Batteries

21' may be considered a "thrifty - efficient" size rig. What is your budget and how long a stretch do you stay boondocking?

High CCA is actually a bad thing as it indicates a starting battery.
A deep cycle battery will have lower CCA.

How old is that original battery? Like other I recommend a pair of GC2 golf car batteries and let the small 12 volt go toward the core charge.

Next is to review your charging system. Very easy to get tricked into thinking the battery is full when it is just 70 percent.

If you can find room, go to 4 six volt batteries - you need the capacity.
Also, get an inverter gen to recharge during the day.

kaysdriver wrote:
My 21 foot TT came with a small deep cycle battery. My Problem is when I dry camp it doesn't last the night running my cpap machine. Cpap has a real low draw. I am going to install a 2 battery system. The question for me is 2 high capacity deep cycle batteries better than 2 900 cca regular batteries.

THe problem is the CCA is meaning less in this context

What size battery do you have now. You said one "Small"

group 24 is about 75 amp hours, perhaps 25 usable
Grupos 27/29 are just under/over 100 (ROund to 100) perhaps 35-40 usable Each.

A pair of GC-2 Golf Car DEEP CYCLE batteris are 220 AH give or take depending on the precise model (Mine are 230) and you can use half that (NOTE: when you wire batteries in series you add VOLTAGE and that is how you wire the pair of GC-2)

THey might also be less expensive

You absolutely want deep cycle batteries. The batteries listed CCA (cold cranking amps) are designed only for cranking. High output for a short period of time. The only battery that would be applicable for house batteries are deep cycle.

RoyB wrote:

Going with the two 6V golf cart batteries in series to give you the 12VDC is the way alot of members go to get high AH rated battery service.

Roy Ken

X2
Best route to go.

I wouldn't know why you wouldn't buy deep cycle batteries.
If you think you are going to get more longevity from starting batteries for your money, you're not.

If you take even a little care of your deep cycle batts, like keep them clean, watered and fully charged as possible on a 3 stage converter charger, they will last.....like forever.

Moved from Forum Technical Support

kaysdriver wrote:
My 21 foot TT came with a small deep cycle battery. My Problem is when I dry camp it doesn't last the night running my cpap machine. Cpap has a real low draw. I am going to install a 2 battery system. The question for me is 2 high capacity deep cycle batteries better than 2 900 cca regular batteries.

CPAP are not really "a real low draw" when you are talking about a small 12V battery. My wife's takes almost 100 watts A.C., I assume you have similar. Add 15% to allow for the efficiency converting to AC from the battery. As you have found that will pretty solidly drain a group 24 battery which only has something like 80 Amp hours capacity and you are taking about that much out if it's on for 8 hours at like 8 Amps draw. Double that as you don't want to draw most batteries down less than 50% and that is what you need for the CPAP alone. 130 AHs. This means with 2 standard 6V 'golf cart' batteries you should have enough to get through the day assuming reasonable other current draws, but you would be charging at least some every day as they don't like to get below 50%.
There is endless discussion about the best route to go for batteries. There is no best answer. the 6 volts are rugged, if cared for properly, but with only 2 if one fails you have nothing. They are likely the most cost effective if that is a criteria. I favour AGMs, for a couple of reasons but cost is not one since they are at least twice as much for a given capacity. They will charge much faster, take more abuse, and they are practically speaking sealed so no worry about watering or leaks.

Deep Cycle batteries is what we need to be using as we will be doing a lot 50% to 90% re-charging cycles during our camping experiences... The standard Truck Start batteries are not designed for the many re-charge cycles and will start dropping off in performance right away.

Going with the two 6V golf cart batteries in series to give you the 12VDC is the way alot of members go to get high AH rated battery service.

Roy Ken