Battery distance

prattvan

Cadet
Joined
Nov 13, 2014
Messages
20
What is the maximum distance from the outboard you can mount the battery ??

It's a 70 HP 4 stroke

Suzuki DF70
 
Last edited:

bruceb58

Supreme Mariner
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Mar 5, 2006
Messages
30,454
As long as you increase the wire gauge suficiently you can put it anywhere you want.
 

prattvan

Cadet
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Nov 13, 2014
Messages
20
As long as you increase the wire gauge suficiently you can put it anywhere you want.

It's going to be a 14ft cable.

The reason I'm asking is because I had an ECM issue. And after many, many hours and many weeks of research (including talking to several Suzuki dealers), I have learned that the Suzuki ECM's are VERY sensitive. One guy thinks he damaged his ECM because his cable length was long and too small (guage-AWG). Another boater with a bad ECM thinks it was because he didn't have a tinned cable.
 

bruceb58

Supreme Mariner
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Mar 5, 2006
Messages
30,454
That's why you size the cable up to get a lower voltage drop than what you currently have.

If your curent cable had too much voltage drop, calculate the voltage drop for an arbitrary current(let's say 200A) with the next size gauge cable. Then increase the length in the voltage drop calculator and pick the gauge that has equal or better voltage drop for the new length you want.
 

roscoe

Supreme Mariner
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Oct 30, 2002
Messages
21,657
Mercury factory battery cables are 12' long, 4 AWG, used for motors through 115 hp.

If you need 14', I would suggest going to 2 AWG.
 

H20Rat

Vice Admiral
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Mar 8, 2009
Messages
5,199
Keep in mind that if it is 14', it is actually 28'. Your ground needs to be the same size, and counts towards the voltage drop just as much as the red wire does.
 

Ned L

Commander
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Sep 17, 2008
Messages
2,266
Not being Tinned copper would have nothing to do with damaging an ECM. Tinned copper actually has a higher resistance than bare copper, but tinned is used in marine applications for the protection against corrosion.
 

K-2

Chief Petty Officer
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Apr 3, 2011
Messages
406
What has a higher resistance, tinned copper or corroded non tinned ? Could a corroded non tinned possibly damage an ECM?
 

UncleWillie

Captain
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Oct 18, 2011
Messages
3,995
Corroded wire, tinned or bare, will have a high resistance than non corroded wire of either construction.
There is nothing inherently wrong with non tinned wire.
Having corroded connections that have not been serviced is the problem. Not the lack of tinning.
Is tinned wire better for corrosion control? Yes!
Does it guarantee you will never have connection problems? No!

The ECM is not going to be damaged by low voltage. That happens every time you turn the engine Off.
When a bad connection causes an intermittent disconnect of the Battery;
The voltage regulator in the Alternator can spike to over 100 volts, killing the ECM.

Could a corroded NON Tinned wire possibly damage an ECM? Yes!

Could a corroded TINNED Wire possibly damage an ECM? Yes! Again!

Don't blame the wire! Blame the lack of preventative maintenance.
 
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