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--- opinion:frater_secessus:prebuilt_van [2024/12/10 11:40]
frater_secessus [general approach to understanding the house power setup]
+++ opinion:frater_secessus:prebuilt_van [2025/03/28 13:53] (current)
frater_secessus [TL;DR]
@@ Line 3: / Line 3: @@
 ====== I bought a pre-built van.  How does the power system work? ======
+You already bought the van; it's a done deal.  The time to beat the "understand what you're buying //before// you buy it"  dead horse has past.  Right now we need to figure out, make use of, and possibly modify the system you have.
-This is a difficult problem, since neither you nor the people who want to help you know know how your system works.    Coulda/woulda/shoulda((ie, could have identified what was installed //before// buying it)) don't matter right now because
-  - you already own it; and
+===== TL;DR =====
-  - the existing [[electrical:12v:intro|"house" power system]](("chassis" power is the stuff that came on the vehicle from the factory.  "House" power is the the separate power system in  your living area)) might or might not be working as designed by the Previous Owner; and
-  - even if it //is// working as designed  it might or might not meet //your// needs
-Let's get you on your feet first, then we can worry about possibly changing or improving things.
+  * **observation** is a major part of both figuring out a system and of troubleshooting.  Look.  Notice.  Pay attention.  Document.
+  * look up the manual or specs for for every component you find
+  * the job of the power system is to accept charge from [[electrical:12v:power_mix|one or more sources]], store that energy, and use it for [[electrical:12v:loads|loads]] you want to run.  On average **charging must be ≥ discharging**((the "average" part is provided by bank capacity)) or you will [[opinion:frater_secessus:running_out_of_power|run out of power]].
+  * a system can be working-as-designed and still not do what you want or meeting your needs
+  * Some problems are easy to identify ("hey, what happened to the lights?").  Some are so subtle we (or the PO) might not notice them or see them as a problem.
@@ Line 38: / Line 41: @@
 Caveat: If someone upgraded/changed the vehicle after purchase the VIN will not know about that....
-You can find a free lookup tool by searching ''[brand] VIN lookup``.  [[https://duckduckgo.com/?t=lm&q=chevy+vin+lookup&ia=web|Example using Chevy]]
+You can find a free lookup tool by searching ''[brand] VIN lookup''.  [[https://duckduckgo.com/?t=lm&q=chevy+vin+lookup&ia=web|Example using Chevy]]
@@ Line 96: / Line 99: @@
-==== shore power charging ====
+=== shore power charging ===
 This is the least common form of charging since few vanfolk have the luxury of access to [[electrical:shore_power|grid ("shore"). Having steady access to shore power is like winning the vandweller lottery because you can do almost anything you want, power-wise.
@@ Line 105: / Line 108: @@
+==== inverters ====
+[[electrical:inverter|Inverters]] are used if/when you need to run 120vac((in the US)) loads from 12vdc((typically)) battery banks.
+They will typically have a wattage rating labeled on them.  With more reputable manufacturers this will be the continuous duty rating.  With less-scrupulous manufacturers this might be the peak/surge output rating.
+Unless the inverter says ''pure sine wave'' or ''PSW'' on it there is a reasonable chance it is Modified Square((or Sine)) Wave.  See link above.
-===== troubleshooting problems =====
-if it ever worked before and doesn't work now then at least one of these is probably true;
+==== wiring and fusing ====
-  * an electrical connection is compromised:  wiring terminal loose, fuse blown / breaker tripped
+While poking about taking stock of the components, also notice the wiring and fusing.
-  * something was inadvertently turned off by physical switch or app setting
-  * something has failed or worn out((like batteries))
-If it's never worked then perhaps
-  * something is installed but not hooked up or turned on (see above)
-  * it wasn't installed
-  * it failed before you bought it and the seller didn't know or didn't say
-It's also possible that it's working fine but you don't know it. Example:  "[[electrical:solar:status#setups_with_no_float|my charger isn't charging my lithium batteries]] even though they are not at 100%".
+It can be difficult to tell the construction and gauge of wiring by externals.  If you are lucky that information might be printed on the insulation of the wiring itself.  This kind of info might be printed only on one side maybe only every few inches or feet so it might be hidden at first.  Keep tracing and looking.
-==== get a handle on the symptoms ====
+Fuses and breakers are usually labeled with their current limit
-Pay attention to what is happening so you can describe it clearly and accurately to people who want to help //but who cannot see your van.//
+[[https://www.bluesea.com/support/articles/Circuit_Protection/1437/Part_1%3A_Choosing_the_Correct_Wire_Size_for_a_DC_Circuit|This Blue Sea article]] describes appropriate wire gauge for a given current and circuit length.
-  * useful information:
-    * "My inverter gives a E3 error and stops working when the battery monitor says voltage is below 11v"
-    * My inverter worked as expected until yesterday
-    * my inverter has never worked
-  * ok information:  "my inverter doesn't work when voltage is 11v"
-  * useless:  "my inverter doesn't work"
-When describing charging/noncharging problems, please report voltage and current changes you observe when any charging sources are added.  "My battery monitor shows 12.4v and does not change when I start the engine."
+===== upgrades =====
+You may have to make some upgrades to meet the demands of your particular use case.  A rational approach might be:
+  - understand your use case, including [[electrical:12v:dailypowerrequirements|daily requirements]] in Watt-Hours or Amp-Hours and [[opinion:frater_secessus:run_this_load|load requirements]] in Watts or Amps.
+  - understand what the  existing system can do (see above)
+  - find the bottlenecks and open them up so it //can// meet your needs
+An irrational-but-common approach would be to [[opinion:frater_secessus:beginner_mistakes#buying_random_stuff|buy stuff at random]] based on impulse,  marketing, or "good deals".
+===== troubleshooting problems =====
+There is a famous saying that
+> clearly stating the problem is 90% of the solution
+...so we are back to //observation// again.  One you can clearly state the nature of the problem continue to [[troubleshooting:electrical|this overview of troubleshooting]].

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