| Both sides previous revision
Previous revision
Next revision
|
Previous revision
Next revision
Both sides next revision
|
electrical:solar:shallow_cycling [2017/11/09 19:07]
frater_secessus [how it works] |
electrical:solar:shallow_cycling [2018/03/02 09:47]
frater_secessus [how it works] |
| This article describes a small, simple, space-efficient, and inexpensive solar configuration that may be of use to cardwellers or minimalist vandwellers. | This article describes a small, simple, space-efficient, and inexpensive solar configuration that may be of use to cardwellers or minimalist vandwellers. |
| |
| Most of the RV world is familiar with deep-cycle 12v systems; these are intended to store power for use overnight. If most power is only needed in the daytime then deep-cycle batteries are not required. | Most of the RV world is familiar with [[electrical:12v:deep_cycle_battery|deep-cycle 12v systems]]; these are intended to store power for use overnight. If most power is consumed [[electrical:solar:nonessential|in the daytime when the system has excess power]] then deep-cycle batteries may not be required. |
| |
| Instead of deep-cycling, the starter battery is //non-cycled//((never discharged below 100% state of charge)) as described below. It can also be [[electrical:solar:shallow_cycling#shallow-cycling|shallow-cycled]].((discharged to 90% state of charge)) | Instead of deep-cycling, the starter battery is //non-cycled//((never discharged below 100% state of charge)) as described below. It can also be [[electrical:solar:shallow_cycling#shallow-cycling|shallow-cycled]].((discharged to 90% state of charge)) |
| ==== 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 gassing point | - 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 |
| - 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; 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 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. |
| |
| |
