Mounting battery in the front?????

[Chaz]

Is a Perco "master disconnect" switch considered a splice

Or does a fella get a "pass" if he uses marine grade cable, self-gluing heat shrink, solder pellets and plated lugs ...

Buy in bulk .. they give ya a great deal ... If I ever buy three more boats to do .. I'll let ya know ..

Chaz = thinkin, I'm too ()*&^%&* old to crawl under a dashboard .. and live to crawl back out again

[David - WI]

The Optima weighs less than the old led acid. I noticed it doesn't spin the engine as hard on starting as the 27 series led acid flooded battery.

Did you go with (much) larger diameter cable... like #2 instead of #6 (stock) to compensate for the extra length?

http://www.bestboatwire.com/media/ca...auge-Table.pdf
https://www.jamestowndistributors.co....do?docId=1098

[Whaaaaat]

Is a Perco "master disconnect" switch considered a splice

Or does a fella get a "pass" if he uses marine grade cable, self-gluing heat shrink, solder pellets and plated lugs ...

Buy in bulk .. they give ya a great deal ... If I ever buy three more boats to do .. I'll let ya know ..

Chaz = thinkin, I'm too ()*&^%&* old to crawl under a dashboard .. and live to crawl back out again

Worked on a fountain many years ago with a soldered crimped, heat shrink wrapped battery cable. Came from the factory that way. Corrosion still got to it and cost the owner a new cable and ECM.

[69MyWay]

Did you go with (much) larger diameter cable... like #2 instead of #6 (stock) to compensate for the extra length?

http://www.bestboatwire.com/media/ca...auge-Table.pdf
https://www.jamestowndistributors.co....do?docId=1098

This is awesome! Great info. I've been playing with solar power for a while and currently have a 1,300 watt 24 volt system for my shop. It runs #6 gauge trunked from the panels - Each leg generates 80 volts then drops to 24 for the main pack. I spend hours - days...heck, weeks reading about amps, volts, watts - and was surprised that HIGHER volt applications require smaller cables. Seems backwards, but true. I had a 12 volt system to start and had to run 0 gauge.

I recently bought a military Humvee (it is my primary local tow to the lake truck now) that runs 24 volt - but has a 12 volt sub system. The military WAY over spec the wire on it - but never a problem in that case going too large.

I think in the current configuration the boat would be best at #2 gauge, But, I believe I'm good to go. I'm right on the edge on those charts. I went with high quality #4 gauge. I'm at 16' now, but will be under 14 feet of wire. And, I'm going to take more out between the motor and the stock end of the motor harness. Turns out I have time because while It thought this was my last big project before boating season, I'm still without functional hydraulics for the motor.

To know for sure, I should test the amp draw while starting. That is the big factor. I think the 2 stroke starter pulls far less amps than a four stroke - but haven't confirmed yet. I really should have started this whole build and discussion about wires and lengths and gauge as much as any other factory like beating the crap out of a battery up front, types of batteries best for that...and mounting bulkheads to hold them.

I can say I'm super pleased though that the spare fuel tank is OUT OF THE NOSE! And tweaking wire length is just money and time - as al the hard stuff is in and done!

[David - WI]

I think in the current configuration the boat would be best at #2 gauge, But, I believe I'm good to go. I'm right on the edge on those charts. I went with high quality #4 gauge. I'm at 16' now, but will be under 14 feet of wire. And, I'm going to take more out between the motor and the stock end of the motor harness.

One thing to keep in mind is that most of the wire size "calculators" & charts are based on the total wire length... in a car it's usually one positive wire (since the frame of the car is the ground) but in a boat you have the length of the positive cable plus the length of the ground cable.
(I would think the Merc chart would be for a "set" of cables; but I'm not certain.)

NOTES:
A) This is for a ONE WAY wire with the ground assumed to be the car chassis. If 2 wires needed to complete the circuit calculate for the total length of wire used for both legs.
To use the calculator, enter the Maximum Current in Amps of the circuit, and the Length of the Wire, and operating Voltage. Typically most automotive systems run at 13.8V, but you can select 6, 12, 13.8 (Default) or 24 volts. If the wire gauge is OK to use it will have a 'Check Mark' on the same line. The 'Max Length' indicates the maximum length of wire of that gauge that can be use at the given values you entered.

https://www.wirebarn.com/Wire-Calculator-_ep_41.html

[olboatman]

One thing to keep in mind is that most of the wire size "calculators" & charts are based on the total wire length... in a car it's usually one positive wire (since the frame of the car is the ground) but in a boat you have the length of the positive cable plus the length of the ground cable.
(I would think the Merc chart would be for a "set" of cables; but I'm not certain.)


https://www.wirebarn.com/Wire-Calculator-_ep_41.html

This is exactly why l kept my battery in
the stern....that and my Viper flys better
with weight to the stern.
Gary

[69MyWay]

One thing to keep in mind is that most of the wire size "calculators" & charts are based on the total wire length... in a car it's usually one positive wire (since the frame of the car is the ground) but in a boat you have the length of the positive cable plus the length of the ground cable.
(I would think the Merc chart would be for a "set" of cables; but I'm not certain.)






https://www.wirebarn.com/Wire-Calculator-_ep_41.html

Interesting - based on that...4 gauge would be on the borderline right out of the gate (stock size of these main wires) by doubling it! In that regard, I was already at 12 feet!

[David - WI]

Interesting - based on that...4 gauge would be on the borderline right out of the gate (stock size of these main wires) by doubling it! In that regard, I was already at 12 feet!

I was just getting at possible explanation for your "slower cranking" since you changed batteries and extended the cables.

[69MyWay]

I was just getting at possible explanation for your "slower cranking" since you changed batteries and extended the cables.

So, I ran the numbers. My 27 series battery is a high CCA than the Optima - It is enough to impact the speed. I found another chart and looked up all the specs. I am losing some power here but gaining weight and space savings.

Except, when my tanks are full I'll have more weight in the rear of the boat before. By the end of the day, my nose will weigh more due to the battery.

[69MyWay]

One thing to keep in mind is that most of the wire size "calculators" & charts are based on the total wire length... in a car it's usually one positive wire (since the frame of the car is the ground) but in a boat you have the length of the positive cable plus the length of the ground cable.
(I would think the Merc chart would be for a "set" of cables; but I'm not certain.)


https://www.wirebarn.com/Wire-Calculator-_ep_41.html

This is fascinating the more I read it. Yes, in a typical car we ground the battery right at the battery or engine block -then we string ground from the block to the chassis, unibody, and frame rails. Grounds become a nightmare on many cars causing systems to go offline because of this process. The fix is often to run more and better grounds back to the battery. In fact, that's what I've recently done on my Humvee - major grounding kit. It essentially extends the path of ground well beyond what the positive cable distance is.

My thinking since learning about solar and DC cable that it is each run - Until today I never viewed it as max length in one direction. And, as said on a car while the one cable is shorter, the total travel of the current back the battery can be very lengthy.

I put a rear battery in my 69 Camaro - and it grounds right at the trunk. But I then lugged that and took it all the way to engine with the positive cable. It is #2, but a lot of wire. Stock Corvette though for example from the same year has a #2 from the positive on the battery behind the driver to the starter lug - and a ground right off the battery to the frame. There is another ground strap from the frame to the engine block. Guess what they have problems with all the time too? Poor grounding.

[Chaz]

Worked on a fountain many years ago with a soldered crimped, heat shrink wrapped battery cable. Came from the factory that way. Corrosion still got to it and cost the owner a new cable and ECM.

You can only build parts the best you can with American made products. If people chose to grow mash~ama~taterz rather than maintain what they have .. CAN YOU REALLY POINT YOUR FINGER AT THE CABLE ...


Both my motor's have a #10 wire that jumps from the alternator to the CDM plate to the PCM mount to the battery cable ground lug on the block, in conjunction with the factory grounds.
As far as a bad cable killin the box .. I'm more inclined to believe that a "tech" grounded out a driver in "key-on "mode and killed a section of the board .... Oooppsss

Cable guides are for each cable. Notice the picture shows "ONE CABLE" , no footnote about -return - sizes.

Speakin of that .. is it the return .. or the start ..

A 6 volt DC battery has 3 , 2-volt cells

A 12 volt DC battery has 6 , 2-volt cells

Seems to me power starts building from someplace 0 @ ground and builds from there. We send it off to work , the more work we ask it to do , the bigger wire , switch's , relays we stack up on the hot side to deal with the work load.

The aircraft industry wires to the load , does the work , then puts a minimal size switch and wire size on the return side. The work has been done, "no more load" just need to complete the circuit back home at that point.

My 25' boat (twin 300's) is wired #4 from the Solenoid's to the Perco switch then #2 two each battery's hot side.
The ground goes from each engine block #4 to a big ground lug , where a single #2 goes forward to one battery and then jumps to the other . Same principle as having a steel car frame to drop a ground where ever it's convenient. All roads lead back to the starting point of DC powa ..

[69MyWay]

So I took out the last bit of wire this weekend - down to the minimal length needed to reach the motor and battery. Now...once the hydraulic cylinders come back from the machine shop I can slap it all back together and go give it a spin!

I met a young man at the auto part store this weekend by the way - returning his deep cycle trolling motor battery for the SECOND time in four weeks. It is a fast bass boat - the trolling batteries mount up front and get beat up. Cells shorted (according to him) on both batteries. Flooded style batteries. He said the boat came that way - and he has had a terrible time keeping batteries up front. I just thought it was interesting timing.

[XstreamVking]

I worked on flats boats with batteries up front for 25 yrs. I never saw a big problem with the cells breaking etc. IF you mount them correctly. I bet the guy you talked to had the batts just sitting in open boxes allowing them to flop around. Bass boat mfgs are notorious for using the little web straps over the boxes and not really securing the batts. Do not worry about your batt failing from that problem.

[Will hedrick]

Same thing with me, u could see the corrosion around the terminals where it beat them to death when running in 5 ' + chop, barge waves, etc.

[Captaincj]

As another member said previously, if you start getting porpoise problems it the extra weight up front.