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9 HF Panels
On the next day that it is not 40 degrees and raining, I am going to build a frame to mount on the roof. It is doing "OK" but it is sitting at about an angle of 19 just laying on the existing slant of the roof, when it should be at 39. Hopefully, that will be it's optimal setting. It is taking about 2 to 2 and a half days to recharge and that is on very very cloudy and rainy days. We haven't had a full sun day since I have put the 6 new panels in, so I am not sure exactly how much power I will be generating. Wish me good luck all.
I have tried out some of our usage and I am running a heater, a fan, a TV and some lights and I am calculating that I will get about 10 hours running at that rate. I have already ran almost 5 hours and have gone from 12.5 to 12.0 (meter flashing between 12.0 and 12.1 right now) on my battery bank voltage. The 30 amp charge controller I am using is supposed to shut down when the power gets too low, so I am monitoring how long we will be able to run in an emergency situation with the same loads that we are testing with. We figure that would be a safe "constant or continuous" load that we would use if the power was out. Once we have the baseline of the continuous run, I will start to play around with miscellaneous usage that are short in duration but high on wattage, at least in spurts (i.e. refrigerator, microwave, etc...). So during the day we are charging up the batteries, We have a generator and if we need to, we can run the freezer and/or refrigerator by generator on days and in the evenings and weekends, we can use the battery banks/inverters. Just know that we will continue to tweak the system and find the best level. While I was typing, I had to go out and tend to the battery. The inverter started alarming after 6 hours and I looked and saw that the meter was reading 11.9. I shut off the load and the meter went back up to 12.0 and the alarm was silenced. I am guessing that 11.9 is the lowest that I will be allowed to run. I thought 11.5 was the bottom. Anyway, I am still calculating and will keep everybody updated in case you have interest in what I find. Of course of I am doing anything wrong or if anyone has knowledge or advice to share , it is always welcome.
Thanks for posting Mike. And testing or not, don't get in the habit of visiting 11.9 on a regular basis unless you are willing to sacrifice the battery to the test. You'll get years of service out of your batteries if you can keep the cycle moving back and forth between 12.7 to the 14+ range.
Thanks Ray. Help me understand something if you can. The only thing that I have to monitor the battery level is the sunforce 30 amp charge controller. During the day, when the sun is shining bright, I see the reading on the controller go to 13.9 to 14.5 regularly, but as the sun goes back down, it drops to anywhere from 13 4 to 12.7. That is with nothing pulling from the battery bank. Is there something else that I should be using to monitor the battery? The readout on the controller is always swinging, increasing when the sun shines brighter and dropping when the sun goes behind a cloud. Should I be using a special meter to read the battery condition and monitor the battery condition as it is used? If the controller reads 13.4 during the day, it will be 12.9 or 12.7 at sundown. Then when I start using the power, it will slowly go down. Is that how do read your battery strength? I dont know that I have ever had the batteries read 14 at the end of the day, only in bright sunlight.
In fact, when I started using the battery tonight, it was reading (swinging between) 12.7 to 12.5, before it started going down. When it charged, the charge controller quit charging and said that it was completely charged, but it was at 12.5 by that evening
A couple of things, sounds like the batteries are still healthy and reaching a float charge as they jump back and forth between 13.9 and 14.5. Then settles to a normal charge as the sun goes down. Keep in mind that most people consider a fully charged battery to be 12.7 volts. 12.5? Don't make to much of that, these controllers aren't going to be exact. Sounds like it's working great, just watch that low end like I said earlier. Maybe just keep that heater offline a bit [I personally would take it out of the mix], that has to be your killer when it comes to power draw.
Thanks Ray. That was actually the first time I had drawn off of them. So 12.7 should be the lowest I drain it down? SO you would use the meter from the charge controller to read the battery? I will have to notice again as soon as the batteries are completely charged, when the charge controller shuts off what exactly the meter reads. I did wait a couple of days before I put a load to test everything. If it is only 12.7 in the evening, then I won't have much room to run a load on the batteries. It could be something that is putting a drain on the system if it is running down before I use it. I will check into that and post for everyone.
BTW, I only used the heater to try and put a large load on the system. It really sounds like everything is fine with the charging side of the system. Thanks for the advice.
I would check voltage directly at the batteries with a volt meter?
12.7? No, you can safely go to 11.9 - 12 volts. Personally I don't like cycling that low EVERY night, but it is considered safe. For me the "dollar equation" in all of this has always been about battery life.
I have 3 or 4 of these on my bench and I have one hard wired into my system that reads Volts / Amps coming in from the array before it gets to the Charge controller. They are about 5 bucks at HF. They have one for a few dollars more that has a back light feature also.
Hey Mike, as a personal rule I try to not discharge my battery bank below 50% if at all possible. The deeper the discharge the shorter life span you can expect from your batteries. Here is a chart that might help. If these are flood acid batteries you nee to check there specific gravity with a hydrometer and add distilled water when needed.
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