FWC Dual battery charge

[rustyshackleford55]

Hey everyone, I have 2 deep cycle batteries (new) from FWC that I'm finding loses charge after 3 nights.

I'm running a 2 way fridge, furnace at night, charging phones, some fan usage, some lights, etc.

Is this normal for 2 batteries to lose charge after 2-3 nights with that usage?

Would the 160watt or 120watt portable be good options to extend the charge of the batteries?

Does the roof mounted 160watt charge the batteries while driving? I'd hate to park in the sun just to charge the batteries.

 

[Cayuse]

Without knowing all the specifics it's hard to say for sure. What is the total Ah for your system? Before I put solar on my roof I was running 2 Group 31 deep cycle batteries for a total of 210Ah and figured 2-3 nights without recharging with usage similar to yours. That was during the summer in the PNW with an Isotherm Cruise 65 fridge.

After that first summer I put 2x100W solar panels on the roof and have been pretty happy ever since.

 

[PaulT]

Hey everyone, I have 2 deep cycle batteries (new) from FWC that I'm finding loses charge after 3 nights.
I'm running a 2 way fridge, furnace at night, charging phones, some fan usage, some lights, etc.
Is this normal for 2 batteries to lose charge after 2-3 nights with that usage?
Would the 160watt or 120watt portable be good options to extend the charge of the batteries?
Does the roof mounted 160watt charge the batteries while driving? I'd hate to park in the sun just to charge the batteries.

The batteries are not “losing charge”. The fridge, mostly, is consuming the charge along with the other uses. Add up how long the fridge runs times it’s current draw to compute the total amp-hours you need to replace daily. For example, my Dometic fridge draws about 4.5 amps and if it runs for 10 hours/day, that is 45 amp hours per day. My factory batteries total 150 amp-hrs. Should use only 50% of charge to not shorten battery life, so that 75 amps is less than two days use between charges.
160 Watts / 14 volts is about 11 amps in full sun. 45 amp-hrs / 11 amps is about 4 hours of full sun while directly overhead. You won’t get 4 hrs full sun overhead so adding more solar can make up the difference as can power from the truck while moving.
Yes, the solar panel charges the batteries while moving.
Keep in mind if you have the older battery separator rather than the newer BlueSea ACR that your truck won’t be able to charge the camper batteries after they drop below the critical voltage. You will then need to plug into shore power or wait for solar to partially charge them first.
There are several complicating factors in managing camper state of charge and why many have installed a battery monitor like the Victron or Trimetric units to really know what’s going on.
I added a 160watt panel to the 100 watt unit on my 2014 Hawk and there are still times in the PNW where I have used a campground with electrical hookup for a night to fully recharge the batteries.

Paul

 

[rustyshackleford55]

Thanks Paul for detailed response. I run the fridge 24 hours a day, do you recommend turning off at night?

I'm in Colorado we get a lot of sun, I was hoping the 120watt portable unit would extend our trips a few nights

 

[Vic Harder]

Rusty, do you have solar on the roof now? a 120W portable will extend your camping time without charging, for sure. How much depends on the factors Paul and Cayuse were calculating above.

I have 220AH of battery, and 265W on the roof. The fridge is on full time when the camper is parked in front of my house, and the batteries are always fully charged by end of day.

 

[rustyshackleford55]

Are you using a 3 way or 2 way fridge Vic? I don't have any solar now, I was considering the 120w portable panel. I've heard a roof mounted system adds weight to the roof and is difficult to position for maximum sun angle

 

[Vic Harder]

2 way fridge. Solar on the roof works "good enough". I also have 200W of portable panels, but I have yet to use them. They will come in handy when camping in heavily treed areas.

 

[ckent323]

Rustyshackleford,

I suggest first figuring out how much current you are drawing per day on a typical or average camping day (for example there will be seasonal high and low days due to temperature). You could make a worst case and best case calculation and then pick the mid point.

Once you know the current draw you can determine how long you can reasonably go between FULL recharges of your house battery.

You will need to know your battery type and capacity in amp hours. For example do you have a standard 12v battery , a 12V marine battery or perhaps a 12v true deep cycle battery or even two 6v true deep cycle batteries?

The type of battery will dictate how much of the capacity you can use on a regular basis before you significantly shorten the battery life.

If it is inconvenient to connect to shore power or turn on the truck you can evaluate adding solar to extend the charge time of the battery.

You could add a deployable panel if you do not want the extra weight on the camper roof.

Look at the second post in this thread for an amps per day spreadsheet to calculate your usage.

http://www.wanderthewest.com/forum/topic/3887-ultimate-solar-thread/


You can find a lot of battery info here:

http://www.wanderthewest.com/forum/topic/15574-ultimate-battery-thread/


Regards,
Craig

 

[rustyshackleford55]

Thanks Craig, the batteries are the stock ones included with a new FWC purchase, I'm assuming 2 marine batteries. I'll have to take a look, thanks for the links!

 

[smlobx]

Thanks Paul for detailed response. I run the fridge 24 hours a day, do you recommend turning off at night?

....

I believe what Paul was referring to was the actual amount of time that the fridge compressor is running. Under "normal" fridge operations it does not run continuously. It may run 15-30 minutes per hour or so depending on a lot of factors like the temperature set, the amount of food in the fridge, how often you open the door, the outdoor temperature and if the side of the camper that your fridge is on is exposed to direct sunlight...