Can anyone please advise charging two 12-volt deep cycle 100amp leisure battery with a Renogy Rover 40 Amp MPPT Solar Charge Controller to 100% and left connected overnight with nothing attached only the solar panels and battery and down to 80% is that normal or possibly problem with the batteries any device would be appreciated
Battery drain overnight
- Thread starter Getaway
- Start date
Rednecktek
Solar Wizard
Are you checking that 80% via multimeter or the SCC? SCC's usually use voltage as a guess and there's a bit of a voltage difference between charging in bulk and floating. I'd re-verify those numbers with a meter directly to the battery.
pollenface
Solar Addict
What is the resting voltage before sunrise, what is the battery type?
Just the Renogy LCD Screen 100% when fully charged and left overnight LCD Screen down to 80% no other device used just Renogy Rover 40 Amp MPPT Solar Charge Controller
The two batteries being used are 12V 115AH EXPEDITION PLUS AGM LEISURE BATTERY (EXP12-115) the resting voltage is 80% and slowly dropping until sunrise
pollenface
Solar Addict
Can you tell us the voltage? 80% doesn't really mean anything. We need the actual battery voltage. Check with a multimeter at your batteries, there will sometimes be a small dependency in readings taken from the SCC
KellyDood
New Member
It's curious cuz my BT-1 says 91% capacity but 13.0 volts overnight, so I wonder how it measures 'capacity'?
Abodyofscience
New Member
- Joined
- Feb 21, 2022
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- 168
See if the resting current draw from the batt. is within specs.
Drawing down 115 A-h in 8 hours to 80% is about 2 Amps.
Drawing down 115 A-h in 8 hours to 80% is about 2 Amps.
6:30 p.m. the reading on the controller display was 100% checked this morning at 6:30 a.m. the reading was 73% this information is only on the Renogy controller display at the same time using a multimeter reader at 6:30 p.m. Directly on the battery with everything still attached solar panels controller to the battery the reading was 13.08v then checked this morning 6:30 a.m. the reading was 12.82v .
Minimoose
New Member
The same thing was a head scratcher for me too with my Rich Solar mppt until I figured out it was looking for 13.2 volts to return to boost mode. If I lower the boost return mode down to 13 volts it shows 100% charged. my batteries rest at about 13 to 13.2 volts overnight.
mikefitz
Solar Wizard
- Joined
- May 28, 2020
- Messages
- 3,098
The Renogy Rover cannot measure battery capacity. The instructions provider by Renogy clearly state the capacity display is based on voltage alone. Once an agm battery is fully charged and left with no charge or discharge circuits connected its voltage will fall to its 'resting voltage'.
I guess you are in the UK as Expedition Plus in a branded Leoch battery sold on UK Internet sites. This is an economy battery and will give passable service.
It's probable the battery is not completly charged by your solar charger. It needs 14.7 volts charge with a long absorbtion period and a float of 13.7 volts. Expect with a new battery, fully charged, after an overnight rest to read just over 13 volts. It may need a few days charging if solar is your only charge source to get completely full.
The reading of 12.8 volts is OK, expect this to rise slightly after a few charge cycles.
The solar charger you have and similar variants make a poor guess at battery capacity, its very inaccurate. Note that low cost meters may not read with a high degree of accuracy, this is also the case of voltage readings in solar controllers.
Mike
I guess you are in the UK as Expedition Plus in a branded Leoch battery sold on UK Internet sites. This is an economy battery and will give passable service.
It's probable the battery is not completly charged by your solar charger. It needs 14.7 volts charge with a long absorbtion period and a float of 13.7 volts. Expect with a new battery, fully charged, after an overnight rest to read just over 13 volts. It may need a few days charging if solar is your only charge source to get completely full.
The reading of 12.8 volts is OK, expect this to rise slightly after a few charge cycles.
The solar charger you have and similar variants make a poor guess at battery capacity, its very inaccurate. Note that low cost meters may not read with a high degree of accuracy, this is also the case of voltage readings in solar controllers.
Mike
Very much appreciate this information it's a learning curve my intention is to use the solar system to supply electricity to my greenhouse possibly combined with a wind turbine
Alan
chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,431
The only way I found to measure the State of Charge for a battery is to use a shunt. Some are more accurate than others.
For Cost I like the AiLi Battery Monitor
And For Bluetooth and more accurate tracking I like the VIctron Battery Monitor or Smart Shunt
For Cost I like the AiLi Battery Monitor
And For Bluetooth and more accurate tracking I like the VIctron Battery Monitor or Smart Shunt
I have one of these, and for the price, it can't be beat. It's actually more accurate than my $100 Renogy unit.
Bayite DC 6.5-100V 0-100A LCD Display Digital Current Voltage Power Energy Meter Multimeter Ammeter Voltmeter with 100A Current Shunt https://www.amazon.com/dp/B013PKYIL...t_i_CF2XT4EPANVZ9B4VJ0G0?_encoding=UTF8&psc=1
Bayite DC 6.5-100V 0-100A LCD Display Digital Current Voltage Power Energy Meter Multimeter Ammeter Voltmeter with 100A Current Shunt https://www.amazon.com/dp/B013PKYIL...t_i_CF2XT4EPANVZ9B4VJ0G0?_encoding=UTF8&psc=1
