Monday, April 17, 2017

Blah, Blah, Blah

I started the manual battery equalization on Saturday morning since it looked like we would be getting another fabulously, sunny day. The panel received enough sun, i.e. enough that the array voltage was higher than the target voltage for equalization (15.68volts @ 53°F). From the graph it looks like it took about 3½ hours to complete. You can tell by by looking at the battery voltage as it transitions from "BulkCharge" to "Equalization" and back to "Absorption". At Absorption, only enough current is sent to the battery to maintain the configured absorption voltage. In this case, 14.8volts@75°F which in this case translates to 15.15volts@55°F.

On Monday, I'll check the water level in all of the battery cells and start to disassemble the system. To say that I'm thrilled with the overall system would be an understatement. On the status pages, I colored the cell background to easily see the control state of the TriStar charge controller. This is the abbreviated page for display on the RPi. Green for Absorption or Float, yellow for Equalization, orange for BulkCharge, blue for Night and red for anything else such as errors.

At this point, the Trimetric monitor is indicating that I am 17.5amp-hours ahead of the fully charged state as a result of the equalization.

From this casual testing, it looks like I am getting about 40-50 amp hours from a 130 watt panel on a good day. This suggests that I might get around 150 amp-hours per day from the four 100 watt panels. The lower amp-hour days on the graph are when I wasn't really putting much of a load on the battery bank and it would reach absorption and/or float early in the day. This graph is made from storing a single data point (cumulative amp-hours produced) every day at 11:59pm. The numbers on the graph don't exactly match up and I am still trying to figure out why.

I was asked to make a line drawing of the solar setup. The line size indicates the size of the wire. Red is +12volts and black is ground. The curved lines are the small 22 awg for the shunt and sense wires for the Trimetric and the serial communications cable to the Raspberry Pi. What is not shown is the remote battery temperature sensor and the battery sense wires for the charge controller.

12 comments:

  1. I honestly don't have a clue what you're talking about, Richard, but it looks like you had your kind of fun ;-)

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    1. Yes, my kind of fun. All this was new to me. I've learned a lot about batteries and DC wiring from this. AC stuff also as I have an automatic transfer switch to install when I get to WA.

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    2. I'm with Sonja. And it is a perfect title to the post for those of un-tech types.

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  2. Thanks for the drawing Richard! I'm hoping to add the monitoring function to our RV's solar charging system to chart its performance before I make any changes. David

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    1. No problem. I've been wanting to make a diagram for quite a while but couldn't find a suitable app. I hear that monitoring needs to be the first step before doing anything. I'm just making my best guess especially regarding power consumption.

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  3. I'll be honest, Richard, I only skimmed this blog post (it ain't really my cup of tea), but... The post title made me laugh. :D :D :D At least you have a sense of humor about it. ;-)

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    1. This was a fun winter project. Learned some new things and it may prove to be useful.

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  4. Perfect title, and I am glad you are thrilled with the results! ๐Ÿ˜‰

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    1. The title was a natural after earlier comments… ;-)

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  5. Holy cow! I just get lost trying to navigate my email!

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    1. Email is much more confusing. All of those offers for free stuff...

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