12v for life build. No inverter. No PWM/MPPT.

Cariboocoot

Re: 12v for life build. No inverter. No PWM/MPPT.

waynefromnscanada wrote: »

That unfortunately is my experience in life as well. Furthermore, I've learned that life leads to death, no matter what we may try to change that fact.

I'm not so sure about that. I may already be dead and just too stubborn to lie down and stop wiggling.

stmar

Re: 12v for life build. No inverter. No PWM/MPPT.

When we bought our place the main frig was a Sun Frost FR-16 @ 24VDC. I had no experience with DC appliances so was skeptical that it would be sufficient, but 15 years later it is still our main frig. The guy I bought the property from said that it was a "lifetime" appliance, again I was skeptical but after some research I am more positive. The compressors and controls are on top and have plenty of ventilation/circulation around any heat creating components. When my inverter went down the frig was the only load on my alternative system, solar array (768 watts) and battery bank (512 amp hours), and it ran for several months with no problems and no other charge methods. With all the different options now available you should be able to pick and chose just about anything you are comfortable with so good luck in your quest.

jwh

waynefromnscanada said:

Re: 12v for life build. No inverter. No PWM/MPPT.

By the way, my great grandfather, before modern medicine and electricity, died a horrible slow death wracked with pain. 

wayne: heating systems (fireplace etc) pollute the air heavily, arsenic was common in the old days, electricity and xray diagnostics around since 1900.

jwh

waynefromnscanada said:

Re: 12v for life build. No inverter. No PWM/MPPT.

That unfortunately is my experience in life as well. Furthermore, I've learned that life leads to death, no matter what we may try to change that fact.

It is not about trying to avoid death, but rather avoiding being a vegetable in a wheelchair.

jwh

BB. said:

Regarding charge controllers... The Shunt Type (Flexcharge) are actually not the best way to charge a battery bank. Series type (PWM, MPPT, etc.) are more accurate and will give you a longer battery life (plus series charge controller systems are slightly less likely to fail in a dangerous manner--A failed shunt controller or shunt load will over charge the battery bank and can cause a fire--And why the NEC would require two shunt controllers in parallel--the second being a backup for the first).

Bill, thanks, but I'm finding a defense for FlexCharge.

It is not a "shunt type". It is a "series regulator" with the ability to divert excess solar power.

Google AI says this:

"...the manufacturer claims the Flexcharge method eliminates overcharging by allowing the battery to take exactly what it needs, rather than forcing a set voltage . They state that you can charge your battery bank indefinitely without overcharging."

BB.

Yes, that is true... It is both a series charge controller (main function) with a diversion output put.

https://www.flexcharge.com/products/
https://www.flexcharge.com/product/flexcharge-nc25a/

Don't get too "wrapped up" in electrical efficiency... There are lots of "variables" in calculating efficiency, and design choices, such as array voltage/controller type/length of cables, etc. that will effect overall system efficiency.

Also, in the "olden days" when solar panels cost $10-$30 a Watt... Saving 11 Watts could be $100+ savings in solar panels.

Today, with solar panels costing in the $0.50 to $1.00 per Watt (for high volume, large format panels), an 11 Watt power savings could be $0.05 to $0.11 saving in array/panel sizing.

My first suggestion is to measure your power needs (AmpHours or WattHours per day), and figure out your voltage needs (12/24/etc. DC/AC) and define your power/energy needs per day (by season--Winter/Summer/etc.).

More or less, it is not easy (and can be expensive) to send significant amounts of DC power any more than a few 10's of feet...

For example, how far can one send 100 Watts on 12 AWG copper cable with 0.5 VDC drop?

100 Watts / 12 volts = 8.33 Amps

Using a voltage drop calculator and playing with some numbers:

https://www.calculator.net/voltage-drop-calculator.html?necmaterial=copper&necwiresize=1&necconduit=steel&necpf=0.99&material=copper&wiresize=0.4066&resistance=1.2&resistanceunit=okm&voltage=12&phase=dc&noofconductor=1&distance=15&distanceunit=feet&amperes=8.33&x=Calculate&ctype=nec



Works out to around 15 feet using 12 AWG cable... Sending more power (current) longer distances, heavier copper cable...

I guess you are in Southern Arizona (by your IP address)... So you do have lots of sun compared to most areas in the USA...

For an array tilted at 31 degrees from Horizontal, fixed, facing south:
https://pvwatts.nrel.gov/pvwatts.php


So, lots of available sun all year round...

-Bill