Can anyone tell me the charging voltage of a "standard" alternator on a 3GM30 Yanmar? Don't know specifics on alternator other than it's the one that came on the Yanmar in my '94 35.5 Hunter. Wondering if it will overcharge AGM or Gell batteries.
Alternator output?
- Thread starter Honeyman
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Alternator Output 3GM30
We had the same series engine in our B321. Typical output should be about 13.4v to 13.6v. This should not be a problem for either AGMs or GEL batteries. The more important factor is: will the internal regulator properly ramp down the alternator output as your batteries begin to reach reasonable capacity. I would not waste too much money on expensive batteries until you optimise your charging system. An empty battery can accept a high charge rate. Its the nearly charged battery that can go up in smoke even at 13.6v. Consider going with a name brand multi-stage smart charger. (about the same cost one of those fancy batteries.) You will need to have a electrical shop remove or bypass the internal regulator. If you have the bucks, I would strongly recommend installing HO alternator such Balmar 100AMP at the same time. We have been quite pleased with the Balmar 100AMP and Balmar Smart regulator, charging good wet cell batteries. The time to near full charge is a fraction of the OEM setup and there is never a problem with overcharge. Standard batteries often take the rape when the real culprit is the charging system. I still don't understand why manufacturers continue to spit out $150,000 boats with 25 year old electtrical technology.
We had the same series engine in our B321. Typical output should be about 13.4v to 13.6v. This should not be a problem for either AGMs or GEL batteries. The more important factor is: will the internal regulator properly ramp down the alternator output as your batteries begin to reach reasonable capacity. I would not waste too much money on expensive batteries until you optimise your charging system. An empty battery can accept a high charge rate. Its the nearly charged battery that can go up in smoke even at 13.6v. Consider going with a name brand multi-stage smart charger. (about the same cost one of those fancy batteries.) You will need to have a electrical shop remove or bypass the internal regulator. If you have the bucks, I would strongly recommend installing HO alternator such Balmar 100AMP at the same time. We have been quite pleased with the Balmar 100AMP and Balmar Smart regulator, charging good wet cell batteries. The time to near full charge is a fraction of the OEM setup and there is never a problem with overcharge. Standard batteries often take the rape when the real culprit is the charging system. I still don't understand why manufacturers continue to spit out $150,000 boats with 25 year old electtrical technology.
Charging voltage
Do your batteries a favour and get a 3 stage "smart" regulator - preferably tied in with a high output alternator. The output of your stock alternator is probably 35 amps at best at a voltage of around 14.0 - 14.4 volts. If your batteries are at all discharged it would be difficult to overcharge them with a stock alternator because the amperage output is so low - however with a fully charged battery it is possible to overcharge and damage the battery because the voltage remains above 14 VDC even when the battery is fully charged - too high for a "float" voltage on a fully charged battery. A 3 stage regulator will compensate for this - it increases the voltage when the battery needs charging - then reduces the voltage when the battery is fully charged to prevent overcharge and possible damage. You can also usually preset your battery type (eg. wet/gel) to customize your setup. The final piece is a battery monitor to keep track of what is going on with your charging system. While initially it costs a few dollars to set up it will pay off by extending your battery life and reducing the engine time required to charge your batteries. I made these changes on my '95 35.5 and have been very satisfied with the results.
Do your batteries a favour and get a 3 stage "smart" regulator - preferably tied in with a high output alternator. The output of your stock alternator is probably 35 amps at best at a voltage of around 14.0 - 14.4 volts. If your batteries are at all discharged it would be difficult to overcharge them with a stock alternator because the amperage output is so low - however with a fully charged battery it is possible to overcharge and damage the battery because the voltage remains above 14 VDC even when the battery is fully charged - too high for a "float" voltage on a fully charged battery. A 3 stage regulator will compensate for this - it increases the voltage when the battery needs charging - then reduces the voltage when the battery is fully charged to prevent overcharge and possible damage. You can also usually preset your battery type (eg. wet/gel) to customize your setup. The final piece is a battery monitor to keep track of what is going on with your charging system. While initially it costs a few dollars to set up it will pay off by extending your battery life and reducing the engine time required to charge your batteries. I made these changes on my '95 35.5 and have been very satisfied with the results.
And One More Vote for the Multi-Step Regulator
That makes three now for a multi-step regulator. The stock alternator on the Yanmar is essentially an automotive type and what you want is a house bank of batteries - batteries that will do "work", not just do a momentary effort like start the motor. Remember, this is a tractor engine setup! Consequently, you need a system to replenish those working (not starting) batteries and it takes a good system to do it. The Yanmar alternator is rated COLD while the Balmar is rated HOT. Since the output drops considerably as the alternator heats up the Hitachi 35 (cold) will be considerably less once it gets heated up. Conversely, the Balmar when it is cold will really put out. Our 75 amp was bench tested cold well over 120 amps. As a suggestion, instead of the 100 amp I'd recommend looking at the 75 (maybe they're 70 now?) units instead because of the belt slipping issue. If the belt is tightened to avoid slippage it will be hard on the bearings. If it's too loose it will cause slipage and heat up the armature which is not guarenteed against abuse. Besides, the highest output is only for a little while and then the multistep regulator starts to ramp the charge rate down so take that into consideration too. Hope this helps. http://www.balmar.net/
That makes three now for a multi-step regulator. The stock alternator on the Yanmar is essentially an automotive type and what you want is a house bank of batteries - batteries that will do "work", not just do a momentary effort like start the motor. Remember, this is a tractor engine setup! Consequently, you need a system to replenish those working (not starting) batteries and it takes a good system to do it. The Yanmar alternator is rated COLD while the Balmar is rated HOT. Since the output drops considerably as the alternator heats up the Hitachi 35 (cold) will be considerably less once it gets heated up. Conversely, the Balmar when it is cold will really put out. Our 75 amp was bench tested cold well over 120 amps. As a suggestion, instead of the 100 amp I'd recommend looking at the 75 (maybe they're 70 now?) units instead because of the belt slipping issue. If the belt is tightened to avoid slippage it will be hard on the bearings. If it's too loose it will cause slipage and heat up the armature which is not guarenteed against abuse. Besides, the highest output is only for a little while and then the multistep regulator starts to ramp the charge rate down so take that into consideration too. Hope this helps. http://www.balmar.net/
One more feature to look for.
Soft touch charging. My new Balmar regulator (3 stage) keeps the alternator OFF for the first 45 seconds of engine run time. This gives the engine a chance to get all warm and snuggly with itself. Then the regulator slowly ramps up the output of the alternator to the limit programmed for the first stage. It's slick. The single drive belt on a Yanmar loves it too. But if you set the first stage too high with a Balmar like mine, you'll toast the rectifier. See the text on my web site with this photo describing why the rectifier is now as it appears. (photo #53)
Soft touch charging. My new Balmar regulator (3 stage) keeps the alternator OFF for the first 45 seconds of engine run time. This gives the engine a chance to get all warm and snuggly with itself. Then the regulator slowly ramps up the output of the alternator to the limit programmed for the first stage. It's slick. The single drive belt on a Yanmar loves it too. But if you set the first stage too high with a Balmar like mine, you'll toast the rectifier. See the text on my web site with this photo describing why the rectifier is now as it appears. (photo #53)
Output Curve for 55
That's a good point Fred. Actually, I think the Balmar regulators might come standard with the 45min delay. Just came across my manual and it has an output curve for the Hitachi. There were two models built then - the 35amp and the 55amp. The curve is for the 55amp. Note that the output is based on 20ºC which is 68ºF. It doesn't take long before the temperature is well above that, especially if the output is to discharged deep-cycle bateries.
That's a good point Fred. Actually, I think the Balmar regulators might come standard with the 45min delay. Just came across my manual and it has an output curve for the Hitachi. There were two models built then - the 35amp and the 55amp. The curve is for the 55amp. Note that the output is based on 20ºC which is 68ºF. It doesn't take long before the temperature is well above that, especially if the output is to discharged deep-cycle bateries.
John,
You meant 45 seconds, I'm sure. And that curve is 'real-life'. Full output just above an idle. And you're right, soft-touch is standard stuff with Balmars'. My shop manual has an interesting fact about the two available alternators. The 55amp is standard equipment. The 35amp is optional. Why?
You meant 45 seconds, I'm sure. And that curve is 'real-life'. Full output just above an idle. And you're right, soft-touch is standard stuff with Balmars'. My shop manual has an interesting fact about the two available alternators. The 55amp is standard equipment. The 35amp is optional. Why?
Great info...
...as usual, the HOW site comes through in a hurry! Ok, so we assume the present alternator is the Hitachi 35? So, I need to remove it, put on a Balmar 70 (new 6-series w/"smart ready" internal regulator), plug in a Balmar smart regulator to by-pass the internal regulator, and I should be set for AGMs? I had already planned to add the multi stage smart charger. John, thanks for the link to Balmar.
...as usual, the HOW site comes through in a hurry! Ok, so we assume the present alternator is the Hitachi 35? So, I need to remove it, put on a Balmar 70 (new 6-series w/"smart ready" internal regulator), plug in a Balmar smart regulator to by-pass the internal regulator, and I should be set for AGMs? I had already planned to add the multi stage smart charger. John, thanks for the link to Balmar.
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