Efficiency issue or...????
- Thread starter SHTF Power Anyway
- Start date
SHTF Power Anyway
Power Pig
Actually, I kind of figured that but didn't know how to calculate it. Thank you for responding.
SHTF Power Anyway
Power Pig
This is how I calculated:
1/10 8:50 am figure for battery charge level was 69% x 54 kwh (my total battery bank capacity) = 37.3 kwh
Harvest was: 18 kwh between 8:50 and sundown around 4:45 pm
Without figuring any loss of power for running the Sol-Ark's or batteries the ending total would have been 55.3
I know I have at least the loss of 2.5% to the Sol-Ark's figuring an efficiency of 97.5% so 97.5% x 18kwh = 17.6kwh net harvest from 9 am to 5 pm
My battery bank (before figuring loss to battery power requirements) should be 37.3 kwh beginning + 17.6 net harvest = 54.9 which would have more than filled my battery bank by nearly a kwh. I check my system several times a day because I'm home. It never came close to 90%.
My battery status at 5:37 pm showed a battery charge level at 88% x 54 kwh (my total battery bank capacity) = 47.5
The difference between 54.9 (net harvest) and actual battery level at 5:37 of 47.5 is essentially 7 kwh.
My original question was asking if it could possibly be that the 10 batteries consumed 7 kwh to run. I should have been a bit more specific because those 7 kwh were lost during the 8 hours and 46 minutes I was watching the system. The system dropped another 4% between 5:37pm on the 10th and 8:50 am this morning. That would be another 2.16 kwh consumed by my system itself for the remaining 15 hours and 19 minutes. This number is pretty insignificant in comparison to the daytime figures while the system was uptaking PV.
I know the batteries will consume energy throughout the day but does it not seem excessive to you to lose such a large total of my harvest? I have a message into Fortress to ask them for help too but wanted to hear from other experienced solar users so I have more information and can't be brushed off if I really do have a problem here.
Living where I live, this time of year is absolutely BRUTAL for solar uptake. Honestly, I'm shocked at how little we get on bad days. This system is our security blanket for keeping our water and refrigeration running. We figured it was enough for doing at least that at an investment of $70k+ for a DIY project but we're running out of battery over the course of several days leaving us running a fuel hog of a generator to bring us back up over a matter of several hours. I'm trying to keep our battery bank up as much as I can because we're at that time of year when we do have power outages. If that outage occurs and I'm at 40% battery bank then I'm going to be screwed so I'm trying to claw my way back up to the high 90%'s before reengaging the system to power loads. I have that luxury today but given the attacks on the grid in my own county, I don't trust that I'm in a good position with this ENORMOUS investment.
Thank you for taking the time to help me.
SHTF Power Anyway
Power Pig
No but we will do that tomorrow. Thanks for the suggestion!
SHTF Power Anyway
Power Pig
Yes, we're not powering any loads because our uptake these days has been really horrific and I'm trying to get my batteries recharged as fast as I can. Right now we have the luxury of putting everything back on the grid. We've chosen not to attach our Sol-Ark to the grid for recharging for a long list of reasons but at least for now we can run things while we get our system figured out. Our initial install was in July and had only 4 of the batteries and a single Sol-Ark with our 10.8 kwh array We wanted to utilize more of our harvest but couldn't power enough loads with the single Sol-Ark so we added 6 more batteries, another Sol-Ark and 4kwh more in PV for good measure only to find we're getting no where quickly with all the investment and when we do have good uptake, it's being eaten by the system itself to a great extent.
SHTF Power Anyway
Power Pig
Just to clarify, 3kwh per day for both or each?
John Frum
Tell me your problems
- Joined
- Nov 30, 2019
- Messages
- 15,233
Shouldn't the total battery bank capacity be equal to or larger than the battery charge level?
Both. You should measure the idle consumption yourself with a DC clamp meter to make sure it's about 60W per unit with no loads.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
So you have zero loads on your inverter at all especially while they are charging?
SHTF Power Anyway
Power Pig
I guess I didn't use the right terminology when trying to explain my math for the 7kwh. The 37.3 was the AVAILABLE battery capacity based on the status of 69% full reported by the Sol-Ark and the total bank capacity of 54. Also, I just looked at this in a different light. While my system was harvesting solar, I lost a total of 7.7kwh from harvest to bank in a 8 hr and 46 minute period. I only lost 2.16kwh in the 15 hours and 19 minutes until my check the next morning. If that's the case, the loss during harvest is my problem. That isn't normal, is it?
I'm trying hard to provide enough information to get accurate advice but I'm so new at this, I'm struggling a bit. Thank you so much for being so helpful and patient.
SHTF Power Anyway
Power Pig
That number is SUPER helpful! Thank you! We'll do that next!
SHTF Power Anyway
Power Pig
For the last several days, yes, that's correct.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
Ok. Since you don’t have the WiFi dongles hooked up or Solar assistant running or some way to collect information I’m not sure how to reconcile your issue.
You really need a way to log the PV input, charged Ah and all the other stuff to see what’s going on.
SHTF Power Anyway
Power Pig
Is Solar Assistant for the Sol-Ark reporting? Is it an app for a phone or a software that can be loaded locally? I can set up an ethernet / laptop if I have to. It's on my list to run the cable from my switch.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,682
If you attempt to compute gas mileage of your car by driving from when the gauge shows 3/4 full down to 1/4 full, then you add 4 gallons and it reads 1/2 full ...
you'll have absolutely no idea how accurate the measurements are.
If you top off the tank, drive some miles, add a measured amount of fuel, drive some more miles, measure how much fuel to top off ...
Then you'll have a very accurate calculation of gas mileage (assuming no fraudulently calibrated gas pumps.)
The only time SoC of or battery is sure to be accurate is when it is returned to a resting voltage of around 3.5V or so per cell. Anywhere between about 10% and 90%, you have no idea actual SoC unless input and output current is accurately measured. Shunt properly calibrated, it might be. I'm guessing your SoC reports are off.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
If you don’t want to use PVPro then Solar assistant is the only other way I know.
I use it.
It’s a program that runs on Raspberry PI and you can buy the complete kit from them.
You will need 2 cables. One for each inverter to hook from DB-9 ( where the WiFi dongle would connect) to the PI.
It’s a pretty simple setup and a lot of people on here use it.
It will give you valuable information.
Here is the link to the shop.
Online Shop | SolarAssistant
Shop for battery and inverter communication cables such as USB to RS232, RS485, etc.
SHTF Power Anyway
Power Pig
You know, I'm embarrassed to admit this, my husband, his friend and our neighbor are all the electricians who worked on the installation. Not one of them has an ounce of computer experience, that's my job in terms of using the computer to research and source what they don't have. I never saw anything about monitoring software but was wondering today if there was anything I could monitor the entire system with and if there's any way to monitor my panels to make sure they're all working correctly. I will definitely get on this tomorrow. Thanks for the link and advice!If you don’t want to use PVPro then Solar assistant is the only other way I know.
I use it.
It’s a program that runs on Raspberry PI and you can buy the complete kit from them.
You will need 2 cables. One for each inverter to hook from DB-9 ( where the WiFi dongle would connect) to the PI.
It’s a pretty simple setup and a lot of people on here use it.
It will give you valuable information.
Here is the link to the shop.
Online Shop | SolarAssistant
Shop for battery and inverter communication cables such as USB to RS232, RS485, etc.solar-assistant.io
WindWizard
Solar Enthusiast
I have read the entire post and it appears to be somewhat presumptuous. The Solark which I have no knowledge or experience with is making all of these conclusions. How do we really know what the state of charge of the batteries really is? It is assumed that the battery bank is 54kw. I assume that has not been measured so how do we really know that the battery bank is 54kw? I know my overkill BMS has to have some settings set including the battery capacity. If the battery capacity setting is off then it could report all sorts of numbers that make it seem like power is missing. The power has to go somewhere so it most likely is in the batteries but just not reporting it correctly.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
No shame in that. Everyone has to start somewhere.
Once you get some type of monitoring then we we have more data to figure out what’s going on.
PVPRO is free. It’s the APP Sol-Ark uses but you have to buy the dongles from them.
Solar assistant isn’t free obviously and all the data is on the Raspberry PI.
It boils down to preference.
PVPRO has Chinese Servers but Sol-Ark is moving the servers to the US in next month or so.
I use Solar assistant because it’s real time and PVpro is about 5 minute updates.
PVPRO IMHO has more information but the updates are slow.
SHTF Power Anyway
Power Pig
I do have the dongle to set up for ethernet. I'll check into both. I really don't want my data for this system on the internet if I can help it. But I want to be sure my system is working so...
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