GPS & sonars shutting off on start-up

[lew]

Last weekend while I was fishing, my GPS & sonar units shut down a couple times when I started my motor and I had to turn them back on again, and I'm assuming it happened because my battery is getting weak ??

 

The cranking battery is 9 years old and I'm replacing it before I head to Lakair next week anyway, but I just want to be sure I don't have another problem somewhere.

 

Last month when I arrived at Quinte my battery was totally dead and I found I'd left a light switch on for a week but it re-started with no problem with a boost from my deep-cycle and seemed to charge fine after a few hours of trolling.

 

I've heard before that a weak battery can cause electronics to shut down as there just isn't enough juice to crank the motor over, plus keep the toys running.

 

If it matters, it's a 90 HP Merc 4 stroke, and I use a Lowrance Global map 7200, Lowrance X510c and on the bow is a Humminbird Wide-Optic

 

Never had any problems until last weekend....any thoughts ??

[ecmilley]

you should be fine with the new battery, most boat electronics seem to shut down around 9 volts, so if your cranking battery is failing the voltage drop on start up would shut your sonar/gps off

[duber]

I would say you are rite on the money Lew- bad battery.When you are cranking your motor over the voltage spikes down under 10 volts and shuts the toys down.

[lew]

Thanks boyz, that's what I figured, so I'm off to purchase a new battery.

 

While I was under way, it'd register around 13.75 but drop below 10 on start-up.

 

I sure can't complain though with getting 9 years from a battery, it pays to look after your gear from day one Still going strong with the 2 origianl deep-cycles too, but their days may be getting numbered also.

[workwear]

hey lew....looks like i need to get a new cranking battery also.......seems my problem was the battery.....marine told me i need to get at least a 1000 cranking amps....

 

what battery are you gonna get.....

[Seaweed]

A new battery is always nice Lew. I had to get a new battery myself this spring... the old one lasted 8 years though so I'm not complaining. I hope it solves your issue.

 

I have the same problems with an Eagle finder on my boat sometimes. What I have discovered is that I usually have a connector that is loose. I always take my electronics out of my boat after each use... so I have to reconnect them every time I go out and sometimes in the heat of wanting to get out on the water and fishing I get a little sloppy in plugging it in.

 

Check your connections in case.

[Gerry]

Yep, weak battery. 9 years out of the old one is darn good, a lot better than I've ever had. On my 2002 Optimax I had to replace the cranking after 4 years. The Optis take a lot of juice to turn them over which is why we need a 1000 amp battery. I'm not sure what your 4 stroke needs.

[lew]

I never shop at Wal-Mart but have heard they sometimes have good deals on batteries so I took a run up to the local store this morning.

 

I picked up a group 24 Energizer Marine starting battery with 1000 Amp cranking power. It was regular $88 on sale for $69 so hopefully it'll do the job I need and if it works 1/2 as good as the original I'll be happy.

 

24 is the size of my current battery so it should be good.

 

I stopped into CTC first and told the guy in the battery department what I needed and he argued with me for 5 minutes that I need a deep cycle because it's for a boat and doesn't matter if it's for cranking a motor or not, so I walked away from him and drove over to the Parts Source, and told HIM what I needed and he knew less about batteries than CTC dood, even though he also works in the battery department.

 

How do you get a job in retail these days when you don't even know what the heck your talkin about ??

 

Anyways, I'm off to the lake in a few minutes in search of Mr. Musky so I'll see y'all on Sunday and thanks again for your responses

[Roy]

Lew, I think I remember that you have a Lowrance. Mine will shut itself down if the battery it's connected to (in my case the starting battery) goes below 12V. It's made that way to enable you to still start your motor should you have left the unit on inadvertently.

I guess that's the same answer that everyone else has given you.

[dannyboy]

Although electronics aren't as sensitive as they used to be, it is best to shut them off when starting if they are connected to the start battery.

This helps to avoid spikes from the starter and the alternator when it comes on line.

99.9% of the time you will be ok if you don't but the .1% of the time is expensive, and I haven't figured out how to put the smoke back in the boxes.