Our boat is equipped with (3)8D house batteries managed by a Heart 3000 watt inverter/charger with a link 2000. Here is the question. The Link 2000 reflects a voltage of 13.65 volts as does a check with a mulit meter at the batteries. This is the correct float voltage according to Heart. However a check with a hydrometer reflects a electrolyte level of 1230, borderline between recharge and fair. It's a new hydrometer, and I'm wondering if it is faulty. The batteries are 15 months old and were equalized about 45 days ago. Any thoughts? Dick McKee ONE9TEEN
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resting voltage?
Not sure what you are measuring - if the ressting voltage checks out after allowing the batteries to sit a few hours without charging, it might be the hydrometer. More likely is the hydrometer, which is not typically inaccurate, is measuring the actual density and you are observing (with the voltmeter) the non-equilibrium voltage remaining from the charger
Not sure what you are measuring - if the ressting voltage checks out after allowing the batteries to sit a few hours without charging, it might be the hydrometer. More likely is the hydrometer, which is not typically inaccurate, is measuring the actual density and you are observing (with the voltmeter) the non-equilibrium voltage remaining from the charger
Hi Dick, by float voltage to me it means...
that a charge is being placed on your 8Ds. I get the same reading as you with our 8D house bank and Xantrex Freedom 25 in float charge mode. When the charge function is turned off for about one hour, the resting voltage is about 12.7 according to our Link-1000. Terry
that a charge is being placed on your 8Ds. I get the same reading as you with our 8D house bank and Xantrex Freedom 25 in float charge mode. When the charge function is turned off for about one hour, the resting voltage is about 12.7 according to our Link-1000. Terry
Stir it up Dick
Wet batteries are known for a phenomenom called stratification. Specific gravity changes with electrolyte depth. What you need to do is stir up the electrolyte with your hydrometer. This is why specific gravity measurements are really not a reliable method of measurement - especially with deep(tall) style jars. Once the acid is stirred, you should get a different reading.
Wet batteries are known for a phenomenom called stratification. Specific gravity changes with electrolyte depth. What you need to do is stir up the electrolyte with your hydrometer. This is why specific gravity measurements are really not a reliable method of measurement - especially with deep(tall) style jars. Once the acid is stirred, you should get a different reading.
Did you remember to adjust the reading
on the hydro float to compensate for temperature ? There's usually a table on the hydro somewhere, even so I have little faith in hydrometer readings.
on the hydro float to compensate for temperature ? There's usually a table on the hydro somewhere, even so I have little faith in hydrometer readings.
Turn the charger off for a day
first, too. Calder's Boatowner's Manual and any other good book will give you the parallel readings of voltage and hyrdometer readings, and how to do the measurements.
first, too. Calder's Boatowner's Manual and any other good book will give you the parallel readings of voltage and hyrdometer readings, and how to do the measurements.
So far I've sturred up the electrolyte, same
same reading. Battery temperature is 75 which is in the range for no reading compensation. The standing reading is, after 2 hours off shore power, is 12.7 volts. The batteries seem to function fine at anchor, we just did 3 weeks in the Channel Islands. I leaning twoards throwing the hydrometer in the trash and just going with the readings from the Link 2000...
same reading. Battery temperature is 75 which is in the range for no reading compensation. The standing reading is, after 2 hours off shore power, is 12.7 volts. The batteries seem to function fine at anchor, we just did 3 weeks in the Channel Islands. I leaning twoards throwing the hydrometer in the trash and just going with the readings from the Link 2000...
Dick
sounds like the hydrometer is a candidate for the recycle bin if the batteries hold up as they apparently did for you
sounds like the hydrometer is a candidate for the recycle bin if the batteries hold up as they apparently did for you
Well, this sounds like a similiar issue I have....
and I agree with almost everything that has been posted so far. I will echo Ross' advice to get a calibrated lab grade hydrometer. If you have one of those $5 types that has reads only to the nearest 0.005 or worse yet has the colored floating balls, you really need a good hydrometer. The Francis Freas Glass Works manufacture an excellent line of high quality, calibrated, and easily readable temperature and hydrometer sets for about $20-25 delivered to your door. See the attached link. However you may have another sneaky issue happening here. I think that the Link 2000 is similar to the Link 20 with the exception of the inverter/charger control. I have a Link 20 that has tricked me into thinking my batteries were charged when in fact they were nearer 50% discharged. The Link 20 (and perhaps the Link 2000) considers a battery bank to be fully charged when the voltage is at 13.2V or higher and the charging current drops to less than 2% of the AH cap of the bank for a time period of 4 minutes. These are default values and can be changed. In my case I charge my batteries from a charger that is fed from my genset. The problem occurs if I have some deficit AH still to replace and the charger is supplying more than 2% of the AH rate. If I then shut down the genset (and charger) and start my auxillary to leave an anchorage, the alternator on the aux will be typically supplying 13.8V at perhaps something close to 2% or lower of the AH bank size. The Link 20 now thinks the batteries are fully charged and zeros out the remaining deficit AH. It then recalculates the charge efficiency factor for the next charging cycle. Now I have a battery bank that is really still down some number of AH but the instrumentation claims they are fully charged. This cycle can repeat quite often and each time the batteries sink lower in actual charge. Over a month or part of a season, you have batteries that are perpetually undercharged and sulfation begins. Batteries that are sulfated will not achieve the specific gravity readings that would indicate fully charged banks, and the batteries will "appear" to be fully charged based upon the terminal voltage and the charge current. The tipoff is that the batteries will seem to have much lower capacity. In your case of (3) 8D's, you may not notice the decrease in bank capacity. I think the only recourse in this case is to equalize until the specific gravity no longer increases. In my own situation I am going to look into the capabilities of electronic battery de-sulfinator devices. I hope some of this may be of help to you.
and I agree with almost everything that has been posted so far. I will echo Ross' advice to get a calibrated lab grade hydrometer. If you have one of those $5 types that has reads only to the nearest 0.005 or worse yet has the colored floating balls, you really need a good hydrometer. The Francis Freas Glass Works manufacture an excellent line of high quality, calibrated, and easily readable temperature and hydrometer sets for about $20-25 delivered to your door. See the attached link. However you may have another sneaky issue happening here. I think that the Link 2000 is similar to the Link 20 with the exception of the inverter/charger control. I have a Link 20 that has tricked me into thinking my batteries were charged when in fact they were nearer 50% discharged. The Link 20 (and perhaps the Link 2000) considers a battery bank to be fully charged when the voltage is at 13.2V or higher and the charging current drops to less than 2% of the AH cap of the bank for a time period of 4 minutes. These are default values and can be changed. In my case I charge my batteries from a charger that is fed from my genset. The problem occurs if I have some deficit AH still to replace and the charger is supplying more than 2% of the AH rate. If I then shut down the genset (and charger) and start my auxillary to leave an anchorage, the alternator on the aux will be typically supplying 13.8V at perhaps something close to 2% or lower of the AH bank size. The Link 20 now thinks the batteries are fully charged and zeros out the remaining deficit AH. It then recalculates the charge efficiency factor for the next charging cycle. Now I have a battery bank that is really still down some number of AH but the instrumentation claims they are fully charged. This cycle can repeat quite often and each time the batteries sink lower in actual charge. Over a month or part of a season, you have batteries that are perpetually undercharged and sulfation begins. Batteries that are sulfated will not achieve the specific gravity readings that would indicate fully charged banks, and the batteries will "appear" to be fully charged based upon the terminal voltage and the charge current. The tipoff is that the batteries will seem to have much lower capacity. In your case of (3) 8D's, you may not notice the decrease in bank capacity. I think the only recourse in this case is to equalize until the specific gravity no longer increases. In my own situation I am going to look into the capabilities of electronic battery de-sulfinator devices. I hope some of this may be of help to you.
Re-equalize
Dick, the battery open circuit voltage is low at 12.7 VDC. It should be at least 12.9 at a full state of charge. To get this reading though, you need to have everything disconnected and absolutely NO current draw. It may be that the link system is dragging it down a little because they do draw some current. I would re-equalize the batteries because equalizing batteries every 30 to 60 days is good practice - the only thing you have to loose is water! This is especially true if you dont bring the batteries back up to a full state of charge and let them sit around at a reduced charge state. Your getting good advice here and Rich nailed a common problem with battery monitoring devices. They NEVER can get it 100% right because of so many operating conditions in a real life applications. These devices still require human intervention from time to time to offset the unknown variables that their software developers did not account for.
Dick, the battery open circuit voltage is low at 12.7 VDC. It should be at least 12.9 at a full state of charge. To get this reading though, you need to have everything disconnected and absolutely NO current draw. It may be that the link system is dragging it down a little because they do draw some current. I would re-equalize the batteries because equalizing batteries every 30 to 60 days is good practice - the only thing you have to loose is water! This is especially true if you dont bring the batteries back up to a full state of charge and let them sit around at a reduced charge state. Your getting good advice here and Rich nailed a common problem with battery monitoring devices. They NEVER can get it 100% right because of so many operating conditions in a real life applications. These devices still require human intervention from time to time to offset the unknown variables that their software developers did not account for.
Update....I truned off the charge for 24 hours and
the voltage went from 12.7 to 12.45. We maintained our usual activities TV, lights ect. I'm now in the process of charging. Inverter is doing well 128 amps. Following Richs comments I noted that we had drawn 119 amps before I started to charge. I'll check to see how much it puts back before going to float. Then following Guys advice I will re equalize. It has only been about 45 days since the last equalization, but we were in the Channel Islands on the anchor for 3 weeks after the equalization. If the Link 2000 wasn't returning all the amps drawn a good long 8 hour equalization should help. Ill keep you posted.
the voltage went from 12.7 to 12.45. We maintained our usual activities TV, lights ect. I'm now in the process of charging. Inverter is doing well 128 amps. Following Richs comments I noted that we had drawn 119 amps before I started to charge. I'll check to see how much it puts back before going to float. Then following Guys advice I will re equalize. It has only been about 45 days since the last equalization, but we were in the Channel Islands on the anchor for 3 weeks after the equalization. If the Link 2000 wasn't returning all the amps drawn a good long 8 hour equalization should help. Ill keep you posted.
Batts
Dick, I'm sure you're aware that no charging device can replace all amps drawn from a battery unless it's hooked up for a long period of time, say overnight. A generator or alternator will only bring a batt up to about 80% before it's charge rate drops off so far that it's not worth running any more. You'll generally draw a batt down to 50%, charge to 80%, and repeat. You live in that range until you can get to a plug-in that can sit overnight. I've come to terms with my bank (two 8D) so long as the fridge, TV, lights and stereo are running after a one-hour charge every day, I'm happy and don't worry too much about the numbers.
Dick, I'm sure you're aware that no charging device can replace all amps drawn from a battery unless it's hooked up for a long period of time, say overnight. A generator or alternator will only bring a batt up to about 80% before it's charge rate drops off so far that it's not worth running any more. You'll generally draw a batt down to 50%, charge to 80%, and repeat. You live in that range until you can get to a plug-in that can sit overnight. I've come to terms with my bank (two 8D) so long as the fridge, TV, lights and stereo are running after a one-hour charge every day, I'm happy and don't worry too much about the numbers.
Umm ...Guy
Guy..You said: "Dick, the battery open circuit voltage is low at 12.7 VDC. It should be at least 12.9 at a full state of charge." Would you kindly provide a link to somewhere reputable that says 12.9 V should be fully charged resting voltage on a 12V wet cell? I can cite numerous sources that refute your number. A fully charged 12V battery at rest should be about 12.65V depending on temperature and NEVER above 12.7 Volts. Check out http://www.batteryfaq.org/ section 4.4.2 for a complete table of battery charge states at different electrolyte temperatures. ...and the Link2000 only draws .0028amps...not a factor in the reading.
Guy..You said: "Dick, the battery open circuit voltage is low at 12.7 VDC. It should be at least 12.9 at a full state of charge." Would you kindly provide a link to somewhere reputable that says 12.9 V should be fully charged resting voltage on a 12V wet cell? I can cite numerous sources that refute your number. A fully charged 12V battery at rest should be about 12.65V depending on temperature and NEVER above 12.7 Volts. Check out http://www.batteryfaq.org/ section 4.4.2 for a complete table of battery charge states at different electrolyte temperatures. ...and the Link2000 only draws .0028amps...not a factor in the reading.
Hi Dick, just a comment about equalizing...
IMHO, unless you detect that your bank is losing its ability to accept a full charge, or that your bank seems to have lost its normal storage capacity, equalizing the bank more than once or twice a year is often enough. At least that is what my Link manual infers. We installed new wet 8Ds about three years ago and they have never been equalized. I have yet to detect any symptoms mentioned above. Some day perhaps. Terry
IMHO, unless you detect that your bank is losing its ability to accept a full charge, or that your bank seems to have lost its normal storage capacity, equalizing the bank more than once or twice a year is often enough. At least that is what my Link manual infers. We installed new wet 8Ds about three years ago and they have never been equalized. I have yet to detect any symptoms mentioned above. Some day perhaps. Terry
I finally got through to Xantrex. In the set up
of the Link 2000 the operator can set battery full charge percentage before the system goes into float. The parameter is CHARGED V. The factory set this at 2%. For my 700A bank this means that once the charge voltage drops 14A for 5 minutes the battery is considered fully charged. They also consider the battery charged when it reaches about 85%. I think their reasoning is sound, becasue as they state, as the battery gets closer to fully charged it takes longer to "top" it off. It wiser to run the generator 1 to 2 hrs a day to get to 85% than to run it 5 hours a day to get to 100%. When you hook up to shore power it will trickle the battery until it reached 100%. No one at Xantrex could explain the difference between what the Link 2000 considers fully charged and the low reading with the hydrometer. I'm on a hunt for someone with a hydrometer to check it against mine. Dick McKee ONE9TEEN
of the Link 2000 the operator can set battery full charge percentage before the system goes into float. The parameter is CHARGED V. The factory set this at 2%. For my 700A bank this means that once the charge voltage drops 14A for 5 minutes the battery is considered fully charged. They also consider the battery charged when it reaches about 85%. I think their reasoning is sound, becasue as they state, as the battery gets closer to fully charged it takes longer to "top" it off. It wiser to run the generator 1 to 2 hrs a day to get to 85% than to run it 5 hours a day to get to 100%. When you hook up to shore power it will trickle the battery until it reached 100%. No one at Xantrex could explain the difference between what the Link 2000 considers fully charged and the low reading with the hydrometer. I'm on a hunt for someone with a hydrometer to check it against mine. Dick McKee ONE9TEEN
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