Running with a faulty alternater ... OK?

[merrydolphin]

To answer your question: I cant see any reason that it couldn’t free wheel indefinitely. When fully functioning there is MORE load on bearings etc. and more load on the engine. Belt tension is the same and will not be as prone to needing adjusting/replacing due to less load. The only negative is that you are loosing redundancy and capacity of charge. As long as there is good sun, maybe not an issue. Good luck. Personally, I would fix it when possible but no panic.

[goboatingnow]

Yes you can leave freewheel , there’s no real drag on the engine.

[goboatingnow]

Originally Posted by Cheechako

If both alternators go to the same batterys/ bank, one may not be charging because it senses the voltage from the other.

I dont know how yours is wired.

Err no , both will charge a discharged battery.

[Dieseldude]

Originally Posted by TMarvin

Take a wire brush to all of the connections and put an anti corrosion grease on it. Mine was faulty this weekend (stopped working) and I looked all around town to get it tested (auto zone)or replaced and seemed ordering online was my only option. I came back to the catamaran cleaned all of the terminals and put it back in until I could order a new one. Just for the heck of it I started the boat motors to adjust the throttles and the alternator worked perfectly! Must have just had a little too much rust on a terminal.

Sometimes a baffling problem can boil down to a simple fix. I would caution to grease electrical terminals after assembling. Grease is not conductive, and if put on conductive surfaces before fitting together, it can cause resistance. A dielectric rated grease is best, but any grease will offer some corrosion protection. Silicone grease such as Dow Corning 111 has good temperature stability and should not run off when heated. It is quite pricey but a tube aboard is quite useful for other tasks such as lubing o-rings. It can be used as an antiseize where metallic antiseize is not desirable due to it being a third metal in galvanic reactions.

[pbmaise]

My vessel came with two alternators on a single engine. The port alternator was disconnected when I purchased the vessel. I actually don't even know if it was still good or not. I never connected it to the the port alternator and had a brand new spare starboard alternator as a spare part.

I think that is the key difference here. Do you have a spare alternator?

I didn't remove the port alternator from the equation since it was on the same belt as my water pump and essentially free wheeled since it is not generating electricity. Yes this was a little drain on engine power, however, I figured it was less cost than trying to figure out how to redo the belt to the water pump.

I could really hear the engine load when my working alternator kicked in and started providing power.

.

[goboatingnow]

Originally Posted by Dieseldude

Sometimes a baffling problem can boil down to a simple fix. I would caution to grease electrical terminals after assembling. Grease is not conductive, and if put on conductive surfaces before fitting together, it can cause resistance. A dielectric rated grease is best, but any grease will offer some corrosion protection. Silicone grease such as Dow Corning 111 has good temperature stability and should not run off when heated. It is quite pricey but a tube aboard is quite useful for other tasks such as lubing o-rings. It can be used as an antiseize where metallic antiseize is not desirable due to it being a third metal in galvanic reactions.

Just to be clear dielectric grease is never applied to the mating conducting surfaces , the electrical joint is made and then the grease is applied

[Bowdrie]

If you want to use a grease, then use an electrically "Conductive" grease.
Their are "Parker" stores all over the place, this is but one of many kinds/sources;
https://ph.parker.com/us/en/electric...ductive-grease

[Dieseldude]

Originally Posted by goboatingnow

Just to be clear dielectric grease is never applied to the mating conducting surfaces , the electrical joint is made and then the grease is applied

Yup, that is my standard practice. When fitting top post battery terminals, I run a small bead of grease around the battery top surface immediately next to the post. I then push down the cable terminal. If not excessive. It will extrude over the battery top surface and on the cable terminal under surface, but it will not force up onto the post and terminal surfaces. Ya gotta get just the right amount. Alternatively, each surface can be smeared independently if one is not confident to estimate. This will make a grease seal that will not cover the electrical mating surfaces. After tightening the terminal bolts, I then coat everything with grease. Again, silicon grease is preferred because of its dielectric rating, temperature stability, and resilience. It can take a few minutes with a propane torch to make the stuff melt and run. It is quite tenacious, and not likely to wash off if contacted by water or other fluids.


On the topic of top post terminals, I have suffered grief over cheap cable terminals. The cheapies are made of lead which tends to crack after a few cycles of removal and fitment. Some are just a horrible design that is difficult to get tight. The brass ones are well worth the bit of extra cost for their ergonomics and durability. Brass terminals are a low cost means of increasing reliability of a charging and starting system, as failed terminals are such a common cause of trouble. I re-terminate the wires with high quality eye style lugs. You need a large crimper to do this, and these are not cheap. The impact type that are hit with a hammer are not expensive though. Terminals and crimpers can be had at welding supply shops, as they are used for welding cables. Or perhaps Harbor Freight (US) and Princess Auto (Canada). One need not pay high prices at marine supply shops. They are solid copper, and the better ones are plated with a silvery looking metal, perhaps tin or cadmium. But I have only found plated terminals at industrial electrical suppliers. Welding lugs that I have seen are always bare copper.



If you want, you can solder them to your cable after crimping for added durability. The large terminal and wire will need a propane torch for soldering, and one must be careful not to burn the insulation. Rosin core solder is needed, not plumbing solder with acid flux that will cause corrosion over time. Soldering will seal out water and battery acid. Or you can put double wall heat shrink over the joint. It has a hot glue layer inside that seals out fluids. Taking a bit of extra time and choosing quality materials will avoid the aggravation and potential dangers and expense of dead batteries and failed starts later. Cables can be made that will last the life of the boat.

[Pete7]

Originally Posted by more

and work not 110A but pump 80-90A

No it won't, that one is only rated for 60A. However, this one will:

https://www.startermotor-alternator-...73-15372-p.asp

However, worth noting that older Volvos have thin belts. I think my VP 2003 is 3/8ths rather than later models with 1/2" belts, so attempting to extract too much power is likely to end in tears. Impact wrench likely needed to remove the nut and cooling rotor if there is no hex key in the centre of the shaft.

Pete

[TMarvin]

Yes sorry thats what I used CRC dielectric grease.

[Bowdrie]

The crimping tools that use/produce a "divot, such as most of the "hammer" style units are not really satisfactory for use on the large terminals for use on battery and alternator cables that will have shrink-tubing applied over them.
The divot produces a deep groove that the shrink-tube will rarely seal properly.
The best tools produce a "Hex" crimp, which not only provides a much better swedge effect on the cable, but gives an exterior profile that the shrink-tube will readily form around and seal. For example;
https://www.crimpingtools.com/collec...r-for-10-120mm
Solder?,, Any connector subject to vibration, like a cable on a starter or alternator should be crimped only.
The heat of soldering on a crimped copper connector expands the terminal and only weakens the crimp joint.
On an inspected vessel, the CG will not allow a soldered connection to the starter.

[goboatingnow]

Yes never solder crimps , solder is not a good way to make a mechanical joint. It’s a good way to make a conductive one.

The “divot “ crimp in my opinion done with the appropriate tool is actually the recommended approach by several crimp manufactures , having said that I use a hydraulic hex crimp tool !

I never rely on adhesive lined shrink to make a water tight seal. In my experience it doesn’t work.

[Wotname]

Lot's of diverging opinions of using grease on electrical terminals!

What is the point of putting a protective coating on the outside of a termination, no (DC) current flows through the outside of the termination.

Prevents corrosion you say - well that isn't a real issue until the whole of the termination corrodes away from the outside - not likely to happen in a normal lifetime.

Prevents corrosion from getting into and between the conducting surfaces you say - fair enough but surely it is better to seal these surfaces themselves rather than slopping 'grease' over the outside.

For decades I have ALWAYS used a low pressure dielectric grease (specifically DC4) between all contacts and terminations anytime corrosion might be an issue. Note - a low pressure, dielectric grease. A low pressure grease will easily flow away allowing for metal to metal contact to occur yet sealing air / contaminates out of the termination.

The empirical proof of the process was shown when I did a huge amount of electrical maintenance on flying boats (yes, they still exist). One aircraft in particular had a bad history of recurring electrical instrument faults due to corrosion inside the connectors. Cleaning (or replacing) the connectors, looms and instruments was never ending. One day we decided to fill the connectors (before fitting) with DC4 to see if it would help. The naysayers knew it would be a disaster, never use a dielectric grease between the contacts, its a insulator they said. Well, they were wrong! At least they are wrong if a low pressure grease is used and the connector is assembled correctly.

The fault history dropped to almost nothing, the pilots were happy, management were ecstatic and the accountants approved bulk purchases of DC4!

The practice was extended to the rest of the fleet and the same results were achieved - decrease in electrical connector faults. We are talking connectors carrying currents anywhere milliamps to tens (even hundreds) of amps.

I have never had a corrosion or high resistance issue on any boat terminal when DC4 was applied between the mating surfaces. If you have, I'd suggest you were not using a low pressure dielectric grease or not assembling the connection correctly.

[goboatingnow]

From Garmin

Using Dielectric Grease on the Power Connections of a Garmin Marine Device
Dielectric grease is commonly used to lubricate and help seal electrical connectors to prevent water intrusion in a marine environment. While the power cables for Garmin marine devices are designed to prevent any water from accessing the power connections, if an extra level of protection is desired, dielectric grease can be used.

Since Dielectric Grease is an insulator, do not apply the compound directly to the metal contacts. Instead, coat the outside of the connector and the connector's O-ring seal, if applicable, with a thin coat of grease. This will ensure a seal that will protect the contacts from the elements without impeding the electrical connection.

[goboatingnow]

The issue of whether to allow dielectric grease on contact surfaces can be problematic

Firstly most good quality contacts are designed to have a distinct “ wiping “ action. As the female contact body sheaths the male part, the wipers making electrical contact should “ in theory “ wipe the contact surfaces clean of the grease . Again this grease is not conductive. It must not actually end up between the electrical conducting surfaces.

However in contacts that do not have a wiping action like tightening a battery ring terminal onto a flat surface , poor application can result in reduction in contact area. That’s not to say the connector won’t work but there’s a risk of bad conductivity. The conductivity now relies on the grease being squeezed out of the joint such that metal to metal contact occurs ( and in sufficient area )

So most professional advice I’ve seen limits dielectric grease to the other seals and thread fixtures of a terminal and not the actual contact.

To me this is good advice.