# GPS Shuts off when starting gas motor UPDATE WITH SPECS



## Superlucky (May 1, 2019)

Hi All
I am sure this topic was covered previously, but my searches have come up empty.

I have a 30HP Honda on my 16 Gregor Alaskan. I have one group 24 cranking battery and no battery bank for a trolling motor. 
My GPS/Fishfinder is a Hummingbird Helix 7. 
My battery is mounted in the bow of the boat with 4 gauge wires running from the battery to a terminal block at the stern. From the terminal block, I have 12 gauge wires running to a switch panel for all accessories. 

Whenever I fire up the Honda when the Hummingbird is running, the Hummingbird shuts down. I must then turn off the breaker to the Hummingbird, turn it back on and then press the "Power" button on the Hummingbird to get it to fire back up.

I have had similar set ups in other boats and never had this problem. I don't really want to add a second battery to run the Hummingbird.

Any ideas?

UPDATE:

Got a chance to do a little diagnosis today and here is what I found:

With the battery still in the bow, connected to the terminal blocks at the stern.
Battery voltage while cranking: dropped to 10.25 and then stabilized at 11.42
AMP DRAW (With clamp meter) SPIKE 96, Stabilized 53 amps

I then moved the battery to the stern and hooked the Honda directly to the battery
Crank Voltage 11.29
Crank Amps: Spike 117, Stabilized at 73 amps

So......... I am confused that the cranking amps are higher when the battery is closer to the motor. Is this because the 4 gauge wire has maxed out capacity?

It appears that I might need to up the battery cables from the bow to the stern, but even if I do, it won't solve the problem of the battery voltage dropping off causing the Hummingbird to shut down as was my original problem.

Also, if I am not getting enough amps at the motor when cranking will this starve the starter, causing premature death?

All suggestions will be appreciated. 

Thanks

Bill


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## DaleH (May 1, 2019)

Check to make sure all connections are clean. And was it ever working OK? 

Starters pull a lot of peak amps, like a V6 is ~250 amps peak or so then dropping to 175 continuous whilst cranking. 

I just did the ampacity calculations for a 4AWG 12’ run (that means a 24’ circuit for ampacity) and I thought the total capacity (amps) for 4AWG was 160 or so. And that was for a load 12’ away from the battery. 

You might be pulling a lot of resistance, as even the you have long OB leads too. If your leads are close to 15’ long, 30’ circuit, the ampacity of that 4AWG cable is only rated for 100-amps ... see ampacity table attached, so that could be why you’re pulling down the GPS.

At that length run, even a 10% voltage drop of a typical 12.6 VDC circuit is going to be 11.34 volts and some sensitive electrical devices drop out at around 11 volts. I’d check your cable sizes w/ your OB and the H’bird recommendations, sounds like you’re trying to pull too many amps on too far a run.


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## KMixson (May 2, 2019)

The start switch may be cutting power to the GPS when turned all the way to "Start". Some switches have" Off" in which all power is off. "Accessory" in which your your accessories are on like GPS, radio, and other electronics are on. "Ignition" in which the ignition circuit is on along with the accessories. Then there is "Start" in which power to the starter circuit is supplied along with power to the ignition circuit. When in "Start" the power to the accessory circuit is cut off. This may be the reason the GPS is shutting down while starting. It may be wired into the "Accessory" terminal on the switch.


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## gnappi (May 2, 2019)

Connect a DMM to the battery and start it, you'll likely see the DC dip below 12 volts, that will cause electronic instrument re-starts. I installed a house battery because my FF was dropping out when my TM got bogged down in weeds.


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## Superlucky (May 2, 2019)

Thanks for the replies gentlemen. 
I will test the voltage and see what happens. 
All of the connections are new, clean and tight.
The wire selection was based on info provided by Honda for length/gauge.
For KMixson, the main battery wire run goes from the battery to a terminal block. The GPS is wired from the terminal block and does not go through any wiring on the motor. 
If voltage does not drop, I'll run a secondary wire to the motor to see if that helps. 

Thanks for the help. I'll post back later today if I get a chance to dive into the repairs.

Bill


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## jethro (May 3, 2019)

I know my Helix powers down if it sees less than 12 volts.


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## Superlucky (May 4, 2019)

I have updated the current draw in my first post.
Any input would be appreciated

Thanks
Bill


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## gnappi (May 4, 2019)

Superlucky said:


> I have updated the current draw in my first post.
> Any input would be appreciated
> 
> Thanks
> Bill



Disregard the current draw, the voltage dip is shutting down the electronics. As I said, I had the same problem and it was annoying enough to install a second "house" battery. FYI it won't have to be large, an inexpensive little wheelchair / solar battery @ 35AH or even lower will work. 

The PITA is having to maintain charge on two batteries at home, then for convenience sake a two bank battery tender will work just fine.


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## LDUBS (May 4, 2019)

Or, just start the motor before you turn the Helix7 on.


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## DaleH (May 4, 2019)

As I said, that 4 AWG it’s not big enough for a length of the run you have. I don’t care what Honda said, I would never trust them.

What is the length of your run one way from the battery to that terminal post? Me thinks you need bigger wire than 4AWG. But if you tell me the length of “how far away your battery is from the load “ I can tell you.

You are also quite lucky, a lot of new computerized OBs and the computer won’t even turn on if it doesn’t see a good 11V or more.


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## Superlucky (May 5, 2019)

Thanks for the replies, guys.

I agree that turning the motor on before starting the Hummingbird is a fair solution, unfortunately, I motor into coves, shut the motor off and leave the Hummingbird on to see what is happening underneath the boat. In a perfect world, I would remember to shut the unit off before starting the motor, but I am suffering from "can't remember @#it" disease and I find the shutting down the GPS annoying. 

My 4 gauge wires are 14 feet PLUS the leads from the motor to the terminal block are 5 feet for a grand total of 19 feet. I believe that upping the wiring is prudent, even though it probably won't solve the Hummingbird issue. 

I have also considered the second battery option, but it would not be my first choice, because, as described, it too can be a pain to keep it charged......

Thanks for your thoughts

Bill


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## LDUBS (May 6, 2019)

*". . . but I am suffering from "can't remember @#it" disease . . . "*

I can fully relate to that! haha


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## DaleH (May 6, 2019)

So ... you need battery cable sized for a 38’ (total length of circuit) run. Ouch, that means replacing the 4AWG cable as well as the outboard starting cables. That’s a long way to pull a lot of amps to start the motor ...


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## DaleH (May 6, 2019)

FYI, 1AWG cable - without any splice or connection - is recommended for up to a 20’ run (1-way).


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## Riverdog (Jun 8, 2019)

Just made my first run with my new helix 7. Had the exact same problem. It will shut off when starting and will not restart. I have to pull power cable and plug back in. Then it will turn on.
I was able to put the unit in standby mode, start motor and then out of standby mode with no problem.

Any update on this?


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## DaleH (Jun 8, 2019)

Riverdog said:


> Any update on this?


Hate to say it again, but you guys don’t have enough ampacity in your battery cables ...


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## Superlucky (Jun 9, 2019)

I am sorry for not updating this thread.

I too am convinced that my wiring is too small. I am planning to upgrade it. Unfortunately, life has gotten in the way of this project (Fishing too), and I will be out of action for a while.

I will be ordering the wire soon and I will update any improvements.

Bill


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## eshaw (Jun 9, 2019)

Just a suggestion from a novice, but why couldn't he just install a small 12v battery like comes on a riding mower for power to the FF?


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## gnappi (Jun 9, 2019)

Riverdog said:


> Just made my first run with my new helix 7. Had the exact same problem. It will shut off when starting and will not restart. I have to pull power cable and plug back in. Then it will turn on.
> I was able to put the unit in standby mode, start motor and then out of standby mode with no problem.
> 
> Any update on this?



It sounds like mdubs has the best short term solution...

"Or, just start the motor before you turn the Helix7 on."

I guess it will be a PITA if you start / stop the motor a lot for trolling, but still aside from a installing a little house battery these are to me the most practical approaches before going through exhaustive and expensive methods that may still not work.


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## Riverdog (Jun 9, 2019)

DaleH said:


> Riverdog said:
> 
> 
> > Any update on this?
> ...



On mine, I have an 8 ga 5ft length (duplex,marine) going from the battery to the marine fuse box. Then FF connected to that. Battery is connected separately with factory cable.

I watched my Mercury Smart Craft tach gauge while starting and it went from 12.6 v to 9-8v then back up to 13-14v. Since my current battery is getting old, I'm going to replace it. Still cranks fast though. I'll start there, then redo connectors next. A third battery to worry about is too much, I'll just use the standby mode if a new battery and new connections fail.
Maybe a software update is coming, my previous 597 humminbird didn't have the same problem.





gnappi said:


> Riverdog said:
> 
> 
> > Just made my first run with my new helix 7. Had the exact same problem. It will shut off when starting and will not restart. I have to pull power cable and plug back in. Then it will turn on.
> ...





Like posted before, if I put the unit in standby mode I can bring it back up after starting. Just a few less buttons to press and goes back to the same window.





Superlucky said:


> I am sorry for not updating this thread.
> 
> I too am convinced that my wiring is too small. I am planning to upgrade it. Unfortunately, life has gotten in the way of this project (Fishing too), and I will be out of action for a while.
> 
> ...





Don't mean to hijack your thread, just figured we're having the same problem.


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## Riverdog (Jun 15, 2019)

Put a new battery in and unit no longer shuts off. Watched the volts while cranking and didn't go below 11v.


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## Superlucky (Jun 16, 2019)

Well, that shows another solution to this problem! Glad that worked.

I am still going to upgrade the wiring when I have a spare two hours. (Don't see it in the near future).

I will update this post when I do.

Have a great day

Bill


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