This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision Last revision Both sides next revision | ||
electrical:solar:car [2020/06/24 13:30] frater_secessus [rack-mounted panels] |
electrical:solar:car [2024/01/04 12:56] frater_secessus [performance] |
||
---|---|---|---|
Line 3: | Line 3: | ||
Solar power can be extremely helpful for car dwellers, especially those living in [[rv: | Solar power can be extremely helpful for car dwellers, especially those living in [[rv: | ||
Solar is more challenging for cardwellers due to limited roof space. | Solar is more challenging for cardwellers due to limited roof space. | ||
+ | |||
+ | Framed panels can easily be hidden between the rails of a roof rack. While suboptimal, flex panels can be adhered flat on the roof. Neither are obvious to passers-by. | ||
===== panels ===== | ===== panels ===== | ||
==== rack-mounted panels ==== | ==== rack-mounted panels ==== | ||
Line 15: | Line 17: | ||
* can use the least expensive and most durable (framed) panels | * can use the least expensive and most durable (framed) panels | ||
* the panels get some breeze under them to minimize [[electrical: | * the panels get some breeze under them to minimize [[electrical: | ||
- | * cable gland, low profile vent, etc, can be mounted under the panel | + | * [[https:// |
* less panel heat transferred into the living space | * less panel heat transferred into the living space | ||
* if flush mounted between the racks it can be quite stealthy | * if flush mounted between the racks it can be quite stealthy | ||
Line 29: | Line 31: | ||
* [[http:// | * [[http:// | ||
* [[https:// | * [[https:// | ||
+ | * [[https:// | ||
+ | * [[https:// | ||
==== portable panels | ==== portable panels | ||
Line 64: | Line 68: | ||
**Con:** Most expensive Watt/ | **Con:** Most expensive Watt/ | ||
===== batteries ===== | ===== batteries ===== | ||
- | FIXME | + | |
+ | Batteries are bulky and relatively heavy; | ||
+ | |||
+ | ==== where to put a battery ==== | ||
+ | |||
+ | From front to rear: | ||
+ | |||
+ | * **under the hood** - it is unlikely there is enough room under the hood for an aux battery, but some older full-size vehicles may allow it. Upside: | ||
+ | * **in the passenger area** - Upside: | ||
+ | * **in the trunk** - Upside: | ||
+ | * **in a carrier rack** - a secure cargo box may be fitted on a reciever hitch carrier. | ||
+ | |||
+ | |||
+ | |||
+ | ==== battery types ==== | ||
+ | |||
+ | Deep cycle batteries appropriate for off-grid use are discussed in [[electrical: | ||
+ | |||
+ | * **flooded lead-acid** (FLA) - difficult to have in the passenger area due to venting requirements and small interior spaces. | ||
+ | * **" | ||
+ | * **" | ||
+ | * **AGM lead battery** - a lead battery where the liquid electrolyte is replaced with a saturated fiberglass mat. Theoretically spillproof. | ||
+ | * **Gel lead battery** - gel has excellent longevity((lifetime cycles)) but is sensitive both to overcurrent and overvoltage. | ||
+ | * **LiFePO4 lithium battery** (LFP) - [[electrical: | ||
+ | * **non-LFP lithium battery** - Non-LFP lithium batteries do exist but the bank voltage doesn' | ||
+ | * **" | ||
+ | |||
===== charge controllers ===== | ===== charge controllers ===== | ||
- | FIXME | + | Solar panels don't connect directly to batteries. |
+ | |||
+ | Part of the article linked above covers [[electrical: | ||
+ | |||
+ | |||
+ | If you have a solar generator a solar controller of some kind is built into it. | ||
+ | |||
+ | In any case, read the specs carefully to make the panels you like will work with it. The critical piece is something like **maximum input voltage**. | ||
+ | |||
+ | ====== alternator charging ====== | ||
+ | |||
+ | While cars tend to have smaller alternators than vans they can still be a source of significant power compared to solar. | ||
+ | |||
+ | * small [[electrical: | ||
+ | * relay [[electrical: | ||
+ | |||
+ | |||
+ | ====== example setups ====== | ||
+ | |||
+ | The following DIY setups sketch out what off-grid power systems for cardwellers might look like. These are ideas to compare against your own use case and [[electrical: | ||
+ | |||
+ | ===== general principles ===== | ||
+ | |||
+ | The [[electrical: | ||
+ | |||
+ | 100w **solar panels** are ~$1/ | ||
+ | |||
+ | Larger battery banks don't just store more energy, they allow higher charging rates from the alternator((or solar, but most cars don't have enough room for that much solar)) without stressing the battery)). | ||
+ | |||
+ | ===== $800 ===== | ||
+ | |||
+ | This is a relatively large setup for a cardweller, but at this point we get to leverage the economies of larger batteries and used panels. | ||
+ | |||
+ | * 250w [[electrical: | ||
+ | * [[electrical: | ||
+ | * [[https:// | ||
+ | * small PSW inverter like [[https:// | ||
+ | |||
+ | Dropping to 50A LFP would decrease cost to ~$510. All numbers below would stay the ~same.((alternator should be limited to 25A charging, so 166Wh instead of 200Wh harvested)) | ||
+ | |||
+ | Actual power harvest would vary depending on the amount of driving (alternator), | ||
+ | |||
+ | |||
+ | ==== performance ==== | ||
+ | |||
+ | Solar, conditions described above | ||
+ | |||
+ | * summer (June) - ~200Wh alternator + 1,483Wh solar = **1, | ||
+ | * winter (December) - ~200Wh alternator + 401Wh solar = **602Wh/ | ||
+ | |||
+ | loads | ||
+ | |||
+ | * DC ~50A (650w)((solar might provided another 213w under optimal conditions, allowing loads up to 663w without exceeding LFP's typical 0.5C sustained discharge spec)) | ||
+ | * AC (inverter) ~40A (520w) | ||
+ | |||
+ | ===== $650 ===== | ||
+ | |||
+ | As above, replacing the DC-DC/MPPT combo with separate relay/VSR and 20A MPPT. Solar harvest stays the same, but I'll estimate average alternator harvest [[https:// | ||
+ | |||
+ | |||
+ | * summer (June) - ~130Wh alternator + 1,483Wh solar = **1, | ||
+ | * winter (December) - ~130Wh alternator + 401Wh solar = **531Wh/ | ||
+ | |||
+ | |||
+ | ===== $480 ===== | ||
+ | |||
+ | Simplifying with PWM controllers and relays instead of DC-DC. | ||
+ | |||
+ | * 50A LiFePO4, $160 | ||
+ | * combiner or VSR for alternator charging - $50 | ||
+ | * 2x 100w panel - $200 | ||
+ | * 20A single stage PWM charger - $20 | ||
+ | * small PSW inverter like [[https:// | ||
+ | |||
+ | |||
+ | ==== performance ==== | ||
+ | |||
+ | Solar, same assumptions as the above | ||
+ | |||
+ | |||
+ | * summer (June) - ~65Wh alternator + 488Wh solar = **1, | ||
+ | * winter (December) - ~65Wh alternator + 284Wh solar = **349Wh/ | ||
+ | |||
+ | loads | ||
+ | |||
+ | * DC ~25A (325w) | ||
+ | * AC (inverted) ~20A (260w) | ||
+ | ===== $300 ===== | ||
+ | |||
+ | Half the solar brings the cost (and harvest) down: | ||
+ | |||
+ | * 50A (640Wh) LiFePO4 | ||
+ | * combiner or VSR for alternator charging - $50 | ||
+ | * 100w panel - $100 | ||
+ | * 10A single stage PWM charger - $15 | ||
+ | * small PSW inverter like [[https:// | ||
+ | |||
+ | ==== performance ==== | ||
+ | |||
+ | |||
+ | Solar, Same assumptions as the above | ||
+ | |||
+ | * summer (June) - ~65Wh alternator + 488Wh solar = **553Wh/ | ||
+ | * winter (December) - ~65Wh alternator + 142Wh solar = **207Wh/ | ||
+ | |||
+ | loads | ||
+ | |||
+ | * DC ~25A (325w) | ||
+ | * AC (inverted) ~20A (260w) | ||
+ | ===== $110 ===== | ||
+ | |||
+ | per [[electrical: | ||
+ | |||
+ | * 100w panel - $100 | ||
+ | * 10A single stage PWM charger - $15 | ||
+ | |||
+ | ==== performance ==== | ||
+ | |||
+ | Solar, same assumptions as the above | ||
+ | |||
+ | * summer (June) - 488Wh solar = **488Wh/ | ||
+ | * winter (December) - 142Wh solar = **142Wh/ | ||
+ | |||
+ | loads | ||
+ | |||
+ | * DC ~10A (130w) | ||
+ | * no AC (inverter) loads |