Alternator wire.-gctid378681

[Guest]

Gentlemen, last year mid season i lost volt meter reading at helm on alternator. Upon inspection i found the large orange wire with the hoop connector loose on the alternator the black boot cover rotton away. the orange wire was actually scorched and broken off from the hoop connector. I removed everything cleaned the post and nut cut back the orange wire reattached new hoop connector and shrink covered the connection from wire to hoop connector , made a nice new connection and wholla all good and good charge at voltmeter on helm. now this season getting ready ran boat with muffs to around 1200-1300 rpm to make alt kik in and helm voltmeter charging at just below 14 , its the original equip gauge . My question , i inspected my repair connection from last season and after running only 5 min or so the wire seemed extremely hot and shrink wrap very soft . connection still good but is this normal for that wire and alternator too to be extremely hot in such short time??

[boatworkfl]

Did you check the connection at both ends of the wire, such as at the battery or switch, or the reset button on the engine if it has one.

You may want to take the alt to an auto store that tests alternators, such as NAPA or advance auto, there are others.

I would replace the wire from the alternator to the next connection, have the terminals properly crimped with heavy duty terminals, use 8 GA marine wire.

If you need to replace the alternator go onlin to D&B electrical, they also can be found on ebay, good people to deal with.

[Guest]

Scraping B wrote:
Gentlemen, last year mid season i lost volt meter reading at helm on alternator. Upon inspection i found the large orange wire with the hoop connector loose on the alternator the black boot cover rotton away. the orange wire was actually scorched and broken off from the hoop connector. I removed everything cleaned the post and nut cut back the orange wire reattached new hoop connector and shrink covered the connection from wire to hoop connector , made a nice new connection and wholla all good and good charge at voltmeter on helm. now this season getting ready ran boat with muffs to around 1200-1300 rpm to make alt kik in and helm voltmeter charging at just below 14 , its the original equip gauge . My question , i inspected my repair connection from last season and after running only 5 min or so the wire seemed extremely hot and shrink wrap very soft . connection still good but is this normal for that wire and alternator too to be extremely hot in such short time??

If your batteries are not at full charge a lot of current comes from the alternator. If it wasn't too hot to touch you likely just had a high output from the alternator.

[Guest]

yes . you both have good points . I did not check the connection at the other end of the large wire probubly a good idea to replace entire length ( wonder what it looks like beneath the casing). ANDDDDD my batteries were not at full charge so indeed the alt was putting out some amps. my onboard charger is DOA.

[boatworkfl]

I would suspect that the proplem is solved, check it out, if not the problem, come back.

[captharv]

Running an alternator with no load may have damaged the diodes in it. Very strong possibility.

Take the alternator off and have it tested at an alternator shop.

Note: bad diodes are very repairable.

[Guest]

First, if you have the means, determine the amperage and the direction of flow. There is a 99% the altenator is just putting out a lot of current to charge your batteries. anyway, if the altenator is charging, the current will be towards the batteries; if the diodes are toast, the current will be toward the altenator.

With the altenator output wire being connected to the battery all the time, if the diodes are toast, as soon as you turn the battery switch on you should get current flow and the wire should heat up. Try this. If there is no heat, the diodes are likely fine. If it does heat up, the diodes are indeed toast.

If the diodes are dead, it acts like a high current draw and the wire will be undersized for this high current, thus the heat buildup. If not, and it's the regular maximum output of the altenator which is causing the heat buildup, you may have a high resistance connection. If the connection is good, I'd sure be tempted to get a larger wire on there. Heat is bad for wire!!

Chay

[Guest]

chay , so with the motor off and the batt. switch in a 1 2 or both position the wire my heat up? sounds like an easy check, i will do it. i am going to take your advise and increase the size of the wire also. thanks

[Guest]

Scraping B wrote:
chay , so with the motor off and the batt. switch in a 1 2 or both position the wire my heat up? sounds like an easy check, i will do it. i am going to take your advise and increase the size of the wire also. thanks

If you had 14 volts on the volt meter and the wire warm on the alternator everything is good.It is charging that is why the voltage is above 12.5 volts.

[boatworkfl]

check737 wrote:
If you had 14 volts on the volt meter and the wire warm on the alternator everything is good.It is charging that is why the voltage is above 12.5 volts.

14.0 to 14.2 + is a common voltage coming from the alternator, remember, a battery that measures 12 volts has about 1/2 the battery power that a fully charged battery has.

They just call them 12 volt batteries.

[Guest]

Alternators have voltage regulators. A healthy alternator with in operational RPM should have 14.2 VDC reading on the output. A reading between 13.8 to 14.2 VDC is considered normal.

[Guest]

boatworkfl wrote:
14.0 to 14.2 + is a common voltage coming from the alternator, remember, a battery that measures 12 volts has about 1/2 the battery power that a fully charged battery has.

They just call them 12 volt batteries.

I thought that is what I said.

Lets separate battery voltage. 12 volts is dead 12.5 is ok

A alternator's output is nominally 14 volts on a dash voltmeter +or _

If you see anything above 13 volts your alternator is working, the charge condition of the battery and the regulator will determine the voltage.

Unless you are using a good volt meter just accept anything over 13 volts is charging and 14 is normal.

EOS

[Guest]

737 , yes my antique gauge on the helm reads just under 14, i realize its accuracy leaves something to be desired as does my speliing!so i do believe it is charging.lol. thanks for the input . I actually have a new guest 12a 2bank smart charger on the way. im looking forward to getting it wired in place of the old and plugging in . Im siding with you guys and hoping the alternator is fine and was just pushing out some amps and getting things warm down there. I keep all sorts of connectors and wire on board and last year i had an alternator held aside for me until i found the problem was the wire. I may just go ahead and buy the spare for the hell of it and keep it aboard. becuz like i always say , and my wife hates " ya never know". main reason my garage is so full of extra ****.

[Guest]

You are on the right course by replacing and using a larger gauge wire. If you had a badly corroded terminal on one end, chances are good there is a similar problem on the other end. Also, some alternator wires have a fusable link built in to the wire which also uses connections that may have gone bad in this same period of time. These bad connections all create higher resistance thus making more current flow through the wire resulting in more heat which was well established, not a good thing. Your most certainly should check your connection on the other end and/or replace and upsize your wire. 8ga is minimal in my opinon. 6ga would be a better choice.

You said your dash meter was reading near 14v which is confirmation that your alternator is charging. The post about the bad diodes is misleading. The short version is that your alternator has 3 diodes in it, sometimes reffered to as a diode trio. Their job is to allow the current to flow only one way (making DC not AC). Together they provide the total current of your alt output (65A in your case I'm guessing by year). If one of them should die then your current output will be reduced by 1/3 (43a out max now) and if a second should die 2/3, etc. But your alt will still be charging and you will see the 14v on your dash gauge, it just will take that much longer to complete a charge do to less overall current. An alt will not "draw current" except in the case where the windings internal are shorted and in that case it would be a dead short and you would know it almost immedately after you turned your batt switches on.

In any case, a wire should never heat up to the point that you can actually feel how hot it is and the insulation becomes soft. That is way too close to the point of failure, i.e. fire! A fuse or circuit breaker should break the circuit long before that occurs. There should be protection on every current carrying wire in your boat. This is ABYC and Coast Guard regulation and requirement. Yes, batteries, alternators and even bildge pumps are part of that.

[2850Bounty]

I'm pretty sure that this issue has been resolved by now....... but as an FYI re; post #1: the helm volt meter is not necessarily dedicated to alternator output, unless this boat's electrical system is somehow different from what I'm accustomed to seeing. It will/should show the currently selected battery bank voltage... whether at rest, or while receiving alternator charge.

I'd not rely on this meter for an accurate voltage reading.

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