Battery Choice Opinion Please UPDATE

PT you need an excuse to get out of there before it all turns to gumbo and grasshoppers again now that it is finally above freezing (if it is!). They still have pianos here I think, but I see you can get a digital player piano and app for that, so maybe not! :(

Thanks BFL13,

But I haven't killed my telcom jars yet. This may be my last year to full time and if so the telcom jars may last a heck of a long time with the solar keeping them fully charged between trips.

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pianotuna wrote:
Am glad the new Jar is not Junk. It could not happen to a nicer person. Thanks for sharing your data!

Thanks Don! He has more I guess, since his ad has not been pulled.
You could just pop over and grab a couple :) Been in his basement for a "couple of years" and he hits them one at a time with his little charger "about once a month". I was worried they might be sulphated, but took a chance.

I would like a second one, but I have enough battery now to get by for a good while.

http://www.usedvictoria.com/classified-ad/3000-Watt-Hour-Deep-Cycle-Battery-for-RV-Camping-or-Home-Energy-Storage_31607167

BFL

Trends

And

Tendencies

Using proper analysis

Am glad the new Jar is not Junk. It could not happen to a nicer person. Thanks for sharing your data!

Thanks Mex, I will have to do that next time, since it is already partly charged back up from solar/alternator on the drive home (down 77 on arrival home) My Trimetric already has a default heat loss for recharging in its program so this could get complicated. :)

I plan a "proper" 10 hour run at 12.5 amps to 50% to get a 20hr rate capacity, but not sure where 50% is! This is stupid. No hydrometer AGMs.

I will go with 12.40v resting a while after bounce back unless somebody can give me a better idea how to read that graph volt/SOC. This trip seems to say it is pretty much as rated for 250AH, so the 20hr rate test will confirm that with any luck.

Raise temperature 3c and all your calculations go into the blender...

Amp hours out

Replace amp hours exactly to the number

Then go on to hit the wall at 14.4

How many additional amp hours did it take?

Divide higher number into lower

That is your CEF charge efficiency factor

Repeat the protocol using maximum amperes s recommended by OEM
Versus saturated charging at 14.4 volts
Divide lower time into higher time

That will be your charge acceptance differential

The battery checked out ok for camping. It is rated at 250AH and spec is 95% at about 18C for inside the RV so call it 237ish.

I used about 30AH a day from it at under 20 amp draws, with no charging from solar or alternator during that time. The spec resting voltage vs SOC graph is vague, but here is what I got using the Trimetric. (Start Full 13.04v --Voltages were near resting--under an amp draw.

12.9 down 15AH,12.7 down 32 to 38, 12.6 down 56.6AH, 12.5 down 82AH, then had to use multi-meter to get two decimal places for voltage since "12.4" is somewhere near 50% SOC on the graph (I think).

12.46 down 98AH
12.43 down 104
12.40 down 112
12.36 down 120 (so 50% of 237ish)
12.30 down 130--ends--plugged solar back in and alternator for the drive home.

The spec voltage/SOC graph for this 6GFM250 AGM is the same as for my 12v 100AH AGMs for which I have the link here--so you can see how difficult it is to specify from the graph where 50% is :( If anybody has a clue how to read that for real life work, please post that info! Thanks.

Scroll down to graph on the right.

http://www.wegosolar.com/products.php?product=SKR%252d125AGM-Stark-AGM-12V-Solar-Battery-Sealed-125A

David,

Where do you start with 14.8 volts ... on the charger's terminals or on the battery(ies's) terminals?

If on the battery(ies's) terminals ... what currents are flowing with the battery(ies's) at, say, 50% at the beginning of the charging?

If on the battery(ies's) terminals ... I believe you mentioned having a humongous charger in order for the 14.8 volts to be maintained right on the battery(ies's) terminals?