Charging specs for group 29HM Deep Cycle Marine/RV battery

time2roll wrote:

red31 wrote:
if ya ask JCI about the energizer batts they might send what they sent me.

I know of only one charger that actually has this profile.... Battery Tender High Frequency charger primarily designed for golf carts but available in 12v.

My old Sears Manual 6 amp 12v battery charger from the late 1970's has a profile similar to that. When the ampere gauge gets down to around 2 amps, and the voltage reaches 16.35V on my DMM, it's time to unplug that manual charger on my group 24 DC Walmart special battery that I use for powering my 100w ham radio that pulls about 4 to 5 Ah per hour.

red31 wrote:
if ya ask JCI about the energizer batts they might send what they sent me.

I know of only one charger that actually has this profile.... Battery Tender High Frequency charger primarily designed for golf carts but available in 12v.

That 29HM 12V battery only weighs 61 lbs I think I read somewhere...

The Trojan GP27 12VDC Battery weighs around the same weight so I suspect you would get around the same performance level. When loading down @25 AMPS the capacity will be around 200 minutes (3.3Hours to zero charge state)

Using two of the Trojan GC2 6V batteries in series will weight in around 124 lbs of batteries when you add two together to get 12VDC. You will get alot more capacity @25 AMPs draw down with the GC2 batteries. This will be around 447 minutes (7.45 Hours to zero charge state)...

Of course you would never want to run them down that far and keep them always above the 50% charge state...

When i am charging my GP24 12VDC batteries with my PD9260C converter/charger I immediately see around 52-53AMPS DC Current going into my three GP24 batteries when I hit them with 14.4VDC. SOme have told me my PD9260C may be doing some current limiting at this point but that is what I read on Battery monitor panel I made up. In about 15-20 minutes I see the DC Current start tapering back and in one hour my PD9260C will then switch to 13.6VDC mode. My total DC current is them reading with the three GP24 batteries connected around 8 AMPs or so. If this continues on for a couple more hours at 13.6VDC then I see the DC current for the three GP24 batteries showing around 2-3AMPS DC current. This is what I call the 90% state of charge. I get almost full performance out of my GP24 batteries doing this... i.e. My normal parasitic drain is around 1AMP or so and usually between between 6PM and 11PM I will see up to 22-24AMPS DC current being drawn from all of the the things we are running off the batteries. After we go to bed around 11PM I make it just fine to 8Am the next morning with my DC VOLTMETERS reading around 12.0VDC. This is what I call the 50% charge state. Now I can my my 2KW generator with the shore power cable connected to it and this will bring my three GP24 batteries back up to around 12.6-7VDC in three hours generator run time. This is powering up my PD9260C converter/charger to charge my batteries.

This is what I have been doing since around 2009 camping off-grid in my OFF-ROAD POPUP camper. Just last season my three GP 24 batteries start taking longer and longer to charge up and of course running down to the 12.0VDC level much quicker than before. It is game over for me now with these batteries. Working on a new battery setup for this coming season using two groups of GC2 6V batteries in series to get me in the 450AHs capacity as compared to the 255AH capacity I was getting from the three GP24 12V batteries in parallel.

This is what has been working for me
Roy Ken

If you are referring to a storage situation where the battery remains near fully charged, the settings in MSView allow you to set the absorption stage to a small time window (mine is 15 minutes, IIRC). After that, the controller reverts to the float voltage you have set. With temperature compensation, the Morningstar controller varies voltage according to the battery temperature.
IIRC, the equalization charge is set to once a month and at a standard higher voltage. That can also be removed or changed in the MSView settings. I have mine removed since I run equalization with my shop charger

Usually the Absorption Stage is considered to begin when the current starts to taper, ie, when battery v gets close to charger Vabs. It is true that battery V keeps rising after that until it does reach charger V so current stops, batts full.
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On EPsolar standard profile-- I like it for when and where we use solar. The fixed two-hour absorption time works well for that most of the time. I have used a LandStar PWM and now a Tracer MPPT both with that profile.

The three-hour time mentioned for that other controller would also be ok maybe better. There are days when I would like a longer absorption time.

With my Eco-Worthy controller there is no absorption time at all. It drops to Float as soon as it gets the batts to near Vabs. So I set Float voltage to be near same as Vabs (it won't go quite as high as Vabs) but then it stays there till dark, which can be too long and I lose water if we have a good stretch of sunny weather.

I think if we went South in the winter and used solar, I would find I needed a somewhat different charging profile down there from what works best here in summer.

if ya ask JCI about the energizer batts they might send what they sent me.

I have a "set and forget" type solar controller. It is an Epsolar Tracer that I set up 7 years ago with a pair of GC-2 batteries. I have added a bit of water I think 3 times in that 7 years.

I set my Blue Sky 3024 up and I forgot it. It is important to have temperature compensation enabled. My jars lasted 9 years.

I set my Magnum inverter charger up and I forgot it. So far 2 years and a bit.

Anything 14.3 to 14.8 should be fine. I have mine set toward the low end.
Even more important IMO is the programming to adjust absorption time based on the start voltage. This allows very short absorption when in storage or very light use. The time can automatically extend when the start value is lower. And for extreme use there is a setting for very low battery to stay in absorption all day.

If you go on the low side you can set equalization a bit higher say 14.8 to give them a boost every so many days you program.

Thanks