12v USB power question?

[hotbulb]

Compressors take a lot of power ... probably best run direct from the battery. (I'm no fan of cig-lighter sockets - they seems to disconnect/fall out if you so much as look at them!). Phone charging, though, is low-power..... running a USB socket from the sidelight switched feed should be OK unless the wiring's very ropey.

[catcitrus]

Agree on the USB drain thing--first time we had it was on a Husaberg 390--flattened the battery over about 2 weeks--and they are marginal anyway. I DO run cig outlets--but permanently wired through to the battery and properly fused--for phone charging etc--basically when stopped or when the device is stored in the tank bag. If you want a USB then there are plug in USB outlets which also have a voltage monitor. For Garmin powered cradles I also use a permanently live outlet--BUT near the handlebar I have a waterproof connector (one of those with the yellow bellows and lock)--and my powered cradles have the male on a shortened outlet so that I can transfer between bikes. Basically no drain when stationary EXCEPT that the garmin stays powered up(because if you lose power with a switched supply and don't notice the garmin will shut down--a PITA when trail riding.)

[Tramp]

Yep my zumo 595 is battery fed... Just remove zumo when not used.... I'll get a USB ciggy adaptor rated above 2.1amps so it charges my phone easily..

[garyboy]

If you are going to unplug the usb device after use anyway, why not just fit a new ciggy lighter socket and plug in a usb adaptor when you need it
then unplug it after and bung it in jacket pocket or summat, they take up no space and guaranteed no current drain cos its not plugged in.

yes .. i do this .. just a fuse on the live wire to the battery .. a direct connection, no switch needed ..
I have read reviews that say there is no current drain, and there does not seem to be, in practice.
yes .. the adaptor socket does come out easily, but i only charge up (phone) when stationary, and the blue light tells me if i am connected .. though i suppose a bit of insulation tape to stick cig socket and usb plug in, would work if moving .. easy to peal off after.

the type you got pictured is reviewed as definitely losing current.

[sledgegreen]

Compressors take a lot of power ... probably best run direct from the battery. (I'm no fan of cig-lighter sockets - they seems to disconnect/fall out if you so much as look at them!). Phone charging, though, is low-power..... running a USB socket from the sidelight switched feed should be OK unless the wiring's very ropey.

That is why I would use a relay. Relays use two separate electrical circuits - a control circuit, which carries very little current and is used simply to switch the accessory circuit on and off. Because it draws so little current, it can be connected to practically any other circuit, or it can simply be connected to a switch.

The accessory circuit carries the current to supply whatever accessories are attached. It should be connected to the battery, then a fuse, then the input terminal on the relay. The output from the relay is then connected to the accessory and then to earth.

I suggested this because the OP says that he doesn't have an option for a switched feed, but does have access to connect to the battery. This is a way to create an ignition-controlled power supply. The wiring for the rear lights is easily accessed on most bikes.

[Hugh]

Greetings,

Might this little diagram help.

ABR Basic accessories and relay.jpg (20.76 KiB) Viewed 1624 times

TTFN

Hugh.

[sledgegreen]

Thanks Hugh. That is very helpful.

In that diagram, the control circuit runs through the relay horizontally from right to left and the accessory circuit runs vertically from bottom to top.

To clarify what I wrote earlier:

The control circuit carries very little current and is used simply to switch the accessory circuit on and off. Because it draws so little current, it can be connected to practically any other circuit, or it can simply be connected to a switch. It connects to terminal 86 on the relay (R side in the diagram). That circuit is completed by connecting terminal 85 (left side) to earth.

The accessory circuit carries the current to supply whatever accessories are attached. It should be connected to the battery, then a fuse, then the input terminal on the relay (terminal 30, bottom). The output from the relay (terminal 87, top) is then connected to the accessory and then to earth.

Some relays only have 4 terminals (30, 85, 86, 87). Some have an additional output terminal - 87a. This allows two accessories to be wired independently.

[dodursley]

I usually connect the relay switching into the rear brake switch power feed (not the switch to light wire!) as that is usually near the battery and accessible without taking the loom cover off a as most of my bikes are too old for lights always on.

[Elmer J Fudd]

I fitted a "Fuzeblock" on the Transalp to connect Sat-nav, heated grips and lights al switched and all with different fuses. Transalp is long gone now....

It was good, though for temporary stuff I would probably just connect using an optimate type split cable direct to the battery then swap the leads depending on what you want to connect. no need for relays or switches just pull the cables apart. (so long as you remember). your only issue being if you need a fuse to protect the circuit or not you would need to add inline on the non-permanent lead.

[Sanqhar]

+1 for "Fuzeblock".

tom