Solar Noob Help
RedCon509
Registered Users, Users Awaiting Email Confirmation Posts: 1 ✭
I recently installed a Renogy 400Watt set up with a Rover 40 MTTP with (2) 6v 370AH batteries. I've noticed that the charge capacity shown on the charge controller is constantly changing..... one minute it will read 60% then 70% then back to 60%. Has anyone else experienced this?
Comments
The reported battery capacity by solar charge controllers are very rough estimates (not very accurate--Lead acid batteries not accurate--Li Ion possibly more accurate).
If you want "accurate" estimates of AH capacity/State of Charge for your batty bank... A true Battery Monitor that measures current into/out of the battery bank is a better (and more expensive) option:
https://www.solar-electric.com/search/?q=battery+monitor
There are less expensive shunt based monitors out there from Amazon/Ebay/etc... I have no knowledge of the product(s)... Just FYI:
https://www.amazon.com/AiLi-Voltmeter-Ammeter-Voltage-Motorhome/dp/B07FGFFHC6
There are also Voltage only Battery Monitors--May or may not be more accurate than your charge controller--And they start at pretty cheap prices:
https://www.amazon.com/s?k=12+VDC+battery+monitor+meter&ref=nb_sb_noss
If you have flooded cell Lead Acid batteries, a good quality Hydrometer is the "gold standard" for checking state of charge:
https://www.solar-electric.com/search/?q=hydrometer
Even the "high end" shunt based battery monitors can "drift" over time/cycling... Many of them will "reset" to 100% State of Charge under certain conditions (example: meter "sees" 14.8 volts for > 2 hours -- Absorb charging on FLA battery bank).
Just using a hydrometer and an accurate voltmeter you can get a pretty good idea of the "health"/state of charge of your battery bank... I.e., resting voltage of 12.2 volts ~ 50% state of charge... Under decent loads, you don't want to see below 11.5 volts for more than few minutes or so (discharging below 50% SoC under load)--Short term loads (motor starting surge, etc.) may take bank below 11.5 volts during surge--But that is "OK".
-Bill
I would like some information.
I have solar panels connected to the grid which reduces my electric bill from over $450/month to a $150/month lease and less than $400/year to Edison.
My concern is blackouts. So, I am going to build my own house battery. I want only to power my refrigerator and kitchen lights for up to 2 days.
My plan is to buy 8 100AH 12V batteries, a Jupiter 2000 inverter and some kind self sustaining charging system that will charge and maintain the batteries while the grid is functioning. Any suggestions would be welcome. But, I mostly need recommendations for the charging system.
Johnfrom SBCA
Can you start a new discussion/thread in one of the forums (beginner, off grid/battery systems, etc.). That way we can focus on your exact Q&A's...
Knowing your location, daily loads, and how often your power goes out. In Los Angeles/San Bernardino, etc... Your power may go out only a few days a year (at most--Wild fire seasons in California--Who knows) vs a Caribbean Island where afternoon blackouts are almost every day.
Off grid solar is not cheap power. And for a few days a year, solar may not be a "competitive" answer vs a genset+backup fuel (propane, gasoline with fuel stabilizer, natural gas, etc.).
-Bill