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electrical:12v:self-jumpstarting [2024/03/20 19:41] frater_secessus [starter battery chargers alongside DC-DC chargers] |
electrical:12v:self-jumpstarting [2024/03/20 19:52] frater_secessus [waking lithium batteries] |
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* ensure the DC-DC rating is smaller than the starter battery rating; or | * 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, | * 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' | ||
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+ | 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 | ||