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--- opinion:more_power [2025/05/05 16:06]
frater_secessus [upgrading an existing power setup]
+++ opinion:more_power [2025/05/19 13:50] (current)
frater_secessus [supply problems]
@@ Line 1: / Line 1: @@
 DRAFT
->> “It is cheaper and easier to use less power than it is to make more power.” – highdesertranger
+> “It is cheaper and easier to use less power than it is to make more power.” – highdesertranger
-====== upgrading an existing power setup ======
+> ...the //why// is important. If you are trying to **meet a specific performance goal** you can save money by identifying performance bottlenecks and upgrading the relevant components. If you want to do the upgrades because they sound like **a fun project** then throw all the parts at it you want with my sincere blessing. I certainly am not immune to fun projects. -- secessus((https://www.reddit.com/r/RVSolarPower/comments/1keb0or/dc_to_dc_questions/mqq64ma/))
-This article is for people who are considering a house power upgrade to better meet their needs:
-> ...the //why// is important. If you are trying to **meet a specific performance goal** you can save money by identifying performance bottlenecks and upgrading the relevant components. If you want to do the upgrades because they sound like **a fun project** then throw all the parts at it you want with my sincere blessing. I certainly am not immune to fun projects. -- secessus((https://www.reddit.com/r/RVSolarPower/comments/1keb0or/dc_to_dc_questions/mqq64ma/))
+====== upgrading an existing power setup ======
@@ Line 33: / Line 35: @@
 ===== big picture:  how close are we to the goal line? =====
-* if your existing system usually meets needs but sometimes falls short in anomalous circumstances
+  * if your existing system usually meets needs but **occasionally falls short** in anomalous circumstances it might be simpler/easier/cheaper to reduce consumption at those times.
-* if your existing system is **close to meeting needs** (like within 10% of hitting [your daily power requirements](https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:dailypowerrequirements)) then for several reasons a LiFePO4 swap has a good chance of closing that gap with no other changes needed.
+  * if your existing system is **close to meeting needs** ((like within 10% of hitting [your daily power requirements](https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:dailypowerrequirements)) then upgrading the bottlenecked component can close the gap with no other changes needed.
-* if your existing system is **far from meeting needs** then other upgrades would be required.  Solar, as you say, and/or replacing any existing relay/isolator with an actual DC-DC.
+  * if your existing system is **far from meeting needs** then the [[electrical:12v:power_mix|overall charging mix]] could stand to be reconsidered.
@@ Line 56: / Line 58: @@
 Doctor - "Stop doing that."
-Some loads are mandatory and we can't "stop doing that".  Your insulin might require a powered fridge at all time. But many high-current loads newbies try to run (and crash their power setup) are easy and cheap using traditional methods.  Electric water heating vs propane water heater (or kettle over a stove), for example.
+Some loads are mandatory and we can't "stop doing that".  Your insulin might require a powered fridge at all time or a CPAP might be mandatory. But many high-current loads newbies try to run (and crash their power setup) are easy and cheap using traditional methods.  Electric water heating vs propane water heater (or kettle over a stove), for example.
 === demand scheduling ===
 Sometimes just changing when the load runs can eliminate/reduce required upgrades.  Consider a system with limited Ah capacity that sags under load and trips the inverter's low voltage protection.  Running that same load when the solar or alternator are making power can reduce the sage, reducing or eliminating the problem.
@@ Line 71: / Line 71: @@
 === charging bottlenecks ===
+Charging bottlenecks occur when the battery bank could happily [[opinion:frater_secessus:charging_faster|charge faster]] and more often but we aren't doing so.
+A major cause of underperformance is **reliance on a single form of charging**.   The sun is not always out (solar), you are not always driving (charging from alternator), and access to the power grid is not always available (shore power).
+  * solar
+    * maybe we have no solar at all
+    * maybe we have unused roofspace to devote to more panel
+    * maybe the panel we have is [[opinion:frater_secessus:beginner_mistakes#mounting_or_deploying_panels_where_they_will_be_shaded|shaded by other things on the roof]]
+    * maybe we went with portable panels but [[https://rvwiki.mousetrap.net/doku.php?id=opinion:frater_secessus:beginner_mistakes#believing_they_will_set_out_portable_panels|don't deploy them consistently]] for whatever reason.  Some mounted panel could make a big difference.
+    * maybe we went with mounted panels but park the rig in the shade.  Portables on extensions set out in the sun could make a big difference.
+  * alternator
+    * maybe we are not charging from the alternator at all
+    * maybe we are forgetting to enable charging from the alt after [[electrical:12v:alternator#disabling_alternator_charging|disabling]] it
+    * maybe the alternator has [[electrical:12v:alternator_details#current|excess capacity]] to devote to house bank charging
+  * shore power
+    * maybe we are not [[electrical:converter|charging from shore power]] at all when we have access to it
 === bank capacity bottlenecks ===
+If you can charge the bank consistently but run out of power overnight or in periods of decreased harvest you may just need more bank capacity.  Also see [[electrical:autonomy|Days of Autonomy]].
 === throughput bottlenecks ===
+These are related to the systems above, but are less obvious.
+  * panels and PWM solar charge controllers poorly matched, resulting in [[electrical:solar:pwm_tweaking#pwm_s_achilles_heel|underperformance]]
+  * insufficient panel wattage
+  * panel wattage grossly oversized for the MPPT controller (>30% [[electrical:solar:overpaneling#vs_charge_controller|overpaneled]];  this is relatively rare)
+  * DC-DC [[electrical:12v:b2b#sizing|undersized]] relative to the alternator and bank
+  * wiring undersized for alternator charging with a combiner (relay/solenoid/"isolator", etc.  Since they don't alter voltage this kind of setup is sensitive to resistance between the chassis electrical and battery bank.

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