more power

wvw325

I have been boondocking many times using a 12v, 101 amps per hour RV deep cycle battery that I am charging with a Renogy 100 watt solar panel. I start the night with a charged battery and I am only running the fantastic fan (on the lowest setting) during the night for approximately 8 hours and the battery is discharged to 12 or below. Is anyone else having this kind of performance? Any suggestion on how to improve performance?

wvw325

I should have also mentioned that I own a 2018 TAB 320 CS.

Dutch061

Several things to consider:

1. Dometic offers an upgrade kit to your fan that will lower the amperage draw and add remote control etc. that is cost effective and you don't disturb the sealing of the existing fan to the roof. In my experience there are 2 potential styles of motors in the these fans. One is small in diameter and long (3" +/-) like a soup can and the other is large in diameter and very short (1.5" +/-). The difference is whether or not the motor has brushes (old school - long housing) or is brush-less (newer technology - short housing). The newer style naturally is more efficient in all aspects and s much quieter in operation. I have had booth and have installed the upgrade with both and can assure you that the brush-less is more efficient and quiet  than the brush type any day.

2. I am not sure what your 320 CS has for a refrigerator, but if it runs on 12 volts, that is certainly a large part of the battery usage.

3. You can always change the batteries from a single 12 volt to 2 x 6 volts and gain in Amp Hours. If you have the budget, a single Lithium Ion will easily double the capacity. However, Lithium Ion has additional things that need to be done to make it a successful installation.

4. Adding a Victron Smart Shunt (with or without a gauge) will allow you to better monitor your battery state of charge and usage than watching a volt meter. 

5. Increase the size of the solar panel - You would really need to know if in fact this 100 Watt is actually fully charging the battery (IE Smart Shunt or similar).

Hope this helps a bit.

Brad

pthomas745

What are  you using to measure your battery?  The numbers after 12 on your state of charge are extremely important.....so your reading is 12. what?  Are you trying to see your state of charge while the fan is running and the lights are on, etc?  Any battery that is being used will show you a lower state of charge than it really is.

The fan on low uses about 1 amp per hour.  The trailer by itself will use about 4 amps per day on "parasitic drain."  So, 10 hours of overnight use of your fan would use 10 amp hours, and the trailer maybe 3.  So, 13 of your 50 available amp hours of your battery.

The fridge, as Dutch says, is the real question.  A two way fridge would be the difference maker.

Here is a state of charge chart. Note that they all start with "12".  The numbers after the decimal point tell the story:

wvw325

Thanks for the responses. I will investigate the fan upgrade. I am using the the gauge in the TAB 320 and the gauge on the controller for the solar panels to measure battery usage. The reading in the morning is typically 12.0 to 11.8, which is low as I let it go before recharging. I am checking gauge without the fan or anything else running. I also have the radio fuse pulled to conserve battery usage and I have the fridge turned off. I have confirmed the the fan usage and parasitic usage numbers you quoted with Nucamp. Seems like I have something else going on based upon the usage numbers.

BrianZ

@wvw325, what is the voltage reading of the battery after charging/in the evening after dark & before using battery power?

Marceline

wvw325 said:

Thanks for the responses. I will investigate the fan upgrade. I am using the the gauge in the TAB 320 and the gauge on the controller for the solar panels to measure battery usage. The reading in the morning is typically 12.0 to 11.8, which is low as I let it go before recharging. I am checking gauge without the fan or anything else running. I also have the radio fuse pulled to conserve battery usage and I have the fridge turned off. I have confirmed the the fan usage and parasitic usage numbers you quoted with Nucamp. Seems like I have something else going on based upon the usage numbers.

Just to clarify - are you running the 2way fridge off battery power or not? The fridge consumes about 3ah while running. How is your solar panel doing? Is it keeping up with the depletion so you start each evening with a full charge on the battery?
If you've been letting your battery run down to 12.0 to 11.8 you've been pretty hard on your battery and you may have shortened its lifespan. 

wvw325

We have the fridge turned off and not using. I assume the fridge does not use any battery if turned off? We also are not using any other power during the day. Recently I have been charging the battery in the morning, that being the best sun time but I have not checked the gauge reading before going to bed to see how much battery has drained with no usage.

pthomas745

Sounds like your battery may be failing. Have it checked out would be my next step.

Marceline

wvw325 said:

We have the fridge turned off and not using. I assume the fridge does not use any battery if turned off? We also are not using any other power during the day. Recently I have been charging the battery in the morning, that being the best sun time but I have not checked the gauge reading before going to bed to see how much battery has drained with no usage.

In your first post you said "I start the night with a charged battery." How exactly are you assessing your battery's state of charge? How do you know that the battery is fully charged? When you say "I have been charging the battery in the morning" do you mean that you're not letting your solar panel charge the battery all day? Even on the lowest setting the 3speed fan consumes a fair amount of power and unlike the fridge, it's using that power continuously. If you've been frequently drawing your battery down as low 11.8 I would start by taking your battery somewhere to have it tested. It might not be holding a full charge anymore. 

If you want to run the fan all night, you might consider tackling the mod described in this thread: https://tab-rv.vanillacommunity.com/discussion/comment/140981/#Comment_140981

At low speeds the variable speed motor draws much less power.