Anyone know anything about outboard charging systems?

[petryshyn]

Re: Anyone know anything about outboard charging systems?

thanks 12'er its kinda fun!

 

[ODDD1]

Re: Anyone know anything about outboard charging systems?

A word to the wise, schematic........merc spec's a NON maintenance-free battrery for the unregulated charging systems....seems the possibility of chronic overcharging will call for eventual fluid replacement...such a problem this guy wishes for!!

 

[petryshyn]

Re: Anyone know anything about outboard charging systems?

Hi ODDD1...<br />I wonder what merc is thinking? Main.free would be easier on their charging system.<br />This brings up an interesting point. The delco maintenance-free has a higher internal resistance than a conventional battery. That means it can take a higher voltage across it than a conventional can with very little current flow.(less gassing). 15-15.5v is totally acceptable. Not only that, but the maintenance free also has provisions for condensing escaping gases in the event of charging and discharging. I would recommend a delco main.free in a second, but,...since marine batteries are so abused (left in a discharged state for too long, because of small charging system) I don't recommend them because they can't totally recover from a deep discharge.<br /><br />I wonder what Merc's reasoning is?<br /><br />Now if you had an alternator of a decent size, and you weren't pounding high waves all day, maintenance free batteries rule!!!<br /> Thanks ODDD1!!!

 

[petryshyn]

Re: Anyone know anything about outboard charging systems?

 

[ODDD1]

Re: Anyone know anything about outboard charging systems?

I always enjoy your responses to a problem, schematic......sometimes I think you spend too much time in engineerland, not enough in with the rest of us...LOL...then again, my wife thinks all the hydrocarbons i have ingested over the years has done permanent brain damage.....you think a maintenance free battery would be a good choice on a unregulated system because it will tolerate higher voltages before gassing.....the question [to me] is not when it will gass, but IF it will....and it is gonna, alot.<br />where does the gasses come from? the electrolite....if you cant replenish the electrolite, long term damage to battery capacity will result....I have seen these systems push 17 volts into a fully charged battery.....on ahot day, it makes a mess out of a conventional battery, and will kill a main. free in a short period of time......

 

[petryshyn]

Re: Anyone know anything about outboard charging systems?

Thanks ODDD1, I'll take that as a compliment!<br /><br />Never spent any time in engineerland though.<br />I always maintain that if one doesn't understand how something works, how can one fix it? So for this reason I go the extra mile...... My personality flaw...LOL <br /><br />>You're right, WATER loss is going to be a problem at a charge rate of 17V. While m. free batt. can withstand a higher charging voltage than a low or reg. maintenace battery, a charging voltage in excess of 16v volts will cause WATER loss. The problem is not as simple as having a battery that you can remove the vent caps to add WATER.(heck, they train monkey's to top up maintenance free batteries) The problem is the temperature reached during the overcharging that is killing these batteries.(whole other story)<br /><br />>for about $10.00 we can build a simple addition to the charging system. This would allow us to switch from a "high" to a "low" charge rate if we see our voltage creaping too high. (all that's needed is one switch and one diode)(you could call this a poor man's regulator)<br /><br />>we could obviously install a add-on regulator or build a generic one for about $40.00 that can handle up to 50 amps. with an input voltage up to 100 volts.<br /><br />>or,.....one could continue to relace rectifiers and batteries and sit around whining and complaining cause the manufacturer skruuued up!!....LOL<br /><br />

 

[trevorcday]

Re: Anyone know anything about outboard charging systems?

I have totally lost track of this discussion but it seems that the problem has not been fixed (correct me if I'm wrong). If the battery only charges to 10V it is obviously bad. However, even if it will read 12v with no load that doesn't really mean much. If the battery is suspect have it load tested. Any garage can do this. We have found the best way to test these charging systems is to hook up an ammeter in series between the battery terminal and the battery cable with the motor running. If current flows to the battery, and increases with RPM, the entire charging system is working, if not then a component level check can be done. The rectifiers are the most common problem if the charging system is not functioning. A simple ohs test is called for in the merc manual to test the rectifier.

 

[petryshyn]

Re: Anyone know anything about outboard charging systems?

Well said mrmerc:<br />I can see how you got lost in the posts as they got out of synch.<br /><br />>checking system with ammeter has its advantages.<br />>he has no ammeter<br />>we are waiting for a better voltmeter to check system voltages. The one I recommended has an ammeter and is a cheap investment.<br />>as pointed out, he could check his rectifier now, or wait until he attains a better voltmeter with a diode test function.<br />>although an analog ohmmeter is still recommended to check diodes,(go no go test) the 'diode test function' is far superior and can give early warnings of diode failure from previous damage. Given mnm's history, I'll take no chances. <br />>When we're done...IT WILL BE RIGHT. And if everyones suspicions of overcharging are correct, we'll address that too.<br /><br />any snow out your way?

 

[trevorcday]

Re: Anyone know anything about outboard charging systems?

Schematic: No snow here yet, today it was 15 eg. C ! Worked outside in a T-shirt all day.

 

[petryshyn]

Re: Anyone know anything about outboard charging systems?

that hurts, that really hurts!!<br />enjoy while you can.........<br />

 

[mbb]

Re: Anyone know anything about outboard charging systems?

Ok, you guys got me thinking about my system on my old merc also now. It does appear to put out 16-17 V at full throttle by my dash gage, vs 12-13 for a fully charged battery. Bothers me too because thats outside input voltage range for my GPS (5-15V), which I was planning to wire in but still run on batteries now. I havent begun poking around in it, but is this filtered output from the rectifier, or still a half sine wave, even though it would be 4000 hz or so. In other words the voltage you read may not be real average voltage? <br /><br />Does seem like something ought to be done here though. It wouldnt be too difficult to make a regulator to limit the voltage to a lower value.

 

[petryshyn]

Re: Anyone know anything about outboard charging systems?

The voltage you read at the batteries is real alright! The a/c is rectified into a pulsating d/c. (up to 1200 HZ) There is no filtering needed, as the battery fills in the gaps (acts as a capacitor). Your 16-17V is real.<br /> <br />>You could add a factory reg. $$$$<br /><br />>Build a small reg. for the GPS and a “High””Low” selector switch for the charging system.<br /><br />>Could build a larger reg. for the whole system. Gotta watch though, input voltage can sky rocket if battery disconnected!!!!<br /><br />Good luck!!!<br />

 

[Honeybee]

Re: Anyone know anything about outboard charging systems?

Hey Schematic. You are one smart cookie. Are you an engine designer for Evinrude just having fun with us? Or maybe you work for NASA? I have never seen such high quality responses - easy to understand yet thorough. Please keep up the excellent work, and whatever you do, don't retire.<br /><br />Honeybee <br />(Major Evinrude fan)

 

[mnmfors]

Re: Anyone know anything about outboard charging systems?

Hello Schematic, I just wanted to post to let you know that I have not given up or dissapeared, please bear with me, I will get the battery and the meter soon. I agree with the post above, and thanks again for all the help. Looks like this is a good topic. Talk to you soon.

 

[mnmfors]

Re: Anyone know anything about outboard charging systems?

Ok, I know it has been a while. I am ready to see this through now if you guys are still interested in helping. <br /><br />I have a few bucks to spend and this Sunday to work on it <br /><br />Ok I have a new battery....not deep cycle....fully charged. It did not fix the problem.<br /><br />Schematic,<br />I am concidering spending the 20 bucks (I am told that is what they cost)on a new rectifier instead of the tester you asked me to get. <br /><br />If I need the tester you asked me to get, I need to get it right away, do they sell them in part stores, etc.