Equalizing

[Bob S]

Hey Maine,

It's a full time job just monitoring these posts!
I lurk a lot and appreciate all your advice. I try not to post too often but had a question: I have a pair of group 31's (130ah) I got from Defender back in 09. I charged them using a bench top Martech until they would would only accept 1.9amps @ 14.4v per your instructions previously posted
http://forums.catalina.sailboatowners.com/showthread.php?p=996472&highlight=equalize

#1

Check specific gravity of the batteries note on paper what the readings are.

#2 Charge batteries to full at 14.4V and wait until the current falls to less than 1.5% of capacity or less. So for a 100Ah battery charge at 14.4V until the battery is taking less than or equal to 1.5A of current.

#3 Fill with distilled water, if necessary, to approx 1/8" below the fill well. Be careful not to allow any dirt or contamination into the cells and to not over fill. The water should not be touching the plastic fill well. Contamination is the destroyer of batteries.

#3 With a power supply, adjust the voltage to 15.5V without the batteries connected. Cross check it with a DVM.

#4 Connect battery and adjust/limit the current so that you can maintain 15.5V. too little current and you won't get to 15.5V, too much current is unnecessary.

#5 Stop equalizing at 2 hours, let batteries rest for 40 minutes to an hour, and check specific gravity of the cells. If all cells are equal continue for another two hours.

#6 If all cells were not equal continue for another 2 hours then check again. When the cells get close to equal stop any time before 6-8 hours. You don't want to over equalize but do want the cells to be in balance.

#7 This is all based on temps of 70-80F.. If the batteries are warmer than 80F you'll want a lower temp compensated EQ voltage.


With a battery charger follow the instructions for your charger but many of the steps above apply.

I did not check the specific gravity before starting but did after charging them to 100%. All 12 cells read between 1.25 to 1.27. I just finished the first 2 hour 15.5v and will check the SP and expect them to be pretty close. Your#5 says if they are close equalize for an additional 2 hours. Can this be done tomorrow morning or does it need to be done right away.

Hope this question makes sense! I'm doing this at work and want to head home. (I'll do the second battery tomorrow).

 

[Maine Sail]

Hey Maine,

It's a full time job just monitoring these posts!
I lurk a lot and appreciate all your advice. I try not to post too often but had a question: I have a pair of group 31's (130ah) I got from Defender back in 09. I charged them using a bench top Martech until they would would only accept 1.9amps @ 14.4v per your instructions previously posted
http://forums.catalina.sailboatowners.com/showthread.php?p=996472&highlight=equalize

I did not check the specific gravity before starting but did after charging them to 100%. All 12 cells read between 1.25 to 1.27. I just finished the first 2 hour 15.5v and will check the SP and expect them to be pretty close. Your#5 says if they are close equalize for an additional 2 hours. Can this be done tomorrow morning or does it need to be done right away.

Hope this question makes sense! I'm doing this at work and want to head home. (I'll do the second battery tomorrow).

Does not need to be done right away. You should have seen those batts get lower than 1.9A at 14.4V..... How long were they at 14.4V? Those instructions were really based on a non-controllable battery charger. On the bench top power supply I leave them at 14.4V until the current stops dropping, then I equalize. If they are healthy they will drop below .5% acceptance.

 

[Bob S]

I checked the batteries after winter storage and both were reading 12.36 and 12.37v. It took 8+ hours @ 14.4v to get the amps down to 1.9 (1.5% x 130ah). Is my reasoning wrong? I thought they were fully charged when the amps = 1.5% of the battery's capacity. It took way longer than I thought. I am doing this at work using my cell phone timer. I will give it another 2 hours in the morning. Battery is reading:
1.27 1.27 1.275 1.265 1.265 1.27 @ 12.97v 45 minutes after the first equalize.
That is fair/good on the refractometer.
They are going into their six season and probably their last.

 

[scherzoja]

I've got a few questions on equalization and have searched, but can't figure it out.

First, here is what I have.

1. Xantrex echo charge
2. Four 232AH golf cart batteries (series/parallel for 464 ah at 12v total)
3. Statpower TrueCharge 40 with equalization button
4. start battery wired separate from house

Some of you might recognize this because a few weeks ago you helped me put together this diagram and I finally put it all together in the boat. It works beautifully. Thank you Stu, Maine, et.al. for all the help. This system was very easy to put together and seems easy to manage.
http://forums.sbo.sailboatowners.com/showthread.php?t=162139&#post1115226

I also read the manual for the TrueCharge, but it is not very clear, other than how to push the equalization button.

Here are my questions.

1. Do I disconnect the echo charge from the battery that is to be equalized?
2. Can I equalize all four golf cart batteries at once (keep them series/parallel wired) or do I have to break them apart?
3. How do I equalize the start battery if the out put of the TrueCharge only goes to the house bus? Do I move the TrueCharge output to the start bus?
4. I've read cautions that I should disconnect all loads to avoid damaging the devices. Is it sufficient to put battery switch in Off position and disconnect the "+ Aux Bus 1" (see diagram below)?

Thanks again.

OT: for those who noticed, yes, that is a voltmeter. Need to save up for the Balmar SmartGauge. Maybe Santa will bring it.

 

[Stu Jackson]

Here are my questions.

1. Do I disconnect the echo charge from the battery that is to be equalized?
2. Can I equalize all four golf cart batteries at once (keep them series/parallel wired) or do I have to break them apart?
3. How do I equalize the start battery if the out put of the TrueCharge only goes to the house bus? Do I move the TrueCharge output to the start bus?
4. I've read cautions that I should disconnect all loads to avoid damaging the devices. Is it sufficient to put battery switch in Off position and disconnect the "+ Aux Bus 1" (see diagram below)?

Shouldn't the positive from the 1-2-B switch to the Distribution Panel should be from the C post?

1. Take it off Bus 1
2. Yes, although MS suggests doing each battery (in your case a pair of 2) separately. Your boat, your choice.
3. That would be the easiest way
4. You don't need to do both. The reason is that the equalization voltages are above 15V, so you don't want any 12V loads connected to 15V. Since you understand how it's wired (good job!) then you should be able to answer that, right?

Don't do an eight hour equalization. Read MS's material, IIRC he suggests two hours, check then maybe two more.

Ventilate
Ventilate
Ventilate
Ventilate................................................

 

[scherzoja]

Shouldn't the positive from the 1-2-B switch to the Distribution Panel should be from the C post?

Yes, Stu, you are right about the DC panel coming off the C post. It is like that in reality, but I was sloppy in my diagram. Thanks for catching that and Thanks for confirming my answer to #4