Garmin turns off when I start the engine


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I'm interested.

Are you using this setup?

As I understand the current setup, the factory wiring has the stereo and all electronics wired through the ACCESSORY dash mounted Contura switch.

I plan on separating these and will move the sound system to one battery bank and the electronics to the other.

Another big amperage draw is the windlass.

Plan on running some heavy duty wiring directly from the battery banks through Blue Seas flip breakers first.

This should be more than adequate to cover these loads, then the 7.5 amp fuses (or whatever) for the MFD's, maybe a light breaker as well.

These CAT starters draw a lot of amps, and otherwise, without a dedicated house battery, no easy solution. Maybe run a pair of heavy wires to the genset battery???

BEST !

RWS

Any more tips on this would be appreciated.
 
I’m not running this yet. I’ve been wanting to pose this question to people smarter than me for a while. There’s a good chance those people are here.:)
 
I’m not running this yet. I’ve been wanting to pose this question to people smarter than me for a while. There’s a good chance those people are here.:)

Not sure I am one of those people but I will try and support your response anyway. I have a similar problem but with my digital engine converters (ActiSense EMU-1). I have to start the engines with the parallel switch engaged or the EMU-1 for that engine does not reset correctly and is locked up. It's not a battery issue just a current issue. My starters draw quite a bit of instantaneous current when starting the engines. I have a 1fd cap I use with my power amp and tried it for the EMU and it worked nicely. The issue is they are quite large, bigger then a 16oz. water bottle and finding an appropriate mounting place can be challenging.

I am planning on ordering two cheap-o's for this purpose. The quality of the cap's filtering capability isn't needed here and only it's charged capacity is.

Edit: Embedded link kept going to ebay and not amazon: https://www.amazon.com/gp/product/B00OYFVREA/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
 
Last edited:
Not sure I am one of those people but I will try and support your response anyway. I have a similar problem but with my digital engine converters (ActiSense EMU-1). I have to start the engines with the parallel switch engaged or the EMU-1 for that engine does not reset correctly and is locked up. It's not a battery issue just a current issue. My starters draw quite a bit of instantaneous current when starting the engines. I have a 1fd cap I use with my power amp and tried it for the EMU and it worked nicely. The issue is they are quite large, bigger then a 16oz. water bottle and finding an appropriate mounting place can be challenging.

I am planning on ordering two cheap-o's for this purpose. The quality of the cap's filtering capability isn't needed here and only it's charged capacity is.

Edit: Embedded link kept going to ebay and not amazon: https://www.amazon.com/gp/product/B00OYFVREA/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Wow! Great response. I would love to pick ur brain more as this project approaches
 
This problem is easily solved with the addition of a Bosch 30amp relay. During cranking the voltage drop is too great causing the unit to power down. Rather than the switch turning on the unit directly, use the switch to turn on the relay coil and wire unit directly to the load side of the unit. Cost is a couple bucks and a few minutes to wire it up.
 
This problem is easily solved with the addition of a Bosch 30amp relay. During cranking the voltage drop is too great causing the unit to power down. Rather than the switch turning on the unit directly, use the switch to turn on the relay coil and wire unit directly to the load side of the unit. Cost is a couple bucks and a few minutes to wire it up.


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I'd love to see the wiring diagram for this.

Another possible alternative that I just thought of would be to wire the supply side of the electronics to a toggle that could select to source the supply from one battery or the other battery or BOTH batteries. However without a diode setup this could this possibly cause problems between the battery banks??

I like the idea of the Bosch relay. My understanding is that it would then automatically switch the source from one battery bank to the other instantly when the starter is engaged.

Is this assumption correct?

BEST !

RWS
 
No. Currently there is a toggle or accessory switch that turns on the Garmin unit, correct? Rather than using the switch directly to 12V to power the unit, use the switch to power a relay.

Here -

86 - comes from the accessory switch
87 - 12v+ to Garmin. Garmin also gets grounded.
85 - Ground
30 - 12v+ direct from battery or main buss bar

Screenshot_20220607-054904_Edge.jpg
 
No. Currently there is a toggle or accessory switch that turns on the Garmin unit, correct? Rather than using the switch directly to 12V to power the unit, use the switch to power a relay.

Here -

86 - comes from the accessory switch
87 - 12v+ to Garmin. Garmin also gets grounded.
85 - Ground
30 - 12v+ direct from battery or main buss bar

View attachment 128189

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So in this instance the relay is allowing for a direct connection to the source (battery) with no voltage/amperage/resistance loss through the switch - correct?
 
Yes, minimal voltage drop through the relay. Most importantly minimizing voltage drop during cranking which is where your problem lies.
 
Yes, minimal voltage drop through the relay. Most importantly minimizing voltage drop during cranking which is where your problem lies.
Could you explain specifically how this solves the problem? Currently the voltage at the Garmin is dropping below its turn on threshold, by the starter draw. A poster here said the Garmin turn on is in the 9 volt area. With the relay, the voltage drop is moved to the trigger input. But the trigger turn on for those relays is in the 9.5v volt area. So it may not turn on either. Has he measured the voltage at the battery itself during starter cranking? Isn’t it where the voltage drop actually occurs? So would the new direct feed to the Garmin also see the same voltage drop it?

I just don’t understand how this fixes it and would like to get educated better so I understand.
 
I installed a small sealed battery under the helm wired in parallel, then wired in a normally closed solenoid to disconnect it from the main batteries. I start all my electronics then when I'm ready to start the engines, I hit the switch disconnecting all the electronics from the main batteries, start the engines, then switch back. This also provides emergency battery power for radio/electronics if there is a problem with the main batteries.
 
My Raymarine MFD has always done this. It did it before and after I replaced all of the batteries. I have a couple other things on the same 12v helm circuit like the USB power to the Tablet I use for VV Mobile and my Sirius XM player and it does not affect those -- just the Raymarine. As a result I fire it up after the engines are running so I don't have to start it up twice.
 
Could you explain specifically how this solves the problem? Currently the voltage at the Garmin is dropping below its turn on threshold, by the starter draw. A poster here said the Garmin turn on is in the 9 volt area. With the relay, the voltage drop is moved to the trigger input. But the trigger turn on for those relays is in the 9.5v volt area. So it may not turn on either. Has he measured the voltage at the battery itself during starter cranking? Isn’t it where the voltage drop actually occurs? So would the new direct feed to the Garmin also see the same voltage drop it?

I just don’t understand how this fixes it and would like to get educated better so I understand.

I am with you, this doesn't fix anything. It just changes/switches the problem to the relay now.

Regardless of the new/old battery conversation. The issue is when the starter is engaged the voltage drop is significant enough to cause the electronics to see a "brown out" condition and they try and reboot. This is a very bad situation for the electronics and over time can damage the devices seeing this voltage drop. Using a relay to switch the power on/off is a great way to use a lower current rated switch to turn on a higher current draw application. But this will not fix a low power condition.

Not many way's to fix this. The easiest is to turn on the electronics after the engines are started, also the safest for the electronics. Another way is to use a dedicated house battery and connect your electronics to that, but will need the 12v supply to the panel to be re-wired. Another possible solution is my post #24.
 
Could you explain specifically how this solves the problem? Currently the voltage at the Garmin is dropping below its turn on threshold, by the starter draw. A poster here said the Garmin turn on is in the 9 volt area. With the relay, the voltage drop is moved to the trigger input. But the trigger turn on for those relays is in the 9.5v volt area. So it may not turn on either. Has he measured the voltage at the battery itself during starter cranking? Isn’t it where the voltage drop actually occurs? So would the new direct feed to the Garmin also see the same voltage drop it?

I just don’t understand how this fixes it and would like to get educated better so I understand.
Most 30A relays that I've come across require 6-8V for power up. It's possible it doesn't work as I suggested. If not, we can add a small capacitor inline with a diode (not a big stereo cap like suggested earlier). That would be a belt and suspenders approach.
 
Most 30A relays that I've come across require 6-8V for power up. It's possible it doesn't work as I suggested. If not, we can add a small capacitor inline with a diode (not a big stereo cap like suggested earlier). That would be a belt and suspenders approach.
Got it. My 9.5v relay trigger assumption was just based on one google search. Nothing scientific.
 
I am with you, this doesn't fix anything. It just changes/switches the problem to the relay now.

Regardless of the new/old battery conversation. The issue is when the starter is engaged the voltage drop is significant enough to cause the electronics to see a "brown out" condition and they try and reboot. This is a very bad situation for the electronics and over time can damage the devices seeing this voltage drop. Using a relay to switch the power on/off is a great way to use a lower current rated switch to turn on a higher current draw application. But this will not fix a low power condition.

Not many way's to fix this. The easiest is to turn on the electronics after the engines are started, also the safest for the electronics. Another way is to use a dedicated house battery and connect your electronics to that, but will need the 12v supply to the panel to be re-wired. Another possible solution is my post #24.

I have been doing aftermarket engine swaps in vehicles for over 25 years that experience the exact same problem when the ECU's are wired directly to a 12v switched source. The computer looses voltage during cranking and thus goes dead and the engine doesn't start. When someone brings me their swap, 9x out of 10 I see it wired this way. As soon as I wire it through a relay, the voltage drop is minimized and the car starts. As I mentioned in my earlier post, if for some reason it doesn't work, he could always wire in a small capacitor inline.
 
I have been doing aftermarket engine swaps in vehicles for over 25 years that experience the exact same problem when the ECU's are wired directly to a 12v switched source. The computer looses voltage during cranking and thus goes dead and the engine doesn't start. When someone brings me their swap, 9x out of 10 I see it wired this way. As soon as I wire it through a relay, the voltage drop is minimized and the car starts. As I mentioned in my earlier post, if for some reason it doesn't work, he could always wire in a small capacitor inline.

I am not going to trade experience comments with you and will stick to the facts. The voltage drop at the supply is going to be what it is regardless of using a relay or not. All the relay does is change the voltage trigger point. Starting a car is significantly different then starting a diesel engine in a boat. If you put a voltage monitor that records on the battery when the engine is started you will see what the voltage drops to. In my case, the instantaneous voltage drop was 2.15v and that is with a 1200cca 8D Battery. So using a ~6v trigger relay will not fix this.

I agree using a 1fd cap is not the best fix, but the only way to fix this is to replace the power source for the time that voltage is lower then required. Using a cap and diode will only fix the voltage drop as long as the RC constant is greater then the time of the voltage drop lasts for and that takes a large cap. 1fd caps are super easy and relatively inexpensive. Using an RC network to power the relay may work as well, but a bit more complicated then putting a cap in parallel with the device.
 
I am not going to trade experience comments with you and will stick to the facts. The voltage drop at the supply is going to be what it is regardless of using a relay or not. All the relay does is change the voltage trigger point. Starting a car is significantly different then starting a diesel engine in a boat. If you put a voltage monitor that records on the battery when the engine is started you will see what the voltage drops to. In my case, the instantaneous voltage drop was 2.15v and that is with a 1200cca 8D Battery. So using a ~6v trigger relay will not fix this.

I agree using a 1fd cap is not the best fix, but the only way to fix this is to replace the power source for the time that voltage is lower then required. Using a cap and diode will only fix the voltage drop as long as the RC constant is greater then the time of the voltage drop lasts for and that takes a large cap. 1fd caps are super easy and relatively inexpensive. Using an RC network to power the relay may work as well, but a bit more complicated then putting a cap in parallel with the device.

My response wasn't meant to be argumentative. Yes, I agree with everything you stated. I have never experienced a voltage to 2V during cranking and thus why the relay solution typically works. And as long as RC is greater than your instantaneous voltage drop, the cap/diode solution would likely fix the 2V drop as well.
 
Would this solve the problem:

let's assume electronics normally run off port battery

Wire the solenoid in so it is energized when port battery starter is engaged

Wire the solenoid so it feeds the electronics from the starboard battery during the time the port engine is cranking.

Would this be a simple fix?

BEST !

RWS
 

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