Batteries and Cold Weather

[nighthawk87]

My cheap cigarette lighter volt meter shows 11.9 volts early in the morning, but the battery meter on the trailers info gauges shows 2/3. Which is correct. It’s about 38-40 outside and I’m wondering if that’s why the voltage shows lower?

Also, is cold weather something that just makes the voltage shows less or is it actually less. For example. If I start with a 70% charged battery and it drops to 30 degrees does that mean my batteries now dead without any use?


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[nighthawk87]

Also, with two 6V 240 amp hr batteries shouldn’t I end up being above 11.9 volts when starting at 12.5 the night before? Usually run from 7-7 without generator. Batteries are brand new. It’s 38 outside at night and I keep the trailer at 65


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[Dave55]

Originally Posted by nighthawk87

My cheap cigarette lighter volt meter shows 11.9 volts early in the morning, but the battery meter on the trailers info gauges shows 2/3. Which is correct. It’s about 38-40 outside and I’m wondering if that’s why the voltage shows lower?

Also, is cold weather something that just makes the voltage shows less or is it actually less. For example. If I start with a 70% charged battery and it drops to 30 degrees does that mean my batteries now dead without any use?


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Time to start charging your batteries. Use a good digital volt meter at the battery terminals to get an accurate reading.

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[Mustang65]

Originally Posted by nighthawk87

My cheap cigarette lighter volt meter shows 11.9 volts early in the morning, but the battery meter on the trailers info gauges shows 2/3. Which is correct. It’s about 38-40 outside and I’m wondering if that’s why the voltage shows lower?

Also, is cold weather something that just makes the voltage shows less or is it actually less. For example. If I start with a 70% charged battery and it drops to 30 degrees does that mean my batteries now dead without any use?

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The heating system fan is your biggest load. Your battery will discharge a lot faster if the heating system runs a lot. Just saying you keep it at 65 degrees really does not say much, but when you add that the outside temperature is around 40, that means your heating system will have to keep cycling overnight.

Question is what do you have plugged in at night?
Do you have any electronics plugged in? Tablet charging, cell phone, lights? LED's or regular bulbs? Batteries water level?

How log are you charging your batteries? Usually you will only recharge your batteries to the 90% level using a generator each day. When you mention that you are starting the night at 12.6 means that you have already used some of your power, or they are not being charged enough. Normally my nights start with a battery voltage right around 12.9VDC.

So, either you are not putting enough charge back into the batteries or the heating system is just cycling a lot to keep it warm. Try running the generator an hour longer.

Those "Idiot Lights" that come with the units are useless. As mentioned, the best place to get a voltage reading is right at the batteries.

Don

My Registry

RVing with SOLAR

[GrumpyDad]

Cold weather reduces battery performance, and your furnace overnight can draw an awful lot of power from the batteries. It's a double - whammy camping in cooler weather. Actually triple because in winter we all spend more time inside and use more lights too.

Hard to say if your batteries are in good shape unless you start with them fully charged.

[nighthawk87]

Originally Posted by Mustang65

The heating system fan is your biggest load. Your battery will discharge a lot faster if the heating system runs a lot. Just saying you keep it at 65 degrees really does not say much, but when you add that the outside temperature is around 40, that means your heating system will have to keep cycling overnight.

Question is what do you have plugged in at night?
Do you have any electronics plugged in? Tablet charging, cell phone, lights? LED's or regular bulbs? Batteries water level?

How log are you charging your batteries? Usually you will only recharge your batteries to the 90% level using a generator each day. When you mention that you are starting the night at 12.6 means that you have already used some of your power, or they are not being charged enough. Normally my nights start with a battery voltage right around 12.9VDC.

So, either you are not putting enough charge back into the batteries or the heating system is just cycling a lot to keep it warm. Try running the generator an hour longer.

Those "Idiot Lights" that come with the units are useless. As mentioned, the best place to get a voltage reading is right at the batteries.

Don

My Registry

RVing with SOLAR

Thanks, Don. I only have one led light on al night in the bathroom for the kids. Other than that, just the gas water heater and gas fridge. I have/had a WFCO 8955 converter. I literally just replaced it an hour ago with a Progressive Dynamics pd4655L MBA converter with charge wizard. Now in bulk mode my cigarette lighter states 14.2 volts and the batteries show 13.67. In regular mode batteries show 12.62 and the cigarette lighter shows 13.2. I’m guessing I have some voltage loss from the converter to the batteries. We’ll see if that helps on the next trip to get me up to charges faster.

Quick question...any idea on how I’d know when my batteries on done charging using my generator? Obviously I can’t use the voltage to see since I’ll be charging at 14.4. Hopefully I didn’t screw up getting a better converter first instead of solar. Wonder if solar would have worked just as good.


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[SkyBound]

I *think* that when you reach your 90% charge target, the voltage drops from 14.4 (boost) down to 13.7 (normal) indicating that you've hit that threshold. I have the same PD converter upgrade and Trojan 6Vs but this will be my first season with a generator to charge them back up, so I'm learning too.

[curver900]

Originally Posted by SkyBound

I *think* that when you reach your 90% charge target, the voltage drops from 14.4 (boost) down to 13.7 (normal) indicating that you've hit that threshold. I have the same PD converter upgrade and Trojan 6Vs but this will be my first season with a generator to charge them back up, so I'm learning too.

correct... the voltage drops as they reach certain criteria...

[GrumpyDad]

Originally Posted by nighthawk87

Now in bulk mode my cigarette lighter states 14.2 volts and the batteries show 13.67. In regular mode batteries show 12.62 and the cigarette lighter shows 13.2. I’m guessing I have some voltage loss from the converter to the batteries. We’ll see if that helps on the next trip to get me up to charges faster.

Does that seem like a HUGE voltage difference to anyone else? I'd expect like 0.1V . Am I out to lunch on this? I haven't measured mine ever, but the converter can't charge the batteries properly when it can't get the voltage to them.

Everyone would freak out if their converter was putting out 0.6V less than optimal.