time and increase the capacity for around 5%...

compared to what is positive inn that 4.2V cahrge method i think that does not worth.

4.1V is safe. and will preserve their life cycle.

it exist two model of these sony Konoin cells: the V and the VT

The V have more capacity (1.5-1.6 Ah) but have a bit less max current... 15A max per cell
The VT have more capacity (1.3Ah) but have a bit more max current... 22A max per cell.

The max charge current on the V is around 3A recommanded and max 5 (I acheived that but it reduce a bit the cycel life)

On the VT it is 20% more.


the V have around 5Wh per cell and the VT have more 3.75Wh

The recommanded cut voltage is really 3.0V.. dont go lower. (30V min for the fatpack)

So that fatpack have 44A max at around 34V( take account of the V drop) full charge

that is 1500W max during short time.. but i would recommand using them at 5A continus max per cell so 10A per fatpack... and you should get around 10A x 38V = 380W per pack continuous power

Doc

Doc

[theyerb]

Thanks for the great info, Doc I'm gonna try to keep my cells in that voltage sweet spot, 3-4.1v, from now on.

[RealPeterPan]

Thanks Doc.
That was a good summary about the konions.
I read all the other posts about them but to have it all in one always helps the one of us who don't natively think in electric to understand

But what I still didn't get:

Can you charge these green babies with a regular SLA smart charger like this one:?

http://www.conrad-int.com/websale7/?mallid=websale&shopid=conrad-int&subshopid=int&act=product&cat_index=SHOP%5fAREA%5f14724%5f0502152&prod_index=510141

There are more detailed specks in the "multilingual instruction" link but here is a short version:

End charge voltage: 41.4V
Charge current: 6.4A +- 7%
Characteristic: I/U/U
And a picture of course:


I know the current is a bit high but should be alright if I charge more than one fatpack at the same time right?!

What I'm also wondering about is the actual price for the fatpacks.
Is it even reasonable for the sellers anymore?
Compared to dewalt they are less than half the price now.
They are actually coming in the price range of SLAs already.
Even without considering the lifetime.
How is that possible so suddenly?

Regards Sven

[theyerb]

Sven-

Maybe not quite *approaching SLA- I can get 220wh of SLA for $30 whereas 220wh of these Fatpacks would cost me $130- but they are getting pretty cheap compared to other packs.

Bosch might be taking a loss on the batteries to entice customers to buy their tools. The old "give 'em the razor for free and then charge 'em like crazy for the blades"- except the other way around.

My SLA charger overcharges my packs to over 43v, but maybe the above one is different.

[theyerb]

Hey Doc,

As I stated earlier in the thread, I accidentally let these Bosch packs charge up to 43.5v on two occasions using my old SLA charger. What sort of affect do you think this would have on the batteries?

Also, does anyone know where I can find a 41v lithium ion charger?! I've been looking around for a while, and still haven't found one that will suffice. Maybe I'm not looking hard enough...

[gmouchawar]

Here is a suggestion for those who are using SLA chargers that go up to 43V. By adding diodes in series with the charger you can reduce the voltage.
Every diode will reduce it by 0.6V. So by adding 2-4 of them you get close to the ideal voltage. You still have the burden of turning the charge off when charging is done buy at least it will go to the correct voltage.

[pwbset]

Also, does anyone know where I can find a 41v lithium ion charger?!

I've used this one from batteryspace.com for 10s LiMn and it works fine. It does take the string to about 41.8v so that's still a little high for "VT" cells, but not as bad as 4.35v/cell.

As mentioned maybe this and a diode and you're right around 41v and not having to worry about it.

http://www.batteryspace.com/index.asp?P ... rodID=4211

[Russell]

Inspired by this thread I ordered a set of 3 Bosch Fatpacks from eBay.

The price: $135 delivered less $16 (12%) Microsoft Live Cashback = $119

They arrived today and here they are:

Three little fatpacks

Bosch 002.jpg (91.06 KiB) Viewed 2104 times

They measure 6.17"L x 3.74"W x 2.92"H (157mmx95mmx74mm) and weigh in at 2 lbs 11 oz (1.215 Kg) each.

They all measured 35.9V on my cheap multimeter. That seems rather low but at least they are all the same.

Much of this info is already in the thread but I'll attempt to add some things and post different pictures.

Bosch 005.jpg

Starting disassembly

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Bosch 007.jpg (82.95 KiB) Viewed 2109 times

I'll be assembling my pack much the same way that John did however I'm going to try to do it with less work

Instead of grinding which is quite messy I cut things out whenever possible.

Lots of vertical cuts then snip the pieces out

Bosch 013.jpg (71.86 KiB) Viewed 2101 times

Cut the top pieces off with a hacksaw blade

Bosch 015.jpg (89.93 KiB) Viewed 2094 times

Applied some RTV and strapped them together

Bosch 017.jpg (77 KiB) Viewed 2097 times

The size has shrunk a good bit and the weight is down from just over 8 lbs (3.65Kg) to a little over 6 1/2 lbs (3Kg).

Wires dressed with clamps

Bosch 018.jpg (90.3 KiB) Viewed 2088 times

Parallel harness made up using every last one of my Anderson connectors

Bosch 020.jpg (86.67 KiB) Viewed 2112 times

Size comparison with my 36V/9Ah SLA pack in bag

Bosch 022.jpg (77.97 KiB) Viewed 2074 times

That's as far as I got today. I have a Lithium charger on its way but in the meantime I used my SLA charger to bring the pack up to 41.5V. Judging by the 4.815Ah the WU meter said the pack took they were pretty well discharged.


-R

[Doctorbass]

Nice Job Russell !

This is a nice cheap Diy Lithium manganese Battery exemple! you have 3.7V at 1.1Ah (1.3Ah theorical) per cell so you get 6.6Ah to 7.8Ah at 37V for 135$ without bothering with Balancer BMS !! =)

Oh.. this is normal that the battery are not fully charged even though they are brand new! The storage Ah is normally recommanded to be around 40 to 60% to preserve the cells..

They stress if they are kept too long period at 100% charge.. like many lithium cells.

Doc

[Russell]

Nice Job Russell !

This is a nice cheap Diy Lithium manganese Battery exemple! you have 3.7V at 1.1Ah (1.3Ah theorical) per cell so you get 6.6Ah to 7.8Ah at 37V for 135$ without bothering with Balancer BMS !! =)


Doc

Thanks Doctorbass though I got to thinking it probably would have been even easier if I had simply taken off the tops, brought out the wires and strapped the three toolpacks together Oh well.

One question for you; is the 7.8Ah available when the 3 packs are charged to 4.2V/cell for 42.0V total?

The LVC on my Bafang 15A controller is set to 31.5V so how much capacity do you think I'll have if I charge the pack to 41.5V and discharge to 31.5V?

The weather is awful here so I can't ride to check it out.

-R

[Russell]

Completed the pack...for now anyway.

I removed the Andersons from the negative side and hard-wired those connections which made for better harness routing. I can still isolate individual packs if need be with the red disconnects. I then cut some sound padding I had leftover from a entertainment center PC and applied it to the sides.

Finished size: 6.5"L x 5.7"W x 3.5"H (about 4"H to clear wires)

Bosch 026.jpg (90.08 KiB) Viewed 1967 times

Finally I (temporarily) put the whole thing in an 8"x6"x4" cardboard box which drops right in the rear trunk bag in place of the SLA pack. The finished weight is 7 lbs compared to almost 18 lbs for the SLA's

Bosch 034.jpg

(73.34 KiB) Downloaded 1544 times

I noticed that the no load speed with the Bosch pack at 41.5V is 0.9 mph higher than the SLA pack right off the charger which should raise my top unassisted speed to 17.0 mph Hey I'll take every little bit I can get.

Now I just need the weather to improve to get out and test it.

-R

[John in CR]

Nice Job! Welcome to the Konion Team.

John

[theyerb]

Yah, some great info, Russel. I have been using just two fatpacks on my ebike with excellent results. I just bought a third battery for extra distance and current capacity. Team Konion all the way

[ad3pt3]

I have been planing to make an ebike for two weeks now and have been trying to learn as much as possible from all the forums. I came across these Bosch packs and they seem to be a great price and provide good performance. I like the fact that they have a high c rating vs other packs and are very cheep.

I was wondering if it were possible to link six of these Bosch packs together to get a 37V 14aH pack? I would use the Anderson connectors and keep it similar to what Russell did. If so, what would be the best charger for this pack? I would like to charge them all at once.

Thanks for your help,



Ad3pt3