What did I do now?

LastSupper · February 2013

Hi Ya'll!
I am new to solar and I'm am looking for someone to shed some light on my situation. Please don't scold me too harshly, but I bought two of the Harbor Frieght 45 watt kits just to get my feet wet. I recently hooked up all six panels to a hub with one output to my solar charger, and I have two batteries hooked up parallel. Now they way it usually works is during daylight hours I see fluctuating numbers on my solar charger readout depending on time of day, clouds going by and so fourth. At night I have just a steady readout as there is no light. I am assuming it is strictly telling me the battery voltage since there is no sun.

For the last several days, my solar chager is giving me a steady readout of 12.4 during daylight without any fluctuation. I unhooked all my connections and used a voltage meter and I am getting juice at all my connections. When I unhooked my battery, the readout on the solar charger jumped up to 13.5 and began fluctuating with the sunlight as I have been used to seeing. When I hooked the battery back up the readout went back to a steady 12.4.

I tested my battery with my voltage meter and it showed 10 volts, not 12.4. So have I fried my batteries???

Thanks for any insight.

westbranch · February 2013

Re: What did I do now?

Welcome. Are you powering any lights or ??

BB. · February 2013

Re: What did I do now?

It sounds like you started out with "deficit" charging. Basically, the loads (inverter, DC loads, etc.), on average, exceeded the ability of the solar array to recharge the battery bank every day.

So, over time, your batteries' average charge slow decreases until the batteries were taken "dead".

First thing to do is try to recharge the battery bank back to full (use an AC Battery charger). The faster get the batteries back to full charge, the better the chance you have of getting some more useful life out of them (the longer the spend discharged, the more they sulfate).

In the mean time, you need to look at the system design (6x34 watt panels?), size of battery bank 1x 12 volt * xx AH batteries?

Next, the load. Average wattage/Amp * how many hours per day.

That will give us an idea of how much energy you were drawing vs how much was replaced on an average day... For example, say you have 6x 45 watt panels, 4 hours of "noon time" sun per day, and 52% overall system efficiency:

6x 45 watts * 0.52 system eff * 4 hours = 562 Watt*Hours of AC power per average sun day

That means, for example, you could run a 50 watt load for ~11 hours per day, or a 200 watt load * 2.8 hours per day (all numbers are approximate).

Next, do you have flooded cell batteries or sealed (like AGM)? If you have flooded cell, you should get a hydrometer to measure the specific gravity of your battery cells.

While your batteries are charging, you should read a couple of battery FAQs:

http://www.windsun.com/Batteries/Battery_FAQ.htm
http://www.batteryfaq.org/

Next, you might want to look at some additional tools... They are optional, but depending on how deep you want to get into all of this, they can be very useful:

Kill-a-Watt type meter (used for measuring AC household loads for conservation work and solar power system planning)
DC Amp*Hour / Watt*Hour meter (handy for smaller system to measure loads/charging current and AH/WH. For a larger system, a battery monitor is the way to go
DC Current Clamp / DMM (very nice for debugging)
Battery Monitor (really for a full sized system)

You only need one or two of the above meters to start. Your volt meter can be useful, but is difficult to measure how much power your devices are using and the system is supplying.

-Bill

waynefromnscanada · February 2013

Re: What did I do now?

LastSupper wrote: »

during daylight hours I see fluctuating numbers on my solar charger readout depending on time of day, clouds going by and so fourth. At night I have just a steady readout as there is no light. I am assuming it is strictly telling me the battery voltage since there is no sun.

This sounds like the system was at least TRYING to operate properly. BTW any shading on any part of a panel will hugely reduce it's overall output.

LastSupper wrote: »

For the last several days, my solar charger is giving me a steady readout of 12.4 during daylight without any fluctuation. .

This could normally indicate there is no longer any energy arriving from the solar panels. Is there a fuse between the charge controller and the panels? Or a broken / disconnected wire?

Slappy · February 2013

Re: What did I do now?

The fluctuations is the controller turning on/off when Batteries are full. When steady it is trying to steadily charge the batteries. But two HF kits is only 90 Watts under perfect conditions in which is never done plus the inefficiency of any system. I have two kits my self. They are a cheap way to get your feet wet. But I just call them toys. But on those controller is you batter voltage.

LastSupper · February 2013

Re: What did I do now?

My panels are 15 watts each for a whopping 90 watt total.

The way I have been using the system thus far is once my solar charger shows 12.8 or so (at night) I will run a mini clothes washer for a small load of laundry. One cycle takes about an hour with the most power draw during the spin cycle of course. It will take my battery down to about 12.4 according to my solar charger readout after the cycle is complete. Then I will let the system charge for a couple days back up to a 12.8 or so (no sun readout). Then I will do another load usually in the daytime.

Bill Thank you for the helpful links. I have to be honest, the equations are Greek to me, but I know there is wisdom in there. I will do my homework. I have had my eye on a Kill-A-Watt but have not purchased one yet. So I have no idea what type of load I am placing on my bank yet, but I have tried not to be too hard on it. I did buy the Midnight battery monitor. I also took your advice and purchased an AC charger to get my bank back to full charge. The interesting thing is that the AC charger readout confirmed my solar charger readout (12.4 I believe it was) and the 70% readout the Midnight monitor was showing!

Wayne, I checked the fuse, and all connections and the juice is flowing right up to the terminals on the solar charger. After today’s test with the AC charger confirming all my readings, it almost seems as if my solar charger is deciding not to charge?? I switched out the solar charger with the one from my second kit and experienced the same phenomenon. I will be performing another wire connection test just to be sure.

Slappy, thanks for the input since you are using the same equipment. What you are saying about the steady readout is exactly what I am seeing. I did not think they were charging at all when the numbers stopped, but after a full day in the sun, I did manage a 0.2 gain. (maybe that's about right for 90 watts????) I thought I should be doing better than that since that was more like the gain I was getting when I only had three panels hooked up, but I guess it did indicate something was happening. Another full day would bring me back to the 12.8 I am used to seeing. What threw me for a loop and initiated this post was that I had sat at a 70% charge with no gain for several days. I did have some high wind during that time. I suppose I could have had a loose connection, and when I started pulling things apart and putting it back together, I could have overlooked that initially.

I welcome any thoughts on the added information and I will keep at it until I get it sorted out.

Thank you all again!

BB. · February 2013

Re: What did I do now?

I know the equations look like Greek... But it is (for the most part) just a series of multiplications. And the one "fudge" factor (0.52 derating) which, basically means that the wattage ratings of the panels, the losses in wiring/charge controller, AC Inverter losses, and the battery bank, only ~1/2 of the "solar panel's rating" gets to the AC load you are attempting to run.

I try to make the equations read like an English sentence so that you (the poster/reader) can substitute their exact setups (or planning a new installation) without having to come back to the forum and have a few people that hand out answer magically derived from "on high" based on some guesswork/unknown assumptions which may, or may not, work for the reader.

-Bill

Slappy · February 2013

Re: What did I do now?

Ok. You have two batteries hook in parallel. What amp/hr are they. And are they deep cycle/or starting Batteries. This will help to get an better answer.

LastSupper · February 2013

Re: What did I do now?

Slappy wrote: »

Ok. You have two batteries hook in parallel. What amp/hr are they. And are they deep cycle/or starting Batteries. This will help to get an better answer.

Oh yes, the batteries! Sorry.
They are Kirkland Deep Cycle /Marine 750 MCA - 115 Amp Hrs
They have the pop off lids on the top. (does that mean they are the "flooded" type?)

One thing I failed to mention was the .02 gain I made was on one battery as I have disconnected stuff trying to figure out what is going on. So something still doesn't seem right.

I am going to the get the proper equipment in order to flesh out the equation shared by Bill. I know this will answer some important questions for me too. I did purchase a Hydrometer and I will get a better meter reader later today. A Kill-A-Watt will be on its way soon too.

BB. · February 2013

Re: What did I do now?

Yes, those are flooded cell if you can open them up and see electrolyte (liquid) inside.

Marine Batteries are not (usually) true deep cycle, so they will not last as long if deep cycled (25-50%+ cycling).

I am not sure what you mean by 0.02 increase--Batteries voltage will float up (or down) a bit over time and temperature and how recent the loads/charging currents were.

-Bill

Photowhit · February 2013

Re: What did I do now?

LastSupper wrote: »

I unhooked all my connections and used a voltage meter and I am getting juice at all my connections. When I unhooked my battery, the readout on the solar charger jumped up to 13.5 and began fluctuating with the sunlight as I have been used to seeing. When I hooked the battery back up the readout went back to a steady 12.4.

I tested my battery with my voltage meter and it showed 10 volts, not 12.4. So have I fried my batteries??? .

I'm not sure your 'seeing' very good numbers here. To be clear, with out any batteries connected your seeing 13.5 volts at the battery connection?

I would check each panel individually to see what output your getting, before the charge controller, you should see around 17 volts. If you have less than this on any single panel I would disconnect that panel! (and if you purchased recently return it as defective) How far is your array from the batteries? How is it connected?

While charging you should be able to test the battery voltage, when above 80% full you should see between 13.8 and 14.5 volts.

With maybe 200watthours of electric to play with likely even a table top 'egg' washer would be too much, motors are usually pretty high wattage, while it doesn't run continually if you have a wattage number for it, usually near where the cord connects, it might help understand the load.

What did I do now?

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