100W USB charging on bike

[P675]

Hi,

Planning for a trip and I will want to charge a powerbank from the bike. It can charge at 65W. I currently have a cigarette socket which is 12v 10a, good for 120W. But the USB plug I have actually only charges at 10W, so I want another one. This might be charging the powerbank, my phone and sat nav at the same time which would draw 100W or so.

Is this ok on a bike (S1000R)? Would this strain the alternator? Just thought I'd check before I buy anything. Don't want to kill the charging system when I'm hundreds of miles from home. I have had odd things happen before like the satnav crashes when I put the heated grips on (factory fitted).

Thanks.

[black-k1]

A 100W draw will not overload the output of the alternator. I assume the socket you have has been added and is not part on the CAN Bus controlled output as the CAN Bus will likely "not like" such a load.

[P675]

It's just wired directly to the battery.

[black-k1]

P675 said:

It's just wired directly to the battery.

You should be fine then. I assume the relay is ignition switched. If not, you risk getting up in the morning to find a bike with a very flat battery!

[P675]

No when I'm touring i just pull the socket out when the bike is off. I have read that USB ports have a small drain so im glad I didnt just add ports, which i would then need to replace with faster ones. It would be more convenient to wire a relay in so I may do that as I'll be stopping for photos a lot in Ireland I would imagine.

[s p a c e m a n]

Just slapping things straight into the battery is one of my pet hates, get a fused relay box and make it switch off with the ignition. Run your grips, satnav, chargers whatever through it and then you've got no risk of parasitic draw when the bikes parked up.

https://www.ebay.co.uk/itm/326336502829?mkcid=16&a...

[black-k1]

P675 said:

No when I'm touring i just pull the socket out when the bike is off. I have read that USB ports have a small drain so im glad I didnt just add ports, which i would then need to replace with faster ones. It would be more convenient to wire a relay in so I may do that as I'll be stopping for photos a lot in Ireland I would imagine.

At the end of a long day, with the rain pissing down and having struggled to find somewhere to stay, you'll forget what's plugged in and it'll drain the battery.

It's really easy to run things through a switched (fused) relay that avoids the flat battery risk. I know other BMWs, so I assume the S1000R also, provide a plug that can be used to provide the switching circuit. Details of the auxiliary socket for the switching circuit here:

https://www.s1000r.co.uk/index.php?topic=9949.0

Note: Read the whole thing as the early poster says it's not there but it is later shown that it is there.

Edited by black-k1 on Friday 28th February 12:07

[CarCrazy73]

s p a c e m a n said:

Just slapping things straight into the battery is one of my pet hates, get a fused relay box and make it switch off with the ignition. Run your grips, satnav, chargers whatever through it and then you've got no risk of parasitic draw when the bikes parked up.

https://www.ebay.co.uk/itm/326336502829?mkcid=16&a...

Or without branding for half price

https://www.ebay.co.uk/itm/176794524114?_trkparms=...

[gareth_r]

CarCrazy73 said:

s p a c e m a n said:

Just slapping things straight into the battery is one of my pet hates, get a fused relay box and make it switch off with the ignition. Run your grips, satnav, chargers whatever through it and then you've got no risk of parasitic draw when the bikes parked up.

https://www.ebay.co.uk/itm/326336502829?mkcid=16&a...

Or without branding for half price

https://www.ebay.co.uk/itm/176794524114

4 x 5 amp outputs only.

If you need more, use a 30 or 40 amp (micro?) relay and a fuse box with a busbar.

Can use a piggy-back fuse tap for the relay trigger if there is clearance in the factory fuse box.

Any socket for a battery charger obviously needs to be permanently live or manually switched.

[black-k1]

gareth_r said:

4 x 5 amp outputs only.

If you need more, use a 30 or 40 amp (micro?) relay and a fuse box with a busbar.

Can use a piggy-back fuse tap for the relay trigger if there is clearance in the factory fuse box.

Any socket for a battery charger obviously needs to be permanently live or manually switched.

Don't use a piggy-back fuse tap! Use the cable that BMW supply specifically for this type of use. That way there is no requirement to attack, in any way, the existing wiring.

[P675]

Are you saying use the usb connector (don't think my gen 2 has that) or tap the cable for it? The USB port would be no good for modern stuff as watts won't be good enough, which is why I've got the 12v socket, so I can put higher output ports in there.

At the moment I'm looking at tapping the fuse for the number plate light but I haven't looked under the seat myself yet. Would prefer something that only comes on when the engine is running but I'm guessing that would be more difficult.

[black-k1]

P675 said:

Are you saying use the usb connector (don't think my gen 2 has that) or tap the cable for it? The USB port would be no good for modern stuff as watts won't be good enough, which is why I've got the 12v socket, so I can put higher output ports in there.

At the moment I'm looking at tapping the fuse for the number plate light but I haven't looked under the seat myself yet. Would prefer something that only comes on when the engine is running but I'm guessing that would be more difficult.

Noooo! Don't tap into the tail light or an on-board USB feed.

BMW include a plug in the wire harness to feed auxiliary equipment like a sat nav. On the K1200S, the K1300S and the R1250RT it lived near the headstock. By the looks of the posts I linked to previously, that's where it is on the S1000R. You can buy a plug for it from the likes of Nippy Norman's or MotorWorks.

It provides a switched live and an earth. Just connect the switching pins of your relay to it.

[gareth_r]

black-k1 said:

Don't use a piggy-back fuse tap! Use the cable that BMW supply specifically for this type of use. That way there is no requirement to attack, in any way, the existing wiring.

Perhaps I should have made it more clear that I was speaking generally rather than about a specific make/model. My Enfield doesn't have BMW wiring.

[P675]

black-k1 said:

Noooo! Don't tap into the tail light or an on-board USB feed.

BMW include a plug in the wire harness to feed auxiliary equipment like a sat nav. On the K1200S, the K1300S and the R1250RT it lived near the headstock. By the looks of the posts I linked to previously, that's where it is on the S1000R. You can buy a plug for it from the likes of Nippy Norman's or MotorWorks.

It provides a switched live and an earth. Just connect the switching pins of your relay to it.

Right I see, this thread explains it https://www.s1000rrforum.com/threads/gps-wiring-in... So yeah keep my 12v socket connected to the battery and add a relay to the + wire with this plug as the switch on signal.