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--- opinion:frater_secessus:run_this_load [2024/04/20 22:30]
frater_secessus [TL;DR]
+++ opinion:frater_secessus:run_this_load [2024/05/09 15:44] (current)
frater_secessus [watt-hours]
@@ Line 8: / Line 8: @@
   - current (power), in Amps (A)
   - Watt-hours (Wh) ((or Amp-Hours)) (energy)
+  - any [[electrical:12v:power_mix|charging sources]] that are active at the time
   - recharging afterward
@@ Line 46: / Line 47: @@
-==== watt-hours ====
+===== watt-hours =====
+Energy use is often done in Watt-hours, although Amp-hours will also work.
 This is time (hours) x watts.  Our 518W (39.3A at 12v) load run for 20 minutes would be ~173Wh (518 x 20 minutes / 60 minutes in an hour) or 13.1Ah.
+Battery chemistries have recommended depths of discharge.
+  * Lead batts are usually run down to 50%, so we would need at least 28.8Ah of lead to run our 173Wh load for one day (173Wh / 0.5 / 12.0v nominal).
+  * LiFePO4 batts are usually run down to 20%, so we would need at least 16.9Ah of LFP to run our 173Wh load for one day (173Wh / 0.8 / 12.8v nominal).
+Then multiply by the "days of autonomy" (ie, without recharging).  If you want two days then multiply the above by 2, for example. If you know you will be able to recharge fully each day then days of autonomy is 1.
+Note that running loads while sufficient charging is active is basically a freebie and does not count against the battery capacity.((it //will// slow down recharging if done during Bulk or and //may// slow down recharging in Absorption stages))

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