This shows you the differences between two versions of the page.
electrical:solar:synopsis_puzzle2 [2017/07/31 17:06] frater_secessus [Synopsis: HandyBob's RV Battery Charging Puzzle 2] |
electrical:solar:synopsis_puzzle2 [2020/10/11 19:48] |
||
---|---|---|---|
Line 1: | Line 1: | ||
- | |||
- | |||
- | This page aims to distill the knowledge contained in HandyBob' | ||
- | |||
- | Particularly useful and pithy statements are quoted directly. | ||
- | |||
- | ====== Synopsis: HandyBob' | ||
- | |||
- | |||
- | |||
- | HandyBob and his wife are fulltimers in a 5th wheel and have no generator. | ||
- | |||
- | ===== charging batteries is like airing up tires ===== | ||
- | |||
- | |||
- | > " | ||
- | |||
- | ===== volts, volts, volts ===== | ||
- | |||
- | |||
- | Manufacturers give absorption voltages ranging 14.4V - 14.8V (temp compensated) and that is not too high. | ||
- | |||
- | Chargers do not read specific gravity, but can estimate [[electrical: | ||
- | |||
- | > " | ||
- | |||
- | > "The difference between 14.4 & 14.8 volts is not 3%. That difference is nearly 20% of the charging range (12.2 to 14.8 volts)" | ||
- | |||
- | Use short runs and oversized wires to minimize voltage drop. | ||
- | |||
- | |||
- | ===== battery monitors ===== | ||
- | |||
- | Most OEM monitors (led displays, gauges, and idiot lights) are bad, tricking the owners into believing their batteries are fuller than they are. The monitors will read too high when charging and too low when discharging. | ||
- | |||
- | The battery bank must rest at least an hour before a reasonably accurate measurement can be made. A hydrometer reading is best but a multimeter will get you in the ballpark: 12.7V is full and 12.2V is 50% state of charge (the bottom of the deep cycle). | ||
- | |||
- | Battery bank life will be longer when it is charged fully and not discharged past 50% DoD. A full charge is also important to capacity: | ||
- | |||
- | > "a 95% charged battery has 10% less usable power in it than a 100% charged one, since you are trying to keep it in the top 50% of its operating range (5% of full = 10% of 50%.)" -- HandyBob | ||
- | |||
- | |||
- | ===== recording meters ===== | ||
- | |||
- | Bob recommends the use of AH e-meters like Link or the Trimetric 2020/2025: | ||
- | |||
- | > " | ||
- | |||
- | The meters will require configuration/ | ||
- | |||
- | It is common to find appliances use less power than their placards state: | ||
- | |||
- | > "The label has to show what the appliance will not exceed, not the actual energy use." | ||
- | |||
- | |||
- | ===== batteries ===== | ||
- | |||
- | Bob recommends matched 6v golf cart batteries. | ||
- | |||
- | Get charging specs from the manufacturer and follow them; this is particular important with new or exotic chemistries. | ||
- | |||
- | In multibattery systems the connecting cables should be the same length and gauge. | ||
- | |||
- | |||
- | ===== converters ===== | ||
- | |||
- | Most OEM [[electrical: | ||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||
- | |||