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--- 12v:sg_troubleshooting [2024/12/11 00:41]
frater_secessus [maxxing out the solar input] added dc-dc
+++ 12v:sg_troubleshooting [2025/06/24 19:47] (current)
frater_secessus [must I use the PS brand's proprietary solar panels?]
@@ Line 12: / Line 12: @@
 ===== must I use the PS brand's proprietary solar panels? =====
-No, you can use any panel that meets spec.  Consult the power station's [[lifestyle:faq_solar_generator#solar_charging_limits|solar ("PV") input specs]] and buy panel[s] whose [[electrical:solar:panels#specifications|output specs]] are within the the stated limits of the PS' internal [[electrical:solar:charge_controller|solar charge controller]].  For the purposes of this section we will use these actual specs for reference:
+No, you can use any panel that meets the PS' requirements.  Consult the power station's [[lifestyle:faq_solar_generator#solar_charging_limits|solar ("PV") input specs]] and buy panel[s] whose [[electrical:solar:panels#specifications|output specs]] are within the PS' limits.  This will ensure that the PS' internal [[electrical:solar:charge_controller|solar charge controller]] is not damaged by overvoltage.  For the purposes of this section we will use these actual input specs for reference:
 ''12v-45v, 10A''
@@ Line 20: / Line 20: @@
   * panel((or panel string, if wired in series)) Vmp must be ≥12.0v
   * panel Voc must be ≤45.0v
-  * the controller will allow ≤10A of input current((although the inner workings of PS are often undocumented, //generally speaking// MPPT controllers will [[electrical:solar:status#in_absorption|drive Vpanel > Vmp toward Voc to limit current]] to a particular spec))
+  * the controller will allow ≤10A of input current.((Standalone solar charge controllers typically are rated on output rather than input)).  The panels could theoretically present >10A to the controller but an [[electrical:solar:overpaneling#how_mppt_controllers_clip_power|MPPT controller will "clamp" the incoming current]] at 10A.((see the documentation for specifics))
 Sometimes the spec will also state the voltage range where the panels can be run at maximum power:
@@ Line 28: / Line 28: @@
 This tells us that Vmp can be anywhere from 15v to 38v.  Outside that range (but within the absolute limits above) the panels will make //something// but not maximum power.
-==== maxxing out the DC input ====
+==== maxxing out the solar input ====
+[note:  the overall logic also applies to alternator charging input inputs - see also [[electrical:12v:b2b#examples_-_power_stations|this subarticle on DC-DC for power stations]].]
 Power station solar input docs give a Max Wattage spec with a voltage range and usually a current limit.  In the case of our example that limit is ''10A''.
@@ Line 38: / Line 40: @@
   * 40Vmp x 10A = 400w
-[[https://amzn.to/3ZsgPYd|{{ https://m.media-amazon.com/images/I/61JNM0C6vyL._AC_UL320_.jpg?125}}]]
+So a general rule of thumb to get the most power out of panel + SG combo is to select panels that will (by themselves or when arranged in series) have a Voc toward((not //at//)) the upper end of the PS' input limit.  This will place the Vmp as high up in the input voltage range as practical without going over.
-The same logic applies to 12v input from the ciggy port or alternator, hence products like [[https://amzn.to/3ZsgPYd|Bluetti's DC-DC charger]], or [[https://amzn.to/3Zv1VjR|Ecoflow's DC-DC charger]].
-Sometimes no current limit is stated and we have to back into it.  In our case the 500w will be attainable at at 45v, suggesting the current limit is 11.11A (500w / 45v).  Remember the panel's Voc cannot exceed 45v so we cannot really run a 45Vmp panel.((Voc is always > Vmp, typically by ~20%))
 ==== can I overpanel my power station? ====
@@ Line 61: / Line 57: @@
 ===== the DC outlets don't have enough power to run my DC loads =====
-There is no easy/cheap way around this.  Buy a PS that has sufficient specs to meet your needs.
+There is no elegant or power-efficient way around this.  Best to spec and buy a PS that has sufficient specs to meet your needs.
+But **if you already own the PS** you could run [[https://www.amazon.com/Universal-Regulated-Switching-Transformers-Surveillance/dp/B07J6SBJ5L|a 12v power supply]]((example, not necessarily a recommendation)) off the AC output to power the hungry DC load. ([[https://pastebin.com/raw/NEUKRixD|diagram]]) \\
+For loads that only exceed 10A on startup (looking at you, [[hvac:heating#diesel_ventilated_heaters|diesel heaters]]) you could put the power supply on a timer. ([[https://pastebin.com/raw/nqqmrt6Z|diagram]])
 ===== my PS doesn't charge well from the 12v ciggy port =====
-  - bad connection - [[electrical:12v:ports#the_cigarette_outlet|12v ciggy ports]] are substandard even on their best behavior.
+The basic issue is the power station is throttling input to 10A avoid popping the ciggy port's  ~10A fuse.  Since volts x amps = watts, **limiting the amps limits the watts**.
-  - the chassis voltage is varying, so the 12v volt outlet voltage is varying, so the charge rate is varying (I=V/R)
-  - the power station is throttling charge rate
+The approach to [[12v:sg_troubleshooting#maxxing_out_the_solar_input|maxxing solar input]] described above [[https://amzn.to/3ZsgPYd|{{ https://m.media-amazon.com/images/I/61JNM0C6vyL._AC_UL320_.jpg?125}}]]
+also applies to DC input from the ciggy port or alternator.((sometimes they share the same port)) Hence products like [[https://amzn.to/3ZsgPYd|Bluetti's DC-DC charger]], or [[https://amzn.to/3Zv1VjR|Ecoflow's DC-DC charger]].
 > and if theres a way to have it always charge at 100w?
@@ Line 80: / Line 83: @@
-If the wall charger output is 100w you could even run a cheap inverter from the ciggy port and plug the wall charger into that.  It would be inefficient but we don't really care because the numbers are small and alternator output relative massive.  This approach would work because the wall charger's output is usually at the higher end of the SG's DC input voltage limit.
+If the wall charger output is 100w you could even run a cheap inverter from the ciggy port and plug the wall charger into that.  It would be inefficient but we don't really care because the numbers are small and alternator output relative massive.  This approach would work because the wall charger's output is usually at the higher end of the PS's DC input voltage limit.
 If the wall charger >100w((>100w wall charger + inverter losses could exceed the ciggy port's output limit, typically 10A.)) you could get more consistent charging by boosting/regulating voltage up as described above.  So if the wall charger runs at 15v one might boost the outlet's voltage to 15v.
@@ Line 88: / Line 91: @@
-===== Can I charge my SG with a regular DC-DC charger? =====
+===== Can I charge my PS with a regular DC-DC charger? =====
 Maybe.  There are several factors involved:
-  - some [[electrical:12v:b2b|DC-DC chargers]] need to see the target battery's voltage before charging will start.  These are often called "smart" chargers.  If the DC-DC needs to see the voltage before charging but the SG does not expose that voltage to the DC charging //input// then the charger will not start.
+  - some [[electrical:12v:b2b|DC-DC chargers]] need to see the target battery's voltage before charging will start.  These are often called "smart" chargers.  If the DC-DC needs to see the voltage before charging but the PS does not expose that voltage to the DC charging //input// then the charger will not start.
   - if the above condition is met, then the DC-DC's voltage output needs to be within the PS's voltage input range. If the input requires ≥20v then it will not charge from a nominal 12v DC-DC charger.
   - if the above conditions are met the PS input current may still be quite limited.   See the [[#maxxing_out_the_solar_input|maxxing]] section to get the most from the charging run.

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