HDS-8 screen lost!

[Bassinkorea]

I have a HDS-8 on tne bow of my boat, and every time I make a run with the big motor I usually shut it down before I move.
However, one time today I started the motor without shutting down the HDS and the screen changed a strange color and was almost impossible to read. I rebooted it several times but it didn't fix the problem. I had to reset the unit to it's factory default settings and then it worked ok.

Is this normal, or is something a miss?

[Todd Driscoll]

Quirks like this can be caused by low input voltage to the unit.  The fact that it did this when you started your engine (which will create a voltage drop to the unit) makes it even more likely.  Could be a weak cranking battery, or faulty/corroded wiring or switches between the battery and the unit.  One way to quickly check is to measure voltage at the battery, then at the unit power plug (largest two pin holes in plug are input voltage).  Compare the two volt readings.  A slight drop to the unit (maybe 0.5 volts max) is normal due to resistance from the wires, but anything more that this difference would indicate wiring issues or a bad battery.

[Bassinkorea]

Thanks for the reply Todd.
I am pretty sure the wiring is ok as I only re-wired it up at the end of last year and all appears to look fine. I had to borrow a battery from a friend as my starter battery had drained itself to 6 volts over a couple of weeks sitting and it now will not recharge fully. Perhaps there's an issue in the wiring that is causing the batteries to drain even though the units are not powered up or even connected.

[Bassinkorea]

Quirks like this can be caused by low input voltage to the unit.  The fact that it did this when you started your engine (which will create a voltage drop to the unit) makes it even more likely.  Could be a weak cranking battery, or faulty/corroded wiring or switches between the battery and the unit.  One way to quickly check is to measure voltage at the battery, then at the unit power plug (largest two pin holes in plug are input voltage).  Compare the two volt readings.  A slight drop to the unit (maybe 0.5 volts max) is normal due to resistance from the wires, but anything more that this difference would indicate wiring issues or a bad battery.

Todd, I tried this test today and the results were very interesting. The voltage at the battery was 13.4 volts and the volts at the HDS plug was 13.6 volts 

I think my wiring is fine 

[Mike Cork]

You need to figure out how you created energy and patent it

BK, you'll need to see how much drop is happening when you fire up the big motor too. I have heard of this happening during starting from others, not specific to Lowrance but across the electronics community. A large voltage drop to the unit is not good no matter what electronic type device your using.

Could have been a connection that is now fixed because you've been troubleshooting or your motor could have been sitting on a compression stroke that caused a little extra drag on the battery when you went to start it.

[manbearpigbass]

my humminbird does this..... its wired to the same battery as the motor and when it hasnt been run in a while i have to turn it off before i crank the motor.... if i forget i have to release it from its mountt and re- install. i need to get a three bank charger to charge all three....but moneydont grow on trees and the two bank is working fine

[Bassinkorea]

Update;
When this issue first happened I was using a deep cycle battery as a cranking battery. Sometime later I was told that deep cycle batteries are not ideal for cranking the big motor, so I bought a new battery recommended by a local marine supplies store.
After fishing several times with the "new" battery, I have started the motor with the HDS-8 unit powered up and have had no issues with this problem so far.

Problem solved, thanks for all the helpful responses