I didn’t post about this latest battery observation on Monday because I wanted to repeat the experience, which I did tonight.
When I shut down for the night on Sunday, my battery voltage was very low, about 12.3 when I was only down a few amps. I had left my computer plugged in all day, but it draws only about an amp when it’s fully charged rather than 4 or 5 to charge it, so I’ve decided to sacrifice the laptop battery for the sake of the house batteries.So, really, I should have been sitting at 12.55V once everything was off and the computer unplugged.
When I got up up the next morning, voltage was about 12.45V, much better than the night before but still not right. I ran the engine for all of five minutes. An hour after shutting down the engine, voltage had stabilized to 12.57V. It’s almost like the computer exhausted the batteries and they needed a little boost.
Similar situation tonight, except that when I unplugged the computer to see where I was at voltage-wise, it was 11.99V!!!!! Even though I knew that was not a true reflection of my amp hour capacity, I couldn’t spend the night with that little voltage! I ran the engine for five minutes and now voltage is holding steady at 12.5V, even with the computer plugged in and a light on.
I’m sure some of my experts have been chomping at the bit to jump back into the electrical theories arena, so have at it! 🙂
And for those who have heard enough about my batteries to last a lifetime, I do apologize. 😉
There is a casino, East of Oklahoma City that you can stay for free for three nights. You will need to get a players card before you go to the gift shop to register. It’s called Firelake Grand Casino in Shawnee, Ok. Maybe 25 miles East of Oklahoma City. Google it and that will give you directions. I have seen people stay longer than three days. Have you tried casinocamper.com to find casinos you can boondock at? If you need other info, let me know.
Thanks for that, Bill. And, yes I use Casino Camper. Love that site!
Us nerds that are attracted to your Blog will not easily tire of technical stuff so don’t fret.
As you know, we are rarely “off the grid” so I do not spend a lot of time thinking about stuff like this but this morning as I read your Blog I wondered what my HP laptop drew. I unplugged it and when it was down to 15% battery left, I plugged it into the inverter, It is drawing 106 watts of power, or about 8.0 amps. Before I plugged the computer in my batteries were at 13.8 volts and plugging in brought them down to 13.3 volts (I am however, plugged in so it is probably a worthless comparison).
What has the sunlight been like at where you are in the last couple of days?
It is good to know that running the engine for even a few minutes will bring the batteries up to a workable level when they are that low.
No sun to speak of the last few days. I’ve been holding steady at about 15A down when I got to bed (94% battery capacity). I don’t care about the voltage displays when the computer is plugged in because we’ve already established that I have a huge voltage drop due to inadequate wiring. My issue is that once everything is off and the batteries have had a chance to rest, my voltage does not reflect the amp hours available to me.
So batteries are not truly low and I’m not concerned about using power when I’m seeing 12.2V on the monitor because I know that I’m at 95%, not 60%, capacity. But if I want to do anything that’s power hungry in this situation, I need to run the engine for a bit to boost the voltage back up to it’s correct amount. Doing so does not give me an more battery capacity; I’m lucky to get 0.1AH back in that short amount of time.
So again, it’s a question of having an adequate water supply but not enough pressure.
Anyway, not a big deal beyond the fact that I am seeing the gas in the motorhome go down now and I need to start rationing myself unless I want to run out to the gas station and back to fill up before I leave!
Your inverter is installed close to your batteries already right? That should have controlled the voltage drop. Or is your computer plugged into a 12 volt outlet with a longish cable? Sorry, I cannot remember.
The inverter is not a factor in this equation as the computer is plugged directly into the DC circuit.
Let me try to rephrase my observation. I’ve noticed that when I leave the computer plugged in for a long time, it brings about, after the batteries have rested, a voltage reading that does not match the amp hours used and that a short burst of incoming charge is enough to reset the voltage to its expected level.
I’m not concerned about the voltage drop while I’m plugged in or right after I’ve unplugged, but rather that 12 hours later of the batteries resting, I’m still a whole two or even three points below what my voltage should be based on my amp hour capacity remaining.
Here’s a voltage at rest compared to battery capacity chart:
If I wake up to my batteries being at 95% according to my battery monitor, I should be seeing 12.48 to 12.5V in the morning, not 12.2V! And this is another reason why a battery monitor is so important. If I didn’t have it, I would think that my batteries were hopelessly depleted when they are not.
Mac, who runs Casino Camper, loves feedback on his casino listings. Feedback, updates and new listings all find their way to his website.
I used to send updates/reviews until I noticed that they were not getting posted. 🙁
Ah, I have not sent one for a year or so.
I love Firelake Grand Casino! They had free ice cream and hot chocolate the last time I was there. They also had a Subway in the corner we ate at.
Croft, I actually wonder if the site is still being maintained.
Caroline, free ice cream?! 😀
Mac, who runs Casino Camper, is the same Mac who fights with me over guns on Facebook. Nice guy but a little hung up on the Second Amendment so I have fun with him.