I got this question and answered it off line but thought it was a good one to post here as it contains a lot of information.
Drain and re-fill the hydrometer 3X in each cell before taking a reading. Batteries must be charged to 100% full before you can begin an EQ cycle. Most good quality smart chargers will not allow it to go into an EQ cycle without being full first. Full will be an acceptance rate of less than 1% - 3% of the banks 20 hour capacity. If the batteries are older and sulfated you may be closer to 3% but on new/newish batteries your 100% acceptance rate at 14.4V can easily be under 0.5% of capcity...
It sounds to me like your batteries are sulfated. Sulfation can dramatically slow the charging as the current has a tougher time penetrating the plates. A straight 14.2V may be chronically undercharging the batteries, especially if it is temp compensated. In a hot climate, like you are in, 14.2V could easily become 13.8V based on battery temp. By starting at 14.6V or higher you'd then be at 14.2V when hot and doing better on charging... Trojan wants to see daily absorption voltages of 14.6V to 14.8V temp compensated to 77F - 80F. By boosting the voltage (on your charger you can use the dip switches and set them to the highest voltage and the "COLD" setting), your batteries will charge faster, have less sulfation and reach a full charge faster.
They will also use a little more water with a higher voltage. 14.6V is a good compromise between the 14.8V Trojan wants to see, charge speed, minimization of sulfation and the ability to charge to a higher state in a shorter time.
These batteries need to see higher voltages (temp compensated of course) than 14.2V to really even get to 100%. Without a high enough absorption voltage it can take 24+ hours to get them back to 100% SOC..
Older ferro chargers performed HORRIBLY at low current requiring them to switch on and off to try and maintain a float voltage. As such they chronically over charged even in "float" mode...
All chargers, solar controllers and alternator regulators will "cycle back" as batteries reach the absorption voltage. All these devices really do is BULK / CONSTANT CURRENT or LIMIT VOLTAGE.
Once you hit the absorption voltage, in your case currently 14.2V, the chargers job is to maintain that voltage and not over shoot it. The acceptance of the battery at a given SOC determines how much current is needed to not over shoot 14.2V, or what ever your absorption voltage is set at.
To charge any flooded battery to 100% is a simple time equation. With a properly sized charger it takes on average about 10 hours to charge to approx 96 -99% SOC and another 3-6 hours to get to 100%.
Why?
As your battery becomes full it requires less and less and less current to maintain the voltage limit. As this acceptance rate declines it extends the time it takes to get to full. This is why many cruisers cycle between 50% SOC and 80-85% SOC and only go for 100% once per week, bi-weekly or even tri-weekly.
A compounding problem is that many chargers switch to FLOAT mode far to early and you don't actually get to 98-99% SOC before the voltage is dropped back to float. Voltage is pressure, drop the voltage and you've now dropped the "accepted current" needed to maintain the new lower voltage and also greatly extended the time it takes to get to 100% SOC.. I call this "preamture floatulation"...
The trick with some chargers, that are not "smart enough", is to simply re-boot them when they drop to float and watch your current. When the accepted current in absorption mode gets to 1-3% you can then allow the charger to go into an EQ mode. The TC40 will do all this automatically.
This all assumes you have no loads sucking off the batteries while equalizing them. NO LOADS ON WHILE EQUALIZING! You should see less than 1% to 1.5% of "bank capacity" being "accepted" at 14.4V +/- before the battery bank can be considered ready for an equalization.
It sounds like you have solar too? The best way to charge back to full is to use the genset and charger to bring you back to roughly the average output of your solar panels in current. So if your array can pump out 15A then shut off the charger/gen slightly before you get to 15A of acceptance at roughly 14.4V. Now shut off the DC loads and go for a walk on the island and let the solar panels "finish" the batteries. It is best to begin this process early in the day so you have 5+ hours of solar to help get the bank back as close to 98-99% as can be. If your array is not big enough you may need to adjust your gen/charger times. If you have two chargers, as you stated, you can shorten your time in BULK mode by using both chargers simultaneously. Once at absorption voltage (14.2V, but should be higher) turn one of them off...
The fix:
I would start with a one hour EQ then check SG. Then, if all cells seem balanced, go for another two hours and re-check SG. Don't stop the EQ session just because the cells are in balance. You likely need 4+ hours at 15.5V if this has never been done. I would then repeat this in about 4 weeks.
ALWAYS use distilled water when re-filling batteries. Using water containing ANY minerals, or allowing contamination to get into the cells when you remove the caps or a dirty hydrometer that has been sitting with RUSTY tools, will destroy batteries faster than you can say the word JUNK. Cell contamination can cause batteries to begin gassing as low as 13.2V!!!!! Keep your hydrometer 100% clean and in its very own Tupperware container that has been washed with distilled water only. DO NOT put anything else in this container. I see more people destroy batteries by checking the SG and re-filling them than you'd ever imagine. When I get to a boat and see 13.4V yet the batteries are bubbling.......TOAST !!!!!:cussing:
Three hours of gen set is barely enough to get you out of bulk mode but combined with the solar it should be taking you to at least to absorption voltage.
Here's a hint: If your batteries come up to absorption voltage/14.2V quickly, they are likely very heavily sulfated and the rise in voltage is noting more than a surface charge. This is BAD. It should take deeply cycled batteries a considerably amount of time to approach absorption voltages.
This three hours is still way under what is needed in time to get to 100% SOC. Not getting back to 100% SOC every one to three weeks will cause accelerated sulfation and shorter battery life. It will also cause cycle depth creep meaning you keep getting deeper and deeper into your capacity..
Boosting your absorption charge voltages can cause quite an improvement in "time" needed to charge. Voltage is pressure and with higher pressure this means higher current, even at higher states of charge. It will also help to limit sulfation and stratification of the electrolyte.
If you don't want to run the big gen set then more solar or the addition of wind can help. A small Honda EU2000 can also be a good option to drive your TC40 but may not be the neighborly thing to do for 14+ hours unless you find a bay all to yourself.
Your boat has a good gen set and should be easily able to run 24/7 if needed, or, as long as you or fellow anchorage neighbors can stand it. Don't let it run lightly loaded powering just the charger. While it is running make good use of it. If you have AC, cool off, a water maker fill the tanks etc. etc..........
In summary:
*You really need to be charging at closer to 14.6 - 14.8V temp compensated. 14.2V is far too low for your Trojan's.
*You need considerably longer charge times to get back to 100%
*You need to get back to 100% as often as possible perhaps once weekly or once bi-weekly to limit sulfation and increase bank longevity.
*If not getting back to 100% that often you will need more equalization cycles.
*If you don't have a battery monitor it is a good investment. Battery monitors get out of sych, and develop counting errors, if the bank is not "reset" to 100% and the monitor also re-set when the bank reaches full. The longer you go between "full" events the more out of whack your battery monitor will become.
Hope this helps...
When was the last time the batteries were equalized? I like to do this in pairs not as an entire bank as it allows easier monitoring and careful attention to each set. It can be done in a bank but I would stop after the first hour, let the batteries rest but not use any loads, then check specific gravity levels. You are looking for any cell that is in disagreement with the others. As always use a CLEAN hydrometer so you don't contaminate the cells. I prefer the use of a sight refractometer as you use an eye dropper as opposed to multiple ounces of corrosive acid.Cruiser Question #1 said:
Drain and re-fill the hydrometer 3X in each cell before taking a reading. Batteries must be charged to 100% full before you can begin an EQ cycle. Most good quality smart chargers will not allow it to go into an EQ cycle without being full first. Full will be an acceptance rate of less than 1% - 3% of the banks 20 hour capacity. If the batteries are older and sulfated you may be closer to 3% but on new/newish batteries your 100% acceptance rate at 14.4V can easily be under 0.5% of capcity...
Cruiser Question #2 said:
It sounds to me like your batteries are sulfated. Sulfation can dramatically slow the charging as the current has a tougher time penetrating the plates. A straight 14.2V may be chronically undercharging the batteries, especially if it is temp compensated. In a hot climate, like you are in, 14.2V could easily become 13.8V based on battery temp. By starting at 14.6V or higher you'd then be at 14.2V when hot and doing better on charging... Trojan wants to see daily absorption voltages of 14.6V to 14.8V temp compensated to 77F - 80F. By boosting the voltage (on your charger you can use the dip switches and set them to the highest voltage and the "COLD" setting), your batteries will charge faster, have less sulfation and reach a full charge faster.
They will also use a little more water with a higher voltage. 14.6V is a good compromise between the 14.8V Trojan wants to see, charge speed, minimization of sulfation and the ability to charge to a higher state in a shorter time.
These batteries need to see higher voltages (temp compensated of course) than 14.2V to really even get to 100%. Without a high enough absorption voltage it can take 24+ hours to get them back to 100% SOC..
First the newer "switch mode charger" are MUCH kinder to the batteries than the older ferroresonant chargers ever were. The ability to deliver miniscule currents at float voltages, and match battery acceptance, is what sets them apart.Cruiser Question #3 said:
Older ferro chargers performed HORRIBLY at low current requiring them to switch on and off to try and maintain a float voltage. As such they chronically over charged even in "float" mode...
All chargers, solar controllers and alternator regulators will "cycle back" as batteries reach the absorption voltage. All these devices really do is BULK / CONSTANT CURRENT or LIMIT VOLTAGE.
Once you hit the absorption voltage, in your case currently 14.2V, the chargers job is to maintain that voltage and not over shoot it. The acceptance of the battery at a given SOC determines how much current is needed to not over shoot 14.2V, or what ever your absorption voltage is set at.
To charge any flooded battery to 100% is a simple time equation. With a properly sized charger it takes on average about 10 hours to charge to approx 96 -99% SOC and another 3-6 hours to get to 100%.
Why?
As your battery becomes full it requires less and less and less current to maintain the voltage limit. As this acceptance rate declines it extends the time it takes to get to full. This is why many cruisers cycle between 50% SOC and 80-85% SOC and only go for 100% once per week, bi-weekly or even tri-weekly.
A compounding problem is that many chargers switch to FLOAT mode far to early and you don't actually get to 98-99% SOC before the voltage is dropped back to float. Voltage is pressure, drop the voltage and you've now dropped the "accepted current" needed to maintain the new lower voltage and also greatly extended the time it takes to get to 100% SOC.. I call this "preamture floatulation"...
The trick with some chargers, that are not "smart enough", is to simply re-boot them when they drop to float and watch your current. When the accepted current in absorption mode gets to 1-3% you can then allow the charger to go into an EQ mode. The TC40 will do all this automatically.
This all assumes you have no loads sucking off the batteries while equalizing them. NO LOADS ON WHILE EQUALIZING! You should see less than 1% to 1.5% of "bank capacity" being "accepted" at 14.4V +/- before the battery bank can be considered ready for an equalization.
It sounds like you have solar too? The best way to charge back to full is to use the genset and charger to bring you back to roughly the average output of your solar panels in current. So if your array can pump out 15A then shut off the charger/gen slightly before you get to 15A of acceptance at roughly 14.4V. Now shut off the DC loads and go for a walk on the island and let the solar panels "finish" the batteries. It is best to begin this process early in the day so you have 5+ hours of solar to help get the bank back as close to 98-99% as can be. If your array is not big enough you may need to adjust your gen/charger times. If you have two chargers, as you stated, you can shorten your time in BULK mode by using both chargers simultaneously. Once at absorption voltage (14.2V, but should be higher) turn one of them off...
The fix:
I would start with a one hour EQ then check SG. Then, if all cells seem balanced, go for another two hours and re-check SG. Don't stop the EQ session just because the cells are in balance. You likely need 4+ hours at 15.5V if this has never been done. I would then repeat this in about 4 weeks.
ALWAYS use distilled water when re-filling batteries. Using water containing ANY minerals, or allowing contamination to get into the cells when you remove the caps or a dirty hydrometer that has been sitting with RUSTY tools, will destroy batteries faster than you can say the word JUNK. Cell contamination can cause batteries to begin gassing as low as 13.2V!!!!! Keep your hydrometer 100% clean and in its very own Tupperware container that has been washed with distilled water only. DO NOT put anything else in this container. I see more people destroy batteries by checking the SG and re-filling them than you'd ever imagine. When I get to a boat and see 13.4V yet the batteries are bubbling.......TOAST !!!!!:cussing:
Three hours of gen set is barely enough to get you out of bulk mode but combined with the solar it should be taking you to at least to absorption voltage.
Here's a hint: If your batteries come up to absorption voltage/14.2V quickly, they are likely very heavily sulfated and the rise in voltage is noting more than a surface charge. This is BAD. It should take deeply cycled batteries a considerably amount of time to approach absorption voltages.
This three hours is still way under what is needed in time to get to 100% SOC. Not getting back to 100% SOC every one to three weeks will cause accelerated sulfation and shorter battery life. It will also cause cycle depth creep meaning you keep getting deeper and deeper into your capacity..
Boosting your absorption charge voltages can cause quite an improvement in "time" needed to charge. Voltage is pressure and with higher pressure this means higher current, even at higher states of charge. It will also help to limit sulfation and stratification of the electrolyte.
If you don't want to run the big gen set then more solar or the addition of wind can help. A small Honda EU2000 can also be a good option to drive your TC40 but may not be the neighborly thing to do for 14+ hours unless you find a bay all to yourself.
Your boat has a good gen set and should be easily able to run 24/7 if needed, or, as long as you or fellow anchorage neighbors can stand it. Don't let it run lightly loaded powering just the charger. While it is running make good use of it. If you have AC, cool off, a water maker fill the tanks etc. etc..........
In summary:
*You really need to be charging at closer to 14.6 - 14.8V temp compensated. 14.2V is far too low for your Trojan's.
*You need considerably longer charge times to get back to 100%
*You need to get back to 100% as often as possible perhaps once weekly or once bi-weekly to limit sulfation and increase bank longevity.
*If not getting back to 100% that often you will need more equalization cycles.
*If you don't have a battery monitor it is a good investment. Battery monitors get out of sych, and develop counting errors, if the bank is not "reset" to 100% and the monitor also re-set when the bank reaches full. The longer you go between "full" events the more out of whack your battery monitor will become.
Hope this helps...
