Coach Deep Cell Battery

[Pavelich]

Hello, we have a used 2000 Mountain High Residency Model 3790. We need to replace the coach battery. We purchased the coach used from a private person with no paperwork. The previous owner put in a regular car battery. Any assistance on the group number for this coach battery? Thank you in advance for any help.

[wa8yxm]

Thank you OldWiz Oh I mentioned I have a pair of LI batteries
One is a 10 amp hour "Jump start" battery never used fully charged
The other is a Bioenno energy LiFePO4.. It's being topped off for use on Field Day (2 weeks) I'll feed it to a Kenwood TS-2000 likely cranked down to 5 watts. No more than 10. (Transmit power)

Ton of fun Field day promises to be. Small club.. Not planing on any winner awards but who knows. Good chance to play with assorted antennas day before then decide which we will use. (And top off battery)

[theoldwizard1]

There are multiple different lithium chemistries. You want LiFePO4.

GC-2 batteries can be purchased at Sam's Club or Costco or Walmart at very reasonable prices.

GC-12 batteries typically can only be purchased at a golf cart shop and are very expensive.

[wa8yxm]

Ok there are several different batteries but I'll cover 3x3 plus 1

First on the 3x3 all hold nearly identical amounts of energy per pound and per square foot, the only exception is the Optima which holds less per square foot (Weighs less too) about 60% the reason is obvious if you look at it.

# number 1
Starting: High peak current, but need to be kept near full say 80% or fuller
MARINE/deep cycle. a Starting battery basically but can go a bit lower like 75% State of charge

DEEP CYCLE: Fewer peak amps but do not mind half full (50% state of charge) if recharged fairly soon.. Also where as the first to often do not recover from an "OH C###" I ran 'em way way down.. DEEP CYCLE often do.. though their life is shortened.

The GC batteries (Golf Car) both GC-6 and GC-12 are DEEP CYCLE
most "Group ##" are starting or MARINE/deep cycle which is why we recommend GC.

3#2 Flooded wet, Maintenance free, AGM
Flooded wet you need to take leaking fluid precautions and top them off to about 1/4" below the bottom of the filler tube with DISTILLED water. Terminals may need fairly frequent cleaning. But they are least expensive and long lived.

Maintenance free are Valve Regulated Sealed Lead Acid. they are designed so as to NOT need "Watering" and require less cleaning, NOT LESS not none

AGM is kind of Extreme Maintenance free and can be installed other than "This Side Up". They are however most expensive of the Lead Acid types.

Finally the +1 The king of the Jungle. LiON types There are multiple. They are very expensivwe but most of them can go down to near zero state of charge and recover or so I'm told (will know more next month) I own 2 of them but have nto yet put 'em to the test (mine are small 10 and 20 amp hours)

Capacities
Group 24. just under 75
Group 27 and 29 Just under/over 100
Group 31 about 130
Remember only use 25%

GC-2 220 give or take about 10 (you can use half) Putting two in series to get 12 volt does not change amp hour capacity

GC-12 I would have to look but I think around 150 and again you can use half.

[theoldwizard1]

2 6V golf cart batteries.

[Matt_Colie]

Pavelich,

1-Do you plan to do much if any dry camping or real boondocking?

2-How big is the space for the house battery?

For 1, if the answer is no or very little, a large single jar (like a grp31) might be just fine.
If you think you might need more, go to 2:
If you can, measure and see if you can fit in 2ea GC2 (golf cart batteries). You will need a cable to make them in series for 12V. These are real (but less expensive) deep cycle batteries. If you drag them way down, but recover them promptly, they will not be damaged as much as non-deep cycle jars.
Matt