off grid camping vs 405cca batteries as delivered new

[jostby]

My previous camper (motorhome) had (2) 6v deep cycle golf cart batteries and never had a hiccup when we were being conservative with power usage over a 4 or 5 day stint. Our new (March 2020) 303RLS has (2) 405cca 12v batteries that died after the 3rd day, even after running a generator for 2 hours each morning the prior 2 days. Does anyone know if there is something that is causing this, or is it just the weak 12v batteries? (by weak I mean low cca).
we don't have a 110v converter (fridge was running on gas), furnace was rarely used as were the lights. The original 12v batteries test good with a professional tester. Thanks for any input,
Jeff

[Cate&Rob]

jostby ,
Hi Jeff,

To start with, 3 days out of two 12V batteries with the usage you describe is very normal.

There are lots of possible paths and unknowns in this discussion. The condition of your batteries, the amount of power you are using, the rate of charge from your generator amongst others. A place to start is the capacity of your batteries. This is the Ah (amp hour) rating and is likely something around 120 Ah per battery. The CCA (cold cranking amps) rating is not particularly useful in figuring this out.

There are Ah meters that are great devices for monitoring what is going on. Something that you might want to consider.

Rob

[tgodrich]

Hi Jeff,

I have a 2016 303 RLS. I use two deep cycle batteries from Costco, but I do not run in parallel. I switch between them. They do pretty well long term, but I also have a generator I can run in the evening when dry camping. The heater is a pretty good current draw. Also, you have a lot of electronics these days that can slowly drain the batteries even with no heater or lights use. The fridge needs 12 volts for its electronics even when operating in gas mode. The radio uses a bit to keep the time. I am not sure on the inverter power center or leveling circuitry when not being used.
Best way to see your current draw is to connect an ammeter in series with the batteries and see what current is drawn while switching on certain items. You will also see how much current is drawn with everything "off". My experience is that the only sure off is to disconnect the battery + leads. To calculate current draw, you would simply look at the ammeter. 0.5 amps is 500 mA. 1 amp is 1000 mA, etc. Drawing this much current for an hour is 500 mA hours. If the battery is rated at 120 Amp-hour, you could theoretically draw 500 mA for 240 hours.
Even though you likely have LED lighting, it all adds up. LED lights are low current, but there is draw. If you are utilizing the rear camera on the 303RLS, be aware that the camera, as wired, is always on. I put a switch on mine I can shut off from the inside. Ping me if you want to know how to add a camera switch.
Now, some appliances (like the TV) may not rate the current draw, but instead rate the power usage in watts. You can calculate the amps by the formula Power (Watts) = amps X Volts. In the example above for 500 mA, power would be 500 mA X 12 Volts = 6 watts. Switching around, if you have an appliance rated at 60 watts; 60 watts divided by 12 volts = 5 amps. Simple as that.
Hope this helps. But I agree with Rob that 3 days out of two batteries, with some heater usage and water pump usage, is probably normal for these newer trailers with all their electronics.
Tony