Hardwire GPS to Auxiliary Battery?

[AlexUSA]

+



Good idea or bad idea? Any tips for a guy who has no electrical common sense before I do this? My XR has no battery and the standard AA's are always losing contact (tried the typical fixes already).

How many mAh do I want to run my GPS for how long? I can carry a recharger for multi-day trips if we stop overnight.

Is there a transformer or something inside the Garmin car 12v adapter plug end or can I chop it off?

 

[KTMphil]

Inside the Garmin male cigarette lighter connector/jack, there will be 2 wires (+ve & -ve), all you will have to do is crimp these to a matching jack and connect to the +ve & -ve wires on your aux. battery pack.

I'll try and think of the easiest system setup for this, its all pretty simple just need to think of the way that's the least pain in the ass for keeping it charged, shame you don't dave ant DC on the bike!

 

[KTMphil]

TPMB - Advice from a navigation electrician:

"Simplest way would be to get a free hanging lighter socket, which you can get at Radio Shack easily here. not sure about there. connect that to the battery.
That way there's no cutting and the garmin adaptor cable can remain intact..
I'd imagine that battery would run the GPS for a good long time".

 

[johnnysneds]

That would mean an extra connection using the ciggy lighter adapter. Snip the ciggy connection off the cable you have and find the male connector that fits the battery connector in the photo. Your GPS had a step down transformer fitted. So you'll have a connection at your unit on the handlebars and another one wherever so you can disconnect and charge the lithium battery up.
A better and more permanent idea that was discussed with you in another post, convert your headlight to DC, I can do this for you when I get back if you like. I'm assuming you have already found out your headlight is ac.

 

[alexuk]

if 2x 1.2v 1500maH nimh batteries power the gps for 8hours, that battery should run it for 40hrs

 

[KTMphil]

Alex- from another highly respected navigation electrician:

Not too simple there unfortunately. You will need a rectifier to convert from AC to DC then it would be the same. You may have problems with his generator if it’s output varies with the rpm (the light brightens and dims with the engine speed). Also most low voltage ac circuits are 24 volt so you will need a 24 to 12 transformer in front of the rectifier or 24 to 12 dc converter after the rectifier.

What is the lighting circuit voltage?



Paul Dow

Manager

Mechanical/Electrical Department

New England Boatworks Inc.

1 Lagoon Road

Portsmouth RI 02871

 

[johnnysneds]

I think Alex is after an easy solution and doesn't want to mess with his bike electrics too much. What he has proposed is ok and will work with the external battery.
My ac headlight brightness varies with RPM, there is a transformer/rectifier after the stator and the dc power to my ancillaries work without any issues.

Consider one of these if you have room to house it. This will power your GPS for a long time, and then get yourself a cheap 12V battery charger.

from this website: http://www.turntechbattery.com/TurnTech ... lcome.html

 

[LivinLOS]

Why not simply cable it up from the bikes battery ??

I have mine wired into the ignition so that turning the bikes on and off cuts or restored power to the GPS. I amso bought a slightly different garmin cabling package, with no cig lighter on it only the cable and end cap.

What am I missing in this ?? What bike is it that this is to go on ??

 

[Lone Rider]

LivinLos,

I guess you missed this in the first post of this topic: My XR has no battery and the standard AA's are always losing contact (tried the typical fixes already).

 

[Midnitemapper]

A couple of alternatives
Tourtech power converter I have used this it does everything they say yes it will not power a Zumo, That screen on a zumo is bright lots of juice for that baby!

http://www.touratech-usa.com/Store/PN-0 ... -15v-160mA
This photo from the touratech web site


The lithium battery that Johnny posted looks like the hot go!
Hard to beat those lithium for power to weight! I use a locally made alternative 500b that is used in emergency lighting. This battery is designed to sit in a wall lighting unit waiting for a power outage. Not designed for offroad motorycycles, lots of vibration and heat. I expected short life, but have been suprised the first, one 6 mos is still going!

 

[KTMphil]

Don --you have generators (alternators) on your kick start bike (for the lights) that will also recharge these batteries?

you have some home made wiring to do this?

 

[Midnitemapper]

Oh yea thats a long story, I will give you the short one.

I re wound my stator, using a dual output system. This required experimentation with wire sizes, long story.
Each side is estimated at 100 watt max output.

This required 2 complete systems including regulators, so a complete re-wire of the bike x 2.

The objective was to have enought power for all the electronics and 2 metal halide lighting systems.

So now I have 2 batteries, and the power Touratech power converter. So If I do not turn on too many things at once, I am charging those batteries while riding.
When the metal halides start to flicker its time to turn something off or I will be riding by brail!

The whole thing was quite experimental and took weeks to get it right,not to mention lots of expensive parts. I do not want to do that again! But the result has been outstanding!

 

[KTMphil]

Oh yea thats a long story, I will give you the short one.

I re wound my stator, using a dual output system. This required experimentation with wire sizes, long story.
Each side is estimated at 100 watt max output.

This required 2 complete systems including regulators, so a complete re-wire of the bike x 2.

The objective was to have enought power for all the electronics and 2 metal halide lighting systems.

So now I have 2 batteries, and the power Touratech power converter. So If I do not turn on too many things at once, I am charging those batteries while riding.
When the metal halides start to flicker its time to turn something off or I will be riding by brail!

The whole thing was quite experimental and took weeks to get it right,not to mention lots of expensive parts. I do not want to do that again! But the result has been outstanding!

I had a felling is was a "project", but it's worked incredibly well.

 

[Erictheviking]

Just to re-cap as it may be a bit difficult for some readers to fully understand (not in any way taking the piss mind you):
A bike stator produces alternating current (AC), the voltage is unregulated and that means that at low rev's the voltage can be as low as 7-10 volts and when revving the voltage goes as high as 70 volt.
Most stators produces three phase AC as above and has a separate winding for the ignition that is connected directly to the ignition coil.

A light bulb does not care if it is fed AC or DC, in the above scenario the strength of the light will vary with the rev's.

If your bike has a battery then the AC is put through a rectifier/regulator to make it 12 volt DC and this is fed to the battery.
-the rectifier/regulator is simply speaking 4 diodes (turning the AC into DC) and then a fast acting "relay" that switches the voltage to ground if it is over 12 volt -thus stopping high voltages from reaching (and destroying) the battery.

When adding a 12 volt DC item to your bike with no battery you need to not only rectify the current from AC to DC but also regulate it to 12 volt and/or otherwise "stabilize" it as the current coming from the diode rectifier is not very "clean" -if you look at it using an oscilloscope you will see spikes in it that can mess with items such as GPS's and similar.

Eric

 

[Midnitemapper]

Thanks Eric for that explanation,

So this is what the Tourtech "converter does"
"cut and paste" from their web page.

http://www.touratech-usa.com/Store/PN-0 ... -15v-160mA

Many dirt bikes have a very simple electrical system to reduce weight. Many run only a headlight and tail light with12vAC (no battery). These systems can be suitable to charge a battery by the simple addition of a regulator / rectifier. But to supply expensive electronics, a more elaborate system is required, to provide smooth output without voltage spikes. There are two ways to do this. One is to use a large battery. If your battery is large enough to run a starter motor then this unit may not be necessary. If you don't have electric starting then the battery is probably too small to protect electronics from dirty input power.Our power converter is a regulator / rectifier, with output smoothing by capacitors. Electronic circuitry boosts voltage during times when generator output drops (engine idle) - it can produce 15v from as low as 6v input.



This unit is recommended to operate certain GPSs which allow a wide input range (some accept up to 30V). GPSs which accept a wide input range must have smooth power input! (not 30v spikes!). If the input voltage varies a lot (with RPM or spikes) then the GPS can set up input voltage incorrectly and damage itself. Another condition which is dangerous to electronics is when the motorcycle battery is very low, the resistance is high thus voltage spikes are not absorbed by the battery. For example an electric-start dirtbike with a low battery (using the kickstarter?) is a dangerous situation for electronics. If you are not using this device we recommend that you disconnect the GPS until the battery has recharged to the point that it can start the engine. Use this converter to ensure a constant safe supply for your electronics.The other model 030-0020 will work as well, but having a higher voltage (15v)provides better headroom for low generator output conditions (such as idle speed). To charge a small 12v battery in addition to running a 12v GPS you will need the 15v model. We cannot guarantee suitability of this item for your GPS or for charging batteries - this is just a suggestion. Be sure to verify that the input requirements for your GPS allow for 15vDC input at 160mA (= 2.4Watts).



NOTE: Most handheld GPSs require less than 2.4 watts. This unit does not produce enough current to operate a Zumo. The Garmin GPS276C input requirements (~10W) are substantially higher than this unit's 2.4W output.

 

[Midnitemapper]

In addition,
Aboard yachts, we usually run strictly DC systems. These DC systems are quite susceptible to "spikes " of current many times the base voltage. Also the wiring harness can "receive" HF radio frequency and light up lights with no power on! Sensitive electronics, computers can start acting funny and eventually fail. For this reason I use the converter Tourtech.
Aboard ship, all the electronics power supply is isolated from the rest of the ships DC power, Inline on the electronics supply, are isolators and spike arresters.

 

[dellboy218]

As there seems to be a little confusion I hope you dont mind if I stick my five pennyworth in.

If you measure an a.c. voltage with a cheap meter it will read around 60% of its peak value. A good meter will read the RMS value which is 70.7%.

To change this to DC it has to be rectified. The more efficient is full wave rectification which uses 4 diodes or buy the block bridge rectifier with 4 legs on it, it makes life simpler. This will give you a continuous ac signal but all in one direction, all positive or all negative whichever you require. This still has peaks in it so it has to be smoothed to make it as near as possible a flat d.c. signal. To do this one uses fairly large elctrolytic capacitors, several hundred microFarad. To eliminate spikes a small capacitor can be added, say .001 or .01 microFarad. You now have a smoothed but unregulated power source. i.e. the voltage can wander as it pleases.
If you now use your meter to check the dc Voltage it should be roughly the same as the ac peak voltage. Hence 12V ac rectified and smoothed becomes around 17V dc. This will start to drop though as soon as you put any load on it. Which is one reason why you need the output regulated.

There are several ways to regulate a supply depending on the job you want it to do. For light duties you can buy one of the family of 78 devices (+ve output), i.e. for 12 Volts use a 7812. These are generally available up to 2 Amps, more than sufficient for most GPS's. The regulators are another plastic block but with three leads, in, out and ground. Simple. The downside is their maximum input voltage is 35V. It is not difficult to make a variable output regulator that will work on a wider voltage range with a few cheap components. I dont know of any regulator relays that takes the supply line to ground. Electronic Regulators dispense excess energy off in heat.

After that of course you can go to Amorn and buy one their car power plug to 5V USB adaptors for 139B. That will give you 2 regulators more than ample isolation to protect your GPS I would have thought

However, you do need to know precisely what supply voltages you are up against before you start.

 

[AlexUSA]

Appreciate all of the alternative options but I'll try this easy option before anything else. 1600mah should run my unit for a long time. I left the battery, female cigarette lighter plug, etc. with my mechanic (who is 100% preoccupied with his new YZF250 right now). We'll see how it works out.

Just need a good box to enclose the battery in now.

Learned a thing or two about bike electrics here, too.

Midnitemapper - any pics of your MH lighting setup? Big lights on enduro bikes are awesome.

 

[KTMphil]

Alex - on a multi-day trip how do you plan to charge this battery does it come with a charger?

Appreciate all of the alternative options but I'll try this easy option before anything else. 1600mah should run my unit for a long time. I left the battery, female cigarette lighter plug, etc. with my mechanic (who is 100% preoccupied with his new YZF250 right now). We'll see how it works out.

Just need a good box to enclose the battery in now.

Learned a thing or two about bike electrics here, too.

Midnitemapper - any pics of your MH lighting setup? Big lights on enduro bikes are awesome.

 

[bigntall]

Great informative post for those of us sitting on the sidelines trying to soak it all in.

 

[AlexUSA]

Phil -

It comes with a charger but of course it uses the same socket that will go to the GPS unit so we have to split the wires.

 

[AlexUSA]

Full back light on for the past 18 hours and it hasn't run out of juice yet. We'll see how long it goes.

Just have to brainstorm a bit about how to weather-proof and secure the battery so I can still remove it easily - probably put it somewhere behind the headlight but not sure what sort of bag/box to use.

 

[MastaMax]

[attachment=0:1n5z1aka]Photo0014.jpg[/attachment:1n5z1aka]

Nice setup! Look at this website if you can find any ideas: http://www.waterproofcases.net/

 

[dellboy218]

Just as a by the way in case it ever comes in useful for another electrical project. If you were/are concerned about connecting the wires round the wrong way and damaging your equipment there is a simple way so that you can never ever get it wrong. As long as you can afford to lose 1.2-1.4 volt or so that is. Use a bridge rectifier. That might sound strange when you have already got dc but.......... if you connect your equipment to the + and - terminals of the bridge (the right way around) and have that fixed then your wandering lead power input goes to the ac terminals. It doen't matter which way around you put those wires as it will always come out of the bridge rectifier the same way. Just buy a bridge that can handle the current. It's simple and can save a lot of grief!

 

[AlexUSA]

 

[KTMphil]

Well done Alex, project finished!

 

[KTMphil]

Alex - i just finished having the Garmin hard wire power kits fitted to 3X DRZ 400's. These are the power leads that go from your 12V battery and have a converter to take the voltage down to 5.5V for a mini USB power connection. The nice thing about these is that you can power many other things that run off USB power from this power lead.

Here's the voltage converter box in the power lead tucked away out of the rain when the plastic is put back on.




This is the mini usb end ready for the gps on the handle bars




Gadget Trend in Bangkok sell these power leads.

 

[Midnitemapper]

Just a reminder, I remember Dave posted this also somewhere, when he had problems with his Zumo contacts.
Make sure that the power is switchable, and that it is off, when not in use. Otherwise water will get in there and turn those nice new contacts, inside that plug foamy green.
Electrolisis will not help the connection!

 

[KTMphil]

That's a very good idea about adding an on/off switch to the gps power line, I will do it for that reason.

Re: Hardwire GPS to Auxiliary Battery?

Postby Midnitemapper » Sat Jul 09, 2011 9:47 pm
Just a reminder, I remember Dave posted this also somewhere, when he had problems with his Zumo contacts.
Make sure that the power is switchable, and that it is off, when not in use. Otherwise water will get in there and turn those nice new contacts, inside that plug foamy green.
Electrolisis will not help the connection!