How much current does a DF25 draw when starting.

[OrangeQuest]

Hi, I am building a 14 foot skiff that will be powered by the DF25 and I am trying to figure out the current the starter will draw to run the starter wires to the battery that will be located in the bow some 12 feet from the motor. I ordered all my wiring last year and at the time I had a chart that showed the information. I have since decided to move the battery forward more and don't remember the spec. I ordered 10 gauge wire so it can't be that much. I ordered all my wiring based on less than 3% voltage drop.

Thanks for any help offered.
OQ

[boats.net]

You need to use at least 4 gauge battery cables, if the cable will be over 5.2 meters long then use 2 gauge cables.

[OrangeQuest]

You need to use at least 4 gauge battery cables, if the cable will be over 5.2 meters long then use 2 gauge cables.

If I consider that the round trip (both pos and neg cables) will be a little over 7.6 meters you are suggesting that the starter will be drawing over 100 amps. That seems extremely excessive amount of energy to fire such a small motor. I am retired automotive mechanic and the permanent magnet starters of V8 cars would not draw that kind of current to turn over. Which I do under state that the distance from the motor to the battery does cause voltage drop and I am refencing the ABYC standards on wire gauge size to length

Is there any way I can get the specs on how much current the starter will draw so if in the future I have to trouble shoot a starting issue I would know the spec.

[2014DF25ARS]

I have a DF25A and am willing to measure the starting amps of my 4-year-old motor if you like, but it might take a couple days, as it's raining heavily here now.

For what it's worth, from the Service Manual:

Battery specification
650 Marine Cranking Amps (MCA)/ABYC, or 512 Cold
Cranking Amps (CCA)/SAE or 160 Reserve Capacity
(RC) Minutes/SAE or 12 V 70 AH

Starter motor specs, DF25A DF30A:
Max. continuous time of use Sec. 30
Motor output 0.6

kW

[OrangeQuest]

I have a DF25A and am willing to measure the starting amps of my 4-year-old motor if you like, but it might take a couple days, as it's raining heavily here now.

For what it's worth, from the Service Manual:

Battery specification
650 Marine Cranking Amps (MCA)/ABYC, or 512 Cold
Cranking Amps (CCA)/SAE or 160 Reserve Capacity
(RC) Minutes/SAE or 12 V 70 AH

Starter motor specs, DF25A DF30A:
Max. continuous time of use Sec. 30
Motor output 0.6

kW

That would really be great! Thank you for the offer! It is raining here in Houston as well. We seem to be getting the same pattern every week.
I found a really good price on some 4 gauge wire that I am adding to the budget. Figuring 15 feet for red and black. That will cover me till about 80 amps then the voltage drop will be to much.

Knowing what the amperage is when it is all working good helps diagnose problems when it is not. With an amp gauge and a volt meter can pin point starter, battery or wiring issues pretty quick.
OQ

[boats.net]

Attached is the cable chart from the Suzuki DF25 service manual.
Recommended Battery Cable .pdf

[OrangeQuest]

I have a DF25A and am willing to measure the starting amps of my 4-year-old motor if you like, but it might take a couple days, as it's raining heavily here now.

For what it's worth, from the Service Manual:

Battery specification
650 Marine Cranking Amps (MCA)/ABYC, or 512 Cold
Cranking Amps (CCA)/SAE or 160 Reserve Capacity
(RC) Minutes/SAE or 12 V 70 AH

Starter motor specs, DF25A DF30A:
Max. continuous time of use Sec. 30
Motor output 0.6

kW

After sleeping on it last night the 0.6 Kw number you gave equals to 600 watts, which converted to amps is 50 amps!!

Thank you so much for your help. That is very valuable information and again thank you for sharing it.

OQ

[2014DF25ARS]

I agree with your theory; that was my thinking as well. But... I measured my motor this morning. First, I measured my battery voltage at rest = 12.5V. Then I disconnected the safety lanyard from my remote control so the engine would not start, and I put a clamp meter on the positive lead from my battery to the engine. When I turned the key to the RUN position (the warning buzzer beeps), I measured 0.7A current. When I turned the key to the START position, the starter motor began running, and I was surprised to read only 3.1A current with the starter running! Also enlightening: I re-connected the safety lanyard and started the engine, and when it was running I measured -3.5-4A, as the motor began charging the battery. So there was actually MORE current flowing when the engine was running than when it was starting.

I'm not sure how to explain this. It's possible that my meter or technique are wrong; I am now compelled to do some testing elsewhere. But I suppose the starter motor is CAPABLE of producing 600W, in which case it should draw approx. 50A. But I also suppose the engine does not present that much load for the starter, so it is producing much less power when running under normal starting conditions.

I was curious about the cable running to the starter motor within the cowling. Unfortunately, I don't find any markings on mine. But I measured the diameter (including insulation), and it is 0.225 in. I found this chart on the internets, based on which I'd guess it's an 8-10 guage wire. Of course the internal cable is only 8 inches long, so a thicker cable would be appropriate to run the length of your boat.

AWGchart.JPG


As a final obsessive point, I noted the P/N of the starter motor. It is marked:

Hitachi 31100-94402
S108-94C 12V
41M

[OrangeQuest]

2014DF25ARS, the Hitachi number you posted fits a lot of other motors from 9.9HP to 90HP from what I found on a quick search. With that in mind it makes sense that in a small hp motor the starter would require less than the full 50 amps. The 50 amps would be under full load turning a cold 90hp engine over. It is good to know that your starter motor is THAT beefy! Thank you very much for your help with this issue. I think we both came out a little wiser!

[OrangeQuest]

I now have a 2022 DF25 Suzuki outboard. Using the factory battery cables connected to a 12V 7amp battery, I was able to start it quickly and easily. I ran 12 feet each of both pos and neg of 4ga wire. The dual batteries connect to a 60amp breaker each then to the battery control switch. I have no problems turning the motor over and with 4 hours on the motor still breaking it in.
BTW, this motor is very quiet even on a plane. So far, loving it.

Again, Thanks to everyone that commented on this subject and hope it will help others.
One thing I will add, it is sad that even in the troubleshooting section of my service manual does it state what the amperage draw is for a good starter motor.