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opinion:frater_secessus:adding_dc-dc_charging_to_solar [2020/05/11 18:06] frater_secessus |
opinion:frater_secessus:adding_dc-dc_charging_to_solar [2020/10/11 19:48] |
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- | ====== Opinion: | ||
- | When combined with nontrivial amounts of solar, | ||
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- | **Reasoning: | ||
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- | * a $25 constant duty solenoid would get the bank up to Valt, at which point 70% of the current needed to charge Pb and 100% of the current needed to fully charge Li has already been provided. | ||
- | * a $100 voltage sensing relay would do the same. Cost more for the autoswitching magic and possible crude overcurrent protection via internal autoresetting breaker | ||
- | * a $200-400 DC-DC charger (CTEK, Renogy, Sterling, etc) would bring battery voltage right up to Vabs (14.4v). | ||
- | * Solar would just handle the high voltage, decreasing current Absorption proper. | ||
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- | What we are **paying $100-$175 extra for is raising voltage from 13.8v -> 14.6v faster than solar would have done it alone**. | ||
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- | Exceptions (where solar + DC-DC can be valuable): | ||
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- | * underpaneled systems that would struggle to make the 13.8v -> 14.6v slog on their own in normal insolation. | ||
- | * using a smaller DC-DC charger to limit the amount of power Li or large AGM banks can pull from the alternator | ||
- | * people who drive for hours at night (delivery folks, etc) | ||
- | * people who live in [[opinion: |