| Both sides previous revision
Previous revision
Next revision
|
Previous revision
Next revision
Both sides next revision
|
electrical:solar:shallow_cycling [2018/03/02 09:45]
frater_secessus [how it works] |
electrical:solar:shallow_cycling [2020/01/13 16:41]
frater_secessus [effect on starter battery] |
| ===== non-cycling ===== | ===== non-cycling ===== |
| |
| //Non-cycling// is the use of solar power only when the battery is fully charged. | //Non-cycling// is the use of solar power only when the battery is fully charged. The starter battery is even more fully charged than in normal vehicles. |
| |
| ==== how it works ==== | ==== how it works ==== |
| |
| - a simple [[electrical:solar:charge_controller#shunt_controller|shunt charge controller]] holds the battery at a mild Absorption voltage (14.0, - 14.2v) when charging, just below the significant gassing point | - a simple [[electrical:solar:charge_controller#shunt|shunt charge controller]] holds the battery at a mild Absorption voltage (14.0, - 14.2v) when charging, just below the significant gassing point |
| - the controller's LOAD output disconnects (LVD) at 100% SoC (~12.7v) | - the controller's LOAD output disconnects (LVD) at 100% SoC (~12.7v) |
| - the controller's LOAD output //re//connects (LVR) at ~13.0v); see discussion below | - the controller's LOAD output //re//connects (LVR) at ~13.0v); see discussion below |
| - power is //only// taken from the controller's LOAD output;((or from a circuit control by a relay on the LOAD output)) this ensures the starter battery is never discharged below the intended setpoint | - power is //only// taken from the controller's LOAD output;((or from a circuit control by a relay on the LOAD output)) this ensures the starter battery is never discharged below [[electrical:12v:lvd|the intended setpoint]] |
| |
| === Low Voltage Reconnect (LVR) setpoint === | === Low Voltage Reconnect (LVR) setpoint === |
| If **running larger loads** (fans, laptop chargers) the setpoint should be set higher (like 13.5v - 14.0v). This is because the panel will be able to make more power closer to Vmp. Consider the popular [[http://amzn.to/2you3Kj|Renogy 100w panel]] that puts out about 5.29A. At the lower LVR the panel((under lab conditions)) will make **68.77W**. At the higher LVRs the panel will make **71.42-74.06W** | If **running larger loads** (fans, laptop chargers) the setpoint should be set higher (like 13.5v - 14.0v). This is because the panel will be able to make more power closer to Vmp. Consider the popular [[http://amzn.to/2you3Kj|Renogy 100w panel]] that puts out about 5.29A. At the lower LVR the panel((under lab conditions)) will make **68.77W**. At the higher LVRs the panel will make **71.42-74.06W** |
| |
| Note: running a small MPPT [[electrical:solar:charge_controller|charge controller]] would make this immaterial, as the controller would run the panel at max power (Vmp) at 18.9v. | Note: running a small [[electrical:solar:charge_controller#mppt|MPPT]] [[electrical:solar:charge_controller|charge controller]] would make this immaterial, as the controller would run the panel at max power (Vmp) at 18.9v. |
| |
| |
| ===== shallow-cycling ===== | ===== shallow-cycling ===== |
| |
| //Shallow-cycling// is a more aggressive approach, allowing for a bit of power after sundown. It is most **suitable for starter batteries with removable cell caps**. | //Shallow-cycling// is a more aggressive approach, allowing for more power in the daytime and some power for use after sundown. It is most **suitable for starter batteries with removable cell caps**. |
| |
| The charging setpoint is set somewhat higher, ~14.4v. This will result in minor outgassing and a bit more power (**76.18W** using the panel data above). [[electrical:12v:charging#watering_batteries|Battery watering]] is mandatory. | The charging setpoint is set somewhat higher, ~14.4v. This will result in minor outgassing and a bit more power (**76.18W** using the panel data above). [[electrical:12v:charging#watering_batteries|Battery watering]] is mandatory. |
| Starter batteries are designed for about 15% depth of discharge((http://forum.solar-electric.com/discussion/comment/60412#Comment_60412)). We can set the Low Voltage Disconnect (//Vlvd//) to 12.5-12.6v as a floor. In a typical starter battery this could be 5Ah of power usable at night, enough to run an LED light for hours as well as run a small fan all night. All device charging should happen in daylight when power is relatively plentiful. | Starter batteries are designed for about 15% depth of discharge((http://forum.solar-electric.com/discussion/comment/60412#Comment_60412)). We can set the Low Voltage Disconnect (//Vlvd//) to 12.5-12.6v as a floor. In a typical starter battery this could be 5Ah of power usable at night, enough to run an LED light for hours as well as run a small fan all night. All device charging should happen in daylight when power is relatively plentiful. |
| |
| If the starter battery (when it eventually dies a natural death) were replaced with [[electrical:12v:deep_cycle_battery#chain_store_batteries|a 12v wally world marine battery]] one might be able to cycle to 25% DoD. This would mean an Vlvd of ~12.4v and 8-9Ah of power at night. | If the starter battery (when it eventually dies a natural death) were replaced with [[electrical:12v:deep_cycle_battery#chain_store_batteries|the heaviest 12v wally world marine battery]] that would fit one might be able to cycle to 25% DoD. This would mean an Vlvd of ~12.4v and 8-9Ah of power at night. |
| ===== effect on starter battery ===== | ===== effect on starter battery ===== |
| |
| |
| |
| | Anecdote: TreborEnglish runs his 75A flooded 12v wally world deep cycle to 87% SoC regularly and it has lasted 3 years as of this writing. He reports it requires 20-30ml of water/month.((https://www.reddit.com/r/vandwellers/comments/enwq70/best_car_battery_for_van_life/fe670is/)) |
| |
