Troubleshooting Power to Headunit

[wanderful]

I'm struggling to figure out why I can't power on my fishfinder, and I'm hoping the sharper and more experienced minds of this forum can help me make traction. Here's the situation: I recently purchased a Garmin Echomap UHD 93sv with GT54UHD transducer. I also purchased an Amped Outdoors 15Ah LiFePO4 battery to power it. My multi-meter is reading 14.5V at the battery, at the end of the power cable, and at the pins of the fishfinder cradle. The headunit needs 12V to power on, so I can confirm I'm getting enough power to the cradle. When I plug the head unit into the cradle, even though the cradle is getting 14.5V, it will not power on. This seemed like the issue would be a bad headunit or cradle.

 

I took the headunit and cradle to Scheels to test on their power and confirm. I plugged the headunit and cradle into a demo station and the headunit powered on as soon as I hit the on button. So I'm at a loss.

 

The issue clearly isn't the cradle or headunit, since it turned on at the store. So it must be my wiring setup, or my batter, right? But I'm reading 14.5V from the battery all the way to the cradle. Any help would be greatly appreciated!

 

[MN Fisher]

Reversed the polarity during install?

[wanderful]

20 minutes ago, MN Fisher said:

Reversed the polarity during install?

Would that just be at the battery, as in positive and negative switched?

[Fishingmickey]

17 minutes ago, wanderful said:

Would that just be at the battery, as in positive and negative switched?

Yes, If the polarity is wrong/reversed it won't power up. I think MN's spot on.

FM

 

[MN Fisher]

17 minutes ago, wanderful said:

Would that just be at the battery, as in positive and negative switched?

Could be at the battery if you ran the Garmin power cable directly to it...or could be where you connected the Garmin cable to 'where-ever' - either butt-joined to a cable from the battery or the fuse box.

[wanderful]

1 hour ago, MN Fisher said:

Could be at the battery if you ran the Garmin power cable directly to it...or could be where you connected the Garmin cable to 'where-ever' - either butt-joined to a cable from the battery or the fuse box.

I checked the battery and cables - it's all red and red and black on black, which I think means the polarity is correct? Anywhere else I should check?

[Tennessee Boy]

Is there anything else connected to the same battery?

[wanderful]

1 hour ago, Tennessee Boy said:

Is there anything else connected to the same battery?

Great question - there's nothing connected except the power cable for the fishfinder. 

I called Garmin support and they think it's the cradle or power cable, so are shipping out new ones. I'll update this thread of that resolves the issue.

[casts_by_fly]

since they are sending new ones, I would check it with the battery as the current one is hooked up, but without running it anywhere and skip the cradle if that's possible. On my Hbird I can plug the cord right into the back of the unit.  At least then you'll know you have a working set before you start wiring things around.

 

That said, it doesn't make any sense that the cradle has power without the unit and the cradle and unit power up at the store.  I'm with MNFisher on this one.  I would reverse your wires at the battery and plug it in.  I bet something is switched somewhere.

[slonezp]

Wife sabotage. She wants to keep you at home. 

[Maggiesmaster]

On 7/24/2023 at 2:01 PM, casts_by_fly said:

since they are sending new ones, I would check it with the battery as the current one is hooked up, but without running it anywhere and skip the cradle if that's possible. On my Hbird I can plug the cord right into the back of the unit.  At least then you'll know you have a working set before you start wiring things around.

 

That said, it doesn't make any sense that the cradle has power without the unit and the cradle and unit power up at the store.  I'm with MNFisher on this one.  I would reverse your wires at the battery and plug it in.  I bet something is switched somewhere.

This sounds worth doing.  Be sure to double-check any connections, splices etc. for good connections. I recently had much the same problem and discovered a poor connection. Same thing happened to me several years ago with a trolling motor.  Bet your problem is something simple.

[WRB]

It’s DC so you can check continuity of the ground battery post to any positive contact to eliminate reverse polarity using your multi meter. 

Tom

[wanderful]

On 7/24/2023 at 8:26 AM, MN Fisher said:

Reversed the polarity during install?

This was it! I had the black cables hooked up to the black contacts, and red cables hooked to the red contacts on the battery. When I swapped it so that it was black-red, black-red it suddenly worked! I'm confused because I had thought you always connect the same colors, but clearly not with this battery ?

 

Thanks for the advice!

[MN Fisher]

15 minutes ago, wanderful said:

Thanks for the advice!

Is that direct from the Garmin, or is there another connection between the battery and the head unit?

 

By the picture....

Plain red wire should be positive - currently connected to negative

Red/Black wire should be negative - currently connected to positive

 

So it looks like there's a polarity reversal somewhere between the battery and the unit. Since it worked fine at Scheels maybe even the plug that connects to the cradle...did you bring your cable or use theirs?

 

Or it could even be the connections inside the battery - what's the brand of that battery?

 

I know it might seem anal...but that's how nit-picky I am when wiring up things.

[WRB]

Check the metal tabs with a multimeter, takes about 1 second. My guess the battery is correct, wherever the end of those 2 wire connect are reversed. The OP was getting a new power cord, but should check the battery 1st!

Tom