GPS? Blink Out
 

Installed my garmin for a trial run (check out build thread to see mods) and the short answer is I like it.

Now the problem (I think I know one solution but seeing if there is something else I can do) the gps is hooked up to the house battery. I have a starting battery on its own. GPS is on and when I start the boat everything is fine no blink out. However when running I went to use the mercruiser power trim and NYC black out on the GPS(trim is on house battery). Had to hard start GPS.

Any ideas? Fixes or suggestions....thanks in advance.

Hmmm. Could be as simple as a loose battery connection, but I suspect you've checked for that.

Do you have the house battery wired to a fuse block and then the GPS and power trim fed from the fuse block? Wire sizes and lengths?

Low voltage systems are much more sensitive to voltage drop from wire resistance. I was surprised at how big the recommended wire sizes were for pumps and such. I wired most of my circuits with 12 gauge, or 10 gauge wire.

You can prop it up with a capacitor. Much like the kiddies do with "bang caps" for their crazy car stereos, you can use something much smaller. A diode in the supply wire, followed by a small resistor, like 1 ohm, followed by a big capacitor would help with this. The diode is a one way valve that means the capacitor only props up the voltage on the GPS, not everything else.

It will keep the GPS alive for the time when the trim motor starts and hogs all the current, browning out the GPS. I can elaborate with a sketch and part numbers if you want.

Heh... NYC blackout.
Nice. :D

Please do...I need to get this done by Wed. ;)

A shopping list from digikey. Skip the first capacitor- it is too small. Actually skip them both and get a car audio capacitor from Wal-Mart.

Most anything should work. 0.5-5F (Farad) would be fine. The 100,000 uF cap from digikey is a 0.1Farad cap. The Walmart ones are ~10x the size for the same $25.

The (big, metal can) resistor is to limit current when you reconnect the battery (or else BANG). You want it low resistance, like 0.33 ohm so the GPS doesn't lose voltage thru the resistor. But enough that when you connect the cap (or turn the switch on the house battery), the rush of current into the capacitor doesn't blow it up, or the fuse. It is a balancing act. You might need a 10A fuse to the cap, or a 15. And then a 3A fuse after the cap(acitor) inline to the GPS.

The diode keeps the capacitor from feeding anything but the GPS unit. Which limits you to a 10A fuse. The diode is the check valve for electricity. The silver band is the output (GPS) side. You will have to do some soldering.

Equivalent parts might be available from digikey.

Schematic to follow.

I am figuring your GPS doesn't draw more than 24 Watts. I think mine uses 8 or 9?

I think the schematic is attached.

This is readable as a PDF

Why is the trim not on the starting battery? Am I missing something?

strick

You aren't missing something...I did :eek: So I think the easiest thing to do is re-route the cable to a common post and then hook up a direct line to the starting battery.

I guess I did not think this whole thing out when installing...:mad:

FS thanks, but now I think moving it to S/B is the right thing to do...

Problem solved :)

The long answer to an easy fix.

After running a temp. wire from battery to power trim on starting battery everything worked fine. Then at the Seacraft outing while at idle speed I turned on the blower for the motor and the gps blinked out...hard start :confused:

On Sunday on the way home the gps crapped out and would not come up to load. It would show the logo and then die. :( I really need this.

Monday call Garmin and they tell me go check my house battery...sure enough it was on its last legs, enough to run stuff but not taking a real charge. so just under 8v and the Garmin would not fire up. Tried gps on starting battery turned on trim and blower and it just smiled pretty and stayed running. :D

Very good Terry!!! I had the same thing happen to me with my Raymarine....they are very sensitive to low voltage, bought a new deep cycle house battery and a two bank on board charger, all fixed. When you brought it up, we were thinking just a "spike" in voltage when you kicked on the blower . Take care!!

When I rehabbed my 18sf last winter I installed a dedicated starting battery and a dedicated "house" battery (electronics etc).
I tied them together with this kit from Blue Sea:
http://www.bluesea.com/products/7649...tery_Kit_-_65A
A single on off switch that independently switches each battery on and off and an automatic charging relay to keep them both topped off while also keeping them isolated from each other.
Worked flawlessly all summer.
You could even throw an emergency parallel in there if you wanted some backup starting capability.
http://assets.bluesea.com/images/pro...nails/7649.png

The blue seas kit already has an emergency parallel built in. Still debating installing one on my boat, whenever I start my motor it knocks out my gps.

To solve that problem Blue Seas has the starter interrupt on there ACR unit. I have the same switch as above plus the Automatic Charge Relay system on my electrical hook up.

Attachment 5750

Ditto on the Blue Seas ACR kit, along with the other Blue Seas items I see in the picture.....worth the extra few bucks!!!

Oh... Well then, carry on. :)

Doh!
Thats right. I forgot about that "third" battery switch position.
So far havent needed it!