PHP Warning: Use of undefined constant VBA_SCRIPT - assumed 'VBA_SCRIPT' (this will throw an Error in a future version of PHP) in ..../includes/functions_navigation.php(802) : eval()'d code on line 1
Yamaha Outboard Charging Circuit - Help needed
Page 1 of 3 123 LastLast
Results 1 to 15 of 37

Thread: Yamaha Outboard Charging Circuit - Help needed

  1. #1
    Ausfish Bronze Member
    Join Date
    Aug 2008

    Yamaha Outboard Charging Circuit - Help needed

    Hey guys,

    I have a 2004 F100 Yammy 4 stroke and have been doing some serious troubleshooting of late, trying to figure out some issues I've had starting the engine. I'm running 2 x Supercharge Allrounder 80Ah 650CCA batteries on an isolator and have recently had the startermotor refurbished with a new brush plate assembly and the commutator cleaned up nice and shiny.

    I located a significant voltage drop over the original Yamaha high tension leads and replaced with new 4 gauge leads. (The original Yamaha HTs had significant corrosion on the copper for over 2 foot from the end of the cable!)

    Anyway, long story short the electrical system from engine to batteries has been completely rewired and the engine starts a treat with the batteries fully charged. The issue is, I dont believe my engine is correctly charging the batteries. I drove the boat yesterday at wide open throttle for about 10 minutes and the volt meter on the Yammy gauges never got over 13.2v and generally sat at 13.0v.

    My understanding is that the charge voltage should be regulated at between 13.6v and 14.8v depending on RPM. So I'm not convinced that my alternator / rectifier / regulator system is up to scratch. Any ideas on where to look at first? I can confirm that the voltage at the engine is now the same as the voltage at the batteries / gauges so I'm not getting a big drop in the HT leads any more. Any help would be much apprecated!

    Cheers,
    Trav

  2. #2

    Re: Yamaha Outboard Charging Circuit - Help needed

    A wild stab based solely on my personal observation over the years is never trust original equipment volt meters, never sit on full throttle for that long but that is another subject and finally that it is best to check for the difference in charge V charging ie check the state of charge of the battery static then check the output once running all with a multimeter or trusted gauge because it has been checked for accuracy.

    You can also partly flatten the batterys before the test as this will give a better indication of what charge the alternator is capable of providing.

    Hope someone can help more.

    cheers fnq



  3. #3
    Ausfish Bronze Member
    Join Date
    Aug 2008

    Re: Yamaha Outboard Charging Circuit - Help needed

    Thanks FNQ,

    The 10 minutes may have been a bit of an exaggeration but I take your point

    I agree definitely on the accuracy of the original volt meters, however I was on the boat alone and I'm sure nobody would have liked to see me at the stern with a multimeter and nobody at the helm! haha... I have verified the voltage on the gauge previously using a DMM and it was pretty much spot on. I also had the internal voltage overlay on my HDS 5 sounder which was reading the same +/- 0.2v.

    As I actually used the boat as the "limo" for my sister and her husband to arrive at their wedding reception, I couldn't really take any chances with partially discharging the batteries beforehand! In fact I actually had 4 batteries on board just in case...

    Cheers,
    Trav

  4. #4

    Re: Yamaha Outboard Charging Circuit - Help needed

    firstly.....what is the charge capacity of your motor......how many amps will it deliver....and what is the specified charge voltage?

    typicaly outboard motors have relativly small charging systems in comparison to cars........12 to 15 amps is not an unusual maximum charge current....if it is a small motor is could be as low as 8 or 5 amps.
    You realy need to know for sure, before you get any expectations.
    The bro'inlaws 30HP merc pushes 15 amps, my 60HP everude pushes 12 amps, another member on here has a 75 everude that only pushes 8 amps.

    you potentialy have 160AH of battery connected..............if you have any sort of discharge state it may take a bit more than 10 minutes to return to full charge.

    you should not have to run at WOT to get a decent charge rate.....you should be kicking out a decent rate ( near capacity) at 3000 to 3500 RPM...........even at idle you should be getting some charging happening and if the battery isn't discharged much you should be back up to voltage in a short time.

    Have you baught the factory manual yet?

    I recon the best place to chek this is at home with the leg in a bucket........bunnings have a big black rectangular tub for about $50 which is just the ticket.

    Have you tried charging one battery only, at atime.

    If you have access to a DC clamp meter you could confirm the current going to the battery.

    cheers
    Its the details, those little details, that make the difference.

  5. #5
    Ausfish Platinum Member
    Join Date
    Jan 2006

    Re: Yamaha Outboard Charging Circuit - Help needed

    hey trav, have you checked all the basics? (this will have no influence on the output voltage of your motor but will affect your batteries charging correctly) ie. wire brush the battery terminals, sand the inside of the connecting lugs, grease them once installed, check your main isolator switch for corroded contacts. that voltage does sound a little low for charging if your voltmeter is reading correctly. check it at home (with the motor running in a bag or with muffs) with a multimeter, the rev's shouldn't make too much difference if the regulator/rectifier is doing it's job properly.

  6. #6

    Re: Yamaha Outboard Charging Circuit - Help needed

    There is a site in the US called marine engine.com which is full of yamaha fanatics and a huge backlog of answered questions should the problem require even deeper fishing around.

    Cheers

  7. #7
    Ausfish Bronze Member
    Join Date
    Aug 2008

    Re: Yamaha Outboard Charging Circuit - Help needed

    Thanks guys for all the replies. I will clarify a few things in the hope that I can find a solution:

    Oldboot, the motor is a 100hp and the Yammy specs say it has a 20A alternator.
    The charge current does not go any higher than 13.2v at any point in the rev range from 800rpm idle to 6000rpm WOT. I have kept the batteries fully charged (particularly prior to this weekend! ) by use of a Jaycar 16A charger as recommended in another thread here, and by a solar panel that has a 5A regulator with reverse current protection hard wired direct to both batteries. After rewiring everything from the motor forward, I'm not convinced my alternator is charging at all!

    Paddles, all terminals have been re-terminated with new lugs when I replaced all the wiring. Inox grease has been used after tightening the nylock nuts on the terminal posts and I even used those little washers that cut into the terminal! I checked the voltage with a DMM on the ear muffs and there was no change in voltage between the motor off and the motor at idle to about 1200-1500rpm. (I wont go above that on earmuffs as I dont want the motor to overrun).

    Jarra Jack, I will check out that marineengine.com site, thanks. I have always had a good read on the iboat forums in the US and learnt a great deal from that one so hopefully marineengine.com might have some answers for me. Iboats has a regulator check on one of its threads that I will be trying when I can next get down to the boat... I'd just hate to replace the rectifier / regulator and find that the alternator stator or something else was the problem! These things get bloody expensive!

    Any other tips on where I should be looking would be much appreciated, thanks guys!

    Cheers,
    Trav

  8. #8
    Ausfish Platinum Member
    Join Date
    Jan 2006

    Re: Yamaha Outboard Charging Circuit - Help needed

    sounds like you've got the basics sorted trav. if the voltage is not changing from not running to stopped, i'd definitely be getting the alternator/regulator checked by either a yamaha techo or auto electrician, i would think the voltage should be a smidge higher to charge batteries. is there any fuse or protective device on the output of the alternator, can the alternator output voltage be checked whilst disconnected? (ie. open circuit) there'll be guys on here that know heaps more about alternators than i do, but i have a feeling there's issues with the regulator when it's open circuited.

  9. #9

    Re: Yamaha Outboard Charging Circuit - Help needed

    DO NOT... repeat ..DO NOT run any outboard motor that has a charging circuit connected without a battery connected.....it is almost guaranteed to snot the regulator and or rectifier.

    Most outboard motors( except the realy big ones) run permanent magnet, magneto type charging circuits....without a load connected the charging coils can produce very high (hundreds of volts) voltages that will snot any electronics connected.

    here is a basic test procedure.
    leave the boat and battery sitting unmolested for some time.....at least a few hours.....this will let the battery settle to a "resting state".

    measure the terminal voltage at the battery......should be around 12 to 12.5 volts...a bit lower or higher maybee

    put the leg in a tub or fit the muffs...tub is best because with the leg in water you can reasonably give it a little rev....and you can run in a tub quite happily for half an hour and the neibours wont get pissed.....it is so much quieter.

    start the motor and check the battery terminal voltage.....depending on how quickly you get there....it may be a little lower from the cranking... but the battery voltage should slowly increase....if the charging circuit is working it should soon be over 13 volts......over time it should increase to the maximum charging voltage which will vary depending on charging system.

    Remember almost all sounders have the ability to display battery voltage and reasonably accurately.....as long as the battery that the sounder is powered from is connected to the charging system.

    now if the charging circuit isn't working the battery will seem to recover from the cranking...but..it will not go above the original voltage tested.

    as I said before.. don't expect too much of these charging systems....they are generaly quite small in comparison to cars......even the smallest cars have a 40 amp charging system.

    definitely buy the manual.....it will give you all the details you need and should give test procedures for the regulator out of circuit..

    cheers
    Its the details, those little details, that make the difference.

  10. #10
    Ausfish Bronze Member
    Join Date
    Aug 2008

    Re: Yamaha Outboard Charging Circuit - Help needed

    Oldboot,

    Yep no worries, I've heard that the no battery thing is a no-go. Thanks heaps mate, I will try your test method this afternoon and see what I get I have ordered the Seloc Manual today from a book store in the states... $42 delivered express international air mail A lot better than $74 in a bookshop here! Only problem is the wait that I have to receive it! However, thanks heaps for the tips on how to diagnose whether I am getting any charge at all! It will give me a good heading in the right direction anyway! I will update on how I go...

    Cheers,
    Trav

  11. #11
    Ausfish Bronze Member
    Join Date
    Aug 2008

    Question Re: Yamaha Outboard Charging Circuit - Help needed

    Ok, after diagnostics last night, I have also determined that my starter motor is not up to scratch either! Even after getting a full new brush plate last week. However, that is another matter...

    Testing the batteries at rest (after a few days isolated except for a solar charger)
    Battery 1: 13.18V
    Battery 2: 13.18V

    Due to my starter difficulties, I was not able to start the motor on one battery, so battery 1 got a bit more draw than battery 2 as I tried battery 1 then switched to 1+2 to start it. So, after starting:
    Battery 1:12.92V
    Battery 2: 13.04V

    With the motor running at idle (800RPM) and the isolator set back to battery 1 (on 1+2 the charge rate was negligible and I noticed no increase in voltage), I observed the voltage increasing on battery 1 from the 12.92V gradually, back up to about 13.04V at a rate of about 0.01V every 5 seconds. Even after running for 10 minutes the charge rate never really changed, just plodded along like that, putting 0.01v back in every 5 seconds or so.

    I checked the voltages at the engine to make sure the new HT leads and terminals didn't have problems and the voltages and charge rates were identical. Increasing the revs to 2500RPM had minimal effect on the voltage, and only slightly increased the rate that the 0.01V was being added to the batteries (0.01V per 2-3 seconds).

    I switched the motor off with the volt meter connected and observed the voltage drop from 13.01V to 12.97V at the motor. So it appears my magneto/rectifier/regulator is providing only 0.04V to charge my batteries?? This seems far too low to me... What do you guys think? My understanding was that when you kick the engine over, the voltage should jump up from the 12V or so to about 13.6V and when you rev the engine toward WOT it should increase up to the regulated 14.8V?

    PS: the starter is off and headed back to the autoelectrician today to test the windings and plates in the armature. However this is a side issue and does not directly relate to my charging concerns (with the exception of the bad starter draining my batteries when I try to crank the engine! )

  12. #12

    Re: Yamaha Outboard Charging Circuit - Help needed

    Do you have the old analogue rpm gauge, does it work? It can be indicator of charging problems on some engines, Can you fit a flat battery (say 12v) to number 2 , then switch to it. IMO it's hard to assume what's going on for certain at the battery until the differential is large and the alternator/regulator knows this and decides to do something about it..or not.

    My old yam on full battery's doesn't fully behave like you say yours should and it so far is working fine, i know this because I have tested it with a flat battery as my testing was done at the battery.

    cheers fnq



  13. #13

    Re: Yamaha Outboard Charging Circuit - Help needed

    trav mate you have made some errors in your method.......because the batteries are on the solar charger.....they are not at rest... but anyway.
    Having batteries at rest makes it all look better because you will start with a lower voltage and the spread of figures will be wider.

    You can not make assumptions from your charging voltages the way you are...the charging voltage will only rise as fast as the battery lets it......we do not know the age or condition of the batteries so we can not make assumptions.

    it is the current that charges the battery......the voltage is a side show....important but still a sideshow.

    the charging system is applying SOME charge.....that is the only conclusion we can safely draw.

    we do not know the charging capacity of the motor..so we cant make assumptions.

    as for the starter motor.....have you tested it with a known good battery

    If you want to test the charging system you will need to get some means of measuring the current......a DC clamp meter is your only real option......and you need to know the chargong capacity of your motor.
    Even better a set of charge curves would be good.

    have you had your batteries tested?

    try this it isnt great bit it might give an indication................charge the batteries with a known good charger.....disconnect from everything.....measure the voltage.....over the next hour or so the voltage will drop till the battery is at rest....12 to 12.5 volt ..ish.....over the next couple of days....the voltage should not drop much at all.....a good marine battery should hold its resting voltage ... more or less for a couple of weeks... more or less...if the resting voltage drops significantly over a couple of days.....the battery is sus.

    better still take the batteeries down to the autolec and get him to test them with a battery tester.

    or.... put them in the car and see how they crank that in comparison to the battery that belongs there.....if it is a normal pasenger car....85AH will be bigger than what is there so they should do better.

    If you hadn't gathered I'm sus of the batteries.

    remember....small charging system....large battery........so much we don't know.
    lets not jump at conclusions.

    cheers
    Its the details, those little details, that make the difference.

  14. #14
    Ausfish Bronze Member
    Join Date
    Aug 2008

    Re: Yamaha Outboard Charging Circuit - Help needed

    Thanks FNQ, I will try a flat battery and see what happens...

    Oldboot,

    I concede the fact that the solar charger could possibly be still trickling the batteries however I started testing the boat about an hour after dark, I would have thought it would have settled by then... maybe not!

    Both batteries I am using were purchased new in May 2009 from Bias... Funny you mention it though because the auto electrician who is looking at the starter today reckons there is nothing wrong with the starter and is suggesting that I bought dud batteries The engine manual says it requires a battery with 70Ah and 430CCA minimum. These batteries are 80Ah and 650CCA. Surely I couldnt have got 2 duds?!

    My Yamaha manual specifications indicates "Alternator output for battery DC: 20.0A" I dont have a clamp meter, only a standard DMM so I'm not sure on checking the charge current output unfortunately

    Yeah I agree, I think the next step is to get the auto electrician to test my batteries. I'll be really peeved if they are stuffed, considering I spent nearly $400 on them only a couple of months ago! On the same token I'll be happy if the problem is as simple as that! I have my doubts however....

  15. #15

    Re: Yamaha Outboard Charging Circuit - Help needed

    If it has a 20 amp charging capacity. and requires a 70 AH battery .. I gather it is a reasonable sized motor.......the manual says "alternator".....does this machine have a seperate alternator or a charging coil under the flywheel?

    Does the manual state a maximum charging voltage.......It may only charge at 13.8V or such like a normal car..........there realy is no standard voltage.
    13.6, 13.8, 14.2, 14.5, 14.8, 15 volts......they are all to be found and there might be small differences but they make a big difference if you are looking at behaviour and have an incorrect expectation.



    Need the manual..... there is no substitute for accurate information.


    have you tried substituting the car battery........both ways.

    And the number of times I have heard people say....It cant be, such and such, its new........when you have a problem you just cant assume that anything isn't faulty.

    cheers
    Its the details, those little details, that make the difference.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •