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electrical:12v:b2b [2024/12/09 11:31]
frater_secessus [Kisae] 		electrical:12v:b2b [2025/03/10 11:54] (current)
frater_secessus [examples - power stations] added link to solar input limit workaround
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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." 
  
 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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   * modifying the existing ON/OFF switch - [[https://diysolarforum.com/threads/kisae-dmt1250-partial-disassembly-and-remote-disconnect-addition.15454/|Kisae DMT1250 partial disassembly and remote disconnect addition]]   * modifying the existing ON/OFF switch - [[https://diysolarforum.com/threads/kisae-dmt1250-partial-disassembly-and-remote-disconnect-addition.15454/|Kisae DMT1250 partial disassembly and remote disconnect addition]]
  
-and of course putting a heavy switch on the incoming POS wire. +The brute force method would be a battery cut-off switch or relay on the POS wire coming from the chassis. 
  
  
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-==== examples - without current limiting ====+===== examples - without current limiting =====
  
 The [[https://sterling-power.com/products/alternator-to-battery-chargers-up-to-130a|Sterling A2B]] uses DC-DC conversion to boost voltage but has no ability to limit current.   The [[https://sterling-power.com/products/alternator-to-battery-chargers-up-to-130a|Sterling A2B]] uses DC-DC conversion to boost voltage but has no ability to limit current.  
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 Also see the Votronics section above for their DCC 25A 1224 charger.  Also see the Votronics section above for their DCC 25A 1224 charger. 
 +
 +===== examples - power stations =====
 +
 +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. 
 +
 +**Warning:** exceeding the power station's **input voltage limit** will/may damage it.  Verify specs //before// purchasing, configuring, or installing.
 +
 +  * [[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.
 +
 +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. 
 +
 +==== a word about nomenclature ====
 +
 +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.  
  
 ===== installing inline with a relay ===== ===== installing inline with a relay =====
electrical/12v/b2b.1733761914.txt.gz · Last modified: 2024/12/09 11:31 by frater_secessus

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