Replacement sealed AGM battery for Deeres 22NF series or others please post - Page 2 - Machine Underground -Tractor & Commercial Equipment Discussion Forum

Mickey · 11-09-2007, 07:53 PM

I think the explanation has more to do with the way typ wet cell automotive batteries are made. Cell vents have tube like structures that projects down towards the plates. When electrolyte is low and charging at a hgher rate than I would like, the cell starts bubbling or better know as boiling, there is more room for the splash of the bubbles to find ther way up and out the top. When electrolyte is up to at least the bottom of the tube, before and splashing can happen they have to get their way past the small slits in the tube side walls.

Anyway that my take on it.

As for charge voltage, 14.25 is tops for me if engine is running for long periods. and would prefer something closer to 14. A nom 12v battery can rise to about 13.9v without overcharging but when voltage exceeds that you can over charge and that's when the "boiling" begins.

**Ducati996** · 11-09-2007, 09:19 PM

Thank you for these details Mickey - its nice to know why this can occur..

You know the Cubs have a much better battery then Deeres - 4 yrs old and no way for it to vent or spill, same size as a group 51 series too

Mickey · 11-10-2007, 01:42 PM

Just my take on the issue. May be some other explanation but I can see a combo of low electrolyte and high charge voltage contributing to acid escaping from the vents.

**gunmaker** · 11-10-2007, 07:16 PM

Mickey's right on about high voltage evaporating off the battery acid. If you check out most smart chargers, they charge at 13.2 VDC or below to prevent this.

**Ducati996** · 11-10-2007, 08:29 PM

Quote:

Originally Posted by gunmaker

Mickey's right on about high voltage evaporating off the battery acid. If you check out most smart chargers, they charge at 13.2 VDC or below to prevent this.

I have had great luck using battery tenders (some are weather proof & handle AGM batterys) for my Diesel dual battery truck. The others are either a mix of Yuasa and battery tenders, and they all have extended my battery life on everything already a few years

**gunmaker** · 11-10-2007, 08:45 PM

Those 'smart' battery tenders are great, I've a bunch myself. I've seen reports of a new manufacturer by the name of 'C-Tek' (sp), who is turning out quality smart chargers also.
I had the battery on my JD 425, and a Honda scooter last 10 years, while using these chargers.

Mickey · 11-10-2007, 10:48 PM

Once a battery is fully charged, a float voltage of 13.2 is a very good setting. For LA batteries, a charge voltage of 2.2 - 2.4V/cell is the reccomended charge voltage. A lot depends upon state of charge and duration of charge. Temperature is also a factor but not an important one for normal kinds of environment/operation. If the battery is partially discharged and the charge duration is relitively short, 2.4 or 14.4 V for a nom 12V batery is acceptable to min recharge time. As a battery gets closer to being fully charged and charge duration lengthens, one needs to drop back on voltage. A nom 12V battery can rise to about 13.9V without without damage with moderate charge times. When the battery is fully charged 2.2V/cell or 13.2V for the battery is an ideal voltage rate for the battery and can be kept on the charger for ever without a problem.

Back when I was a working man and about 20 yrs ago I spent some months studying LA batteries for a medical product I was working on. Learned a lot about care and feeding of LA batteries but certainly not the expert I would be if Chemistry and how it applied to batteries were my strong suite.

nuru · 03-09-2008, 11:28 AM

Gee a lot of good experienced-based info has been provided in this forum, please keep it coming.

**PaulChristenson** · 03-09-2008, 10:07 PM

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