Bosch 36V fatpacks opened up

[stiffi]

How about this guy?

The max output is 41.6 volts, http://www.all-battery.com/TenergyBatteryCharger01222.aspx

 

[pwbset]

The max output is 41.6 volts, http://www.all-battery.com/TenergyBatteryCharger01222.aspx

Sure, that works. Really depends on how much you care about cycle life. 41.6v is still .6v/cell over the Sony recommended max charge of 4.1v/cell for the VTs. If Bosch is only charging to 40.5v they can probably claim 1,000+ cycles pretty easy. I'm charging my VTs to 4.2v/cell because that's the ecitypower charger I have and will be happy if I get 2-300 cycles out of them. That's still 2-3 seasons of riding for me.. last year I did ~115 cycles. Some people really care about having 2,000+ charge cycles... why I'll never know, but they do. I don't think it's justified unless you've invested in an $$$$ eCar that's gotta last forever. By the time you actually use your 2,000 cycles on a little ebike I'll be riding around on antimatter. :wink: Even 2x/day full DOD that's still like 2.75 years riding every single day... I doubt many people do that.

So yeah, really just depends.

 

[TPA]

yes, the ecitypower chargers would be good for your 4 packs. they are discussed here:

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=9054

doc posted a pricelist on pg 1

and the website is here:

http://www.ecitypower.com/index.php?page=70

The EP-A would get you about 1C on 4 packs

 

[Russell]

So, nobody can recommend a good (yet smaller) charger for these packs? I'm having a hard time finding any 36 volt Li-Iion chargers, really

I'm thinking more and more about just sticking with the Bosch charger.

I would appreciate it, if anyone could point me to a particular replacement, however

thanks

So much of what you've been asking has been covered extensively earlier in the thread :?

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=7569&start=105#p151224

-R

 

[stiffi]

So much of what you've been asking has been covered extensively earlier in the thread :?

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=7569&start=105#p151224

-R

I actually have read the entire thread, several times. I just don't always know what I'm looking at. I'm not the most technically inclined.
So, if you would indulge me again...

Are people using a BMS in their packs, if they are using the Bosch charger? I was all set to purchase an ecity charger, and then the rep said I should get a BMS. then I panicked. I know 1 pack with the Bosch charger doesn't require a BMS, but do I need one with multiple packs chained together?

 

[TPA]

If you look at the diagram below, you can see that the charger would be placed at the output of the parallel connection.
Now follow all the wires, you can see that even the last battery has a direct unbroken connection to the charger, just as all the others do. This means that it has the same effect as charging only one battery as far as voltage is concerned.
In the case of this picture, every battery would have about the same voltage across its terminals, but they would divide and share the current coming from the charger. The more batteries you parallel, the longer it will take to charge using the same charger.
So, when a block of series batteries are connected in parallel with another equivalent block of series batteries (second picture), then it is the same thing as charging only one block, only it will have less current.
Then, if one series group does not need a BMS then all paralleled series groups will not need a BMS.
The cells in the Bosch pack are unique in that they do not generally need a BMS even though they are lithium batteries. If the nice folks at ecitypower are not aware of this, it would make sense that they would recommend a BMS since all other lithium batteries need one, generally speaking.

 

[stiffi]

The max output is 41.6 volts, http://www.all-battery.com/TenergyBatteryCharger01222.aspx

Sure, that works. Really depends on how much you care about cycle life. 41.6v is still .6v/cell over the Sony recommended max charge of 4.1v/cell for the VTs. If Bosch is only charging to 40.5v they can probably claim 1,000+ cycles pretty easy. I'm charging my VTs to 4.2v/cell because that's the ecitypower charger I have and will be happy if I get 2-300 cycles out of them. That's still 2-3 seasons of riding for me.. last year I did ~115 cycles. Some people really care about having 2,000+ charge cycles... why I'll never know, but they do. I don't think it's justified unless you've invested in an $$$$ eCar that's gotta last forever. By the time you actually use your 2,000 cycles on a little ebike I'll be riding around on antimatter. :wink: Even 2x/day full DOD that's still like 2.75 years riding every single day... I doubt many people do that.

So yeah, really just depends.

You mentioned you have the ecitypower charger. Do you watch the charging process closely, and pull the packs off as soon as they are charged? Or can you let it sit a while? I was told by the ecity power folks that their chargers are not smart, they will run constant current/constant voltage.

thanks.

 

[pwbset]

they will run constant current/constant voltage.

Yeah.. they are CC/CV charge profiles.. like my main ecitypower charger is 58.4v which for my 14s LiMn/Konion battery is 4.17v/cell, which is fine for V cells and OK for VT cells (like the Bosch) as long as you recognize that'll shorten lifespan somewhat. My 18s charger outputs 75.6v, which is exactly 4.2v/cell... also fine for me for V cells. I don't leave them plugged in over night, but I'm also not too worried about going to a party or BBQ and forgetting about them for a few hours at max charge either.

 

[stiffi]

Is there any fear of explosion leaving them plugged in after they are charged?

 

[John in CR]

Is there any fear of explosion leaving them plugged in after they are charged?

No such thing as infallible when it comes to batteries. You'll quickly become accustomed to how long charging takes, so at least plug the charger into a timer. The piece of mind is worth the $10-15.

John

 

[Russell]

You mentioned you have the ecitypower charger. Do you watch the charging process closely, and pull the packs off as soon as they are charged? Or can you let it sit a while? I was told by the ecity power folks that their chargers are not smart, they will run constant current/constant voltage.

thanks.

These Fatpacks are about as foolproof as it gets for lithium. I use the cheapest little charger ECity offers with good results. I don't know what they mean by "smart" but there's nothing to worry about if you leave a lithium charger attached as long as it has the proper setpoint (I adjusted mine to 41.3V from the standard 42.0V). Once the LED on my charger goes green the current is less than 16ma and the pack is 99% full and the charger can be disconnected. If left connected the current will reach essentially zero in a couple of hours as the last tiny bit of juice is stored in the battery. Since there is no BMS there is nothing going on at this point and no reason to leave the charger connected but there's also no real danger in leaving it on.

-R

 

[icecube57]

Im using a Tenergy LiPo 36v charger. It charges to 42 and switches to CV until it drops down to certain level and then it terminates charge and floats. It charges at 3A realistically 2.7-2.8A. I have it charging 6 packs in parallel. I have 2 packs with three packs in parallel. I solder the packs together using bus bars and left one positive and one negative lead on each pack. I cut the rest off. I made a special connector that i use to connect the packs in parallel. I let it self balance between the two packs for like 30 min and use the third connector to plug in my charger. My packs are never out of balance. They are always within .02v of each other.

 

[64ragtop]

I actually have read the entire thread, several times. I just don't always know what I'm looking at. I'm not the most technically inclined.
So, if you would indulge me again...

Are people using a BMS in their packs, if they are using the Bosch charger? I was all set to purchase an ecity charger, and then the rep said I should get a BMS. then I panicked. I know 1 pack with the Bosch charger doesn't require a BMS, but do I need one with multiple packs chained together?

I don't THINK so, but I might be wrong. Sometimes I need these things 'splained in more detail than some folks might - and I spent many years
working in electronics. I GET that some folks are using the Bosch charger without a BMS and I think they manage just fine, but some users are cutting up the Bosch chargers and series and paralleling the guts and that goes beyond my interest. Modified chargers won't get warranty service! - which makes no diff to some folks. When I want to charge series paralleled packs made up of stock FatPacks, I'll get a "smart" charger that will charge at the voltage needed for proper pack maintenance and, as someone stated earlier, I'll tweak the pack for proper voltages and currents AND almost certainly use a cheap timer for positive charger shut off, just to be SURE!!!

I just hate it when these things spark, go up in flames, or the magic blue smoke gets out! Mainly 'cause I'm a cheapskate - and that's 'cause I'm on a tighter budget than some folks....

For now, I'm not hardwiring my packs together and I'll just charge the packs individually with the two chargers I have. Not the most efficient space useage, but I have more space than money. That's MY reasoning! Others will want to do it differently and I might change my mind later. I can DO that!!!

ATB

BC

 

[D-Man]

No one has yet documented and measured the exact ah gain of using a higher voltage charger. There might not be anything measureable. You think the engineers that made the Bosch charger to go with Bosch packs are fools and don't know jack about batteries? Or I guess people in here think endless-sphere is smarter then Bosch engineers and would rather buy offbrand. I'd use the Bosch charger! Good luck.

 

[pwbset]

I'd use the Bosch charger! Good luck.

Any old CCCV charger will work provided you respect the cells specs. Sony states 4.1v/cell for VT cells... this is a fact. Bosch chargers take them to 4.05v/cell presumably to lengthen cycle life a tiny bit. That's fine, but there isn't any reason you can't take them to 4.2v/cell and get an extra .2-.3ah at the cost of cycle life... it's not like they will explode or anything... I've had (accidentally ) VT cells to 4.35v+ without issue. They are tolerant cells to say the least. Just saying.. every penny saved counts these days so why not save $100 on a charger if it'll get the job done?

 

[D-Man]

$100 savings on the charger?

I'd use the Bosch charger! Good luck.

Any old CCCV charger will work provided you respect the cells specs. Sony states 4.1v/cell for VT cells... this is a fact. Bosch chargers take them to 4.05v/cell presumably to lengthen cycle life a tiny bit. That's fine, but there isn't any reason you can't take them to 4.2v/cell and get an extra .2-.3ah at the cost of cycle life... it's not like they will explode or anything... I've had (accidentally ) VT cells to 4.35v+ without issue. They are tolerant cells to say the least. Just saying.. every penny saved counts these days so why not save $100 on a charger if it'll get the job done?

Ok Einstein.

 

[pwbset]

Ok Einstein.

Way to contribute asshat. I'm sure everyone appreciates it.

 

[liveforphysics]

I'd use the Bosch charger! Good luck.

Any old CCCV charger will work provided you respect the cells specs. Sony states 4.1v/cell for VT cells... this is a fact. Bosch chargers take them to 4.05v/cell presumably to lengthen cycle life a tiny bit. That's fine, but there isn't any reason you can't take them to 4.2v/cell and get an extra .2-.3ah at the cost of cycle life... it's not like they will explode or anything... I've had (accidentally ) VT cells to 4.35v+ without issue. They are tolerant cells to say the least. Just saying.. every penny saved counts these days so why not save $100 on a charger if it'll get the job done?

The life cycle graphs for many LiCo cells shows more than a 10x improvement in the number of cycles when the cells are charged to 4.1v vs 4.2v. This is LiMnCo not LiCo, but it seems to be even more sensative to life cycle deterioration. That 0.1v may be the difference between getting 250cycles or getting 1500 cycles.

No one has yet documented and measured the exact ah gain of using a higher voltage charger. There might not be anything measureable. You think the engineers that made the Bosch charger to go with Bosch packs are fools and don't know jack about batteries? Or I guess people in here think endless-sphere is smarter then Bosch engineers and would rather buy offbrand. I'd use the Bosch charger! Good luck.

So far, no tool pack company, even dewalt, has managed to make a BMS/Charger combo that was worth a damn, or showed any design interest beyond making it work for the absolute minimum cost in parts possible. This is how you end up with 10s of thousands of Dewalt A123 packs that all have the first cell dead, because the charger/BMS setup doesn't work worth a damn. The bosch packs are no exception, the charge circuit and BMS are extremely well designed around the goal of saving every penny possible. The cells don't know what brand of device is pumping electrons into them, they just want to never go above 4.1v or below 2.7v, if you have a better method of making that happen than the bosch charger, no reason not to use it.

 

[stiffi]

Hey pwbset, what kind of connector is on your ecitypower charger?

I just ordered one, but it was unclear what kind of connection is uses.

thanks

 

[pwbset]

Hey pwbset, what kind of connector is on your ecitypower charger?

I don't know if they are all the same, but mine came with a 3-prong "AC" style plug. I used a multimeter to find + and -, ignored the "ground" and added anderson connectors so it plugs right into my battery pack. As mentioned on the thread linked below you could just nix the entire end plug they give you and just attach andersons diretly to the output of it.. depends on how you hooked up your packs I suppose. I use andersons for everything.. very easy to work with.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=9054&start=105#p153529

I'm digging this charger... puts out about 350 watts so charges my pack quickly and despite 120+ degress in my garage in the afternoon it's happily charging away on it's ~20th cycle... so far so good... :wink:

 

[icecube57]

I charge to 4.2v and get about 6.3 to 6.4 AH out of my 3 Bosch packs in parallel before the packs take a serious dive in voltage under full load at 35A. I can go for the full 6.6 at a lower amp draw of 5-10A and not hit the lvc of 29v or 58v if in series. but its not worth it. I adjust my riding or switch to economy mode on my controller so i dont have to hit the CA set LVC. My charger peaks at 4.2v and charges until the current drops to a certain number but it settles down to 41.8 after terminating charge.

 

[stiffi]

Hey pwbset, what kind of connector is on your ecitypower charger?

I don't know if they are all the same, but mine came with a 3-prong "AC" style plug. I used a multimeter to find + and -, ignored the "ground" and added anderson connectors so it plugs right into my battery pack. As mentioned on the thread linked below you could just nix the entire end plug they give you and just attach andersons diretly to the output of it.. depends on how you hooked up your packs I suppose. I use andersons for everything.. very easy to work with.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=9054&start=105#p153529

I'm digging this charger... puts out about 350 watts so charges my pack quickly and despite 120+ degress in my garage in the afternoon it's happily charging away on it's ~20th cycle... so far so good... :wink:

so which wires did you decipher to be + Red and Black - ?

 

[pwbset]

so which wires did you decipher to be + Red and Black - ?

Get a multimeter... if the voltage reading is positive you've identified red and black... if it's negative you've got it backwards. :wink: Seriously though... be careful and research it before monkeying around... you hook it up wrong even once and it's likely bye-bye brand new charger unless it's got a built in fuse somewhere.

There is plenty of basic information on this board about this sort of thing... search around and you'll find it.

 

[stiffi]

Hey Everybody,

In case you are interested, I finally put together my pack. I used 4 Bosch Fatpacks, and I left them in tact, and wired them together with some flat spade connectors stuck right into the terminals built into the pack casing.

I don't know why I didn't think to take pictures, but there is not going back now! I'll try to break down the steps.

1. Created wiring harness.
Cut 4 six inch pieces of red 12 guage wire.
Cut 4 six inch pieces of black.
I took the 1st end of the red and twisted it together with the 2nd. Then I stuck a spade connector on the twisted ends and soldered it.
I repeated this step 2 more times.
I then took the opposite end of the 1st wire and twisted it together with a loose end from my original battery connector, that has 2 anderson powerpoles connected to it, for connection to the motor. I put another spade connector or these two ends and soldered.
Then, I took the opposite end of the last red wire, and twisted it together with another piece of red 12 guage, and capped both with a new anderson powerpole.
I then, repeated these steps for the black wires.

2. Pack setup. This is where it gets complicated . I put all 4 packs stacked together in a 2 x 2 block, with the terminals facing out, and up. Then I taped the 4 together with duct tape.

3. Wiring. I then took my pre-made harness and simply stuck the spade connectors into the terminals, in order. To secure them, I electrical taped the connector wires to the side of the packs, to hold them in place.

4. Placement. I stuck the pack into my Topeak trunk, and onto the rear bike rack. I thought I had much more space, but the 4 packs, along with the wiring harness that sticks out of the top of the pack, fit perfectly snugly into the trunk.

So that's it. So far, I only hooked it up to my motor for a ride to the neighbor's house. I just wanted to make sure the connections worked. Pluse I have a bad ankle right now so I can't ride anyway.

I can tell you rigtht off the bat, I could feel the power seemed to be about the same as my old SLA pack. I did get up to 17 MPH, with more throtlle to spare, I thought. It felt good overall on my 48 Volt controller paired with my Go-Hub motor. I think the pack will do nicely!

Next step is to set up my charger. I ordered an ecity power charger that hopefully will arrive soon. I'll then attach that to my pack with Andersons for charging.

Thanks to everybody for their help in getting this off the ground!

 

[stiffi]

Well, Nuts!!!

I took my ecity charger and slapped a couple of Anderson powerpoles on to it. Positve with a red pole and Negative with a black. I ran into a couple of problems.

1. When I put on the power poles, and connected to my battery, they didn't fit. They were upside down. So, I took off the andersons, and reversed the color coding on the caps. I still have the positive connected to the positive just with mismatched colors. Is that right by the way? To connect positive on the battery to positive on the charger? Or should it be reversed?

2. The charger won't charged. It just sits there with the green light on. Is it possible, it won't charge because the batteries are full? I have only run the bike a few feet to make sure it worked. The batteries are pretty full, just not totatlly full.

There is one note. When I was checking with the multimeter the bare wires from the charger fell and touched briefly showing a small spark. The charger didn't smoke or anything and the indicator lights still work.

One thing I was thinking. Does the Fatpack need some 3rd connection, like the Bosch charger has to be able to accept a charge?

Any thoughts?

thanks.stiffi
100 mW


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