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electrical:12v:self-jumpstarting [2022/04/30 10:37] frater_secessus [maintaining starter batteries] |
electrical:12v:self-jumpstarting [2024/03/20 19:52] frater_secessus [waking lithium batteries] |
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====== Self-jumpstarting ====== | ====== Self-jumpstarting ====== | ||
- | Self-jumpstarting means jumpstarting one's own vehicle without the use of another vehicle. | + | Self-jumpstarting means jumpstarting one's own vehicle without the use of another vehicle. |
+ | Note: regardless of specific method used, it will be gentlest on the system to **combine the batteries and wait a few minutes for the starter battery to come up** instead of immediately attempting to start. This will minimize the amount of current flowing from house bank to vehicle chassis. This may be especially important with Li chemistries that have BMS protections. | ||
===== jumping from the house bank ===== | ===== jumping from the house bank ===== | ||
- | It will be gentlest on the system to combine the batteries and allow the starter battery to come up a bit instead of immediately attempting to start. | ||
This will be easiest if one already has some kind of [[electrical: | This will be easiest if one already has some kind of [[electrical: | ||
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* [[https:// | * [[https:// | ||
* Precision Circuits [[http:// | * Precision Circuits [[http:// | ||
+ | * [[https:// | ||
==== diode isolators ==== | ==== diode isolators ==== | ||
- | [[electrical: | + | [[electrical: |
==== DC-DC chargers ==== | ==== DC-DC chargers ==== | ||
- | As with diode-based isolators, DC-DC chargers | + | As with diode-based isolators, DC-DC chargers |
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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. | ||
- | ===== jump packs ===== | ||
- | [[https:// | ||
- | ' | + | 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:// | ||
+ | * The [[https:// | ||
+ | Experimental: | ||
+ | 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. | ||
+ | - 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: | ||
+ | |||
+ | - 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. | ||
+ | |||
+ | * 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:// | ||
+ | |||
+ | ' | ||