Formula Battery Wiring
06-30-2003, 06:52 AM
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Formula Battery Wiring
Got a call on Sat from a friend that was stranded with two dead batteries. The boat is a 353 Fastec. There is only one battery switch. Now, I have always seen boats wired port battery to port engine and starboard battery to starboard engine. That way each motor will charge it's own battery and if you have a problem you just switch to the battery for the other motor.
So what's the deal with the way formula wired this boat? I'd like to install another switch and wire it so one battery for each motor. With both batteries charge is the switch is on batt 1 or just batt 2 or does he need to run on all, which caused the problem.
So what's the deal with the way formula wired this boat? I'd like to install another switch and wire it so one battery for each motor. With both batteries charge is the switch is on batt 1 or just batt 2 or does he need to run on all, which caused the problem.
06-30-2003, 07:36 AM
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My Formula is also wired with both batteries running to a single selector (#1, #2, both) switch. Each battery also has a "preference" for one motor, as the grounds go direct to one motor, but the motors are connected with a ground strap as well (this is and should be the only place both grounds connect to prevent ground loop problems). I normally run with the switch to "both", but you can lock out one or the other. If the switch is set to #1 or #2, the other battery is completly out of action, so wouldn't charge either.
-Greg
-Greg
06-30-2003, 09:41 AM
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Don't know why they do this, it totally sucks. What happend to my friend was one batter went bad and took the second battery out with it. If you're you're going to run on all you might as well save the weight and just use one battery.
I'm putting Optimas in the boat tonight, until I have a chance to wire in the second switch I'm telling him to run batt 1 on the way out and batt 2 on the way in. Never use all unless both are nearly dead and BOTH may get you started.
Pure dumba$$ move on formula to wire the boat this way. I just can't figure the logic behind it.
Greg, where do the alternator output wires go to? Do the go to the switch or do they just run to the lug on the starter.
I'm putting Optimas in the boat tonight, until I have a chance to wire in the second switch I'm telling him to run batt 1 on the way out and batt 2 on the way in. Never use all unless both are nearly dead and BOTH may get you started.
Pure dumba$$ move on formula to wire the boat this way. I just can't figure the logic behind it.
Greg, where do the alternator output wires go to? Do the go to the switch or do they just run to the lug on the starter.
06-30-2003, 09:41 AM
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If i'm reading this right you have a twin engine...twin battery but one switch?
If thats the case then each engine starter goes to the output pole of the switch....then each batt goes to the respective battery post (i.e. #1 and #2) so whats happening is that bothe motors are being started from either the #1 or #2 battery or both depending on how its switched.
If you wanted to add another switch it woudl be very easy to do. Go and get yourself another switch and you will need two extra battey cables to cross connect the batteries to the opposite switch.
Heres a diagram on how to do it......from this diagram you take the second starter wire and go to the second out put of the new switch...
If thats the case then each engine starter goes to the output pole of the switch....then each batt goes to the respective battery post (i.e. #1 and #2) so whats happening is that bothe motors are being started from either the #1 or #2 battery or both depending on how its switched.
If you wanted to add another switch it woudl be very easy to do. Go and get yourself another switch and you will need two extra battey cables to cross connect the batteries to the opposite switch.
Heres a diagram on how to do it......from this diagram you take the second starter wire and go to the second out put of the new switch...
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Last edited by Wally; 12-28-2006 at 12:50 PM.
06-30-2003, 10:36 AM
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Yes, two motors, two batteries one switch. Go figure.
I would have wired that boat exactly the way your pic is, in fact that is how I rigged my Velocity. I just can't understand why formula didn't wire the boat that way. Are they trying to save on not installing one extra switch?
BTW, if you don't plan on switching the switch with the motor running you don't need the field wire. Haven't seen a setup yet with the field wire hooked up, unless it's a setup that uses a battery isolator (2 motors 3 batteries)
Still just baffled why they did what they did. What is their logic?
I would have wired that boat exactly the way your pic is, in fact that is how I rigged my Velocity. I just can't understand why formula didn't wire the boat that way. Are they trying to save on not installing one extra switch?
BTW, if you don't plan on switching the switch with the motor running you don't need the field wire. Haven't seen a setup yet with the field wire hooked up, unless it's a setup that uses a battery isolator (2 motors 3 batteries)
Still just baffled why they did what they did. What is their logic?
Last edited by mr_velocity; 06-30-2003 at 10:39 AM.
06-30-2003, 12:34 PM
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Garry,
My boat originally had a genset, don't know if that has anything to do with how it is wired or not. The alternator wires disappear into the harness ... and I think they come out on the small lugs of the battery switch but I've never tried to actually trace them. There must be something that isolates them, as I have two sets of voltage gauges (one pair in the panel, another with a "test" switch in the breaker panel, and I do see different readings on the two different banks.
-Greg
My boat originally had a genset, don't know if that has anything to do with how it is wired or not. The alternator wires disappear into the harness ... and I think they come out on the small lugs of the battery switch but I've never tried to actually trace them. There must be something that isolates them, as I have two sets of voltage gauges (one pair in the panel, another with a "test" switch in the breaker panel, and I do see different readings on the two different banks.
-Greg
06-30-2003, 04:14 PM
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Greg,
My 89 311 is wired the same way (no genset). Hot wire from alternator runs right back to starter lug and only one battery switch. I never quite understood it either. Both battery systems are connected together no matter what position the switch is in. I still run it on one or the other - never both.
My 89 311 is wired the same way (no genset). Hot wire from alternator runs right back to starter lug and only one battery switch. I never quite understood it either. Both battery systems are connected together no matter what position the switch is in. I still run it on one or the other - never both.
