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electrical:12v:self-jumpstarting [2024/02/19 02:39] frater_secessus [jump packs] |
electrical:12v:self-jumpstarting [2024/03/20 19:52] frater_secessus [waking lithium batteries] |
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Note the Smartpass does this when added to the CTEK D250-series chargers. | Note the Smartpass does this when added to the CTEK D250-series chargers. | ||
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===== maintaining starter batteries ===== | ===== maintaining starter batteries ===== | ||
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Some standalone solar charge controllers like the [[https:// | Some standalone solar charge controllers like the [[https:// | ||
- | [[electrical: | + | [[electrical: |
Some Victron Multiplus models have a 4A starter battery maintenance feature. | Some Victron Multiplus models have a 4A starter battery maintenance feature. | ||
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Also see [[electrical: | Also see [[electrical: | ||
+ | ==== 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. | ||
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+ | - starter battery at 12.7v before charging applied | ||
+ | - starter battery voltage rises from 10A charging | ||
+ | - DC-DC sees >13.4v and [[electrical: | ||
+ | - 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, | ||
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+ | |||
+ | ===== waking lithium batteries ===== | ||
+ | |||
+ | Lithium banks can go dormant at low voltages in order to protect themselves: | ||
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+ | - the BMS turns off the DISCHARGE channel to keep cell voltage from going any lower | ||
+ | - so the battery internally has ~11.0v or whatever but does not pass that voltage to the terminals on the outside of the battery case | ||
+ | - which means smart chargers don't see battery voltage | ||
+ | - and think there' | ||
+ | |||
+ | What we need is a //dumb// voltage source to get the party restarted. | ||
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+ | * Rigs with IGN-triggered relays can briefly turn the key to ACC then back off.((don' | ||
+ | * Rigs with voltage-sensing relays will have to actually start the engine or press a manual override switch to activate the VSR and wake the lithium bank. | ||
+ | * Rigs with diode- or FET-based isolators would start the engine to spin the alternator and get power flowing through the isolator to the sleeping lithium | ||
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+ | ===== jump packs ===== | ||
+ | [[https:// | ||
+ | ' | ||