On Mon, 17 Aug 2015 11:47:31 -0700 (PDT), Tim
wrote:

AGM Greg. That's why I said "dry" because that's a common term for them. The gel cells will slowly leak when punctured.
But that's rare. I'm sure they're around, but gel's aren't popular in my area.

===

Both gel cells and AGMs are somewhat more finicky about how they are
charged. That said, I've switched over to AGM starting batteries on
the big boat. So far, so good. Almost two years and several major
cruises and they still seem to be going strong. I've made no changes
to the voltage regulators. Previously each engine had a single 8D
starting batt. I replaced them with two Group 31M AGMs in parallel
(Sears Platinum DieHards). The combined AGMs have more cold cranking
power than the single 8D, are much easier to change out, and so far
seem to be more durable. THe only downside that I can see is that
the AGMs will be more difficult to source in the boondocks if that
ever becomes necessary.

On 8/17/2015 3:45 PM, Wayne.B wrote:
On Mon, 17 Aug 2015 11:47:31 -0700 (PDT), Tim
wrote:

AGM Greg. That's why I said "dry" because that's a common term for them. The gel cells will slowly leak when punctured.
But that's rare. I'm sure they're around, but gel's aren't popular in my area.

===

Both gel cells and AGMs are somewhat more finicky about how they are
charged. That said, I've switched over to AGM starting batteries on
the big boat. So far, so good. Almost two years and several major
cruises and they still seem to be going strong. I've made no changes
to the voltage regulators. Previously each engine had a single 8D
starting batt. I replaced them with two Group 31M AGMs in parallel
(Sears Platinum DieHards). The combined AGMs have more cold cranking
power than the single 8D, are much easier to change out, and so far
seem to be more durable. THe only downside that I can see is that
the AGMs will be more difficult to source in the boondocks if that
ever becomes necessary.



When we were in Florida, I had a small boat and electric trolling motor
for use on the little man-made pond behind our house (shared with the
resident alligator). After doing some reading I opted for an AGM
battery for the motor. The AGM recharges faster and is rated to
discharge lower than a wet, lead acid. It was a little more expensive
but wasn't ridiculously priced.

Richard, that's what I'm going for. Besides that I understand that not only do they have a faster recovery rate, but like for my tractors they have a lot less thermal discharge in the cold weather.

Wayne I think you did the smarter thing by replacing the 8-Ds in this way. Yes replacing them in the unknown might be tough but small traditional batteries are still a universal option.

At least you can still get home...

On 8/17/2015 6:59 PM, Tim wrote:
Richard, that's what I'm going for. Besides that I understand that not only do they have a faster recovery rate, but like for my tractors they have a lot less thermal discharge in the cold weather.

Wayne I think you did the smarter thing by replacing the 8-Ds in this way. Yes replacing them in the unknown might be tough but small traditional batteries are still a universal option.

At least you can still get home...



That reminds me. My John Deere tractor is on it's second lead acid
battery and, being a diesel, has a tough time turning over in the dead
of winter unless I keep it in one of the heated garages. I think I
might replace it with an AGM before next winter (assuming we are still
here) and see if it can handle the cold weather better.

I tried putting one of those magnetic heaters on the oil pan last
winter. It was worthless. I ended up keeping the tractor in our "barn
garage" that has a 10kw and a second 5kw electric "kicker" in the air
handler for the AC unit. I just set the thermostat at about 40 degrees
and the tractor has no problem turning over or starting. If I leave it
outside in 20 degree or less temps overnight it can't turn over.

I just picked one up at the local Rural King store. 975 CCA, 685 reserve, 2 yr warranty $129.00 and core (I've got plenty of them). Tomorrow it goes on the test bench to see how it holds. If its satisfactory then I'll change out more as needed.

On 8/17/2015 9:46 PM, Tim wrote:

I just picked one up at the local Rural King store. 975 CCA, 685 reserve, 2 yr warranty $129.00 and core (I've got plenty of them). Tomorrow it goes on the test bench to see how it holds. If its satisfactory then I'll change out more as needed.


That seems like a very reasonable price. I just bought a new lead-acid
for my truck (the original finally gave up the ghost). Got it at
AutoZone for $158. 1000 CCA.

The tractor doesn't need anything that big. AutoZone carries the AGM
batteries as well, so I'll check them out.

I noticed something interesting after I replaced the truck battery.
It seemed to have more pep .. or maybe just more response to the
throttle. Shift points were different also. Then I realized that the
truck computer was re-learning my driving habits. I normally drive
like an old lady, rarely exceeding 3,000 RPM when accelerating. So,
after 7 years, it apparently had adjusted the timing and shifts
accordingly.

Richard, part of the better throttle response is that with the new battery, the computer is getting better voltage due to less drag on the alternator. So with the efficiency of the new storage box, the computer and ignition as well as injector system benefited from a slighter higher amp flow. And that could be as little as .2 volts difference.