I have a Perko 4-way battery switch, off, battery 1, both, battery 2. Battery 1 is the cranking battery and is mounted in stern right next to switch, battery 2 is a deep cycle trolling motor battery mounted in bow, single battery 12V trolling motor set up, boat cranks fine on battery 1 and fine on both but will not crank on battery 2. I initially thought trolling battery did not have enough juice so I had it load tested and it is putting out 550 cold cranking amps, good for a deep cycle battery and enough for a 4-stroke 115 hp. Then thought I had a bad connection or that one of the long battery cables running from stern to bow was messed up, but that is not the case. I finally concluded bad Perko switch. I took back to West Marine today and they exchanged as the switch carries a 5-year warranty and I had proof of the sale. Installed new switch and still the same thing. I can physically join the positive from battery 2 to the common lug on the rear of the switch with the motor positive and it will crank, but if I put it back to the #2 post and switch to number 2 the motor will not crank. The motor will sound like it wants to turn over but not enough juice to turn the fly shell. Motor makes exact same noise if I flip the kill switch and try to crank it. Any ideas??? I use the switch to isolate the trolling motor battery when trolling to make sure I don’t run down the cranking battery. I mostly just want to have the trolling motor battery as a back up just in case cranking battery were to go dead on the water for some reason. Help!!
Check your grounds. I would suggest…main ground from engine to bat. #1 negative, same sized ground wire from bat. #1 neg. to bat. #2 neg.
Or you could run 2 grounds from engine, one to each battery neg. terminal. You will need good sized wires to use the battery in the bow for cranking.
Main positive (starting) wire from engine to “comm” on switch
bat. #1 from switch to bat. #1 positive
bat. #2 from switch to bat. #2 positive
Position 1 starting
Position 2 starting w/ bat. #2
Both…well both
Take a continuity tester across the proper studs, wiggle them. Tighten the bolts down. Play with it see if you can make it have a bad connection. Check your wire ends for corrosion. Have heard of them corroding from the inside out. Check it all over real well again. That’s what I would do.
Make sure you’re hooked up correctly. Try again! Hope this helps.
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Use a selinode and a momentary switch to jump both batterys!
Good advice.
Also check your battery cables for corrosion, both positive and negative. From end to end you should have less than 10 ohms resistance. Corrosion inside your cables causes resistance. That resistance is the opposition to current flow by definition.
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I will check the battery cables from trolling motor battery with ohm meter. What does not make sense is if that was the issue why is it that battery with those cables will start the motor when the switch is bypassed? It is obvious I am getting enough voltage and amperage to the stern of the boat, just not through the switch. It is like position two on the switch is not allowing enough amperage to flow, the switch is the resistance?
quote:
Originally posted by contender1I will check the battery cables from trolling motor battery with ohm meter. What does not make sense is if that was the issue why is it that battery with those cables will start the motor when the switch is bypassed? It is obvious I am getting enough voltage and amperage to the stern of the boat, just not through the switch. It is like position two on the switch is not allowing enough amperage to flow, the switch is the resistance?
That’s where I suggested to ‘play’ with the switch while its disconnected and see if you can make it fail or give you an intermittent tone while testing continuity. Tighten and loosen the bolts like you have it installed, maybe the bolt is pulling the stud off of its contact. I hear the Blue Seas battery switch is half the cost of the Perko, maybe it’s time for a swap of the switch. Keep us posted on what you discover.
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Did you have Battery1 disconnected when you direct connected Battery2 to the common stud? If so, I’d try it again with Battery1 completely out of the equation. My guess is that the added resistance is just enough to cause problems. If the connections are all good, you may have to switch to larger cables going to the front to reduce the resistance. What size are the current cables, and how long are they?
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Contender; cable from front of boat need to be considerably larger
gauge on order to handle cranking current of main motor. You can feel
of pos cable at t-motor battery while trying to use it to crank main
motor , if it starts getting hot while motor is being turned over,
most likely cable is too small…
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use a load tester to check the battery, battery conections, and battery cables.If you don’t have a load tester, you can use your volt meter to do a voltage drop test(google it), if you do an Ohm test, switch the meter to diode test, it send s 2 volt charge thru the cable to test continuity, not enough to find a slight resistance, but it will show more than using the Ohm scale. 550 cca is marginal for a EFI engine. What size cable are you running from the trolling motor battery to the battery switch? How long is that run?
Battery was load tested at Advanced it read 550 CCA. The wire run is 18-feet and I am pretty sure it is #2 wire, it is definitely bigger than #4. Both ground and positive are the same size. I switched trolling motor battery to a newer one rated at 750 CCA and that did not make a difference. Again the motor cranks from the trolling motor battery fine if I take the 18foot cables and hook them directly to the motor, it just will not crank it through the switch. I can only assume the switch is adding just enough impedance to perhaps an already taxed system to keep the motor from turning over. Again the switch is brand new out the box and the old switch was doing the exact same thing so I don’t think the switch is faulty. I will try moving the trolling motor battery over to position 1 on the switch to see if that changes anything. I will also try to get a ohm reading on the cables and then with cables plus the switch on the positive side. All connections have been wire brushed with fresh copper showing so I don’t think the problem is at the connections but that does not rule out interior corrosion within the 18-foot runs.
USE A SET OF JUMPER CABLES IN ADDITION TO THE EXISTING CABLES FROM THE BATTERY TO THE SWITCH AND TRY AGAIN
IF PROBLEM DOESNT GO AWAY, SOUNDS LIKE THE SWITCH ISNT LARGE ENOUGH TO CARRY THE ADDITIONAL LOAD WITH THE LONGER RUN
IF PROBLEM GOES AWAY, YOU KNOW YOU HAVE AN ISSUE IN THE CABLES
THEN TRY POSITIVE ON;Y WITH JUMPER CABLE
THEN NEGATIVE ONLY WIHT JMPER CABLE SO YOU CAN ISOLATE PROBLEM CABLE
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Good ideas guys, thanks. I should have time this weekend to trouble shoot more and will report back. Almost wondering if switch is not capable but will pinpoint easier with these ideas. I have a long set of jumper cables too so that will help with the process.
A simple voltage drop test will identify exactly where the problem is.
This is not a resistance test.
Drop test must be done with a load and the problem will easily identify itself.
Good luck!
Keeping my eyes and ears open…and trying to learn.
I did some testing this weekend. I first connected some jumper cables in parallel with the long set of cables running from the trolling motor battery to pole 2 on the switch and negative on cranking battery. Cranked motor in position two (trolling motor battery side) and it cranked fine. Removed positive jumper wire and it cranked fine, then removed negative jumper wire and it cranked fine! What? System working as it was supposed to. Cranked a dozen times and no problems? Went to try again and would not crank? Tried several more times and no crank? Pulled positive wire and ohm tested, meter showed 1.5? Tried negative and meter showed 0.5? I then hooked wires back up and tried again and motor cranked yet again at least a dozen times in a row. Tried one more time and no luck. Turned switch off, then back on and motor cranked? Checked voltage at battery while cranking at it would drop from 12.7 to about 11 for a split second, then hooked meter to switch at the transom, read 12.7 then when I cranked it would drop to around 9.5 for a split second. The best I can figure one of the two leads is degrading and it right on the verge of conducting enough voltage and amperage to handle the cranking requirements. This is a new four stroke motor, original motor was a two stroke, I assume from my dirt bike days that a four stroke is harder to kick over that a two? In the interim I already had some short pieces of 4-gauge at the house so I made up a couple of two foot jumpers and put them in the side of the battery box, figured I could always hook them to the cranking battery and just grab the trolling motor out the bow should I get in a bind. I have not priced tin coded 2-gauge just yet but figured it is not cheap.