GPS wiring query

[Bender]

I'm wiring a GPS into my TDM850. When I got into the cowling I found a previous owner had wired a socket into the park light circuit so all I had to do was wire a power take off socket into that. Theoretically.

The park light is 12V 5amp.

The GPS plug says on it - 4 - 30Volts, 1 amp max. I'm concerned that if I plug it into the 5 amp park light circuit it may damage the GPS plug.

However, I use the gps and its power plug in my car and I doubt that the power socket in the car is just 1 amp. I often use that power socket with a mini compressor which takes way more than 1 amp to run it.

Is there any expert out there who can assist with a bit of know-how?

Thanks

[Gremlin]

I can't comment on the exact draw of the devices, but it's not normally a good idea to draw extra off circuits like that. Are you sure he didn't relay off the park lamp?

Depending on the GPS, it should have come with a wiring loom anyway, which isn't hard to install.

[Bender]

A relay would involve wiring to the battery and on a TDM that is a mission from hell. Involves taking the shock and hugger out and the foot brake mechanism to get the battery out - it is not accessible and yo have to take it out of the bike to run wires to it. None are big jobs in themselves but I have no way of suspending the bike while the shock is out. It's times like this that the lack of a center stand is a pain in the arse and I would never buy another bike without one. (It turns simple jobs into a major.) Neither can you put a jack or jack stand under the engine because the pipes run under there.

If the draw is 1 amp max, surely that would not have a very big effect on on a 5amp circuit. But that's the query I have posed and your answer is that it's best not to. I could replace the park light bulb with say 2 or 3 amps so the circuit is not over-stressed. The park light runs while the main headlight is switched on but is essentially a waste of time. It doesn't run while the key is turned off so I'm not sure why it's there at all - it certainly would not qualify as a headlight under our laws that require one to be turned on at all times.

The GPS came with a cigar-lighter style plug, that is all, so I have to wire a "cigar lighter" power socket into the electrical system somehow.

[Gremlin]

The GPS came with a cigar-lighter style plug, that is all, so I have to wire a "cigar lighter" power socket into the electrical system somehow.

Yep, with an inline fuse. With such a mission to wire to the battery you may want to consider an accessory box, basically one set of wires to the battery, and the devices wire into the box, like a Fuzeblock, Eastern Beaver PC8 or Touratech has an Accessory Hub.

[Akzle]

The park light is 12V 5amp.

The GPS plug says on it - 4 - 30Volts, 1 amp max. I'm concerned that if I plug it into the 5 amp park light circuit it may damage the GPS plug.

5 amps is what the park light is rated at (WTF??) or what the circuit is rated at? (ie the fuse for it)?

1A is the current your GPS will draw at 4V, it's kindof exponential - double the voltage and you half the current, so at 8V your GPS will draw .5A at 12: somewhere near 300mA

the circuit is not a regulated one, it will only draw as much as the components attached, if you draw more than 5A for a sustained period, the fuse will blow. if you draw 4.9A all day and night, you'll be sweet.

[davereid]

It will be fine.

Even a park light circuit will be able to supply the somewhat less than 1 amp you need.

[Bender]

5 amps is what the park light is rated at (WTF??) or what the circuit is rated at? (ie the fuse for it)?

The bulb is 12V 5amp. No idea what the circuit is rated at.

But thank you for your answers, that's good information.

[p.dath]

The bulb is 12V 5amp. No idea what the circuit is rated at.

But thank you for your answers, that's good information.

I think it will be fine.

If you want to find out what the circuit is rated at, find out what fuse it runs off (pull fuses out till you find it if needed). However many amps is written on the fuse is what it will handle before it blows ...

[bogan]

As p.dath says, pretty likely it'll be fine, if you want to make sure, find out the circuits rating, then subtract the park light draw, if there's more than 1 amp you'll be sweet. 12V 5A for a park light seems a lot, maybe there is a more efficient drop in one you could use?

5 amps is what the park light is rated at (WTF??) or what the circuit is rated at? (ie the fuse for it)?

1A is the current your GPS will draw at 4V, it's kindof exponential - double the voltage and you half the current, so at 8V your GPS will draw .5A at 12: somewhere near 300mA

the circuit is not a regulated one, it will only draw as much as the components attached, if you draw more than 5A for a sustained period, the fuse will blow. if you draw 4.9A all day and night, you'll be sweet.

That assumes a switchmode or similar converter in the GPS, at least equally likely is it will be an LDO reg (30V upper limit is pretty common with LDOs), in which case the current draw will be the same regardless of the input voltage (within range). Better to err on the side of caution and assume the 1amp upper limit.

[neels]

A relay would involve wiring to the battery and on a TDM that is a mission from hell.

Another option is to wire from the battery side of the starter soleniod, if that's easier to get to.

I'm guessing your park light bulb is 12V 5W not 5A, 12V x 5A would be 60W and therefore brighter than your headlight. If your GPS is only drawing 1A then the total on the circuit will probably only be a couple of amps, maybe could include tail light and dash lights.

[Akzle]

That assumes a switchmode or similar converter in the GPS, at least equally likely is it will be an LDO reg (30V upper limit is pretty common with LDOs), in which case the current draw will be the same regardless of the input voltage (within range). Better to err on the side of caution and assume the 1amp upper limit.

cheers for the learning, but 1A @12V for a 4" screen and fuckall thinking power seems a bit excessive, dunnit?

I'm guessing your park light bulb is 12V 5W not 5A,

+1

[bogan]

cheers for the learning, but 1A @12V for a 4" screen and fuckall thinking power seems a bit excessive, dunnit?

GPS uses a lot of power (comparatively), my phone which lasts a few days on standby will only last an hour if its running GPS, and the body probably gets 10 degrees above ambient, brutal eh! The 1amp will be under worst case conditions, startup with full screen brightness etc, would expect the continuous draw to be less.

[Bender]

Feck I'm hopeless, of course I meant W not amps. Brain fade again.

Yes, GPS are power hungry - just try one of those battery-powered hand held ones, they chew through AA sized batteries in hours - and many a boating person has come unstuck by leaving a GPS going and draining the boat's batteries. The 1A max power draw figure came from the specs panel on the plug.

I have to pull all the cowlings off in the next couple of days so I'll find the fuses - I don't even know where they are on the bike.

Thanks for all the help and suggestions, next fine day when I have a couple of hours spare time I'll try it out.

[davereid]

Feck I'm hopeless, of course I meant W not amps. Brain fade again.

Yes, GPS are power hungry - just try one of those battery-powered hand held ones, they chew through AA sized batteries in hours - and many a boating person has come unstuck by leaving a GPS going and draining the boat's batteries. The 1A max power draw figure came from the specs panel on the plug.

I have to pull all the cowlings off in the next couple of days so I'll find the fuses - I don't even know where they are on the bike.

Thanks for all the help and suggestions, next fine day when I have a couple of hours spare time I'll try it out.

Don't waste your time. Just plug the bloody thing in. Everyone is making this way too hard.

[imdying]

Yep, just plug it in. The fuse will blow if it's too much load in any case, it won't damage the plug.