Maine Sail also has a tutorial regarding leaving the batteries in the boat all winter. Which you may find helpful.Maine Sail mentions using a DC power supply to equalize batteries in this article:
Winter Battery Storage & Self Discharge Characteristics - Marine How To
December 11, 2012 After having a discussion with one of my customers, about leaving his battery charger running on-board all winter, a practice I am certainly not a huge fan of, and one his boat yard specifically prohibits, I decided to venture into this article.marinehowto.com
What brand of charger do you use to equalize batteries
- Thread starter sailcapt340
- Start date
And if you haven't already please make a donation to MaineSail through his Compass Marine Website.
I completely agree with you Richard, captcoho, shemandr. It's all about giving back. Even through Rod's recovery he's still helping others. That MaineSails article outlines the equalization process completely. Straight forward easy to read. I hope it helps others in doing an equalization on their batteries as well. I'm equalizing an old battery I have as I'm writing this response to test the equipment I have. After about 2 hours now, the specific gravity is almost equal in all cells. I'll keep checking.
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Just sitting in my garage (1 year) with no loads on it at all. Voltage was 12.38 v. So, approximately at 70 % of capacity.
Sorry, I meant what's the open voltage on your charger before hooking to the battery.
dj
The DC voltage is +\- 18 V The DC Amp is 0.5 Amp
Prior to starting I had Specific Gravity readings of 1.250 (2 cells) to 1.270 (4 cells)
I'm about 3 hours into the process and have Specific Gravity readings now of 1.275 in all but one cell (which is 1.265)
This was a much older, unused battery so I figured it was a good test subject.
Prior to starting I had Specific Gravity readings of 1.250 (2 cells) to 1.270 (4 cells)
I'm about 3 hours into the process and have Specific Gravity readings now of 1.275 in all but one cell (which is 1.265)
This was a much older, unused battery so I figured it was a good test subject.
A modern charger that has automatic equalization is a very good idea. If you REALLY want to do it by hand, here is the info you need: Leave the battery in its box or put it in an old cooler. Cover it loosely with a thick rag or old towel. The objective here is to contain flying acid in case the battery decides this would be a good time to explode. Raise the voltage to 15.6 volts for 15 minutes, no more. Your old Eico may not be "man enough" to charge a Group 24 battery that hard. It was really intended as a bench accessory for auto radio repairmen. Remember that you are deliberately abusing the battery plates to expose fresh lead / lead dioxide. It is better to underdo this treatment than overdo it.
I strongly disagree.
For flooded lead acid batteries, I find that it will often take many hours to properly equalize the battery, depending upon state of sulfation.
Lifeline specifically states for their AGM's to perform this for a 4 hour cycle.
This is not correct, as long as you have excellent control of voltage and current. With proper controls, you are primarily breaking down lead sulfate back into it's respective lead and sulfur.
dj
I did dial back the voltage to 16V. I've been in and out checking this battery for the past 4 hours as it progressed.
I now have an equal Specific Gravity in all cells of 1.275. And an ending voltage of 13.68 - 13.74 V. That's leaving out right now at 13.68V.
So this battery is done and I will be checking it as the days go on.
I'll start my 3 others in the next few days.
I now have an equal Specific Gravity in all cells of 1.275. And an ending voltage of 13.68 - 13.74 V. That's leaving out right now at 13.68V.
So this battery is done and I will be checking it as the days go on.
I'll start my 3 others in the next few days.
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Do you know what the ambient temperature is right now where you are? It's really more for a data point. Specific gravity is the best way to check this. Nice!
dj
It’s 42 F.
I will really know my end results over the next few days and going forward from here. But it’s a straight forward process and I do suggest a new modern DC Bench Top Power supply for accurate readings, if you’re are going to make this one of your maintenance projects.
For some of us, if you remember Sears and Roebuck automotive. They would take your battery and place it on a bench overnight for you, load test and balance them for free. And if it didn‘t hold a charge after that, you bought a new battery. They had rows of them on bench’s all connected everyday. That was then, this is now.
I will really know my end results over the next few days and going forward from here. But it’s a straight forward process and I do suggest a new modern DC Bench Top Power supply for accurate readings, if you’re are going to make this one of your maintenance projects.
For some of us, if you remember Sears and Roebuck automotive. They would take your battery and place it on a bench overnight for you, load test and balance them for free. And if it didn‘t hold a charge after that, you bought a new battery. They had rows of them on bench’s all connected everyday. That was then, this is now.
I've been using a very good DC power supply for decades at this point for doing equalization. I was taught about it years ago by a retired electrical engineer from Hoover Dam. He had told me a well maintained lead acid battery will last 12 to 15 years, sometimes longer, if properly maintained. Not too long ago, I finally found a reference that supported that faded memory as I was involved in a discussion with Mainesail about battery life and equalization...
I recently upgraded my power supply due to an accident destroying my original power supply. I've very pleased with my new power supply. Looking at your specific gravity numbers, I think you'll find that battery will work quite well for some time yet.
dj
I just replaced our undersized and aging charger work a Guest Charge-Pro Onboard Battery Charger 3 Bank 15amp 12v purchased at West Marine.
The unit is built by ProMariner with a lot of the same innards, just not the fancy name on the front.
Amoung it's features are:
Built-in safety: reverse polarity, over-current, over-voltage, over-temperature and ignition protection. In-line fuses for maximum DC wire protection.
- Battery Conditioning
100% Waterproof (IP67) and shock resistant for all fresh and saltwater applications
Dedicated battery charging, sensing and control per bank
For all 12 volt flooded and AGM lead acid batteries. 2 year warranty
-auto senses type of battery connected
how this helps, cheers!
Sam
The unit is built by ProMariner with a lot of the same innards, just not the fancy name on the front.
Amoung it's features are:
Built-in safety: reverse polarity, over-current, over-voltage, over-temperature and ignition protection. In-line fuses for maximum DC wire protection.
- Battery Conditioning
100% Waterproof (IP67) and shock resistant for all fresh and saltwater applications
Dedicated battery charging, sensing and control per bank
For all 12 volt flooded and AGM lead acid batteries. 2 year warranty
-auto senses type of battery connected
how this helps, cheers!
Sam
