Re: [Amel Yacht Owners] Strange Battery charging…


Hi, Alex,
I think you should stop looking at the % charge and amp-hour readings to evaluate your batteries and charging routines.  I don't know why, but they are notoriously inaccurate.  Use Voltage and Amperage in or out to evaluate.

What is your 24V monitor showing as the battery voltage when they should be fully charged and the charger is running?  It should read the float voltage you have set on the charger.

When you turn off the charger and leave the fridges and other usual equipment running, what does the monitor read as -Amps  being used?  Is that typical for your boat?

What kind of batteries do you have?  How old are they? Assuming they are flooded lead acid, here's what I would do:
1. Turn off the chargers and all 24V equipment.
2.  Wait 30 min to an hour, and check your battery bank voltage with the 24v monitor.  Double check it with your multimeter at the battery bank and at the 24v lugs on the chargers.
The voltages should all be very close readings.  The -Amps on the monitor should be very low, certainly less than -1 A.
3.  If you have an electronic battery tester (as recommended by Bill R in an earlier thread), isolate each battery and test it's cranking Amps. (If they are deep cycle batteries, the may not have cranking amps listed). 
4.  While the batteries are fully charged, check the specific gravity of the battery fluid in all cells in all batteries with a bulb type tester.  If the voltage is OK, and the cranking Amps are OK, but the Specific gravity in all batteries is low, the batteries need to be desulfated (Equalization cycle on your charger).  Do you regularly equalize your batteries?
If only one or two batteries or cells have abnormal readings, you may have bad connections at the batteries, or failed/failing batteries.
If everything looks right, you probably don't have a battery or charger problem, just looking at Ahr and %Charge readings that are not an accurate reflection of your 24V system.

Let us know what you find.

SM 243

On Dec 1, 2016, at 3:31 PM, Alexandre wrote:
Good afternoon, 

During the 3 days power outage in Puerto Rico, I noted my batteries were getting weak…
Would not fully recharge.
Accidentally, I reset the Link 10… but it kept the setting, just now showing 100% instead of the 90%.

Due to the lack of wind, I mostly motor to Tortola, then drift for 6 hours to wait for customs and emigration to open, again I noted the batteries were weak (freezer compressor stop).

I have now been at the marina for a month, and something very strange is happening:

The first week, instead to get the usual charge of 0.2 amp/hour on the Link 10, I had 1 Amp hour.
The second week, was over 2 amp/hour charge
The 3rd week, I had 3 Amp/hour charge.
I thought my 40 Amp battery charger could have an issue, so switch to the 60 Amp and still higher charge.
Now I am showing 8 Amp/hour charge ?!?
So the 100% has been reach for 3 weeks and is showing an excess of 470 Amp (above my 100%) which is not possible as my battery bank is only 400 Amp (8 batteries 100 amp each, 4 x 2 in series).

I wish it could be true…
Any idea?
This weekend, going to go back to the smaller charger to see what it charges.

Thanks in advance

Sincerely, Alexandre
Harbor View Marina, Tortola, BVI

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