Boat electrical issue

[Buckrub]

Went fishing again today (18 crappie, 4 bass, 1 bull bream, and a 4 lb flathead, if you must know), and had an electrical short issue that happened last Thursday......I didn't mention it then.

Both times, when I fire up the big motor (NOT every time, sometimes all is OK), both front and console depthfinders go blank! Wham. Will not come back on. Dead.

Last Thursday, I pulled the fuse box (a chore, you have to stand on your head INSIDE the boat) and just pulled out the fuse for the console DF and stuck it back in. Voila, everything worked. NOTHING is labeled on the fuse panel! And it's the stupidest design I ever saw. I have not pulled the fuse panel today..........I cleaned the fish and took a shower, and said HECK WID IT for now.

I do NOT think that the front DF and the back one are on the same fuse, though!!! In fact, I'm sure of it. Yet both of them go dark, wham, when big motor starts sometimes. I tried every other electrical device I could, and all worked..........horn, lights, accessory, bilge, live well pump..........

Sometimes I just wonder if I have shot a puppy or something. I get having a blowout, and a flat, and stuff like that. That's normal stuff. But crazy things like this make me frustrated. I know y'all laugh at me, but I do know how to do most stuff.........but this one is baffling.

??????

[Thumper]

First off, you should never leave your accessories on when you start your big motor. Power surges like that are death to modern electronics. When your voltage drops to the accessories (like Depth Finder, radio, GPS, etc), your amperage increases ... that plays hell with those things. That's my guess anyway (unless you have some sort of isolator and two batteries). I assume your feed wires are a heavy enough guage for the task (?). I'd guess minimum 12 guage.

My suggestion is to have a master switch for all of your accessories, flip it off when starting, flip it back on when running (IF you're only running one battery).

[johnboy]

I know how you feel. I sometimes think crazy shit only happens to me but I guess it's the both of us. Anyway, first thing I would do is check, clean and re-tighten every ground connection I could find. Sounds to me like a bad ground somewhere. Good luck.

Oh yeah, what Thump said as well.

[Big Muddy]

Thump is right about cutting everything off, when cranking your big motor, especially, if your accessories are connected to the cranking battery....even if they're not connected to the cranking battery, it's just a good habit to get in to.

I blew up my on-board trolling motor battery charger, this spring, when I first got my Tahoe out of storage....both of my batteries are hooked in series, and I forgot to disconnect it, after charging the battery, and cranked up the big motor....burned the innerds to a crisp....called the mfr., and it was still under warranty, and they sent me a brand new charger.

Buck, if I had to guess, I'd say your DF wires are either loose or corroded, where they hook to the battery.

[Thumper]

I always ran dual batteries on my "big" boats ... a "cabin" battery and a "cranking" battery. I'd run a battery isolator that would keep the two circuits separate, but both batteries would charge in running mode.

We did the same thing on limousines. Dual batteries with an isolator. A "cranking" battery and one for the accessories ... bar, lights, radio, vcr, tv, etc. As I said above, if you're running ONE battery, you need to kill the accessories during cranking ... or the cranking will eventually kill your accessories! ;)

[Buckrub]

That's the first thing I checked. One DF is almost new. No corrosion.

Have a Minnkota 315D onboard that stays hooked up to all 3 batteries.........but not plugged in of course, unless I'm in the garage. Not sure what that matters.

I have changed nothing............and everything worked fine for years. Now this. Something has gone wrong, something has changed. I have not reconnected anything differently.

Just re-read Ed's........the battery connections in the battery compartment have not been checked. That was my next step. It's possible something is loose or corroded THERE. I'll look at that in the morning............

[Big Muddy]

Check and wiggle the wire that enters your DF puck....they take a beating, when fishing in stumps and brush.

[Thumper]

You run THREE batteries? Easy-peasy ... do the isolator thing ... you'll thank me later.

If all has been working previously, maybe your batteries are heading south. Cranking takes BIG amps ... if the bats aren't up to snuff, your voltages/amps will be doing crazy things while cranking. That plays hell with electronics. (Ummm, I'd have thought the battery connections would have been the FIRST thing you checked)

[Buckrub]

OK..........odd.

I just went and checked all connections AT the battery for all 3 batteries. All are good, all tight, no corrosion, nothing out of the ordinary. I did SQUEEZE the wing nuts tight, but honestly didn't feel them move..........don't think they were loose.

And bingo, the back DF came on. I did not start the big motor, but I did turn the key to 'ON' several times, and the DF stayed on.

SO maybe one of the wing nuts on the battery was ever so slightly loose, maybe?????????????

The Trolling Motor runs on 2 batteries in Series, a 24v. Everything else is on the starting battery for big motor.

[Buckrub]

And yeah, that's the first thing I should have checked. But I was leaving for the day, had fish to clean, and just didn't. My bad.

[Thumper]

Everything else is on the starting battery for big motor.

I believe that will be a problem in the long run. (at minimum, get a switch)

[Thumper]

Well dang Bucky! I was tied up with some eBay stuff and just caught a break, so I figured I'd see if there's anything on the net regarding your problem. Damn! The very first site I brought up almost mirrors persactly what I've been saying! I've "been there, done that" so many times with both cars and boats, I guess the experience actually means something. This is from a boating forum ... the initial post could be YOU talking! ;)

Here's the initial post and the very next two responses:

Hi to all,
I am having a problem with my Humminbird FF/GPS losing power when I switch the key to start the motor. Started as an occasional problem but now happens almost every time.

Current wiring: Two batteries to selector switch (1 & 2) Common power to the motor and 2 feeds to the console.

What I have done: At the end of last season I was curious as to whether I may have corrosion in the selector switch dropping power to the FF while engaging the ignition switch so I ran direct to the battery and seemed to not lose power to FF while engaging switch; so I bought a new selector switch and installed. This season, (with new selector switch installed) I lose power to FF every time that I engage ignition switch. So, I examined all pos and negative connections near the batteries and noticed some corrosion in the wiring. I cut back the two pos and neg feeds to the console until I didn't see any corrosion and replaced the ring terminals with sealable connectors, and replaced the heavy battery to selector switch cables. Still no change; lose FF power every time that I key the ignition switch. I was hopefull that I had a poor pos or neg connection and that the heavy draw of the starter was causing a disruption of power to the FF. I do not seem to notice any other power disruption to any other electronic components.

I am hopeful that someone may have experienced this and or further advice as to where the problem may lie. All systems had been working properly since my ownership of the boat. I hope to resolve the problem but I suppose in the meantime I may bypass the selector switch and connect the positve lead (providing power to the console and FF) directly to the battery as a possible short term fix. I will welcome and investigate any suggestions. Thanks in advance.

Response #1: The problems lies with you starting the engine while your electronics on. Eventually, a spike or surge with get your electronics. All electronics should be on a master switch and it should be off until your engines are started. Turn on your master switch and then repower your electronics.

Response #2: Hi, As an electronics tech I see problems like this all the time. What is happening is when you crank your starter (and there is nothing on your boat that draws more amps than the starter) the overall voltage in your electrical system is probably dropping down. When the voltage drops in a system with everything else staying the same, the amps go up. For example if you drop the voltage from 12 vdc to 6 vdc with everthing else staying the same, the amperage doubles! So while your ff is on when you crank the starter (as previous post said, it shouldn't be) you are dropping the voltage and increasing the amperage throughout the entire electrical system. Not just the ff. Keep it up and the stereo, tv, etc will be next. Also too small a guage wire supplying the power will cause voltage drop. Depending on the wattage of the fish finder you prob should use 12 ga high stranded at the least. Long runs use 10 ga.. Joe

[Buckrub]

I believe that will be a problem in the long run. (at minimum, get a switch)

Have to have 2 batteries for the trolling motor. It is run pretty much nonstop while I'm fishing. I can't fish without it, unless I just luck into some location that has a ton of fish, and a nice convenient limb to tie to! Thus, those batteries run down first. The electronics draw nothing hardly........so I put them on the cranking battery. There's only room for 3 batteries. Anyway, that was my thought when rigging it up.

It's a 2007 boat. This has never once been a problem till last week.

[Nandy]

bucky, corrosion will happen everywhere. That includes in between contact surfaces. I would take the connections out and check them for corrosion, you know, that white/greenish powder. also check the connectors and where the cable gets in the connector. You are better moving everything off your cranking battery other than the motor itself. You can balance your load between the 2 12v batteries for your accessories. Electronics attached to a motor risk getting damage by both low voltage and high voltage spikes during cranking and WOT. Does it happens to everyone, probably do and they dont realize why but why risk it, it will probably be a cable swap or at worst case you will have to add longer jumpers.

Good luck!!!!

[Buckrub]

I appreciate everyone's help.........

[BarryBobPosthole]

Been thinking about this one and comparing it to what my own boat's electrical system does. My accessories are all wired to a separate power switch than the ignotion, but its i,possible to remember to flip it off when you start the big motor. So there's a safety relay thats cuts off the accessories when you turn the ignition key. my electronics cut off when I start the engine but I can just turn them back on manually once its started. sounds like yours doesn't cut the power back on so you can do that.

if yours has that relay, I'll bet that's it. it'll be a relay on like a crowbar circuit that protects the accessory power circuit.

BKB

[Buckrub]

Did I mention I caught a bunch of fish?

[Big Muddy]

Did I mention I caught a bunch of fish?

Without pics, you beez lyin'. ;)

[Big Muddy]

Did I mention I caught a bunch of fish?

Without pics, you beez lyin'. ;)

[Captain]

Without pics, you beez lyin'. ;)
You can say that again. :-)

[BarryBobPosthole]

Though about this some more and I think you're screwed.

no, just kidding. actually I don't think there's a relay but cutting off the accessories when you crank the motor is a function of the ignition switch. you might have your faulty connection in those contacts. not sure if there's much you can do short of replacing it, but it'd damn sure be a simple test with a VOM to prove it out.

BKB

[Thumper]

Yep, that's how the ignition switch on a car works. The weird part is, he said everything stayed on before this problem cropped up. Unless he simply didn't notice the screens cutting off while cranking. But why would they come back on then ... but not now? Unless the battery is starting to crap out and voltages are dropping more than usual. He may be due for a load test on that cranking battery.

[Cards01]

I had a similar issue a couple years ago when my battery was starting to get weak. Replaced the battery and it went back to the DF staying on when firing up the big motor. Congrats on another mess of fish caught during the week!!

[Buckrub]

Yep, that's how the ignition switch on a car works. The weird part is, he said everything stayed on before this problem cropped up. Unless he simply didn't notice the screens cutting off while cranking. But why would they come back on then ... but not now? Unless the battery is starting to crap out and voltages are dropping more than usual. He may be due for a load test on that cranking battery.

Yes, this is first time since 2007 that this has happened. Batteries have been changed once in that time.........but the cranking battery is different than the other two. The other two are Optima Blues in series. It is possible the cranking battery is like me, old and decrepit and tired. I'll check that out. I sure don't want to kill the Depthfinders and then turn back on every time........that's 11 feet of walking for one thing. And then they'd reset........ugh. But I'm learning more about all this than I knew.............thanks!

[BarryBobPosthole]

There ya go. Ought to be easy to test by swapping cranking battery out with a known good one.
BKB

[Buckrub]

Hahaha. Yep! 'Ceptin' "Known good ones" are approximately $150 these days! :crazy

[BarryBobPosthole]

You can swap one of those Optimas out.

I am on my EIGHTH season with the original Blue Top Optima I put in my boat in 2007. Still use it as my cranking battery and its going strong. My two trolling motor batteries are Blue Tops I bought in 2008. In my experience in marine batteries that's just frigging unheard of. don't know if its luck or what, but I'm standing by those Optimas. good battrees.

BKB

[Buckrub]

Yes, mine are not that old, but ........um..........maybe 5 years. No issues.

Guy that owns a tire/brake shop where I trade, good guy (and fisherman!) has batteries made for him, by Trojan Batteries, to his specs and have his name on 'em. He mostly sells tires but got into this because he couldn't find a good boat battery that would last. I have yet to try them, but every local guy that uses them is amazed. If this cranking battery is not good, that's where I'm headed. The two blue tops are fine, I'm sure.

[Thumper]

That's sure what I'd try Bucky. From your description, I suspect a voltage drop more than what you normally have (battery getting weaker). Problem is, your battery could have plenty of life left in it, it just drops during heavy amperage draw (starting) enough to kill your electronics. I'd sure figure a way to disconnect your electronics from that starting battery though (permanently, or at minimum, during start-up). Those voltage spikes are deadly to those things and are sure to shorten their lifespan. If you have a space anywhere, you may want to use that battery as your dedicated cabin battery and get a new one for your cranking battery. Course, FOUR batteries on that boat is a bit much I suppose. S'up to you.

[Buckrub]

Thump, I'm sure you are right. I did just go out and check the battery connections again. There is no corrosion of any kind anywhere. The + on the cranking battery was.........well, not loose by any means, but not cinched down either. I cinched it down tight.

I had lunch with several guys, and all boat owners said that they believed that all new boats with a 24v trolling motor come wired this way from the factory/dealer. That is, only the Trolling Motor is connected to the 2 in-series batteries, and the cranking motor has all accessories. The reason is, that's the one that gets the alternator connected.

And it's worked nonstop until now.

I just read the Humminbird installation manual that I kept on .PDF. All it says about voltage is to A) connect only to 12v source, and B) to put a 3 amp inline fuse in the connecting line. It has that. So, it seems that a voltage spike that might cause damage would blow that fuse. This is a dead drop in voltage. And if starting the motor knocked the DF'ers offline, they would start back up manually if/when the big motor shuts down. These do not.

So, I suspect if I had checked the connection to battery while on the water, I'd have figured it out. Stinking boat layout sucks, though, and you either have to be standing outside the boat to get into the battery compartment, or you have to stand on the transom and hold on to the big motor! Still, that was laziness that I didn't check that first.

[BarryBobPosthole]

my boat is set up exactly as yours is. two batteries in series for the TMs, and everything else off the main cranking battery. only diff is my accessories has a separate power switch. even though, the ignition switch cuts off the accessories when you turn the key to crank the engine and you have to repower up the DFs since they don't have On Off switches like other stuff does.

BKB

[Buckrub]

That confused me (NO SMART remarks!).

I have an accessory switch on the console also. But the only thing run through it is......um....I think the plug for (duh) accessories, like a car phone charger. It doesn't turn anything else on or off. That's how the boat came.

And why would your depthfinders not have an on/off switch. That's what is throwing me. Sure they do. So not sure what you mean exactly. And why would you want to turn those on every time? There are settings and it has built in GPS and has to 'find' the satellites all over again, and all that. I don't want them to go off and have to reset the right 'view' and other settings. Besides, I want to know what's under me when I start the big motor.

[BarryBobPosthole]

well, they have an on off switch but soon as you take away power you have to turn them on again. not so, for example for your aerator for your live wells or bilge. they just come on automatically if the switch is set to on.

and if they're on the same power circuit as the engine ignition you want to turn them off when you crank the motor because of the reasons listed by Thumper and others above. you run the risk of burning out the little naughty bits in them if you do.

if yours doesn't do this , fine.
you're way ahead of the game.

bKB

[Buckrub]

So, do your DF'ers turn off every time you start the big motor? and you then turn them back on manually every time you do that???

And doesn't the fuse stop these from 'burning out'?

[BarryBobPosthole]

mine turn off yes, every time I start the motor. and yep, the power leads are fused. and yep, I turn them all three back on every time I start the big motor if I want them on.

I'd have thought that's the way they all work or are supposed to.

The only time I've had it work differently is if I've hooked them up on a separate power circuit than the accessory one.

BKB

[Thumper]

That's how the ignition switch is "supposed" to work. That's why when you start your car, the radio, electronic dash, (or whatever accessories are on) will cut off while you're cranking, and come back on after the key returns to the run position. It not only diverts all power to the cranking circuit, it prevents damage to the electronics due to the power surge.