Hmmm, thanks Bill.  Yes, I disconnected each battery from the others for testing, and discharged the "surface charge" with a 12v light before testing.

I guess I should read about the discharge characteristics of the batteries, but doesn't it seem to you that the 400Ah bank should not be discharging to 24V after 10-12 hours of discharging at ~4A?  When I first installed them, the lasted almost 24 hours at the same discharge rate.

Kent

On Jun 14, 2016, at 11:46 AM, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Did you totally disconnect each battery when testing it? Also, I think I read somewhere that when testing batteries they should be off of the charger for 30 minutes. I am not sure about this, but this is what I do.

An internal short will account for a battery taking more from the charger, but your tester should identify a short.

Somewhere else I believe that I read that some batteries in a bank will discharge more than others, resulting in those needing more charge...google for this or maybe ask a marine battery expert.

Bill Rouse
BeBe Amel 53 #387
Sent from my tablet
+1832-380-4970 USA Voice Mail

On Jun 14, 2016 11:19 AM, "Kent Robertson karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:

 

Hi all, thank you for your replies.

I have non-sealed batteries.  The water level is fine...I added less than a liter to all 8 batteries.  (that was Derick who added 2 gallons of water).  

The charger is set for flooded lead-acid batteries.  When the voltage is 24V, the charger voltage goes up to 26 v+/- and charges at 50-53 A for a short time, then amps slowly drop and the voltage increases as the batteries fill up. At float charge it reads 26v.  It acts like it is working properly, but I will look up the advertised charging characteristics for the lead-acid setting to see if it matches what I am seeing.

I don't have solar or wind yet.

The voltage and amperage I measure is the same as I am reading on my 24v monitor, but as I said earlier, when I look at the amperage going into each battery pair, one pair seems to be getting an amp more than the other pairs early in the charging cycle.

To me, it seems that the system acts like there is a much smaller Ah battery bank than the 400 Ah I should have.  I have checked all connections,  confirmed that all batteries in the bank are at the same voltage, and tested for CCA with my Solar (TM) battery tester.  The only anomalies I find are that one pair is charging at a higher rate than the others early in the charging cycle, and during discharge (charger off) two pairs are discharging at 1.6A, and two pairs at 0.6A.  That makes me think that either the connections are not all good (they all test No Resistance), or I have a bad battery or two (they all test the same with the battery tester).

During all phases of charging, there are no batteries that feel warm to the touch.

Thanks again

Kent

On Jun 14, 2016, at 10:33 AM, Bill Kinney greatketch@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Kent,

I’ll elaborate a bit on Bill R’s questions…  

The amount of water you are adding to your batteries is above normal.  Water does not leave a battery by evaporation, no matter how hot it is in the Caribbean! It leaves by being converted to hydrogen gas during the charging process.  The amount of water your batteries are using would lead me (and Bill R.  to guess your batteries are being overcharged.

Do all the individual batteries take the same amount of water?

Do you know what the acceptance and float voltages are for your charging system?

How are your solar panels controlled?

Bill Kinney

SM#160 Harmonie

On Jun 14, 2016, at 10:02, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] <amelyachtowners@...> wrote:

Kent,

Is the charger switched to match the charging characteristics of your batteries? Didn't you switch the type of batteries and the charger? Has a qualified person checked the charging characteristics...and, did he determine that the charger is actually outputting the correct charging characteristics?

Bill Rouse
BeBe Amel 53 #387
Sent from my tablet
+1832-380-4970 USA Voice Mail

 

Kent,

Did you get sealed batteries?  If not, have you checked the fluid levels?  I just replaced my batteries with 12 Trojan SCS200 batteries (115AH) in January in Martinique.  Unlike my previous sealed batteries, I am able to/need to open the vents and add distilled water.  I found that even when new, water needed to be added to several of the cells.  In the last 5 months, I have checked the fluid levels twice and have added a total of about 2 gallons of distilled water!  The Caribbean is one hot place!!  I also have an indoor/outdoor thermometer installed in the battery compartment to monitor the temperature when the batteries are charging (thanks for the suggestion Bill Rouse).  The battery compartment usually stays a couple of degrees above ambient.

I will check them one more time before putting Brava up on the hard for hurricane season, leaving the solar power on to keep them topped up i n voltage but with only the freshwater pump and the bilge pump left in the on position.  The former will rinse the Dessalator membranes once a week for three minutes with fresh water from the tank.

It seems early in the life of your batteries to have to desulfate them, but maybe that would be worth a try.

Derick

SM2K#400 Brava