HondaBF50 Starting amps issue

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81venture
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HondaBF50 Starting amps issue

Post by 81venture » Sat Oct 10, 2015 8:52 am

Question for the BF50 owners (and others)

I re-wired my :macx: completely from scratch.... I am retired from owning an access control company, and I wire boats all the time now, so it's not my first rodeo.

The GPS and the Fishfinder are both wired (through fuses) straight to the battery. I did this so that I wouldn't lose GPS memory...it must be turned on and off at the unit so that it won't be accidentally shut off by running it through say the master panel.

Everythings good...except when I start the motor, it always hesitates .001 second, like a dead battery, and then spins over immed like its fine. It has always done this.

However everytime I start it the GPS and the fishfinder cut off...and have to be turned back on again and sure enough lost memory since it was a power interruption

Maybe the starter? I mean it only sounds "slow" for about 1/4 revolution and then goes just fine....

Huge amp draw? and if so how would I rectify this...never had this one before

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Wind Chime
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Re: HondaBF50 Starting amps issue

Post by Wind Chime » Sat Oct 10, 2015 9:25 am

First - I'd start with my batteries. Put a volt meter on the battery terminals and read the the volts while cranking. Battery may be fine at rest, but can no longer handle starting load. Of course once the engine starts the load is off and the alternator is charging, so you may have to unplug the kill switch lanyard. Our Suzuki needs at least 12.5v at the starter to engage, so you'll need at least that at the battery source. (Or whatever volts a Honda starter needs)

Second - I'd check the volts at the starter relay while engaged.

Third - I'd check voltage at the starter itself. Also check that the starter bendex is well lubed and engaging easily. My recent experience is that lots of WD40 on the bendex spring will do wonders for easy starting.

Good luck!
Darry

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Azzarac
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Re: HondaBF50 Starting amps issue

Post by Azzarac » Sat Oct 10, 2015 9:34 am

First: What WindChime said...
If that fails to produce results then are we to assume you also rewired the battery cables to the starter motor? If so, is the gauge adequate for the length of run to the motor? Are all your terminals crimped tightly? It sounds as if you have resistance or a momentary voltage drop for that instant when the starter needs it most. Once it begins to spin the power requirements drop significantly which would give the symptoms you describe.

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Harry van der Meer
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Re: HondaBF50 Starting amps issue

Post by Harry van der Meer » Sat Oct 10, 2015 12:32 pm

I have the exact same problem with my Garmin 168 after the battery has been somewhat discharged. I am sure that with the large current draw of the BF50 starter, battery voltage goes below the minimum required by the GPS. I have been considering putting a large capacity capacitor in parallel with the Garmin. A diode should be installed in series to prevent the capacitor from discharging during starting. I just never got around doing this.

81venture
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Re: HondaBF50 Starting amps issue

Post by 81venture » Sat Oct 10, 2015 2:23 pm

Azzarac wrote:First: What WindChime said...
It sounds as if you have resistance or a momentary voltage drop for that instant when the starter needs it most. Once it begins to spin the power requirements drop significantly which would give the symptoms you describe.
Yes that's the puzzling part. The momentary voltage drop is so brief that if it wasn't for the GPS and fishfinder cutting off I wouldn't even notice I had a problem....It's hard to describe with words but if you heard the motor start you would think it was normal the hesitation is so brief.

I did NOT re-do the wiring from battery to motor...that is original, and again the hesitation so brief I never thought I had an issue... All the rest of the systems are re-wired by me..the entire cabin I gutted as nothing worked.

It's pouring of course...I will check resistance and voltage from the Bat to the motor, and voltage drop at starting... Batteries are brand new, and if not for this little blip I would not even have noticed

thanks

81venture
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Re: HondaBF50 Starting amps issue

Post by 81venture » Sat Oct 10, 2015 2:24 pm

Harry van der Meer wrote:I have the exact same problem with my Garmin 168 after the battery has been somewhat discharged. I am sure that with the large current draw of the BF50 starter, battery voltage goes below the minimum required by the GPS. I have been considering putting a large capacity capacitor in parallel with the Garmin. A diode should be installed in series to prevent the capacitor from discharging during starting. I just never got around doing this.
This was going to be my next avenue of thinking....the drop is so short...milliseconds but is all it takes

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Tomfoolery
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Re: HondaBF50 Starting amps issue

Post by Tomfoolery » Wed Oct 14, 2015 9:13 am

If the wiring to the starter is too light or otherwise has too high of a DC resistance, there will be excessive voltage drop over that wiring to the starter (and back). BUT, because of that extra resistance, it won't draw as much current from the battery at any part of the start cycle. So if the battery voltage is dropping below what the instruments need, it's not because of the wiring to the starter UNLESS it's taking longer to start than it should, in which case the extra time cranking may be just enough to use up what little stored energy the instruments have (I would imagine there's at least a little bit of capacitance in their power supplies). Like unplugging a digital clock - depending on the clock, you may get a fraction of a second of unpowered time, or you may have several seconds, before it resets itself and blinks 12:00 endlessly (assuming no battery backup) when it's plugged back in.

The best solution, though not the cheapest, is to use a house battery and a starter battery, and run a charge relay so the start battery gets recharged first, and any excess from there goes to the house battery. You can use a deep-cycle for the start battery, and use it as a backup for the house battery, but at least if your instruments are on a battery not directly affected by engine starting, you won't lose them every time you start. Heck, even a motorcycle battery would do the job of keeping them alive. Or a capacitor. :D As long as it's not pulled down by engine starting.

81venture
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Re: HondaBF50 Starting amps issue

Post by 81venture » Fri Oct 16, 2015 9:49 am

Well I do have a house battery and a starting battery, but they are wired to distribution panel and fuse block (instruments) through a battery switch (1-2-all)

I checked starter leads and there isn't any corrosion issues..the starter does not "drag" or take excessively long..when the key is turned the starter "hesitates" as if a low battery, but only for a millisecond literally then starts normally.

I installed an auto matic dual bank charger/tender the other day so I let it sit overnight...fully charged I tried again...everything stayed on except the GPS.

It looks like the only way to fix this prob is a Capacitor and diode in the line...any recommendations of one suited for marine use? Suppose i will mount it in line in the pedestal where the GPS connection is

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