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Old 05-03-2019, 05:47   #1
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Bad alternator/AGM batteries

My alternator has been bench tested and is not putting out a charge. The technician is hesitant to get into a rebuild because he cannot find parts or specs for this Valeo Alternator. This what Yanmar put on my 2014 new 4JH5E engine.
I have found a replacement from Yanmar and it is being drop shipped in.
Can I reinstall the old alternator which was putting out a sporadic charge temporarily until the new one comes in order to run the systems on the boat while being docked without damaging my AGM batteries? Unfortunately there is no shore power where we are docked.......thanks for your responses....
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Old 05-03-2019, 06:21   #2
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Re: Bad alternator/AGM batteries

Concerning your question, I am not sure what could cause an alternator to sporadically put out charge, unless failing brushes or a bad connection.

What size is your AGM battery bank? The valeo you mentioned is internally regulated. To get decent charging you should consider using an external regulator. Luckily we (Balmar) makes a kit to convert the Valeo to external regulation. I say lucky as it is the only conversion kit we offer ;> You also take the alternator to a good repair shop and they can convert to external, but our kit is very easy to use, and also includes a Smartready internal regulator for backup. This will give you multistage charging.

Chris
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Old 05-03-2019, 07:44   #3
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Re: Bad alternator/AGM batteries

Thanks Chris. We have 6-85ah AGMs from Fall River Battery. For now the question is can I put the old alternator back in for today so as to be able to run the engine to move the boat a short distance. I would not do this if I run the risk of damaging the house AGM batteries or the starter battery......
Thanks
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Old 05-03-2019, 08:10   #4
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Re: Bad alternator/AGM batteries

Obviously little can damage batteries more than overcharging. If they are left idle to decay they just die. Overcharging can be catastrophic. If you decide to run the old alternator or any alternator you need to monitor the voltage. Not sure if by sporadic you mean failing regulator. Low voltage won't be a crisis but unchecked voltage of course is a problem. Find out what the highest voltage your batteries should get under charge and monitor it.
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Old 05-03-2019, 08:33   #5
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Re: Bad alternator/AGM batteries

+1

Chris

Quote:
Originally Posted by SilentOption View Post
Obviously little can damage batteries more than overcharging. If they are left idle to decay they just die. Overcharging can be catastrophic. If you decide to run the old alternator or any alternator you need to monitor the voltage. Not sure if by sporadic you mean failing regulator. Low voltage won't be a crisis but unchecked voltage of course is a problem. Find out what the highest voltage your batteries should get under charge and monitor it.
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Old 05-03-2019, 09:41   #6
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Re: Bad alternator/AGM batteries

If you are just running to move the boat put the alternator on and donít wire it up
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Old 05-03-2019, 12:05   #7
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Re: Bad alternator/AGM batteries

Thanks all for the responses.....Meridian thanks I had not thought of that...the simplest solution.
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Old 05-03-2019, 14:47   #8
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Re: Bad alternator/AGM batteries

Quote:
Originally Posted by SilentOption View Post
Obviously little can damage batteries more than overcharging. If they are left idle to decay they just die. Overcharging can be catastrophic. If you decide to run the old alternator or any alternator you need to monitor the voltage. Not sure if by sporadic you mean failing regulator. Low voltage won't be a crisis but unchecked voltage of course is a problem. Find out what the highest voltage your batteries should get under charge and monitor it.
Actually depends on the type.

GEL for sure.

AGM, any sealed, yes.

But FLA can tolerate long overcharging long as you keep them wet.

Assuming volts aren't **too** high above spec.

Any lead deteriorates pretty quick left at low SoC, but yes rather than immediately perceived damage, life cycles are lost off the back end.

Personally if the bank is expensive, unless monitoring V&A showed the old alt is "good enough",

I'd rent or borrow a portable genny to bridge the gap.
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