While I do watch the voltage on the starting battery when I camp 🔋 it’s nice to know that solar panel is dumping excess charge into the starting battery ensuring that I can camp multiple days despite opening and closing the doors, using the dome light and other features, and it’s all automatic.
Solar Project
Finally changed the set point on the low voltage disconnect to address greater voltage drop on the accessory battery from the cold
Finally changed the set point on the low voltage disconnect to address greater voltage drop on the accessory battery from the cold. 🔋
It was so easy to do, beats having to either start the truck or hit the reset switch constantly in the cold.
Now I don’t like to abuse my batteries but disconnecting a load at 11.9 volts in the cold rather than 12.1 volts in the summer isn’t the biggest thing ever. Probably it’s still about the same level of discharge as the summer.
It’s easy enough to change that after I’m done winter camping this week I’ll reset it to 12.1 volts. I’ll have to keep this in mind for the future.
God’s alternator is working hard today
God’s alternator is working hard today … 🔋
Cold but sunny! No starting problems for me today when I go out later.
Wednesday, when I last went out to check the truck and knock the snow off it, the accessory battery bank was at 12.4 volts and starting battery at 12.3 volts. It was pretty cold, it was 3 days since I ran the truck, I had the lights on a while while I unpacked my truck on Sunday evening.
Today, with the sun and power flowing from the solar panel, the accessory batteries are at 14.3 volts and the starting battery at 12.8 volts. It looks like starting battery is taking a little longer to charge, but that’s normal as the system is set to charge the accessory batteries first, then once the voltage in system is above 14.1 volts to dump the excess power into the staring battery.
Solar Charger Scam
While lithium batteries are fairly good, I can tell you an advertisement for an 80,000 mAh USB battery bank is a scam. 80 amp hours even at just 5 volts, is 2/5th of a kilowatt hour — which is a lot of electricity to store in a little battery.
The 50 lb lead acid batteries in my truck — each only have about 50 amp hours of usable capacity (to be fair, at 12 volts). Trust me, you’re not going to take a 50 lb battery to the beach to charge your cellphone.
What are they doing to make this claim?
1) First off they’re measuring amp hours at the nominal voltage of the lithium ion batteries at 3.6 volts, ignoring losses in the boost converter, and that 1 amp at 3.6 volts is only 0.72 amp at 5 volts. But discount by the 80% with loses in the boost converter, so you are at .57 amp at 5 volts.
2) A really good 18650 cell — like a pricey one used in an electric car or high end laptop might have 3.5 amp-hour capacity. So the best case scenario if there is three really good 18650 cells in this unit, it could put out 10.5 amp hours or 10,500 mAh if your interested in inflating numbers.
3) But with loses in the boost converter, and the fact that when you increase voltage you decrease amperage, your talking about 5.98 amp hour or 5,980 mA hour if you want to sound impressive. But I doubt the Chinese cheapout 18650 cells in this put anywhere near that capacity.
So yes, these solar chargers are a scam. The solar cells themselves put out maybe 20 – 30 mAh of capacity, so don’t expect much charging unless you have days in the direct sun.
Working out of my truck has me
Working out of my truck has me …
- Really notice how much wildlife there is out there and the many patterns of the clouds.
- Pay much more attention to the weather, notice the impacts of clouds and sun on solar panel and electricity production.
- Be aware of how much energy my little 100 watt panel can actually produce on a nice day.
I am watching the voltage start to sag a bit in my truck, but I have good faith that I’ll make it to five o’clock
I am watching the voltage start to sag a bit in my truck, but I have good faith that I’ll make it to five o’clock. The sun angle is declining now that it’s almost four o’clock and the skies have clouded up. But my battery bank is full and my laptop is fully charged, so I think I won’t go dark for another hour. #trucklife