Re: 175 amp alternator on SM-burned up battery bank.


Alan Leslie
 

Hi Eric,

The batteries used in trucks are generally starting batteries, not deep cycle batteries and that is the difference in charging regimes.

Most, if not all, battery manufacturers will tell you that charging starting batteries is best done with a standard internally regulated alternator (like on your Amel, there is a separate 12V alternator) for charging the 12V starting battery at 14.4 volts and the starting battery is very happy.

Most, if not all, battery manufacturers will tell you that charging deep cycle batteries is a completely different matter. They generally recommend a 3 stage(aka SMART) charger that takes the batteries through a bulk phase, absorption phase and then a float phase as previously described. This maximises the charging of the batteries in the shortest possible time and helps to ensure longevity.

This is a good primer on deep cycle batteries :

http://www.solar-electric.com/deep-cycle-battery-faq.html#Battery Charging

I have had this experience on a previous boat where the 100A alternator was drying out the batteries as they were always kept at the absorption voltage. Removing the internal reg and adding a 3 stage reg, new batteries and the problem went away...

That's why I'm going to do the same with this one.

Leaving the boat hooked to shore power shouldn't harm the batteries PROVIDING there is no fault with the charger....it should charge them up and then go to float or maintenance phase and just stay there.

If your charger is faulty then indeed that could kill the batteries.

Best of luck with it all
Cheers
Alan
Elyse
SM437

--- In amelyachtowners@..., Sailorman <kimberlite@...> wrote:

I saw on my spare 175 amp alternator that is has a label stating for use on
Cummins diesels.

Cummins diesels are used in commercial trucks and power plants. My
alternator fellow ( second generation) says that a constant output of 28.5
volts is not a problem as trucks run for days and power plants work for
months without burning up their battery banks.



I will stick with Amels original idea of the stock alternator. As I
previously said, I had no problem with it for 4 years and I motored a lot. I
believe my problem is the charger.



I get new batteries Monday and will keep you posted. I also leave the boat
hooked into shore power for weeks at a time some times. I believe that was
part of my problem. I am discontinuing this practice.

Fair Winds

Eric

Amel Super Maramu #376 Kimberlite





_____

From: amelyachtowners@...
[mailto:amelyachtowners@...] On Behalf Of seafeverofcuan
Sent: Thursday, June 06, 2013 10:24 AM
To: amelyachtowners@...
Subject: [Amel] Re: 175 amp alternator on SM-burned up battery bank.





Dear Alan and Richard,
Thank you both for you help. I now have a reply from Dolphin stating that my
original chargers are fine but suggesting that things have moved on and
promoting their Dolphin Pro series!
Specification and information on Leece Neville alternator regulator model
8RL 3021 has proven impossible to find other than the manufacturer upgraded
them from 2006 to stop customers self adjusting them.
In the final analysis I am always reluctant to change anything that was
designed and fitted by Amel. I think that Richard is correct with upgrading
to a smart charger when availability finances allow and replacing with lead
acid batteries.
Kind regards,
Trevor

Sea Fever
SM 425
Mexico

--- In amelyachtowners@...
<mailto:amelyachtowners%40yahoogroups.com> , "alan_leslie_elyes_sm2k"
<divanz620@> wrote:

Hi Trevor,

At 28.1-28.6V you are probably OK...its when it stays at 28.8V for days
that I think there is a problem re gassing the batteries and ultimately
battery failure
But WHY your alt puts out 28.1-28.6V is a bit of a mystery when the
standard internal reg is set for 28.8

The Dolphin chargers re SMART chargers, I don't know why the 30 and 100 A
docs would be different...its really a case of whether or not the charger
can keep up with the load imposed on it.

As to why Amel didn't buy an externally regulated alt to put in the
Maramus...well...my only thought is that they didn't understand well how
batteries need to be charged

BUT, having said that, the system we have is perfectly OK..UNLESS we motor
for long periods...like I did..54 hours last week.

I don't agree that it's a "black art"..I think that there is a lot of
"bad" information out there.

I have more than 15 years experience with different alternators, chargers,
batteries, in different boats and I think I understand the best way to do
it...and that is DEFINITELY NOT to have a 28.8V internal reg in the
alternator !

Hence I am trying to find a way to externally reg this 175A beast that we
have, properly !

Cheers
Alan
Elyse
SM#437

--- In amelyachtowners@...
<mailto:amelyachtowners%40yahoogroups.com> , "seafeverofcuan"
<seafeverofcuan@> wrote:


Hi Eric,
I was hoping that you would post your findings re. you alternator. We
are now at the bottom of The Sea of Cortez and hope to get some good
technical help in Mazatlan next week. For now we are running on four
remaining house batteries. The alternator has been putting out between 28.1
volts to 28.6 volts the remaining batteries have not overheated.
I have the original Dolphin instruction paperwork from 2004. The 30amp
charger should boost at 27.7 volts and float at 26.5, the 100amp boost 28.8
and float at 27.2.
However both pieces of paper ( and that is literally what came with the
boat) state

"The charger system will revert to boost when the battery system
requirements equal 50% of the charger rated output"

My reading of this is that in our case with twelve house batteries
giving 630 amps at 24 volts then the 30 amp reverts to boost when the
batteries drop below 97% of total capacity.

My 30amp charger now only produces 27.3 volts, I have asked Reya for
advice and haven't had a reply as yet.
I suspect the answer lies in a total replacement of both chargers with a
smart charger and of course a new set of batteries. From everything that I
have been reading, common sense would indicate AGM and completely disconnect
them when leaving the boat for long periods.
The entire subject is a black art and I suspect in my case choices will
be heavily influenced by what is available in Mexico.
Best regards,
Trevor
Sea Fever





--- In amelyachtowners@...
<mailto:amelyachtowners%40yahoogroups.com> , Sailorman <kimberlite@> wrote:

I had my alternator checked at a very excellent alternator shop and
the
owner showed me what happens as it runs. There is no internal
regulation.
However he said as the battery becomes more charged the resistance of
the
bank increases and the alternator puts out less and less amps . It has
a
constant output of about 28.5 volts. He said the Balmar smart
regulator is a
waste of money -and he sells them.





I had no problems with this alternator with my first set of batteries
for 4
years. I only changed the batteries after a lightning strike.



My current burned out battery bank must have been caused by the
charger. I
will test it when I get my new batteries next week.

Fair Winds

Eric

Amel Super Maramu #376 Kimberlite




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