Thursday, July 12, 2018

Memory Effect?

I recall reading somewhere that batteries have a memory effect. I’ve also recently read that lead-acid batteries should be left to sit for 12 - 24 hours before the voltage can be properly measured. What that means in terms of my battery problems, I’m not sure but I’m willing to try anything as long as it’s free.

After dark I wandered to the back of the bus and checked my watt meter. I’d flipped the power earlier today to reset the watt meter. Already in the maybe 4 hours since then it had racked up 0.3wh of power usage. Now that is the actual watt meter, the broken fuse sensors and the rechargeable fan timer. Nothing else is switched on. 0.3 watt hours isn’t going to kill anybody but I switched the load off in order to let the battery settle. At that point (9.06pm) and it had been dark for about an hour, the voltage read 13.14v.

Tomorrow the plan is to return to turn the battery back on some time after midday. The system will have had about 18 hours to “settle”. Then I shall be interested to see what the voltage reads. Earlier when I checked I was seeing about 14 volts and when I put my battery tester on, the battery was reading full. I think somehow the meter was being misled.
You probably can’t see but I also turned the solar power off. That’s the brown circular switch. That’s so that when I turn the battery back on (big orange switch), the meters etc will not be misled by the sudden influx of 95 watts of power.

Also in the picture you can see I perched my other charge controller on top of my working charge controller. The top one is one of those black $10 charge controllers with a digital diaplay. There are tons of them around for prices ranging from $10 to $200 on Amazon and eBay, frequently misidentified as MPPT controllers whereas in fact they’re PWM. The digital controller has the distinction of being the only controller I’ve ever used that experienced regular software crashes. Ideally a controller would have no software but would work off straightforward bug free electrical circuits.

Oddly enough I grew up loving computers and studied to become a computer programmer. Well I passed all the exams and never could find work as a programmer despite being very good at it and selling shareware that I’d written online. Now the point of that is that I know there’s no software ever written that does not have bugs. This is why I like things that don’t have computers aboard. My bus has no computers. I’d love my charge controller to be computer free too.
In this picture you can see the timer. It’s one of those programmable timers from China. It’s way too fancy for my liking with too many settings but it works. I have the fan set for automatic on-off periods. Given that I’m experiencing issues, I’m not able to use it on timer right now. I’m having to use manual mode which bizarrely neeeds the keypad to be unlocked every time by poking the bottom left button 4 times in quick succession. Needless to say it’s Chinese and probably some Chinese fellow’s idea of a good time.

With the current battery state, the fan left on automatic will just drain the battery, using the current setup. With the digital charge controller, each time the fan comes on, the charge controller will just crash.
This picture shows some 1 microfarad capacitors. I had one spare small Mylar capacitor and put it across the fan motor and reduced crashes from the digital charge controller considerably. I didn’t eliminate them though so I got a bigger set of capacitors. It will be very interesting to see what effect if any, using these willl have. I should not, or course, be having to put capacitors. The charge controller should just work but who knows what was going through the Chinaman’s head when he designed this. If the 18th and 19th century are anything to go by, I would not be surprised if the drafting pen wasn’t right beside an opium pipe.
With the power off for the moment I resorted to my older lighting method. These lanterns are not the best in the world but you can just about see to do things with them. They’re in no way comfortable for reading but they do provide light to see. I even have a shower pump powered by 4 D cells. My original plan had been not to have any native electrical power. I’d figured I could run lighting off D cells and the shower too. I even got a solar D cell charger. Heaven knows how many days it would cost to charge a pair of D cells. I even managed to get some but never managed to get any more of the same capacity. Then I went for a 12v system anyway.

So tomorrow will be interesting. With the battery having rested for 18 hours I will be able to measure it. Of course it might be worth leaving it the full 24 hours to see what difference that makes. I’m in no great hurry.

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