Lowrancs HDS 8 Dropouts

[Bad_Bazza]

I have Lowrance HDS8 Sounders and side sonar fitted to my boat and I am experiencing a problem with the sounder dropping out when I start my main motor.
It does not happen every time but it happens often enough to by very, very annoying as the reboot on these sounders takes a long time as well you lose your recent history.
I have been through just about everything I can to try and overcome the problem but it will not go away. I have replaced the battery, rewired the sounders, had the main motor checked out electrically but have not been able to unearth the problem.
It has bee suggested I fit another battery soley for the sounders but I don't want to do that if I can avoid it as I am already carrying up to 5 batteries when I run on electric motor. The boat is on 4.35 m and there is a limit to what you can carry. I can't run them off the electric motor batteries as there is too much interference.

I would appreciate any help with this especially from anyone who has experienced the same problem and resolved it.

Bad_Bazza

[frankgrimes]

When you crank the engine the voltage drops below the minimum needed to run the device...can be caused by poor connections, old battery, long cable runs etc.

If there's no obvious cause, then you could try fitting a voltage booster to keep it at 12v during cranking.

Mick

[Bad_Bazza]

Thanks for that Mick,
I have fitted a brand new battery and as I said I have rewired the units, had the main motor checked.
I will make enquiries about the voltage booster, that may well be the answer.

Bad Bazza

[leelee]

Baz try this test just before you do anything more -

1. Add the voltage as an overlay on the hds .
2. Note the reading prior to starting the motor

This should give you an idea if you have a dead cell or not.

Also how have you got your LSS1 set up. Is the yellow wire connected (sleep) or does the lss1 come on when you switch on accessories?

Cheers

Lee

[Grand_Marlin]

Bazza,

What motor do you have?
What battery have you fitted?
What size wire are you running from the battery to the dash electrics / sounder?

Cheers

Pete

[Bad_Bazza]

Lee,
I have a brand new battery fitted so I would hope that it is not a cell.
Never the less I will try what you have suggested.
I have wired the LSS1 (yellow wire) to a switch so that you have to turn it on independently.
The sounder/s will drop out regardless of wether the LSS1 is on, or wether either or both sounders are on.
Pete,
The motor is a 50 hp Mercury 4 stroke (about to be updated to EFI 4 stroke).
Battery is a Century Marine N70ZM and is the largest capacity battery that I can fit in the battery space available.
I am not 100% sure on the wiring size but I think it is 6 mm.
It was upgraded so that there was 10 amps at the switchboard and going to the sounders.
Once again thanks for your help

Bad_Bazza

[Boat Hog]

I experienced a similar problem when I changed the motor on my boat (130hp 2stroke to 150hp 4 stroke). On one battery, the electronics would shut down when I cranked the motor. On two batteries everything was okay. Did a bit of research and found that the batteries I had were below the recommended CCA for the new motor. Upgraded the batteries (and yes one of them was a tight fit) and everything works as it should - running on one battery no more drop outs at start up. I would suggest checking your engine power requirements against your battery rating.

Cheers,

[Bad_Bazza]

Thanks Jim,
I will follow that up I know the battery has 720 CCA @ 18 Degrees so will check what my motor requirements are.

Bad_Bazza

[Grand_Marlin]

G'day Bazza,

Your problem is voltage drop, nothing to do with the sounder.
It is just a matter of where it is occurring.

720cca is plenty for a 50hp 4 stroke Merc.
New or not, get the battery load tested... Century Marine Batteries... hmmm

Check your wire size - this is usually where the problem occurs.
A 10 amp circuit normally refers to 3mm wire, maybe 4mm.
Because you are having voltage drop problems, make sure the main wire is minimum 6mm... 8m or 10mm would be even better.
Make sure your earth cable is the same size as the positive.
The connections are very important. I recommend running the big cabe to bus bars, then take your accessories off of the bus bars.
Make sure all connections are direct to the bus bars and not spliced into the wires of other accessories.

Did I mention get that Century battery tested...

Cheers

Pete