Battery life

[frecku]

I have a Class C rig with 6 X U2200 6V interstate batteries, they are about 5 years old, well taken care of, toped off regularly.

This spring cleaned the corrosion off the terminals and did a regular charge. Normally right after charging it shows a voltage of 13.5V and about a week later with the power disconnected a voltage of 12.8V, stable.

Never had any issues with them, I happened to have a battery hydrometer handy and tested all the cells. To my surprise all cells showed a voltage in the "white" between 12.25 - 12.50V.

Is that normal ? I do not think the hydrometer is temperature compensated. Do I still have life left in the batteries, they work just fine ?

[frecku]

From what I have researched, rather than going with the pulse charge desulfator, I went with the high frequency pulsing method.

http://batterylifesaver.com/

http://www.pulsetech.net/PP12L-PowerPulse-12Volt-Battery-Maintenance-System-7291.aspx

[HiTech]

Missed that. The acid is crystallized sulphate in each battery cell. Running the cells at 15+ volts will reverse as much crystal as possible back into the electrolyte. Some will blast away and fall to the bottom but it should still improve things. Ideally voltage at low current will do the most good I believe.

Jim

[time2roll]

I would not replace the acid.

Solar has its place even with 125 amps charging with the magnum as needed.

[HiTech]

Nice!

[frecku]

The reason for 6 X U2200 / CG2 is that I have a power hungry 2800W inverter, 3 kids, a wife that likes her coffee and microwave after quiet hours.

Charging comes from my Magnum Energy Magnasine MS2800 inverter, 125 Amp Five Stage DC Charger.

[frecku]

Correction, the SG is between 1.225 and 1.250 I also forgot to mention that I have the BLS system.

I never let the batteries run down below 75% charge, much easier to top them off.

I have a box of pure battery acid I used to fill dry motorcicle batteries, would it make any difference if I drained the batteries and refilled them with fresh acid ???

[time2roll]

200+ watts of solar and a good controller would be topping them off every day. Probably bring them back to life. With 6x GC2 I assume you are camped off grid a lot and the solar would really help there too.

If you have a problem with corrosion and it is getting worse it might be a sign of battery aging. Or an updated converter with lower float voltage would help. Do you fill to 1/8" below the split ring? Be sure to use a cleaner and then protectant when all put back together.

[Canadian_Rainbi]

Son of Norway wrote:
Some of the hydrometers sold in stores aren't very accurate. I had one that I had to throw away. I replaced it with one I got at a battery company which was about three times the price, but I trust the readings.

Miles

I agree with Miles. But having said that, a variation in SG of .25 is not huge, but would likely (hopefully) respond to a 15V overcharge (equalizing) charge.

By the way, in your post you typed 12.25V and 12.5V as reading on the hydrometer. a hydrometer doesn't measure voltage, it reads Specific Gravity, or the density of the electrolyte compared to pure water, which has a SG of 1.000. In other words, it tells you how much of your electrolyte is acid ad how much is water. As a battery discharges the electrolyte becomes less acidic.

Most (not all) new lead acid batteries at full charge have an SG of around 1.275 to 1.300. Some batteries are produced with a lower SG for various reasons, one being more tolerant of high ambient temperatures.

We would like to hear of the outcome. Please let us know.

As an aside, I have 6 2V 150 AH glass cells, designed for float application, that were manufactured in 1984. They are still in use in my ham radio station and will happily provide the 10 to 15 amps my 100 Watt transmitter needs the voltage does not drop on transmit. The SG in them varies from 1.235 to almost 1.250. An over charge brought them up from 1.230 more or less across the board, except for one cell that was at 1.225 and is now at 1.235.

[Son_of_Norway]

Some of the hydrometers sold in stores aren't very accurate. I had one that I had to throw away. I replaced it with one I got at a battery company which was about three times the price, but I trust the readings.

Miles

[mena661]

X2 HiTech and BFL. The 6's really need that 15+V overcharge after a decent discharge (lower than 85% SOC) AND they need that occasionally top charge at 14.7V (IOTA converters do the top charge automatically).

[BFL13]

Yes, you have your classic "learner set" of batteries right there 😞

they will show good voltage and do fine while camping because you don't really need that much of a battery bank, so nothing bad happens as far as you can tell while camping.

But you never got them fully charged and they gradually sulfated and lost capacity and that does show when using an hydrometer.

Actually five years is pretty good doing things that way. You can go longer if you really only need two batts and you have four at half speed.

For your next set of four 6s, do it like it says here in the US Battery blurb. The trouble is , you need a special charger for that, to get over 15v. A VEC 1093DBD will do it on auto Equalize, or any cheap manual (not "automatic") 10a charger will too, except with those you have to stick around and monitor the action for maybe eight hours.

http://www.wholesalesolar.com/pdf.folder/battery-folder/charging_instruction_2011_2.pdf

[HiTech]

Sounds like maybe they need a long session at 15 volts?

Jim

[frecku]

I am in Idaho where winters can be harsh, they are Interstate, got them from a local store.

[HiTech]

frecku wrote:
I have a Class C rig with 6 X U2200 6V interstate batteries, they are about 5 years old, well taken care of, toped off regularly.

This spring cleaned the corrosion off the terminals and did a regular charge. Normally right after charging it shows a voltage of 13.5V and about a week later with the power disconnected a voltage of 12.8V, stable.

Never had any issues with them, I happened to have a battery hydrometer handy and tested all the cells. To my surprise all cells showed a voltage in the "white" between 12.25 - 12.50V.

Is that normal ? I do not think the hydrometer is temperature compensated. Do I still have life left in the batteries, they work just fine ?

Did you get them from a good battery shop by chance? I have always wanted to tropicalize a battery for warm weather - say Texas - by reducing the specific gravity of the acid. It should make a battery eat itself up more slowly in hot climates.

Also have you top charged it? Once a month or so the batteries need an over charge to return sulphate to the electrolyte and bring up the specific gravity. What voltage and duration do you use for charging and any other battery maintenance?

Jim