mcgivor ✭✭✭✭


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  • Re: Time spent in absorption.

    In addition to Rick's valuable information, it's important to remember if there are any loads present the end amps feature may be offset by whatever the load draws, generally about 2% of battery Ah capacity is the normal setting, intermittent loads such as a refrigerator cycle so do not generally cause issues, just constant ones. The Absorb timer will terminate the absorption regardless of the end amps setpoint, so the timer setting is largely governed by the arrays capacity to provide enough energy, smaller wattage array  will require more time. In addition seasonal adjustments my be required to compensate for lower output, so it's really a custom setting which must be observed over time to find the sweet spot. FWIW, my controller has a default absorption time of 180 minutes adjustable in custom settings, end amps fixed at 2% of entered battery capacity and recharge at 25v should the float value drop below that setpoint, again custom adjustable. For the most part it works fine at default values but during the rare extended cloudy periods I have, I simply extended the time to 240 minutes, as long as your PV can supply 10% of the rated Ah capacity in charging current these values may be a good starting point.
  • Re: New setup off grid camper

    @Mattowens said,  If I go 24 volt can I use two charge controllers to each 24v battery keep my amperage down and then combine the batteries at the inverter? And can I use a pwm charge controller or in a condition like this do I need to go with an mppt which are much more expensive unfortunately running out of cash.

    Unfortunately PWM controllers will not work with the panels you have, assuming 60 cell 240W, the voltage would be too high for 12V, which I would not recommend, as well as being too low for 24V nominal, so either way a MPPT controller is required. 

    As far as running an air conditioning unit goes, the array and battery bank would have to be substantially larger than what you have outlined, trying to achieve this is an expensive challenge, especially if any cooling is required outside of peak sun, which is very limited.

    For informational purposes, there is no difference in capacity of a given battery wether configured 12 or 24 volts, example 12V × 600 Ah results in 7200 watt hours, similarly 24V × 300 Ah results in exactly the same 7200 watt hours, the benifit of higher voltage is smaller conductors fuses/breakers etcetera can bu used. Additionally the battery capacity shold be considered at 50% maximum of the calculation outlined above, this is the usable capacity, so as not to over discharge, which reduces life expectancy.

    It would be prudent to reconsider the air conditioning and build a system to support light or intermittent loads, there is little to no chance of achieving it on a limited budget. Please understand these comments are not intended to be negative, but rather pointing out some potential pitfalls most have experienced during the learning curve.
  • Re: Desuperheater

    A desuperheater is a heat exchanger used to scavenge wasted energy in the exhaust of superheated steam boilers. The only application I can think of  in solar energy, would be in a solar thermal power plants, usually large scale and complex, not for DIY applications.
  • Re: Is there any advantage to covering Solar Panels when Power is not needed for an extended Period ?

    Given the life expectancy of the panels is probably >20 years, the advantages of covering the panels may be in direct proportion to the length of time they are covered, merely speculation, granted the batteries can sit for periods without changing, from my understanding LiPo4 are better not to be on a consistent charge when not cycled, so the question may be, is it better to cover the panels to preserve the battery. Alternatively simply disconnect the charging source and absorb the loss in life expectancy, of the panels , which is probably minimal.
  • Re: Offgrid power options for crypto mining

    There is no way any battery storage system will work in your application and save money, it simply can't be done. EV use lithium technology, they are more efficient, able to deep cycle, would last longer with shallower depth of discharge, as would any battery, best not to fully charge and also way more expensive. If grid tied feeding into the grid is not an option, then a zero injection grid tied arrangement would offset useage during the day, but return on investment would be extensive.