campermama
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Many 12v lifepo4 voltage/SOC charts show 13.20v (resting voltage) as equivalent to 70% SOC. The key here is "resting voltage".
Ok so the 13.2 is not really "resting", then would the actual "resting" voltage show a higher voltage or less?
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2oldman
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otrfun wrote: lifepo4's not needing absorption---that was the lifepo4 charging philosophy a 2-3 years ago when nearly all lifepo4 converters/chargers were single-stage 14.6v (no absorption or float stage). Also interesting is the 48v Dakota charger appears to have bulk only, so perhaps it depends on the kind of Li battery. But, I'm getting off the subject.
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campermama
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Meanwhile, mppt just went to float 13.6v, monitor says 13.4v and ~+4.5 amps, it will stay like this all day, I'm at a loss.
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CA Traveler
The Western States
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What panels do you have? Wondering if they could be connected in series to produce more power. If your voltage readings are accurate then you have 14.4-13.5 = 0.9V wiring loss which is high and should be corrected.
Also not sure of the current wiring but balanced wiring on the batteries is best for a variety of reasons including battery life. Connect all + battery wires to battery 2, connect the shunt to battery 1 - post and all negative wires to the shunt. This is in addition to the + to + and - to - wires between the 2 batteries.
Can your Renogy battery monitor display the battery SOC? Mine can display % SOC which is based on actual power (amps and voltage) available rather than inaccurate voltage as noted in a prior post. Don't want to get technical but SOC is about available power (watts or AH) and using just voltage is often misleading.
Guessing you want to do some amount of boon docking and having accurate input can enhance your power usage and understanding.
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campermama
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I have 3 go power panels in parallel, batteries are connected as you stated above.
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CA Traveler
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campermama wrote:Meanwhile, mppt just went to float 13.6v, monitor says 13.4v and ~+4.5 amps, it will stay like this all day, I'm at a loss. Renogy monitor or MPPT monitor? Renogy monitor should show battery amps ONLY and MPPT shows solar amps to the RV with includes RV loads and any battery charging.
I'm suspicious that there could be additional wiring involved. Turn off shore, gen, solar, turn on lights, does the Renology show - amps?
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campermama
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I have a renogy monitor - yes it shows - amps
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otrfun
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campermama wrote:otrfun wrote:Many 12v lifepo4 voltage/SOC charts show 13.20v (resting voltage) as equivalent to 70% SOC. The key here is "resting voltage". Ok so the 13.2 is not really "resting", then would the actual "resting" voltage show a higher voltage or less? After charging, final resting voltage will be lower. After discharging, final resting voltage will be higher. Higher charge/discharge current means a greater voltage delta (difference) to reach a given resting voltage.
Why do you need/want to calculate SOC based on voltage? A shunt-type battery monitor (properly calibrated) will calculate SOC much more accurately.
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3 tons
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Make sure the rotary selector switch on your charge controller set to position #7…
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campermama
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That's what i am looking at at night, a shunt monitor. I don't need/want to calculate SOC based on V. I'm just looking at what the monitor is telling me and trying to figure out why it's reading 13.2v instead of 13.3 or 13.4 after charging all day.
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