Another battery Question. Next Question.

[hitthebricks]

Thanks for all the input, the group 27 and 29 batterys dont comingile from what I hear!

Next question! A typical starting battery does not seem to be a enough power/voltage

to keep a larger graph running all day.

Towards the end of a full day on the water the graph will shut down when starting the main motor.

Would switching to a dual purpose type battery help this problem?

Thanks,

HTB

[Whoaru99]

Only if the other battery has more reserve/capacity. How much more it would take to avoid the shutdown is the big question.

Whats the issue if the graph shuts down momentarily when the engine is started? You're concerned it could be damaged or?

[hitthebricks]

It's just a pain to have to turn it on, go through all the prompts then get back to the screen I want displayed, 20-30 seconds.

I think that if there is a way to avoid it I should since I'm buying new batterys anyway.

HTB

[delcecchi]

Thanks for all the input, the group 27 and 29 batterys dont comingile from what I hear!

Next question! A typical starting battery does not seem to be a enough power/voltage

to keep a larger graph running all day.

Towards the end of a full day on the water the graph will shut down when starting the main motor.

Would switching to a dual purpose type battery help this problem?

Thanks,

HTB

Is the battery in question fully charged in the morning? If so, then more capacity, or a new battery, is needed.

[delcecchi]

Thanks for all the input, the group 27 and 29 batterys dont comingile from what I hear!

Next question! A typical starting battery does not seem to be a enough power/voltage

to keep a larger graph running all day.

Towards the end of a full day on the water the graph will shut down when starting the main motor.

Would switching to a dual purpose type battery help this problem?

Thanks,

HTB

Is the battery in question fully charged in the morning? If so, then more capacity, or a new battery, is needed.

[delcecchi]

Thanks for all the input, the group 27 and 29 batterys dont comingile from what I hear!

Next question! A typical starting battery does not seem to be a enough power/voltage

to keep a larger graph running all day.

Towards the end of a full day on the water the graph will shut down when starting the main motor.

Would switching to a dual purpose type battery help this problem?

Thanks,

HTB

Is the battery in question fully charged in the morning? If so, then more capacity, or a new battery, is needed.

[BobT]

Thanks for all the input, the group 27 and 29 batterys dont comingile from what I hear!

Next question! A typical starting battery does not seem to be a enough power/voltage

to keep a larger graph running all day.

Towards the end of a full day on the water the graph will shut down when starting the main motor.

Would switching to a dual purpose type battery help this problem?

Thanks,

HTB

A true starting battery will give you more trouble than a dual-purpose battery. There are three basic types of wet cell batteries.

1.

Starting battery. Designed for very high current delivery over very short periods of time. Does not like to be deep cycled and in fact, if you deep cycle (discharge more than 50%) too many times (3-6 times) don't be surprised if it's life expectancy has been shortened considerably. Good battery to use in your car.

2.

Deep cycle battery. Designed for low steady current draw over long periods. Can handle deep cycling more comfortably and more often than a typical starting battery. Does not like to deliver high current loads very well and doing so will shorten its life expectancy more rapidly. This is a good choice for your electric trolling motor.

3.

Dual-purpose battery. Moderate of both worlds. Designed to handle some high current starting loads and still have the reserve capacity to operate low current loads over longer time periods. The trade-off is peak current delivery is less than a starting battery and reserve capacity is less than a typical deep-cycle battery. This is a good choice for a boat starting battery where the console, lights, and sonar are also using the battery.

Can all of these batteries be used to start your outboard? Sure but using the deep-cycle battery for this purpose will result in a performance shortfall.

Can all of these batteries be used to power your trolling motor? Sure but again, using the starting battery for this purpose will result in a performance shortfall.

[Sea Hage]

I had the same thing happening in a Lund. Fixed it by running a 12 gauge positive wire up to the dash and running the HDS10 off of that, still the same battery but not going through all the harness plugs and switches involved with the boat wiring. Works great...

[hitthebricks]

The battery is fully charged and this has happened ever since I bought this graph.

I think the dual purpose battery and a individual line for the graph will solve this problem.

Thanks for the input,

HTB

The last few days this HSOforum was very slow to load but its fine today.

Anuone else have this problem?

[MN Shutterbug]

I just bought a boat that has the depth finder on the same battery as the outboard. My depth finder is just a standard Hummingbird. Will the finder draw enough juice to really have an effect on the starting battery? Should I rewire the depth finder to the same battery as the trolling motor or shouldn't I be concerned. I don't use lights in the boat.

[amateurfishing]

My HB draws from starting battery, after being on water all day it has never been below 85% at end of day, however I do have 2 batteries soley for 55lb thrust troller and have had both near 50% just trolling alone, I would keep graph on starter battery.

[MN Shutterbug]

My HB draws from starting battery, after being on water all day it has never been below 85% at end of day, however I do have 2 batteries soley for 55lb thrust troller and have had both near 50% just trolling alone, I would keep graph on starter battery.

Good to know. I also have a 55# thrust trolling motor and it appears to be an older Walmart battey so I'm guessing it will be replaced real soon.

[BobT]

A marine mechanic can correct me but I think most (if not all) boats are factory wired with all on-board electronics to the starting battery. This includes your sonar, bilge pump, livewell(s), console lights, navigation lights, gauges, etc. The only thing wired to the deep-cycle circuits are the electric trolling motors. A good reason for using a dual-purpose starting battery.

That's how it was done on my 1993 Lund Rebel, my 1998 Sylvan Adventurer, and my brother-in-law's Lund Mr. Pike.

[Hoey]

I have wondered about this. Someone please let me know if this is correct.

Wiring your depth finder (or any 12v appliance) into a 24v or 36v trolling motor system is not good, i.e. connecting to the terminals of only one of the batteries. The appliance will see 12v as long as no switches or relays are closing the circuit, i.e. an open circuit. But when a switch is on, closes the circuit, the appliance will see 24/36v. Is this correct?

If so, then your depth finder is cooked or if it has internal protection, it may reset itself.

[fishnowworknever]

Sounds like your graph is connected to the ignition switch...in which case it's cutting power. Run a dedicated 12v line to your starting battery for the graph like mentioned above. Run it to a switch on the console to further isolate the graph from the electrical system when not in use.

BobT -

I'm no marine mechanic but I'll agree with you that all electronics should be on the starting battery (dual purpose being the best bet) and trolling motor should be isolated to it's own 12v or 24v battery or batteries.

[delcecchi]

I have wondered about this. Someone please let me know if this is correct.

Wiring your depth finder (or any 12v appliance) into a 24v or 36v trolling motor system is not good, i.e. connecting to the terminals of only one of the batteries. The appliance will see 12v as long as no switches or relays are closing the circuit, i.e. an open circuit. But when a switch is on, closes the circuit, the appliance will see 24/36v. Is this correct?

If so, then your depth finder is cooked or if it has internal protection, it may reset itself.

Uh, not sure what you have in mind. Typically a 24 volt trolling motor battery system, so far as I know, is floating. There is no connection to "ground" or the hull of the boat, or the negative of the starting battery. So if a depth finder is connected across one of the batteries it isn't grounded either and there is no way for it to see anything but the 12 volts, again so far as I know.

In fact from what I have seen, there is no contact (unless there is something in the outboard) between the hull and the negative of the starting battery. Of course a fiberglass boat doesn't even have a conductive hull.

I don't think there is an issue but a trolling motor will put a bunch of hash into your depthfinder when the tm is running if they are on the same battery.

Typically the reason you don't want to have loads on one of the batteries in a 12 volt system has to do with charging or over discharging one of the batteries (see the thread about mixing 27 and 29 series batteries)

[Whoaru99]

I have wondered about this. Someone please let me know if this is correct.

Wiring your depth finder (or any 12v appliance) into a 24v or 36v trolling motor system is not good, i.e. connecting to the terminals of only one of the batteries. The appliance will see 12v as long as no switches or relays are closing the circuit, i.e. an open circuit. But when a switch is on, closes the circuit, the appliance will see 24/36v. Is this correct?

If so, then your depth finder is cooked or if it has internal protection, it may reset itself.

Generally speaking, the device will only see the voltage across the points to which it is connected. However, after a bit of thought, I think I see in the case of a 36V (or higher) system where you could, theoretically, get into the problem you describe. Although, I think it would have to be nearly on-purpose to get into that situation.

I'll try to illustrate...

In the first group of schematics, reflecting 24V system, several scenarios of removing connections, batteries, the motor, etc. were contemplated. I couldn't come up with anything that created more than 12V across the graph/sonar, only less than 12V in figure M3, or if the graph was totally disconnected it would be 0V. Didn't show that as I think that's a given.

In the second group of schematics, reflecting 36V operation, if you were to remove the battery to which the graph was connected AND leave the graph connected to the circuit(figure M2), you'd get more than 12V across the graph. I picked some resistance values I thought were reasonable for the components (based on thoughts about current draw of each) to illustrate the voltage drop scenario.

Still unknown if that would be enough to damage the graph/sonar through. Many devices have some degree of over voltage protection in the design.

[delcecchi]

Oooh, nice pictures. In the 24 volt picture when you take out the battery, don't you also reverse the polarity? So instead of 12 volts, the graph sees -12volts?

I would like to think there was a diode inside the graph but I am not that confident about the circuit design prowess of the graph designers after several encounters with their fine products.

[Whoaru99]

Indeed it does look like the polarity would be reversed and on the 36V too.

Perhaps more surprises await.

FWIW, those were drawn with Scheme-it. Free to use on the DigiKey HSOforum if you register. No installation, it runs in the web browser. It's on the left side of the home page in Resources.

[delcecchi]

Thanks for the tip. I can use something like that once in a while.

[BobT]

Oooh, nice pictures. In the 24 volt picture when you take out the battery, don't you also reverse the polarity? So instead of 12 volts, the graph sees -12volts?

I see what you're saying, Del. Kind of the same thing you nailed me on the other day.

I agree too that some electronics have reverse polarity protection but I don't know if I would trust it. While the system might be okay as long as all batteries are good, if the wrong battery goes bad resulting in an open circuit causing that reverse polarity situation you could end up replacing the battery and the sonar unit.

[delcecchi]

If I was cheap like the manufacturers, my reverse polarity protection would be a diode across the power input so that if it gets hooked up backwards, the diode would conduct and blow the fuse.

Of course Murphy's law says the diode will blow and protect the fuse.

[JumpStart73]

Had the same problem in our boat with the graph re-booting every time I started the motor. So I talked the the place that I bought it from, and as mentioned above, they told me to run a delegated wire from the starting battery to the graph. Just make sure to use the right wire size and add a inline fuse. Haven't had any problems with the graph re-booting since I ran separate wires.

[Fish Head]

I have had this same problem with my Humminbird 998 turning off when I start my big motor. Like others have mentioned, I have 2 sonar units and all light, livewell, bilge, etc., running off the starting battery. I don't want to have to fish a new power line to the back of my boat. Would changing my starting battery for a dual purpose battery solve this problem??

[h8go4s]

I have had this same problem with my Humminbird 998 turning off when I start my big motor. Like others have mentioned, I have 2 sonar units and all light, livewell, bilge, etc., running off the starting battery. I don't want to have to fish a new power line to the back of my boat. Would changing my starting battery for a dual purpose battery solve this problem??

No guarantees. Here's the order I'd rate solutions with the possibility of success increasing:

1. New battery with higher CCA rating. Depends on how tired your old battery is and how much power it takes to crank your "big motor". If you'd post more details, it would be easier to help.

2. Dedicated power wire to the sonar unit. Many times that's all it takes, but you have to be willing to do the work to fix the problem.

3. Add a battery for the sonars only and charge it fully between trips. That's a guaranteed solution.

[Sorgy]

Fishhead,

I think the answers to this common problem are already listed. If you fish alot or long days with all the accessories on then you need more amp hours to draw off. that generally means stepping up to bigger battery.

I have had many of the problems mentioned here. Graph rebooting- yada yada yada.

I now have 2 on board chargers 1 for the deep cycle 24 volt and one for the main battery. When I plug in the boat I hook up both chargers now. It has generally fixed my problem.

I just hooked up a Humminbird and now have a power supply going right to the main battery w/ 3 amp inline fuse.

The next step will be a upgrade to a larger battery- I think I can squeeze a series 31 into the main compartment on my Lund Mr Pike 17.

Good Luck -open water is upon us

Steve