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electrical:12v:directcharginglfp [2024/03/20 12:01] frater_secessus [assessing your own setup for direct alternator charging] |
electrical:12v:directcharginglfp [2024/04/04 11:51] frater_secessus [reasons NOT to attempt direct charging] temp |
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* you have a **small or already-overloaded alternator** | * you have a **small or already-overloaded alternator** | ||
* you **already own a DC-DC** | * you **already own a DC-DC** | ||
+ | * your BMS has no low temp charging disconnect and you have no desire to work around that((to be fair, this also rules out DC-DC that lack low-temp disconnect)) | ||
* you **want predictable charging rates**, like 40A over the next hour. DC-DC will provide this((barring interference from big chassis loads, BMS protections, | * you **want predictable charging rates**, like 40A over the next hour. DC-DC will provide this((barring interference from big chassis loads, BMS protections, | ||
* you want **stable charging rates** regardless of state of charge((acceptance will taper in Absorption if present)) | * you want **stable charging rates** regardless of state of charge((acceptance will taper in Absorption if present)) | ||
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- test it with a drive. | - test it with a drive. | ||
- repeat the last two steps with the Li bank at lower and lower states of charge, down to the lowest state of charge you expect to recharge from alternator. | - repeat the last two steps with the Li bank at lower and lower states of charge, down to the lowest state of charge you expect to recharge from alternator. | ||
- | - disconnect the isolator with **a switch** when you come to the desired SoC, when charge rate exceeds your preferences, | + | - celebrate |
**Caveats**: | **Caveats**: | ||
* Only alternator charge while driving ([[rv: | * Only alternator charge while driving ([[rv: | ||
- | * Pay attention while charging from alternator to keep from overcharging the Li or holding for long periods at high [[electrical: | + | * Pay attention while charging from alternator to keep from overcharging the Li or holding for long periods at high [[electrical: |
- | * Fuse the wiring from the chassis so the bank cannot pull more than you specify | + | * if current is excessive but you want to direct-charge, |
- | * if current is higher than you want consider adding resistance | + | |
===== the parts list ===== | ===== the parts list ===== |