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--- electrical:12v:self-jumpstarting [2024/11/21 00:30]
frater_secessus [waking lithium batteries]
+++ electrical:12v:self-jumpstarting [2024/11/21 00:48] (current)
frater_secessus [DC-DC chargers]
@@ Line 34: / Line 34: @@
 ==== DC-DC chargers ====
-As with diode-based isolators, DC-DC chargers typically cannot pass power back from the battery bank to the vehicle; there are exceptions.  Read below for workarounds and different approaches.
+As with diode-based isolators, DC-DC chargers typically cannot pass power back from the battery bank to the vehicle.  Read below for workarounds and different approaches.
+Exceptions:
+  * the [[https://battlebornbatteries.com/product/wakespeed-48v-12v-bi-directional-dc-dc-converter/|BattleBorn/Wakespeed 48v/12v Bi-Directional DC-DC  charger]] can send 50% of it's rated power to the starter battery.
+  * the [[https://amzn.to/40WMp2L|Bluetti 800w alternator charger]] (DC-DC) has a starter battery maintenance function.
@@ Line 43: / Line 49: @@
 Note the Smartpass does this when added to the CTEK D250-series chargers.
-===== maintaining starter batteries =====
-Some [[electrical:12v:b2b#examples_-_combo_with_solar_charge_controller|combo DC-DC chargers]] contain logic to maintain the starter battery when solar power is present.
-Some standalone solar charge controllers like the [[https://amzn.to/2PPTD2L|Morningstar SunSaver Duo]] can, for example,  charge the start battery with 10% of solar harvest and the house battery with 90% using different charging profiles.  As with DC-DC above, it's not self-jumpstarting but can help prevent the dead starter battery.
-[[electrical:12v:alternator#voltage-sensing_relays|dVSR isolators]] (including [[electrical:12v:alternator#lithium-specific_vsr|the Li-BIM]]) automatically connect the banks when the voltage on either side reaches defined setpoints.
-Some Victron Multiplus models have a 4A starter battery maintenance feature.
-There are dedicated maintainers:
-  * Some RVs were equipped with original Trik-L-Start or lithium-compatible Amp-L-Start modules by LSL Products, which is [[http://www.lslproducts.net/|apparently out of business]].
-  * The [[https://amzn.to/47HMMyn|Xantrex echo charge]] maintains the chassis battery at up to 15A.
-Experimental:  RV With Tito has [[https://www.youtube.com/watch?v=exQSsTiclOo|uses a PWM solar charge controller to maintain starter battery from the house bank]].
-Also see [[electrical:12v:alternator#gotchas|the subarticle on combiner gotchas]].
-==== starter battery chargers alongside DC-DC chargers ====
-If a DC-DC is present and relatively weak shore power charging is applied to the starter battery there are circumstances where the DC-DC can cycle on-off constantly.  Let's consider a 20A DC-DC and a 10A starter battery maintainer.
-  - starter battery at 12.7v before charging applied
-  - starter battery voltage rises from 10A charging
-  - DC-DC sees >13.4v and [[electrical:12v:b2b#sizing|starts pulling ~22A]] to charge house battery at 20A
-  - starter battery drops to 12.6v and DC-DC charger stops
-   - repeat forever
-To avoid this scenario either:
-  * ensure the DC-DC rating is smaller than the starter battery rating; or
-  * apply the shore power charging to the house bank side instead((for DC-DC models with starter battery maintenance, see above))
@@ Line 88: / Line 57: @@
 'Dwellers may want to pick a jump pack that has 12v or USB outlets so it can have other uses.
+===== maintaining starter batteries =====
+[this section [[electrical:12v:maintaining_starter_battery|has been moved]]]

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