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electrical:12v:b2b [2024/12/14 11:31]
frater_secessus [examples - power stations] |
electrical:12v:b2b [2025/04/28 20:55] (current)
frater_secessus [Renogy] |
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| * **voltage sensing** - watching chassis voltage like [[electrical:12v:alternator#voltage-sensing_relays|a VSR]] | * **voltage sensing** - watching chassis voltage like [[electrical:12v:alternator#voltage-sensing_relays|a VSR]] |
| * by receiving a **trigger signal** (AKA "D+", "IGN", "ignition", etc) from the chassis: signal = ON, no signal = OFF. This method requires the user to find a chassis circuit that has power only when the key is turned. Caveat: leaving the key in the ACC ("accessory") position can trick the DC-DC into starting before the engine is running; so don't do that. | * by receiving a **trigger signal** (AKA "D+", "IGN", "ignition", etc) from the chassis: signal = ON, no signal = OFF. This method requires the user to find a chassis circuit that has power only when the key is turned (IGN, ACC) or when the alternator is actually making power (D+). Caveat: leaving the key in the ACC ("accessory") position can trick the DC-DC into starting before the engine is running; so don't do that. |
| | * **voltage sensing + trigger signal** - this is often used to tell voltage-sensing DC-DC that the alternator is smart (variable voltage). IOW, "voltage is weirdly low but the D+ signal tells me this is a smart alt //and// the engine is running so I can charge regardless." |
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| Product documentation will tell you how the unit is triggered.((sometimes both methods are used together)) | Product documentation will tell you how the unit is triggered.((sometimes both methods are used together)) |
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| === DCC series === | === DCC series === |
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| | **Heads up**: the specs on the DCC line (30A and 50A) have changed but the model numbers appear to be the same. Most important change is the PV input voltage limit; see below. Doublecheck which one you will be getting BEFORE ORDERING if this is a critical spec for you. |
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| [[https://amzn.to/48L6r1f|{{ https://m.media-amazon.com/images/I/41B+GcTmbyS._AC_UY218_.jpg?125}}]] | [[https://amzn.to/48L6r1f|{{ https://m.media-amazon.com/images/I/41B+GcTmbyS._AC_UY218_.jpg?125}}]] |
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| * DCC50S [[https://amzn.to/48L6r1f|50A model with MPPT charging]]. MPPT input limited to 25v.((per the manual)) - [[https://www.renogy.com/content/RBC3050D1S-G1/RBC3050D1S-Manual.pdf|manual]] (pdf) Total output is limited to 50A from either independent source (see below). | * DCC50S [[https://amzn.to/48L6r1f|50A model with MPPT charging]]. MPPT input limited to 25v on original version and 50v on new version.((per the manual)) - [[https://www.renogy.com/content/RBC3050D1S-G1/RBC3050D1S-Manual.pdf|manual]] (pdf) Total output is limited to 50A from either independent source (see below). |
| * there is no D+ trigger for smart alternators. Instead, the owner adjusts the cut-in voltage setpoint to make it work as desired: "...you can connect to DC Home or Core via Bluetooth, and then **adjust the appropriate input voltage value of the charger** according to the characteristics of the working voltage of different types of alternators."((https://ca.renogy.com/renogy-ip67-50a-dc-dc-battery-charger-with-mppt/)) | * there is no D+ trigger for smart alternators. Instead, the owner adjusts the cut-in voltage setpoint to make it work as desired: "...you can connect to DC Home or Core via Bluetooth, and then **adjust the appropriate input voltage value of the charger** according to the characteristics of the working voltage of different types of alternators."((https://ca.renogy.com/renogy-ip67-50a-dc-dc-battery-charger-with-mppt/)) |
| * a [[https://amzn.to/3fSFDD2|30A combo model]] is also available | * a [[https://amzn.to/3fSFDD2|30A combo model]] is also available. 25v input on older version and 30v input on newer version. |
| * low temp charging cut-off supported in Lithium profile when external temp probe is present | * low temp charging cut-off supported in Lithium profile when external temp probe is present |
| * [[electrical:12v:voltage_sensing|voltage-sensing]] available | * [[electrical:12v:voltage_sensing|voltage-sensing]] available |
| This device's behavior regarding solar+alternator charging is widely misunderstood. | This device's behavior regarding solar+alternator charging is widely misunderstood. |
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| The 50A dual-input charger prefers to charge by solar if possible, up to **50A**. If it cannot meet charging demands alone and the engine is running it will will charge up to **25A by solar and 25A by alternator**: | The 50A dual-input charger prefers to charge by solar if possible, up to **50A**. If it cannot meet charging demands alone and the engine is running it will will charge **≤25A by solar** plus **≤25A by alternator**: |
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| Consider this snippet from the manual; | Consider this snippet from the manual; |
| Note: some have reported better alternator charging performance with the D+ (smart alternator) wire connected, even with plain alternators. Oversizing cables from the alternator may also help. ((https://www.youtube.com/watch?v=LtIe2rIfpW8)) | Note: some have reported better alternator charging performance with the D+ (smart alternator) wire connected, even with plain alternators. Oversizing cables from the alternator may also help. ((https://www.youtube.com/watch?v=LtIe2rIfpW8)) |
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| == disconnecting the solar == | == preventing solar from hobbling the alternator side == |
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| | Because of the behavior described above, people who want maximal charging can approach the problem one of two ways: |
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| | **Max out the solar side** so it's never failing to make it's fair share. This would be 400w of panel on the 30A and ~600w on the 50A. |
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| Because of the behavior described above, people who want maximum alternator charging sometimes add a way to disconnect solar panels. This is typically done by adding some kind of disconnect on the panel POS wire going to the solar charge controller: | **Add a way to disconnect solar panels**. This is typically done by adding some kind of disconnect on the panel POS wire going to the solar charge controller: |
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| * manual switch | * manual switch |
| ===== examples - power stations ===== | ===== examples - power stations ===== |
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| Power stations often suffer from low DC input limits. DC-DC chargers can work around the limit by increasing the input voltage. | Power stations often suffer from low DC input limits. DC-DC chargers (//boost converters// in this case) can work around the limit by increasing the voltage to the power station input.((also see [[12v:sg_troubleshooting#maxxing_out_the_solar_input|this subarticle]] about solar input. The source of the charging is different but the math and concepts are the same.)) If separate DC inputs are present these typically feed power to the solar input; see your power station's product documentation for specifics. |
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| | **Warning:** exceeding the power station's **input voltage limit** will/may damage it. Verify specs //before// purchasing, configuring, or installing. |
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| | * [[https://amzn.to/3DCGu9m|Bluetti 560w charger]] - Adjustable output voltage in the app. Presets for Bluetti products, or you can manually set the output voltage. |
| | * [[https://amzn.to/3PlwcNv|Ecoflow 800w charger]] - Adjustable output 40V-60V. Starter battery maintenance charging/maintaining modes. Firmware updates may be available. |
| | * [[https://amzn.to/41XDQ8o|Etaker 1000w charger]] - ≤500w alternator + ≤500 solar (up to 48v and 20A input). Output ≤42V, 25A |
| | * [[https://amzn.to/3Pidm9V|Pecron DC1242-500]]. 500w, 42v. |
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| | Functionally, the ones with a set output voltage are akin to [[https://amzn.to/4fNKrpe|this]] and the ones with configurable output voltage are akin to [[https://amzn.to/3BRoQxZ|this]], plus a method to [[electrical:12v:b2b#triggering|trigger]] the device when the engine is running. |
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| | ==== a word about nomenclature ==== |
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| | These are listed in the DC-DC article because that is how they are used and how many people think of them. They are really voltage boosters that output a steady voltage, whether configured by the user or set at the factory. |
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| ===== installing inline with a relay ===== | ===== installing inline with a relay ===== |
