Di2 - Charging question

robthehungrymonkey

After writing off my frame, i'm moving my Di2 groupset (6770 Ultegra 10spd) over to a Cervelo S5 frameset (luckily, my old frame was insured!).

At the moment, i've got an external battery and I was considering moving over to an internal (the S5 seems designed around this). I thought i'd be able to just swap the batteries over. I then realised i'd need to charge it, so i'd need the newer style junctions box that goes under the bars... Do I also need to buy a shimano specific charger?

If so, this seems a little ridiculous! At the cheapest online prices, it means £85 for the battery, £65 for the junction box (and most ridiculously!) £60 for what is essentially a USB charger! That's £210 for basically an internal battery.

Is this actually the case?

meanredspider

you don't need a charger. USB is USB (to a large extent - though not all chargers are created equal).

Personally, unless you have some really good reason to go internal, I'd stick external. The older two of my bikes are external and I prefer it.

robthehungrymonkey

meanredspider wrote:

you don't need a charger. USB is USB (to a large extent - though not all chargers are created equal).

Personally, unless you have some really good reason to go internal, I'd stick external. The older two of my bikes are external and I prefer it.

Thanks for the reply.

That sounds promising... So, to clarify can you just plug any usb charger into the junction box at the handlebars? Or is there a shimano specific cable? Do you know if this comes included with the battery?

drlodge

Not sure if this is 100% correct, but as far as I know, a USB charger is a USB charger - charges at 5V nominal while the maximum current varies. Hence different charges may take differing lengths of time to charge the battery. Cables can vary though, which is why I think some people have had issues. Some USB cables have two of the connectors joined I believe...so if your USB charger isn't working then you'll need a different cable (between charger and junction box).

robthehungrymonkey

drlodge wrote:

Not sure if this is 100% correct, but as far as I know, a USB charger is a USB charger - charges at 5V nominal while the maximum current varies. Hence different charges may take differing lengths of time to charge the battery. Cables can vary though, which is why I think some people have had issues. Some USB cables have two of the connectors joined I believe...so if your USB charger isn't working then you'll need a different cable (between charger and junction box).

At the moment, I have an external battery and charger. So I take the battery off the bike to charge.

twist83

The charging port on the junction box used with the Internal battery is not a normal USB one. It has a small connector as per the link below.

https://www.google.co.uk/url?sa=i&rct=j ... 8046932437

A normal USB cable can be used from the chargers box of tricks to the mains.

robthehungrymonkey

twist83 wrote:

The charging port on the junction box used with the Internal battery is not a normal USB one. It has a small connector as per the link below.

https://www.google.co.uk/url?sa=i&rct=j ... 8046932437

A normal USB cable can be used from the chargers box of tricks to the mains.

And I suppose you have to buy a mains charger to get that cable?

pilot_pete

It is the same as one I have that came with a camera...

PP

twist83

Rob, I assumed this was the case. However PP states it is the same as a camera he has. So you might be able to get something.

One thing the charger however does allow is for you to plug it into a Windows Laptop via USB and update all the mechs, junction boxes etc with the ETube software. Not sure a generic one would allow this?

robthehungrymonkey

Pilot Pete wrote:

It is the same as one I have that came with a camera...

PP

Intrguing... What model camera is this?

twist83 wrote:

Rob, I assumed this was the case. However PP states it is the same as a camera he has. So you might be able to get something.

One thing the charger however does allow is for you to plug it into a Windows Laptop via USB and update all the mechs, junction boxes etc with the ETube software. Not sure a generic one would allow this?

Thanks, fortunately (unfortunately?) I already have a box that plugs directly into the etube spare port on the shifters to fiddle with the different bits (which is fun!).

bernithebiker

Just for info, Shimano recommend NOT to charge from the mains, but rather from a computer or similar. (I know it sounds odd, but it cured my problem* and that of a stranger I met in Majorca)

*internal battery not holding a full charge.

pilot_pete

robthehungrymonkey wrote:

Pilot Pete wrote:

It is the same as one I have that came with a camera...

PP

Intrguing... What model camera is this?

Couldn't tell you, camera long gone, cable in our 'cable/ charger/ phone/ anything you'll never use again' drawer...you have got one of those drawers haven't you?

PP

twist83

bernithebiker wrote:

Just for info, Shimano recommend NOT to charge from the mains, but rather from a computer or similar. (I know it sounds odd, but it cured my problem* and that of a stranger I met in Majorca)

*internal battery not holding a full charge.

Really odd. Never heard of this before. Mine and my other halfs DI2 charges just fine from the mains and never had issues with holding charge.

bernithebiker

twist83 wrote:

bernithebiker wrote:

Just for info, Shimano recommend NOT to charge from the mains, but rather from a computer or similar. (I know it sounds odd, but it cured my problem* and that of a stranger I met in Majorca)

*internal battery not holding a full charge.

Really odd. Never heard of this before. Mine and my other halfs DI2 charges just fine from the mains and never had issues with holding charge.

I think it depends on what kind of USB transformer you are using.

teebs_123

I've been using the Iphone charger for my Di2 and they've been fine, I'm sure the voltage is whats recommended.

Gaz777

I also charge mine from the mains using an iPhone charger. Has always been good so far; the iPhone charger must be the correct specs that di2 likes!

bernithebiker

Gaz777 wrote:

I also charge mine from the mains using an iPhone charger. Has always been good so far; the iPhone charger must be the correct specs that di2 likes!

Indeed - I think that not all transformers are equal. In terms of how precise and stable the DC voltage is that they output, i.e. if you need 5.0V, maybe it's putting out 4.7, and then fluctuates (with heat, etc.) to between 4.5 and 5.2 for example.

Anyway, I now use my Mac (desktop or Macbook) and that works fine. I suspect that a Mac can also handle mains voltage spikes better too.

jet_black

I fancied the better looks of a internal battery but didn't want to spend the extra.

I ended up buying a airsoft 7.4v battery (di2 runs on 7.4v batts) for £10 which fits inside my 27.2mm seat post, cut up the external mount to make it really small, cut up a di2 cable and soldering it all together. I still have a normal plug one end allowing me to plug it into the junction box.

My battery charger only cost £3 from China. I also wired it so I only have to remove the cover under the Bb to charge it all. Also the airsoft battery has three times the capacity of the proper battery so lasts even longer!

I did it with a old firmware mount too so I run a 6870 rd with everything else 6770.

I can take pictures and give more detail if you want?

Cheers

robthehungrymonkey

jet black wrote:

I fancied the better looks of a internal battery but didn't want to spend the extra.

I ended up buying a airsoft 7.4v battery (di2 runs on 7.4v batts) for £10 which fits inside my 27.2mm seat post, cut up the external mount to make it really small, cut up a di2 cable and soldering it all together. I still have a normal plug one end allowing me to plug it into the junction box.

My battery charger only cost £3 from China. I also wired it so I only have to remove the cover under the Bb to charge it all. Also the airsoft battery has three times the capacity of the proper battery so lasts even longer!

I did it with a old firmware mount too so I run a 6870 rd with everything else 6770.

I can take pictures and give more detail if you want?

Cheers

This sounds fun!
Any further information would be much appreciated!

jet_black

Ok - give me a bit as I've got to dismantle my bike to do it.

robthehungrymonkey

jet black wrote:

Ok - give me a bit as I've got to dismantle my bike to do it.

Very much appreciated dude. I think there may be an issue with my battery, so it could prove very handy indeed.

bernithebiker

robthehungrymonkey wrote:

jet black wrote:

Ok - give me a bit as I've got to dismantle my bike to do it.

Very much appreciated dude. I think there may be an issue with my battery, so it could prove very handy indeed.

Whats the issue?

robthehungrymonkey

bernithebiker wrote:

robthehungrymonkey wrote:

Very much appreciated dude. I think there may be an issue with my battery, so it could prove very handy indeed.

Whats the issue?

When I first built the bike up on a stand it all worked perfectly. I then took it for a (very) short ride and only had rear shifting. Charged the battery thinking it had died. Still the same problem.

So, i’ve checked all the connections and everything is plugged in as it should be.
I then put the battery on charge again.
Battery back on bike – Green light flash on the junction box.
Still won’t shift the front mech
Plug the battery into the laptop – No errors
Plug the wire back into the battery and now nothing again. At all.
Back into laptop – it still says no errors.
To me, this seems to suggest that battery is only holding enough charge to operate the rear mech, and even then only for 5 minutes. Is it normal to fail so suddenly?
Seems odd that it has failed at the same time as I swapped the groupset onto a new frame!?
Is there any way to check the battery is knackered before I spend loads on a replacement to find that the battery mount is faulty?

bernithebiker

This is internal battery right?

How are you charging it?

robthehungrymonkey

bernithebiker wrote:

This is internal battery right?

How are you charging it?

Nope, this is on the external (that I was considering swapping out for internal until the cost of the shimano parts required became apparent)

jet_black

I had planned on taking some photos but family life has gotten in the way. Please excuse a lack of photos/detail (Picture paints a 1000 words)

It is fairly simple overall just need a bit of confidence while cutting up the external mount.

Parts that you need:
Replacement battery: http://www.hobbyking.com/hobbyking/store/__84545__Turnigy_nano_tech_1300mAh_2S_25_50C_Lipo_AIRSOFT_Pack_T_connector_UK_Warehouse_.html This battery fits easily inside a 27.2 seat post and is about three times the capicity of the Shimano battery.

Charger: http://www.ebay.co.uk/itm/7-4v-11-1v-Li-polymer-Battery-Charger-2s-3s-Cells-for-RC-LiPo-AEG-Airsoft-batter-/232002145795?hash=item360467ce03 Likely not the best but it works for me.

Various cables and connectors: http://www.ebay.co.uk/sch/sis.html?_nkw=3x+Deans+Connector+male+%26+female+T+Plug+3+pairs+of+high+current+connectors+Lipo&_id=330873453653&&_trksid=p2057872.m2749.l2658

http://www.ebay.co.uk/sch/sis.html?_nkw=Lipo+Balance+Extension+Charger+Cable+Lead+2s+JST-XH+%282+cell%2C+7.4V%29&_id=230786425855&&_trksid=p2057872.m2749.l2658

http://www.ebay.co.uk/sch/sis.html?_nkw=Servo+Wire+Cable+flat+Black+Red+White+26AWG+JR+Spektrum+Futaba+extension+meter&_id=330906898746&&_trksid=p2057872.m2749.l2658

http://www.ebay.co.uk/sch/sis.html?_nkw=Stranded+Automotive+Equipment+Wire+Hookup+Cable+14AWG+16AWG+18AWG+22AWG&_id=262256456691&&_trksid=p2057872.m2749.l2658

First cut up the external mount - Looking into the mount where the battery terminals are you should be able to make out this piece on the left.
This is the brains of the mount and the only bit we are interested in keeping. So carefully cut around this area and pull it away from the rest. The Di2 cable can still click on the socket like normal, so at this point I plugged it back in to test that it still worked .

This piece needs to live near the bottom bracket to give the seat post plenty of room. You will need to very carefully and slowly cut the di2 socket away. BUT first use a continuity checker to find out to find which battery terminal connects to which part of the di2 plug/socket (fairly sure the visible terminal is the negative) Eventually, you should end up with two little metal terminals just sticking out of the black plastic lump.

If you have got to this stage and it still works congratulations the hard work is out of the way.

Take a Di2 cable and cut the plug off, then strip the cable exposing the wires, again check the continuity. To ensure I had enough length in the cables I extended these with the same gauge and then soldered these to the terminals of the Di2 socket.

The remaining steps just involve making up a discharge cable and soldering this to the battery terminals of the mount, forming a cable to charge the battery with and fitting the battery into the seat post. Again thinking about cable length and where the mount will sit.

Once everything is soldered together run the cables through the frame and plug both the discharge and charging cables in the battery and insert your seat post.

You now have a fully working internal Di2 battery for ~£20.

TIPS:
When using the continunity checker only the negative terminal will work :?:
I used Sugru to cover the soldered terminals and to resist cables being tugged apart.
Tape an old brake/gear cable around the far end of the battery so you can pull it out again in the future.
Wrap old bar tape around the battery to make it fit snuggly in the seat post.
I made the charge cable about 1.5m long which means I can easily charge the battery while it's still in the frame.

If you need any more info or clarification on bits feel free to ask.

Cheers

Phil

robthehungrymonkey

jet black wrote:

I had planned on taking some photos but family life has gotten in the way. Please excuse a lack of photos/detail (Picture paints a 1000 words)

...
Cheers

Phil

Phil, you are a legend. If I ever find out where you are, I will buy you a beer!
Sounds like a good little project, I will have to brush up a little on my sparky know how, but will definitely be giving it a go.

robthehungrymonkey

Quick question Phil,

If I updated the front junction box to the current model, would I be able to charge through that?

jet_black

Not sure as I've got the original front junction box. Have you got a 3 or 5 port front junction box with the external battery at the moment?

I would imagine you could as the system doesn't know the battery isn't the standard one but don't hold me to that.

Cheers

Phil

robthehungrymonkey

jet black wrote:

Not sure as I've got the original front junction box. Have you got a 3 or 5 port front junction box with the external battery at the moment?

I would imagine you could as the system doesn't know the battery isn't the standard one but don't hold me to that.

Cheers

Phil

Cool, thanks.

I've this morning diagnosed my problem (it was a cable from the junction box to the shifter). I have the older junction box that just has the wires hard wired in. I am going to upgrade to the 3 port junction box now to get the bike up and running and then will look at doing an internal battery hack.

twist83

Impressive hack. However the faff of removing a flap down under the bike would do my nut in. But then I am lazy......