Alternator Overheating Problem

[Pete7]

Originally Posted by hellosailor

crazyhorse-
"The alternator is from a nissan car,"
That explains a great deal.

My first question would be to ask if anyone knows, for a fact, what rpm the alternator is designed to run at, and if the pulley was correctly sized to prevent the alternator from revving too high in the boat installation. Run it too fast, and it can overheat and burn out. They all have a rating for shaft rpm and power output.

My thoughts too. However, that's not a cheap option. What to do in the meantime? well what was the charging amperage before fitting the sterling? It might be that the sterling or the belt ratios are just making the alternator work a bit too hard as Hellosailor suggests and therefore you have to accept the slower charging rate of the alternator on its own. A shame I know and one of the reasons we have held back in fitting one.

Slight thread drift but modern European cars are now coming with 150 AH plus alternators and serpentine belts, to cope with aircon and higher electrical demands which the smaller alternators couldn't cope with.

Pete

[nv5l]

If one were to use the combiner100 to connect a bank of 2 batteries with a starter battery (3 total), how many battery temperature sensors would you need?

[DeepFrz]

Well, I would only use one for the house bank. Under normal conditions your starter battery isn't going to require very much power to charge it and so it wont heat up much.

[nv5l]

Thanks. By the way, could there ever be a case where the batteries in the bank don't heat up at the same rate?

My regulator stopped working correctly and fried my batteries, so I'm replacing it along with the batteries. Just want to make sure I get everything I need.

[DeepFrz]

Its possible, if you had a shorted cell. I don't think there would be much difference otherwise. I think (iirc) that Balmar suggests you place the temp sensor on the first battery in the bank.

[OceanPlanet]

Originally Posted by Pete7

My thoughts too. However, that's not a cheap option. What to do in the meantime? well what was the charging amperage before fitting the sterling? It might be that the sterling or the belt ratios are just making the alternator work a bit too hard as Hellosailor suggests and therefore you have to accept the slower charging rate of the alternator on its own. A shame I know and one of the reasons we have held back in fitting one.

Slight thread drift but modern European cars are now coming with 150 AH plus alternators and serpentine belts, to cope with aircon and higher electrical demands which the smaller alternators couldn't cope with.

Pete

Just an fyi...although some auto alternators are now indeed higher output, they still are usually not designed for long periods at high output (as in charging a large battery bank). A recent client tried McLaren 200A x 24V alts to charge a big lithium bank and they lasted only minutes before overheating. Tried venting, cooling fans, etc, all to no avail. McLaren asked for a reduced charging rate, which would negate the whole reason for getting their "claimed" 200A alt to start with. For a temporary solution the client had to use a thermal switch to cut out the field when they got hot, but still are getting rid of them and going with American Power 160A x 28V (with better internal fans). I've been using the AP alts with lithium banks with good results.

However I know this is off subject for the OP, as those are rather spendy alts.

[DeepFrz]

A link to an interesting read. Balmar has published their alternator specs. for hot and cold and different alternator rpm. Eye opening.

http://www.balmar.net/2011-Balmar-Product-Guide.pdf

[OceanPlanet]

Originally Posted by DeepFrz

A link to an interesting read. Balmar has published their alternator specs. for hot and cold and different alternator rpm. Eye opening.

http://www.balmar.net/2011-Balmar-Product-Guide.pdf

Balmar alts have been notorious for overheating (probably one reason their alt reg has the alt temp & thermal switch). I hear they are working on better cooled units.

[OceanPlanet]

Another worthwhile bit of info in that Balmar pdf is regarding the sizing of the alternator. I often hear the erroneous Old Wives Tale of 25% of battery capacity being the MAXIMUM rated output of the alternator.

25% of bat. cap. should be the MINIMUM rated output, not the max. Otherwise...they run at full output for too long and...drum roll please....they overheat.

[DeepFrz]

For the information of those following this thread (in case anyone is wondering) I removed my last post because it was so similar to OceanPlanet's post #39.

[OceanPlanet]

So...I also removed my last post since it was largely an answer to DeepFrz's post.

[DeepFrz]

ROFL...

[donradcliffe]

Originally Posted by Maine Sail

Don,

With all due respect please explain to us why what the owner of Yandina Marine Electronics posted is rubbish? You can't simply slam someone as posting rubbish then not explain why. I would love to hear your explanation.

Our own boat had a Yandina Combiner 150 installed for 2800 engine hours and used a 50A stock Mitsubishi dumb regulated alternator. That little alt is still kicking and we now have a 375 Ah bank......

It was a pretty blatant sales pitch--knocking the competition and promoting his product. Fact is both systems will keep the alternator loaded up to maximum when the batteries are low. Don't have time to go into a lengthy explanation, as we are leaving in an hour to sail back to the mainland. See you all in a few weeks.

[crazyhorse77]

We currently have two 80Watt solar panels which supply most of our power if we are on the hook and dont use the laptops. Other power saving messures have been taken such as LED lights in the cabins and water cooled refiguration unit with cooling element that freezes and defrosts over time.

We are willing to remove one battery and cut back on power usage and charge more frequently to save the expense of buying a new marine alternator.

After installing a large blower fan that blows on the alternator i got the chance on run the alternator and it produced 30-40amps without the alternator getting too hot to touch. So i still need to intall the thermal switch to disable the multistep regulator if overheating occurs. I can live with 30-40amp charge, just need to charge often.

POSSIBLE battery problem, after running the aternator for 45mins i noticed the charge rate had droped to 6amps. (batteries arround 40-50% at start of charge) I thought the alternator was the problem so i discharged the batteries and went on shore power to see if the Alt or batteries were the problem. The 40amp charger would start charging at 36amps then 24amp then 12amps then after an hour around 8amps!

Maybe the batteries are heavily sulfated?

This would have most likely happened when we were crossing atlantic and Alt failed and was 'repaired' to limp along for remaining 10days. The Alt could not be run long (20mins at a time, many times a day, as voltage would climb to above 15V)

Does having the batteries desulfated really work in peoples experience? Hopefully so one in Grenada offers this service!

Originally Posted by DeepFrz

No, this is not the solution. The solution is to fix the problem so that the alternator never overheats. 100 c is to hot by at least 10 deg. But that is just a stop gap. As long as you realize that you can limp by. Cut back your energy usage, charge more often, etc. Don't let your bank get run down. Taking one battery off of your bank is also not the solution. It is really moving the wrong way. A better answer, for now, is to charge more often.

Any chance you can pick up a used solar panel. Even one that you mount on deck and move below while on passage will help.

You must think of your power generation and storage as a system. Once you decide what you need (energy use inventory) then you can start building toward the solution, one piece at a time if you have to.

[motion30]

I found a large frame 105amp leece neville rebuilt on ebay cheap It runs cool, pumps out the full 105amps,( actually just a bit more) when needed and causes no problems I believe if you can find a fit, a truck alt is much better