Problem with in-car GPS install - interesting challenge

eisenb11

Intro: ----

I recently purchased a Holux GR-230 BT receiver. This is being used in conjunction with an Ipaq 4155, Mapoplis Navigator, and a Seidio mount.

Getting this all to "work" together is simple enough but I ran into a problem that I'm having a hard time getting around...

The Challenge: ----

1) To permanently install a BT GPS unit into the car so that it's on when the car is on and off when the car is off

2) To do this without having to fiddle with wires or power switches

In short, I want to have a GPS system installed so that it behaves in a similar manner to a manufacturer installed system.

What I've done: ----

Mounting the Ipaq was easy thanks to the Seidio mount and the vent kit included with it.

Since I wanted the BT GPS received to have a good view of the sky (and not get in the way) it's mounted in the back under the rear window.

I had a 12V switched cigarette lighter-type power source installed in the trunk that the GPS unit plugs into. Since it's switched, I don't have to worry about the unit draining the car's battery.

The Problem: ----

This is the key to solving this challenge...

The problem that I'm running into is that the GPS unit is behaving undesirably when the main battery pack is drained.

Since they goal is for "auto-on", the GPS unit is left on. When the car is turned off, the GPS unit runs on battery power until the battery dies.

When I return in the morning and switch the car on, the GPS unit will not lock onto sattellites and I cannot connect to it via BT.

After some experimentation and some dialog with Holux I found the problem. Apparently the Holux operates off of battery power. If the unit is plugged in, the car charges the batteries while the batteries power the GPS.

Since the GPS battery is drained upon startup, the unit will not work for quite some time until it's battery is charged beyond some minimal point.

I'm not sure how to get around this problem. The solutions seem to be 1) perform some weird unknown hack or 2) replace the Holux with another BT receiver that is capable of performing this task.

Since I know nothing about electronics I have no idea on option (1) - do you guys have any ideas?

As for option (2) - are there any recommendations on units that would be able to do this?

I tried thinking up a list of what the "ideal" unit would do... I wonder if a product that does this already exists?

-- The ideal unit --

1. Runs directly off of the 12V car power source (unlike the Holux which runs off a battery - even if plugged in)
2. Has a BT transmitter
3. Has a battery backed memory to retain satellite info
4. Is capable of running when the main battery is drained but the unit is plugged in (or alternately, doesn't even have a main battery)

Something like this would be perfect... in a sense it would act exactly like a manufacturer installed system with the addition of BT to communicate with the Ipaq.

Does anyone know if this is possible?

Semsons has recommended returning the Holux for a Fortuna Clip-On, but after doing some research it appears that the Fortuna does not have a battery backed memory so you have to go through a cold boot upon starting the car if the main battery is depleted (apparently this can take it up to 45 minutes to complete)... that is much too long a wait.

Thanks in advance!

eisenb11

eisenb11 · Posted: Thu May 20, 2004 1:58 pm Post subject:

This is a tough challenge... I'm still stuck! Smile

eisenb11

grimbo · Posted: Thu May 20, 2004 7:55 pm Post subject: BT auto on/off

If you can find a Tomtom BT receiver with a car charger cradle this will solve your problem, it turns the GPS on/off with the ignition.

However, I have one of these and you may have seen elswhere in forums that Tomtom BT's are prone to dying, as did mine Crying or Very sad

A post in the forum has said that the new replacement BT receiver ships without the cradle. Im not sure if this is correct.

best of luck

eisenb11 · Posted: Fri May 21, 2004 3:15 pm Post subject:

Hi Grimble,

Yes, I read that those can be hard wired into the car, but that were hard to acquire these days. I wonder what it is that makes the unit so prone to dying?

Anyways, thanks to Darren, we were able to figure out a good solution. Apparently the Royaltek BlueGPS has hardware on/off... so even if the battery gets drained, the unit will run off the car's electrical power (perfect for what I wanted).

The unit should get here on Monday/Tuesday then the first thing I'll do is drain the battery and see what happens the next day! Smile

eisenb11

Gazjen · Occasional Visitor Joined: May 21, 2004 Posts: 11

Hi
I know this sounds daft but what about connecting it to a permanent supply the gps unit can't take much power on its own. As long as you switch the ipac off. How long do you leave your car for each time? Think it would take a long time to discharge a car battery. If there are any power consumptions or rated wattages on the unit you can work out the discharge rate and from that gauge how long your car battery would last. Probably the cheapest option..

eisenb11 · Posted: Mon May 24, 2004 2:43 pm Post subject:

Hi Gazjen,

I think the consumption is 5V, 850 mA, but I have no idea on the wattage. The Royaltek came in on Saturday morning (day after it shipped, which is a surprise) and works like a charm!

I did some discharge tests by allowing the unit to drain overnight. The next day, I'd power the car up and I'd have a lock between 1-2 minutes. I'm sure my actions are going to destroy the internal lithion ion battery, but that's ok since I have no plans on running it off battery power anyways.

The reason, I didnt want to hook the GPS up to a live power source is because of my driving habits. I live 2 miles from work so the commute doesn't really allow the battery much time to recharge... because of this, I wanted to minimize on drainage to avoid any jump starts in the near future! Smile

Ofcourse, I could have easily solved all this by turning the unit on and off when needed, but that solution isn't as "smooth" and will be a lot harder when I move the unit to the trunk and place an antenna on the rear parcel shelf (where the GPS unit currently resides).

eisenb11

gypsy666 · Occasional Visitor Joined: May 24, 2004 Posts: 19

Am i missing something here.....

If your leaving this in hard wired , can you not just remove the battery !!

Wink

eisenb11 · Posted: Mon May 24, 2004 3:59 pm Post subject:

Hi gypsy666,

I believe both units (the Holux & the Royaltek) have internal batteries.

In the case of the Holux, the unit requires the battery - even if plugged into the car. It also requires that the battery be at least partially charged.

The Royaltek doesn't require that the battery be charged, but I'm not sure if it at least requires the battery to be installed.

eisenb11

gypsy666 · Occasional Visitor Joined: May 24, 2004 Posts: 19

Ok , my fortuns is probably the same then......

Not sure if this is an option , but what if you hard wired the power from inside the battery bay , so the unit thinks it has a battery installed , and fully charged !!

You would have to suss out the pinouts etc , and could posibly get hold of a used battery , rip it to bitz , and use it as an adaptor if you get my meaning , save messing it up with a solidering iron etc......

My guess would be you would have to wire the positive to 2 terminals , one that recieves power from the battery to give the unit life , and another to fool the unit into thinking it was fully charged , then one negative......

eisenb11 · Posted: Mon May 24, 2004 4:40 pm Post subject:

It's funny that you mention that... my friend and I were talking about the exact same thing last Saturday!

Wiring the power probably wouldn't be too hard, but where it gets messy is the part where you'd have to "lie" about the battery charge status.

The Holux, for example, does monitor the charge - hence the requirement that you at least be at some minimal charge level. I'm not sure how LiOn batteries work to accomplish this though.

In the end, it turned out to be easier to order the Royaltek which worked right out of the box for my purposes! Smile

I still have 2 weeks to return the Holux to Semsons, but my friend is thinking about buying it off of me. If he does that, I don't lose the $8 to ship it back!

I also heard that the Haicom unit *might* be able to work with a dead battery as well, but it seemed cleaner dealing with an all-in-one unit than the CF GPS + slipper option.

eisenb11

gypsy666 · Occasional Visitor Joined: May 24, 2004 Posts: 19

OK .looks like you will get it sorted then....if you need me to check my Fortuna to see if it works whithout the battery , let me know , will only take ma a couple of mins...

But just an addition to my last post...

I see your point about lion batt's etc , but dont think this will come into play , one that car power is removed it will be as good as switching the unit completely OFF...

Once car power is returned , it's the same as switching ON , i,m sure your right , it will go off and check battery charge state , but it should just get a "fully charged" signal back.....

just found this on a search :

Most devices, such as the iPod, that don't have removable batteries use LiON (lithium ion) technology, as do nearly all notebook computers. LiON batteries are not subject to the memory effect , but like all rechargeables, they can only be recharged a limited number of times before they'll fail. Most LiON batteries die after several thousand charges, typically a couple of years of use. LiON batteries can explode if overcharged, but they all come with circuitry that prevents that.

Steve

eisenb11 · Posted: Mon May 24, 2004 6:26 pm Post subject:

Looks like the LiOn is a pretty complicated beast with its onboard circuitry (I wonder if this is also used to check charge status?).

As for me, I'm all set now with the Royaltek, but if you want to test the Fortuna, it might provide good information for people in the future who are debating which GPS to buy for a permanent in-car GPS solution.

So far, these are supposed to work...

* Royaltek (confirmed by Darren & myself)
* Emtac (confirmed by Darren)

Haicom *may* work, but I have no confirmation.

eisenb11

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