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Post by vasko on Jan 8, 2019 18:51:35 GMT
My original alternator is 50amps ( VP 2003 - 28hp) - I'm thinking to get a spare one as last summer I got issue and was quite a buz to dismount, find a shop to fix and mount again for a day... this time I just want to have a spare.. but now the question..
Do I need to by a exact replacement 50amps or a 70amps will will be also OK with the existing wiring ? any suggestions ?
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Post by sailbleu on Jan 9, 2019 5:17:39 GMT
I'm sure the wiring can stand the upgrade , but do make sure your engine is not one of the ' earth/neg. insulated ' type . An acquaintance of mine bought a boat where the previous owner had replaced the old one and installed a new non-earth insulated alternator on the engine. After he bought the boat he had to find out after a few years his heat-exchanger got eaten away because of that .
Regards
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Post by vasko on Jan 9, 2019 5:53:33 GMT
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Post by sailbleu on Jan 9, 2019 6:08:24 GMT
The wires look more than solid , so a 70 amp will not be an issue .Your engine is not earth/neg. insulated so no need to worry about that. I believe you have a green light for this upgrade , enjoy the extra amps .
Regards
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Post by ianf on Jan 9, 2019 9:45:48 GMT
Just remember that different alternators produce their peak current at different RPMs. Sometimes it is necessary to change the pulley size to optimise performance.
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Post by vasko on Jan 10, 2019 8:35:32 GMT
in the end i decided to go with the standard factory one  the 50A insulated - as found it on very good price and also it will be stored only for backup ... |
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Post by vasko on Jan 11, 2019 13:20:43 GMT
I received the Bukh alternator it claims that it is "insulated earth" model , but as it is a "Made In China" I will somehow feel better if I can check it - any suggestion how to check it it is with insulated earth ?
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Post by sailbleu on Jan 12, 2019 7:01:26 GMT
Just measure from neg. pin ( on alternator) to the body housing . The idea of an earth insulated engine is not to use the engine block or any other part mounted as a common ground or earth .
Although it would surprise me if this alternator you bought is insulated because usually there is a huge price difference between a normal one and an insulated type .
On the other hand it's cheap Chinese ( what isn't Chinese these days) with decent quality control , and German ebay companies normally supple high-end quality stuff
Regards
EDIT:
I edited my text a bit to clarify what I really meant .
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Post by vasko on Jan 12, 2019 20:11:57 GMT
Thank you seems insulated according to what I just measured |
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Post by sailbleu on Jan 13, 2019 7:08:43 GMT
And another thing Vasco , this alternator might not not be ' marinised ' , I'll explain .
These boat alternators are adapted to marine conditions .
In fact, ' marinised ' is a 500$ word to explain a waterproof coating has been applied on the electric parts in the alternator to protect it from the harsh salty environment .
Some years ago I managed to blow up one of the diodes in my alternator whilst experimenting with my propeller shaft generator .
An over voltage destroyed one of the diodes and because it's a complete indivisible set I had to replace it .
I just bought a replacement set for a non-marinised alternator and sprayed it in a black heat resistant ( very important) paint .
I payed a fraction of a ' professionally protected ' diode plate/set . Mine has been working ever since .
So it might be a good idea to open up your new alternator and spray the insides also .
Regards
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Post by vasko on Jan 13, 2019 7:22:17 GMT
And another thing Vasco , this alternator might not not be ' marinised ' , I'll explain . These boat alternators are adapted to marine conditions . In fact, ' marinised ' is a 500$ word to explain a waterproof coating has been applied on the electric parts in the alternator to protect it from the harsh salty environment . Some years ago I managed to blow up one of the diodes in my alternator whilst experimenting with my propeller shaft generator . An over voltage destroyed one of the diodes and because it's a complete indivisible set I had to replace it . I just bought a replacement set for a non-marinised alternator and sprayed it in a black heat resistant ( very important) paint . I payed a fraction of a ' professionally protected ' diode plate/set . Mine has been working ever since . So it might be a good idea to open up your new alternator and spray the insides also . Regards Thank you! Good idea! The original Valeo is Bolvo Green will spray the new one inside/outside volvo green also |
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Post by vasko on Jan 13, 2019 7:26:17 GMT
Btw: I find HUGE differene in the corosion inside and outside of the boat - everythung outside if not ss316 last obout a day with no rust and need spraying , inside if not sprayed with holt salt water(e.g broken hose if raw water or seal of engine) or not on salt water hose last forever no matter the material...
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Post by Mistroma on Jan 16, 2019 0:00:17 GMT
Pretty certain that you will already know this but worth adding for sake of others who might not.
Increasing the alternator from 50A to 70A (or even 700A) will often not result in any significant change in max. amps output as long as your existing alternator is not undersized. A "smarter" regulator will usually have more impact.
This will be true for flooded lead acid batteries but I think that you have hi-tech batteries capable of taking a high charging current. I imagine that your setup is already configured to extract high output from the alternator.
It all depends on bank size, state of charge , battery type, alternator speed and regulator.
However, it is fairly normal for the output to never reach the rated max. and drop to quite a low value fairly quickly with standard alternators and regulators.
Starting from about 60% SOC, my own setup usually gets 35-40A for about 30 minutes before tapering to 25A and then about 10-12A after a couple of hours. I have an 80A alternator and 450Ah T105s in the domestic bank.
Output obviously increases when I turn on nav. lights etc. but the underlying charge to battery doesn't change much. I think that the most I've seen is about 50A from the alternator when motoring at night. It dropped rapidly to about 35A with about 25A out of that going to the batteries.
I keep meaning to fix the regulator to charge at a higher rate but never seem to get around to it. Cheap fix for me as it only entails adding a relay and diode to fool the alternator into increasing the output. My Smartguage unit would control the relay to switch the higher output off before 100% SOC.
Many people seem to think that just replacing a 50A alternator with a 100A model will automatically double the rate at which the battery is charged. Unfortunately, that doesn't normally happen and there's ften very little difference at all.
Wise move buying a spare alternator as it guarantees your original will now last forever. I bought a 110A replacement for my 80A model in 2012 and it is still sitting in a box. I keep meaning start using it. The max. rpm rating and pulley size will let it give a much higher output at fairly low engine revs. Batteries wouldn't charge more rapidly but I'd get my normal 35-40A output at lower engine speed.
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Post by saxofon on Jan 20, 2019 17:16:36 GMT
I think your cablings need some resizing I have 3x110Ah AGM batteries (some cheaper variant, "nobrand") that I bought for the 2011 season, which means they are now soon on their 9th season, and they are performing like new still. Then I also changed all the base cabling (electric panel <-> batteries <-> alternator). Here is a test I did some years ago. First depleting them alot, intention was 60% but I got them even a bit lower... seems I like to overdo things...  Then charging by motor/alternator: if dropbox picture sharing don't work... it shows a battermonitor showing 72A)  www.23hq.com/saxofon/photo/50831514/originalThat current showed for some time but I don't remember the details unfortunately, some 30-40 min perhaps, before starting to show a drop. The motor is a Yanmar 4JH2E with I believe original alternator. Don't remember it's marking but somewhere around 75-80A or so. So the test shows the alternator performing as stated. This is of course depending on a lot. Batteries and their conditions (I think one battery of the standard type is able to consume about 20-25A each, which matches my test too. Lithium would be like a shortcut in this test  ), cabling and its condition, temperature etc. IMHO, we should be able to see currents for what the alternator states if the complete system is in good optimal shape. Often though, the standard cabling is too weak on the systems I've seen. You just can't have too big cables (found the manual and it actually states a 55A alternator as original, so probably someone upgraded the alternator along the time, will look next time I'm at the boat) |
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the 50A insulated - as found it on very good price and also it will be stored only for backup ...
), cabling and its condition, temperature etc.