Cause of flat battery.....

I connected a usb/cigarette lighter socket direct to the battery via fused line. No led indicator on socket. Over last autumn/winter I noticed that the battery was flat on several occasions after laying up for around three weeks (no alarm connected). I put this down to ageing battery (7years old). In February I laid up the GS after the Dragon Rally so I could finish refurbing the paint work. Had to charge battery in April as it was flat again so intended to purchase new one when bike back on the road. In May I disconnected socket and transferred it to my Pan European 1100 as I needed additional power options at short notice. I've left the Pan idle for the last three weeks and today checked it and battery was flat. I then checked the GS which has not been started since April and there was plenty of power to turn over and start the bike. I can only assume that there is some drain via the socket even though there is nothing plugged in. Once the battery is fully charged I'll check it for voltage loss with socket connected and without. In the meantime is there anyone who could please advise whether the socket could be the culprit? It seems too much of a coincidence......

There would be a SLIGHT drain from a usb socket IF left live. There's a little transformer in there. 5 volts. JJH

That sounds like could be the cause of the problem as there is no on/off switch on the socket. Think I'll dig out one I have somewhere with a power switch. Thanks for the input!

I have wired all my auxiliary stuff through voltage sensing relays to avoid this type of thing. They only come live at 13.1 v. This way nothing works until after the bike is started and the battery is healthy.. there are bound to be a few drawbacks to my system . But all in all I think it's ok.

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what have i done said:

I have wired all my auxiliary stuff through voltage sensing relays to avoid this type of thing. They only come live at 13.1 v. This way nothing works until after the bike is started and the battery is healthy.. there are bound to be a few drawbacks to my system . But all in all I think it's ok.

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I needed some power when the bike parked up so I could only go down the direct to power source route. I've just fitted another unit which has a power on/off switch and this isolates the usb power circuitry from the feed when switched off. I shall see how this goes on. Thanks for the reply

west coast traveller said:

I needed some power when the bike parked up so I could only go down the direct to power source route. I've just fitted another unit which has a power on/off switch and this isolates the usb power circuitry from the feed when switched off. I shall see how this goes on. Thanks for the reply

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I got an Optimate twin USB outlet that plugs into the bikes usual scket. Has an LED inducator to give a rough idea of battery state but also shuts itself off if the voltage drops below a certain level to save your battery from going flat. Might be an option ?

http://chainspeed.co.uk/optimate-du...r3dKxc9XQlNBNtGQmATyvJ1TkzvZh354aAvciEALw_wcB

What a good idea. Must look into that one. Thanks.