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electrical:12v:multipoint_charging [2022/03/13 19:48]
frater_secessus [concurrent charging] |
electrical:12v:multipoint_charging [2022/05/25 12:30]
frater_secessus [how to make them cooperate] |
| * **12.2v** at daybreak, approximately 50% [[electrical:depth_of_discharge|Depth of Discharge]]. Charging is in the Bulk stage and **all three sources are contributing**; the battery bank voltage is lower than what they all want to provide. The alternator is contributing the most because it can produce the most current and the panels aren't getting much light yet. | * **12.2v** at daybreak, approximately 50% [[electrical:depth_of_discharge|Depth of Discharge]]. Charging is in the Bulk stage and **all three sources are contributing**; the battery bank voltage is lower than what they all want to provide. The alternator is contributing the most because it can produce the most current and the panels aren't getting much light yet. |
| * **13.9v** a few miles down the road. Voltage is climbing but all three sources are still charging. The sun is higher in the sky so the panels are making more power now. | * **13.9v** a few miles down the road. Voltage is climbing but all three sources are still charging. The sun is higher in the sky so the panels are making more power now. |
| * **14.1v** by the you get to a neighboring town. **Alternator charging ceased at 14.0v**; it has plenty of current but no voltage "pressure" to force that current into the battery. Your battery bank is now being charging only by solar (the two separate controllers).((exception: see [[opinion:frater_secessus:alternatorsolarstall|this gotcha]])) | * **14.1v** by then you get to a neighboring town. **Alternator charging ceased at 14.0v**; it has plenty of current but no voltage "pressure" to force that current into the battery. Your battery bank is now being charging only by solar (the two separate controllers).((exception: see [[opinion:frater_secessus:alternatorsolarstall|this gotcha]])) |
| * **14.6v** in the parking lot as you stop at an Oasis [[water:drinking|water kiosk]]. **The Morningstar stopped contributing at 14.4v**((Absorption is the stage where the controller provides as much current as it takes to hold Vabs, 14.4 in the Morningstar's case. **It takes zero current to hold 14.4v when the bank is 14.6v**, so the Morningstar just sits there. It will drop into Float when Absorption duration is complete.)) so we are down to just the Xantrex. | * **14.6v** in the parking lot as you stop at an Oasis [[water:drinking|water kiosk]]. **The Morningstar stopped contributing at 14.4v**((Absorption is the stage where the controller provides as much current as it takes to hold Vabs, 14.4 in the Morningstar's case. **It takes zero current to hold 14.4v when the bank is 14.6v**, so the Morningstar just sits there. It will drop into Float when Absorption duration is complete.)) so we are down to just the Xantrex. |
| * **14.7v** on your way back to camp. This is Absorption setpoint (Vabs) of the Xantrex, the highest setpoint of all three. The Xantrex will continue the Absorption stage by itself until that stage is complete((duration or endAmps)), then drop back to Float voltage (Vfloat).((where the Morningstar has probably been waiting, twiddling its thumbs)) | * **14.7v** on your way back to camp. This is Absorption setpoint (Vabs) of the Xantrex, the highest setpoint of all three. The Xantrex will continue the Absorption stage by itself until that stage is complete((duration or endAmps)), then drop back to Float voltage (Vfloat).((where the Morningstar has probably been waiting, twiddling its thumbs)) |
| Barring heroic measures((exotic alternators/regulators, [[electrical:12v:b2b|DC-DC chargers]])) the alternator is going to stop contributing at some point during Bulk charging. That is ok, the alternator provided a ton of current while it was charging. | Barring heroic measures((exotic alternators/regulators, [[electrical:12v:b2b|DC-DC chargers]])) the alternator is going to stop contributing at some point during Bulk charging. That is ok, the alternator provided a ton of current while it was charging. |
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| But if you want to the charge controllers (and some [[electrical:converter|converters]]) can be convinced to stay //roughly// in sync and keep charging together. This is done by **configuring the Absorption and Float setpoints on the controllers to be the same**.((including Absorption termination setpoints like time or current)) There will be short periods where one controller makes a change before the other, but for most of the time both will be contributing at the same time. | But if you want to the charge controllers (and some [[electrical:converter|converters]]) can be convinced to stay //roughly// in sync and keep charging together. This is done by **configuring the Absorption and Float setpoints on the controllers to be the same**.((including Absorption termination setpoints like time or current)) There will be short periods where one controller makes a change before the other, but for most of the time both will be contributing at the same time. Even if they contribute unequally it is a non-issue because the voltage setpoint is being held. If a big load is added or conditions deteriorate it will be "all hands on deck" as in the Bulk stage scenario above. |
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| Note: there are high-end controllers/chargers which communicate with each other to coordinate charging. That feature is beyond the scope of this article. | Note: there are high-end controllers/chargers which communicate with each other to coordinate charging. That feature is beyond the scope of this article. |
