Simple Solar For A Simpleton

[VirtualVagabond]

I've taken some readings.
After topping up the batteries with distilled water yesterday (all plates in all cells were well covered but I topped them all to just under the max mark) I ran the generator last night as usual, and again this morning, as usual.
An hour later I checked all 30 cells with an hydrometer.
Every one is in the red with readings of 1.20 - 1.22. At least they're consistant
1.24 is where the line from red to green is.

Does it mean the bank needs some particular nursing back to health?
Or
Does it mean we've found the problem, ie the bank is stuffed?
Could this be the reason for the long generator run times? ie the batteries are not accepting/holding the charge?

I had a quick look at the Xantrex Link 2000 at about the same time I checked the batteries this morning.
Amps were -13.2
Volts 12.50
Amp Hrs - 978.7!
From what I understand so far, after charging, the Amp Hours should be 0 if the batteries are fully charged, or maybe within 15% of the bank capacity, in this case 1125 amps.
Could this amp hr reading be due to some setting being incorrect, or is it confirmation the batteries are stuffed?

I've got a feeling this is going to hurt!

Vic

[atoll]

the link 2000 you have to calibrate amp hours to 15% less than total capcity when the batteries are fully charged if i remember correctly.
ie it should read approx 1000ah when fully charged,and reduce untill you start charging again.

the hydrometer reading does not sound good,this would account for the bent plates in the batteries...............oh the joys of yotting

[Dsanduril]

It should mean that the bank just isn't very charged (somewhere between 50 and 75%, if you are not using tropical electrolytes or anything special in that regard).

State of Charge Specific Gravity Voltage
100% 1.265 12.7
75% 1.225 12.4
50% 1.190 12.2
25% 1.155 12.0
Discharged 1.120 11.9

(sorry, couldn't figure out a good table formatting)

The crucial thing is that all cells in the same battery should have the same reading (within 0.05).

Readings should be taken after charging and after a little use (to remove the surface charge). Best if taken with no load, but sometimes that is difficult to arrange. Charge some more and see if the readings come up higher after more charging.

[Dsanduril]

Sorry, one more thing, what kind of Amps reading is showing on the 2000 during charging?

[Dsanduril]

Got it. Here is the complete table for standard electrolytes. Assuming your batteries are a little warm from recent charging (and it being summer on the East Coast) 1.20-1.22 does not seem that terrible.

Temperature: 7 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.242     12.49
      75       1.187     12.16
      50       1.137     11.86
      25       1.097     11.62
       0       1.077     11.50


Temperature: 17 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.245     12.51
      75       1.190     12.18
      50       1.140     11.88
      25       1.100     11.64
       0       1.080     11.52


Temperature: 27 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.248     12.53
      75       1.193     12.20
      50       1.143     11.90
      25       1.103     11.66
       0       1.083     11.54


Temperature: 37 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.252     12.55
      75       1.197     12.22
      50       1.147     11.92
      25       1.107     11.68
       0       1.087     11.56


Temperature: 47 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.255     12.57
      75       1.200     12.24
      50       1.150     11.94
      25       1.110     11.70
       0       1.090     11.58


Temperature: 57 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.258     12.59
      75       1.203     12.26
      50       1.153     11.96
      25       1.113     11.72
       0       1.093     11.60


Temperature: 67 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.262     12.61
      75       1.207     12.28
      50       1.157     11.98
      25       1.117     11.74
       0       1.097     11.62


Temperature: 77 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.265     12.63
      75       1.210     12.30
      50       1.160     12.00
      25       1.120     11.76
       0       1.100     11.64


Temperature: 87 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.268     12.65
      75       1.213     12.32
      50       1.163     12.02
      25       1.123     11.78
       0       1.103     11.66


Temperature: 97 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.272     12.67
      75       1.217     12.34
      50       1.167     12.04
      25       1.127     11.80
       0       1.107     11.68


Temperature: 107 degrees Fahrenheit

 Percent  Hydrometer  Unloaded
  charge     reading   voltage
     100       1.275     12.69
      75       1.220     12.36
      50       1.170     12.06
      25       1.130     11.82
       0       1.110     11.70

[DeepFrz]

Hydrometer readings should always be taken before adding water as the electrolyte will stratify. Charge them at a rate that will make them bubble for a while. The bubbling will mix the electrolyte and give you a truer reading.

[atoll]

Originally Posted by Dsanduril

It should mean that the bank just isn't very charged (somewhere between 50 and 75%, if you are not using tropical electrolytes or anything special in that regard).

State of Charge Specific Gravity Voltage
100% 1.265 12.7
75% 1.225 12.4
50% 1.190 12.2
25% 1.155 12.0
Discharged 1.120 11.9

(sorry, couldn't figure out a good table formatting)

The crucial thing is that all cells in the same battery should have the same reading (within 0.05).

Readings should be taken after charging and after a little use (to remove the surface charge). Best if taken with no load, but sometimes that is difficult to arrange. Charge some more and see if the readings come up higher after more charging.

+1 removing the discharge load will give a much better idea of what is happening

[foolishsailor]

You beat me to it deepfrz,

Re charge them now that they are full, disconnect them from everything except each other and then let them sit for an hour and take readings from each cell then.

Wouldnt hurt to take a temperature reading from a couple of cells as well to be precise.

[Stu Jackson]

Originally Posted by foggysail

The problem with chargers is the charge current quickly diminishes.

It's NOT a problem with chargers, it is the reality of battery ACCEPTANCE. As they get charged, they accept less current.

The Ample Power Primer http://www.amplepower.com/primer/primer.pdf

All good advice here. One thing missing so far is: start building a wiring diagram, then you can troubleshoot more intelligently.

Your alternator output should have a fuse on it near the batteries. Easy to unhook the fuse to turn the alternator off, but do NOT run the engine without the alternator output connected to a battery bank.

[foggysail]

Originally Posted by Stu Jackson

It's NOT a problem with chargers, it is the reality of battery ACCEPTANCE. As they get charged, they accept less current.

OH, you think so? Try swapping a 50 ampere charger for a 100 ampere charger, both multistage of course. While I agree is related to battery acceptance, a modern charger should be able to control the charge current by increasing the applied voltage. The charge curves are determined by the charger manufacturer with precautions against overheating.

Maybe you're thinking about the older resonant chargers that were sold with high output current capability where it took days to fully charge a battery similar to a car's alternator.

And yes, charge currents follow equations such as I = (Vcharger - Vbattery)/Rbattery internal resistance. That was what the older junk did because Vcharger was fixed.

Foggy

[Dsanduril]

OH, you think so? Try swapping a 50 ampere charger for a 100 ampere charger. While I agree is related to battery acceptance, a modern charger should be able to control the charge current by increasing the applied voltage.

This could be a really fun discussion to follow, but maybe it should be moved off some place else in order to leave the OP's troubleshooting as un-muddied as possible?

[Celestialsailor]

Originally Posted by Don Lucas

Vic

Just what is is your daily amp-hr load and what percentage of battery state of charge have you been trying to mantain?

Both panel sizing and battery capacity is going to be based on your daily loads. There's no upper limit to the panels, just a lower limit of what will recharge your batteries.

I feel I'm a power hog, but if I'll willing to not recharge the batteries above 90-95% I can recharge with my engine in 1.5 hours/day. So your generator run time really has me confused as that's a lot of power.

Wow Don...Way to go...This is a great approach. Yes...calculate your daily load and I would multiply by a factor of 1.5. for those heavy use days. Possibly the OP has one bad cell in one of the batteries.
Personally, I think the OP's battery capacity is ok but I question why he has to charge that many hours with the genny. I think Atolls approach is sound to begin to eliminate the power hog lights and fans. Chances are with careful planning consumption can be reduced maybe 30%. I have 250 watts currently with 400 amps of batteries and the Bluesky MPPT begins to taper off at 11am. and tries to come back on bulk around 4pm. But that's just with the refer and a few lights. I imagine my consumption will double under way.

[Ex-Calif]

Originally Posted by VirtualVagabond

I had a quick look at the Xantrex Link 2000 at about the same time I checked the batteries this morning.
Amps were -13.2
Volts 12.50
Amp Hrs - 978.7!
From what I understand so far, after charging, the Amp Hours should be 0 if the batteries are fully charged, or maybe within 15% of the bank capacity, in this case 1125 amps.
Could this amp hr reading be due to some setting being incorrect, or is it confirmation the batteries are stuffed?


Vic

Assuming the Link is installed properly and calibrated...

Amps - indicates the current draw is currently 13.2 amps - Good advice to disconnect the batteries from the boat after charging and do the hydro test then.

Volts - Indicates the voltage is at 12.5. Not bad considering the bank is "currently" supplying 13.2 amps to the boat

Amp hours - Your interpretation of the reading is correct. A fully charged bank should read "0" - Your negative 978 number could be a result of someone changing the "Bat Cap" setting in the Xantrex setup to a lower value.

I suspect this due to the confusion about how many ah the T105 has. If you or the PO set it up as 105 ah each instead of the 225 ah the monitor will think the battery has < half the capacity it actually has.

I have only skimmed the Xantrex manual. It is very complex to set it up right. Read and reread the manual before changing anything.

Also - Now that you are getting some equipment - hydrometer and meter it is very seductive to start metering things.

As the experts are saying - using the meters without isolating the batteries or waiting for the batteries to cool and stabilize after a charge cycle will result in erroneous readings.

(PS - I am in the camp that thinks "nothing is stuffed" (yet) - If you took those Xantrex readings when you "thought" there was no load on the system there is something on the boat "stealing" 13 amps)

PPS - Just back of the envelope here - If your "standing load" is 13.2 amps that's about 320 amp/day - add a little bigger load for night time due to lights and you could be pulling out 350-360amp/day. If you are running the generator for 6 hours the genny is putting about 60 amps out to fill it back up. 60 X 6 = 360

Someone will surely jump me here but I think things may actually operating normally and we are back to load shedding...

[VirtualVagabond]

Originally Posted by Dsanduril

Sorry, one more thing, what kind of Amps reading is showing on the 2000 during charging?

While charging tonight the Amps reading was 75.

[VirtualVagabond]

Originally Posted by DeepFrz

Hydrometer readings should always be taken before adding water as the electrolyte will stratify. Charge them at a rate that will make them bubble for a while. The bubbling will mix the electrolyte and give you a truer reading.

I was thinking after 2 charging sessions I would have achieved that, no?