Making your own tec pack?

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
I ordered "female" rosenbergers from here: Rosenberger Buchse Steckverbinder Systeme C00-B2-300 C | eBay

sdcoffeeroaster, this your pack looks much nicer now, I think :) Basically it is the same idea as I used, only I also employed the disconnecting cables, which made the construction a bit burly
I've seen that version of the connector before but looks like you need to remove much of the frame around the connector to make it functional. When I ordered my Rosenberg connectors I didn't realized the vendor also had right angle versions. I had to pay 40 euros to ship them to the US and 20 Euros each so I order 5 of them so I probably won't reorder to get the more preferred right angle connector. And using an off the shelf battery rather than some expensive custom one that fits in a standard bottle does result in my bottle or bag being more bulky. The bag I am currently using offers some padded protection but what I don't like is how it does look like a battery, lol. And the Velcro straps have a tendency to scratch the frame over time and dull the finish. The pad I added helps but it doesn't look professional to me and sort of a kluge. I have a new bottle being made with some improvements and an off the shelf one will now be here Thursday so the search goes on. My last ride was about 16.7 miles and 2347 feet of climbing on the external battery. That is all dependent on how hard your ride is and how much assist you use. It seems to be an honest 250wH battery. All of these options are less than 3 lbs total and the battery along is 2.25 lbs.
 

themoon

Member
Sep 12, 2020
96
16
Ukraine
I've seen that version of the connector before but looks like you need to remove much of the frame around the connector to make it functional.

That's not actually the case. It can be used as is, but also you can remove the parts to make it more streamlined if you want, quite easily. Then, of course, you'll have construct some kind of cable pressure relief, perform soldering etc... but in the end you end up with exactly what you want. I even made a right-angled version, using cable insert, like this one (not the one exactly, just to give you an idea: https://www.roadtechmarine.com.au/m...l-right-angle-all-12mm-elbowImageMain-300.jpg). It still does not look as neat as factory-made connector though, but I'm okay with that :)
 

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
That's not actually the case. It can be used as is, but also you can remove the parts to make it more streamlined if you want, quite easily. Then, of course, you'll have construct some kind of cable pressure relief, perform soldering etc... but in the end you end up with exactly what you want. I even made a right-angled version, using cable insert, like this one (not the one exactly, just to give you an idea: https://www.roadtechmarine.com.au/m...l-right-angle-all-12mm-elbowImageMain-300.jpg). It still does not look as neat as factory-made connector though, but I'm okay with that :)
Good to know, thanks.
 

Torpedillo

New Member
Nov 4, 2020
29
11
Spain
I have received my rosenberguer connector from Einfach unterwegs E-Bikes aufladen it took 4 days from Germany at a price of 60€ incuding transport.
Waiting for the battery from Aliexpress
connector1.jpg
connector2.jpg
 

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
I have received my rosenberguer connector from Einfach unterwegs E-Bikes aufladen it took 4 days from Germany at a price of 60€ incuding transport.
Waiting for the battery from Aliexpress View attachment 45377 View attachment 45378
Yes wish I had ordered his right angle version. But the straight one seems to be OK too. Which battery did you order? I'm still working on the 3D printer bottle for the hoverboard battery. I have found a battery voltage level indicator that I'll be putting in the cap so I don't run out expectantly. Maybe by next week I'll have the proto together and working.
 

Torpedillo

New Member
Nov 4, 2020
29
11
Spain
Yes wish I had ordered his right angle version. But the straight one seems to be OK too. Which battery did you order? I'm still working on the 3D printer bottle for the hoverboard battery. I have found a battery voltage level indicator that I'll be putting in the cap so I don't run out expectantly. Maybe by next week I'll have the proto together and working.
Hi, I've order this one:
1606253104610.png



I'll chekc the quality and if it is good enough
The case I will use this bag by the moomment, in the future I also want to print a cage with a coleague that has a 3D printer. This is the bag from Decathlon
1606253261750.png


I plant to connect also a battery meter like this from Amazon, is very cheap.
1606253359343.png
 

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
Hi, I've order this one:
View attachment 45424


I'll chekc the quality and if it is good enough
The case I will use this bag by the moomment, in the future I also want to print a cage with a coleague that has a 3D printer. This is the bag from Decathlon
View attachment 45426

I plant to connect also a battery meter like this from Amazon, is very cheap.
View attachment 45427
That almost looks like the same display I have coming today.

That battery is 3300 mah cells and 40 of them. Lots of range for sure but too heavy for me, lol. The 3d printers for only $236. are pretty amazing compared to what we had 10 years ago costing more than $100K. I'm keeping my bottle holder simple but these off the shelf batteries end up with bottles needing 3.6" ID or more to clear everything. The bag I'm using is OK but looks too much like an ebike then!
 

Torpedillo

New Member
Nov 4, 2020
29
11
Spain
That almost looks like the same display I have coming today.

That battery is 3300 mah cells and 40 of them. Lots of range for sure but too heavy for me, lol. The 3d printers for only $236. are pretty amazing compared to what we had 10 years ago costing more than $100K. I'm keeping my bottle holder simple but these off the shelf batteries end up with bottles needing 3.6" ID or more to clear everything. The bag I'm using is OK but looks too much like an ebike then!
Yes, for sure your option is what I like the most. The ebike is from my wife, we do real hard rides here, some days 50/60 km with 1200/1500 mts climb and the inside battery is too short for this.
I'm looking forward for your last design.
 

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
Yes, for sure your option is what I like the most. The ebike is from my wife, we do real hard rides here, some days 50/60 km with 1200/1500 mts climb and the inside battery is too short for this.
I'm looking forward for your last design.
So here is the latest. It's a bit too tight in the cage and I'm going to reduce the wall thickness so the OD is a bit smaller. The display was very tight and I have to tweak that as well. The next version will be in black and in PETG material not this red PLA.

The battery display read 20% after about 16 miles and it took a 196 wH charge (250 wH battery) so that's about right. I have to mount the display upside down because it's meant for the car dashboard and the viewing angle must be from above the display for clear viewing. It would be better in the side of the bottle but the cap is easier. I don't have any snap fit for the lid now but it's a very tight fit, 1/2" friction engagement. I might have to come up with something. I have enough room inside to add some foam padding for this battery but the typical
Chinese battery will not fit

IMG_5663.JPG
 

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
Since my bottle version is delayed I decided to modify my first "bag" version that has an offset cable routing (center is better) with the addition of a display and removal of all the Velcro that is abrading the frame finish a bit. This seems to work out well with the 0.050" thick aluminum bracket I made and I added a Velcro strap to help secure it but probably not necessary. These type of displays only look at voltage and can be set for 36v by selecting li-ion options and 10 cells. But what happens is that under hard loads the voltage drops and the display will temporarily register these as a lower % unlike the native display. So on an uphill you can see up to 20% drops that recover when the load is low again. I even saw 0% as the battery got lower only to see it recover to 15-20%. You just have to be aware of this but it does give you a fair indication of battery capacity.

I was reading on another thread where someone said when you plug the Focus TEC pack in and turn it on you also need to hit the bike start button so that the display reads the TEC pack battery. At least that's how I understand it but I might be wrong. I never hit the bike button when using this DIY pack and my display always reads the native battery SOC and not the TEC pack, which is why I've added this display. I plan to update my 2nd bag that has the straight cable routing now since this option seems to work and protects the battery well too. Once I get the bottle version back (tech issues with the 3D printer and the PETG material) I'll give that one a try too. This version is at least a bit cleaner than my other bag versions. Overall a right angle plug would also be a better option but I don't have access to any of those and I've spent too much already getting these 5 straight one sent from Germany.

IMG_5679.JPG


IMG_5680.JPG


IMG_5683.JPG


IMG_5684.JPG
 

themoon

Member
Sep 12, 2020
96
16
Ukraine
Not sure why you think angled connector would be better.

This version looks very decent with the battery installed. Not so much without it IMO (this empty cage is a bit meh), and that's why I went for the completely detachable design.

Initially I also used velcro as a backup, to hold battery just in case, but then realized it gets muddy very fast and not that easy to clean.
 

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
Not sure why you think angled connector would be better.

This version looks very decent with the battery installed. Not so much without it IMO (this empty cage is a bit meh), and that's why I went for the completely detachable design.

Initially I also used velcro as a backup, to hold battery just in case, but then realized it gets muddy very fast and not that easy to clean.
I have had a few disconnects while riding. I might not have seated it completely or that clip that I plan to remove might be the part of the cause. I can see in the pic it's does slightly affect the routing and probably better without it. My original bag exited from the side too and that's why I thought I need that clip to straighten out the cable. The new one exits from the center top portion of the bag and I'll be installing that today with it's display installed.

Yes I agree this "cage" is ugly alone. For now I'll leave the bag without the battery in when I just want to use the native battery. I'm still waiting on that bottle and with that one I can either use the bottle or a std water bottle since that ultra large cage is very adjustable.

At least now I don't have the Velcro and padding around the down tube and no scratching of the finish. I have to check on the bottle version this weekend to how that is coming. It's black PETG, holds a display and should look better.

When you use yours do you also hit the bike start button or just plug the extender in and go? I'm wondering if we hit the button within 15 sec of plugging in the extender will the Shimano display read the charge from the extender instead of the native battery? That would eliminate the need for the 2nd display I'm using on the extender. Those data lines unconnected worry me on trying this and I think they must have some purpose interfacing with the Focus TEC pack. TEC pack users say they hit the bike start button in addition to the on switch on the TEC pack so that the display reads and uses the TEC pack battery. I have this vision of frying something if I try to also hit the bike start button after the extender has been plugged in. Everything works now except the Shimano battery display, which only reads the native battery.
 

themoon

Member
Sep 12, 2020
96
16
Ukraine
I do not hit the start button, display turns on immediately after connecting the pack. Never actually tried to... But pretty sure data connection is needed to read the voltage, so no really possible for a diy. And for me it is not really a big problem either. I just run the pack dry each time, then disconnect, put it to a bag and continue on internal battery. No big deal for me. Anyhow, BMS won't allow it to discharge completely, so that's way it is quite safe for the pack.
 

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
I do not hit the start button, display turns on immediately after connecting the pack. Never actually tried to... But pretty sure data connection is needed to read the voltage, so no really possible for a diy. And for me it is not really a big problem either. I just run the pack dry each time, then disconnect, put it to a bag and continue on internal battery. No big deal for me. Anyhow, BMS won't allow it to discharge completely, so that's way it is quite safe for the pack.
Yes in fact by the time I get home after running the pack down it's at about 30 volts. I think most BMS boards shut them off at 2.7-3v/cell or so. If they ran down much below that they become non-functional and bricked.

I don't run the pack down because it almost always quits on a steep uphill just when I need it most, lol. And I think I'm going to try to run the native battery down at least once every two months to let the BMS do a better job of balancing the cells. I mostly only use one or two bars from native battery now.

Yes I use the pack exactly the way you do right now. I did just try to hit the bike start button after plugging it in and nothing happened. I'm sure at least two data lines are used for voltage and if we knew which two and polarity we could get the Shimano display to read the our TEC packs but like you said not a big deal and my new pack display does work very good.
 

Torpedillo

New Member
Nov 4, 2020
29
11
Spain
Yes in fact by the time I get home after running the pack down it's at about 30 volts. I think most BMS boards shut them off at 2.7-3v/cell or so. If they ran down much below that they become non-functional and bricked.

I don't run the pack down because it almost always quits on a steep uphill just when I need it most, lol. And I think I'm going to try to run the native battery down at least once every two months to let the BMS do a better job of balancing the cells. I mostly only use one or two bars from native battery now.

Yes I use the pack exactly the way you do right now. I did just try to hit the bike start button after plugging it in and nothing happened. I'm sure at least two data lines are used for voltage and if we knew which two and polarity we could get the Shimano display to read the our TEC packs but like you said not a big deal and my new pack display does work very good.
As you say, it's very important to dry the main battery time to time. Bms tries to balance all battery pack, bit sometimes it doesn't do it right. I've seen vídeos of people charging manually pack by pack all the batteries and the win a lot of charge because the bms thought that all batteries were charged equally. I would post a video but is in spanish
 

Tooks

Well-known member
Subscriber
Mar 29, 2020
416
504
Lincs UK
I had a Tec Pack but owing to only having used it once in nearly 11 months, it’s winging its way to a worthy new owner on here.

But, I’ve got some bits hanging around so I’ve had a go at my own version of a DIY range extender.

I do a lot of RC flying so I’ve got some chunky Lipo batteries knocking about the place, that I also use on my TSDZ2 home brew MTBs.

I also had a Focus charger go wrong earlier this year, and they never asked for the old one back, so I had a Rosenberg connector to cut off that.

Without further ado then, I present my attempt! It’s 5.0Ah, comprised of 2 x 5s Lipos. I’ve only done a quick test, but it works fine, albeit with no battery level via the Shimano controller, which after reading this thread I was expecting. I had the soft bottle bag and fidloc boa holder as well, so very low cost, albeit the batteries are a very tight fit!

45EBEB92-BCC4-49BF-A120-A089AF61D640.jpeg
7FA8DB7A-6104-4501-B9A7-94D67FE0F8D8.jpeg
9C5C9BB5-D320-4AE8-925D-E7C55EF822CD.jpeg


I’ve since removed the crimp connectors and soldered everything together with shorter cable runs now I know it works. Still a bit fugly, though it’ll be helpful should I ever need it.
 
Last edited:

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
I had a Tec Pack but owing to only having used it once in nearly 11 months, it’s winging its way to a worthy owner on here.

But, I’ve got some bit hanging around so I’ve had a go at my own version of a DIY range extender.

I do a lot of RC flying so I’ve got some chunky Lipo batteries knocking about the place, that I also use on my TSDZ2 home brew MTBs.

I also had a Focus charger go wrong earlier this year, and they never asked for the replacement back, so I had a Rosenberg connector to cut off that.

Without further ado then, I present my attempt! It’s 5.0Ah, comprised of 2 x 5s Lipos. I’ve only done a quick test, but it works fine, albeit with no battery level via the Shimano controller, which after reading this thread I was expecting. I had the soft bottle bag and fidloc boa holder as well, so very low cost, albeit the batteries are a very tight

View attachment 47338 View attachment 47339 View attachment 47340

I’ve since removed the crimp connectors and soldered everything together with shorter cable runs now I know it works. Still a bit fugly, though it’ll be helpful should I ever need it.
Look pretty nice to me. 37 v right (18.5 x 2)? What does the pack weigh using those lipos?
 

Torpedillo

New Member
Nov 4, 2020
29
11
Spain
I had a Tec Pack but owing to only having used it once in nearly 11 months, it’s winging its way to a worthy new owner on here.

But, I’ve got some bits hanging around so I’ve had a go at my own version of a DIY range extender.

I do a lot of RC flying so I’ve got some chunky Lipo batteries knocking about the place, that I also use on my TSDZ2 home brew MTBs.

I also had a Focus charger go wrong earlier this year, and they never asked for the old one back, so I had a Rosenberg connector to cut off that.

Without further ado then, I present my attempt! It’s 5.0Ah, comprised of 2 x 5s Lipos. I’ve only done a quick test, but it works fine, albeit with no battery level via the Shimano controller, which after reading this thread I was expecting. I had the soft bottle bag and fidloc boa holder as well, so very low cost, albeit the batteries are a very tight fit!

View attachment 47338 View attachment 47339 View attachment 47340

I’ve since removed the crimp connectors and soldered everything together with shorter cable runs now I know it works. Still a bit fugly, though it’ll be helpful should I ever need it.
Really nice battery, I love. The one I bought from China is still in the train crossing Europe. I hope to receive it next week to test and show the results here.
 

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
I’ll give it a weigh tomorrow, but the batteries I remember are 575g each, the bottle bag, fidloc and wiring are about another 200g, so 1.35kg?
Just remember that if you jump or take hard hits there's a lot of momentum due to the battery weight (objects in motion tend to stay in motion on the path of that motion, lol) that can rip it free from it's mounts. Just make sure those two bolas are up to the task.
 

sdcoffeeroaster

Active member
Jul 22, 2018
548
204
San Diego, CA
I've been using fidlock with my battery as well... they are fine. Actually guaranteed to 1kg, but I think can handle much more. At least, according to my tests
Nice but pricey too. I found the boa version at $63. Too bad it is meant for an 80mm diameter max or I would consider it for my water bottle version holding my hoverboard battery. Still working on that one (my friend can't run his 3D printer in his garage because it's been too cold in SoCal lately, 60's) but the bag without the straps around the frame are working out for me. Those Velcro straps left some light scratches on the carbon fiber frame.
 

themoon

Member
Sep 12, 2020
96
16
Ukraine
Not sure why it is advertised at only 80mm, maybe for the concerns of weight larger diameters will carry... But actually something even as big as 110mm should fit - see the picture I've taken and note that how much leeway is left in bolis.

Additionally, I found it possible to put plastic wraps where these bolos hold, so weight is not a concern at all. It all boils down to how much the base can hold, and according to customer support, it is bulletproof :) So I assume even 2 kg is not a concern.

Re price - got mine for 34 EUR in Germany. In states it is pricey... But very convenient to use

80576E00-9314-4595-9537-DA29B31041EA.jpeg
 

Torpedillo

New Member
Nov 4, 2020
29
11
Spain
I had a Tec Pack but owing to only having used it once in nearly 11 months, it’s winging its way to a worthy new owner on here.

But, I’ve got some bits hanging around so I’ve had a go at my own version of a DIY range extender.

I do a lot of RC flying so I’ve got some chunky Lipo batteries knocking about the place, that I also use on my TSDZ2 home brew MTBs.

I also had a Focus charger go wrong earlier this year, and they never asked for the old one back, so I had a Rosenberg connector to cut off that.

Without further ado then, I present my attempt! It’s 5.0Ah, comprised of 2 x 5s Lipos. I’ve only done a quick test, but it works fine, albeit with no battery level via the Shimano controller, which after reading this thread I was expecting. I had the soft bottle bag and fidloc boa holder as well, so very low cost, albeit the batteries are a very tight fit!

View attachment 47338 View attachment 47339 View attachment 47340

I’ve since removed the crimp connectors and soldered everything together with shorter cable runs now I know it works. Still a bit fugly, though it’ll be helpful should I ever need it.
Would you be so kind to show this connection in a better zoom, or explain the connection? they are in parellel?
1608274187235.png
 

Tooks

Well-known member
Subscriber
Mar 29, 2020
416
504
Lincs UK
Would you be so kind to show this connection in a better zoom, or explain the connection? they are in parellel?
View attachment 47513

The batteries are connected in Series, each battery is 5s and 5000 mAh, so two connected provide a 37-42v 5.0 Ah battery.

I‘ll take a photo of the final connections, but it’s a Y Series connector with XT60 plugs, and an XT60 male connector on the other end of the Rosenberg. I can then disassemble the battery easily for balance charging. I also put an audible battery alert board on one of the balance cables, I’ve set it to 3.5v and it provides a loud beep alerting me when the battery is exhausted.
 

Torpedillo

New Member
Nov 4, 2020
29
11
Spain
The batteries are connected in Series, each battery is 5s and 5000 mAh, so two connected provide a 37-42v 5.0 Ah battery.

I‘ll take a photo of the final connections, but it’s a Y Series connector with XT60 plugs, and an XT60 male connector on the other end of the Rosenberg. I can then disassemble the battery easily for balance charging. I also put an audible battery alert board on one of the balance cables, I’ve set it to 3.5v and it provides a loud beep alerting me when the battery is exhausted.
Your'e totally right seires connection... :) thanks a lot for the info
 

Tooks

Well-known member
Subscriber
Mar 29, 2020
416
504
Lincs UK
A picture of the connections a bit more clearly, and the low voltage alarm set to 3.6v.

9AB01579-24AE-4804-ACAE-E9A1C8473E99.jpeg

4FB38E4B-9CF0-4072-9356-9F5E7CC2615C.jpeg
 
Last edited:

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