Differences

This shows you the differences between two versions of the page.

--- electrical:12v:multipoint_charging [2022/05/25 12:26]
frater_secessus [why one source wins]
+++ electrical:12v:multipoint_charging [2024/03/29 18:55] (current)
frater_secessus [gotchas]
@@ Line 45: / Line 45: @@
 Barring heroic measures((exotic alternators/regulators, [[electrical:12v:b2b|DC-DC chargers]])) the alternator is going to stop contributing at some point during Bulk charging.  That is ok, the alternator provided a ton of current while it was charging.
-But if you want to the charge controllers (and some [[electrical:converter|converters]]) can be convinced to stay //roughly// in sync and keep charging together.  This is done by **configuring the Absorption and Float setpoints on the controllers to be the same**.((including Absorption termination setpoints like time or current))  There will be short periods where one controller makes a change before the other, but for most of the time both will be contributing at the same time.
+But if you want to the charge controllers (and some [[electrical:converter|converters]]) can be convinced to stay //roughly// in sync and keep charging together.  This is done by **configuring the Absorption and Float setpoints on the controllers to be the same**.((including Absorption termination setpoints like time or current))  There will be short periods where one controller makes a change before the other, but for most of the time both will be contributing at the same time.  Even if they contribute unequally it is a non-issue because the voltage setpoint is being held.  If a big load is added or conditions deteriorate it will be "all hands on deck" as in the Bulk stage scenario above.
 Note:  there are high-end controllers/chargers which communicate with each other to coordinate charging.  That feature is beyond the scope of this article.
@@ Line 63: / Line 63: @@
 Some of these are observed, and some are theoretical.
-  * the vagaries of voltage sag across the system may result in the various charging sources seeing slightly different voltages.  Voltage Sense wires can help with this issue.
+  * the vagaries of voltage sag across the system may result in the various charging sources seeing slightly different voltages and therefore contributing in unpredictable ways.((probably a non-issue as long as the bank is getting properly charged))  Voltage Sense wires can help with this issue.
-  * Multiple controllers set up to trigger Float from endAmps((trailing amps)) may enter float early since they are providing only some of the charging current.
+  * Multiple non-communicating controllers set up to trigger Float from endAmps((trailing amps)) may enter float early since they are providing only some of the charging current.
-  * Multiple sources may inadvertently exceed the bank's recommended charging current
+  * Multiple sources may inadvertently exceed the bank's recommended charging current, or your preferred current.  Example:  a lithium battery wants 50A max but each charging source can make 30A.  This might result in overcurrent (60A) during Bulk.
-  * theoretical:  low-frequency PWM controllers in parallel with MPPT controllers may confuse the MPPT with a varying Vbatt reference.
+  * theoretical:  low-frequency PWM controllers in parallel with MPPT controllers may confuse the latter with an unstable reference voltage.
+  * some systems may throw a warning if chassis voltage > alternator output voltage((https://www.cruisersforum.com/forums/f14/alternator-solar-panel-conflict-233083.html))

RV and vandwellers wiki

User Tools

Site Tools

Differences

Page Tools