If LiFePO4 can handle total discharge, your figure of $1152 for 2kWh is not that far from "the old standard" - at $576kWh (LiFePO4). At 25% discharge, where Flooded Lead Acid batteries will live,on the T-105 would take it to $533kWh (FLA).
I think some research into any problems the newer technology may have are in order. With the smaller size and lighter weight of battery storage and "IF" the battery storage is safe inside a home, the cost of batteries, wire runs and storage MIGHT be cheaper with LiFePO4 now.
Ron Adventure is just bad planning." -- Roald Amundsen
You see, im scared away, from this comparison,because, Im trying to figure 'AH' at 12v.
Lets say, my battery has a storage capacity of '40' amphours[AH] at 12 volts.
It will run my 'television entertainment centre' for 80 minuites.
Which I consider 'good' if the kid takes over the remote.(because, in switching the batts, I can send the little one to bed :) Im sure this cuts energy usage...
Now, if train 'a' heads to the station at '25mph' and train 'b' heads to the station at '75mph' AND,,, they both get there at the same time(thank god for magnetic braking), which one was farther away, train 'a' or 'b' ?
JW[ Parent ]
Does it matter?
Actually, if you are going to any electrical work, Ohm's Law is one of the first things you need to learn. It will help you in wire sizing, fuse sizing, battery sizing, inverter sizing and wind turbine and solar panel guessing. You will learn why 100W of 12V soler panel only net you 60 Watts in your storage device and why the battery bank is still too small... no matter what you do...
And to actually answer the train question, one would need to know, "At what time". The 25mph train may have started its' trip last week and the 75mph train at lunch.
Ron Adventure is just bad planning." -- Roald Amundsen [ Parent ]
Now Ron,
Its harder than most will tend to realize, to get a reply from yourself umm, um.
"Does it matter?"
Well, yes Ron, it does. :)
If I have only 2, 6volt batterys, with an amphour rating of 255 they would have to be wired in series to get 12volts, so 'I' times 'V' equals 'P'. Yet there amphour capacity cannot increase higher than 255 wired in series at 12 volts.
Why is there such a difference with top capacity, such as with a 12volt batt, like 125 amphour? There basically the same size and physical weight?
Further more, unless you give some basic consideration to series-parallel circuit law, the 6 volt batterys you speak of, only confuse the issue.
:):):):):)
JW
[ Parent ]
To make things simple take your Voltage X Amperage and you will get Watts. In our 'amperage' figure there is a time, the hour, so our final figure is in Watt Hours.
12V X 255AH = 3060Wh or, converting to kWh, 3.06kWh at 100% discharge.
Now note if we had worked with 6V Batteries it would have been 6V X 255AH = 1530WH and we would have needed to multiply by the umber of batteries (2) and we end up at the same place.
The 'real' way to calculate power is a lot more interesting and involves a bit of higher math than we want to go into here. It also yields similar results. The power in the bank is the number of batteries X the capacity of each battery.
Don't forget, that is at 100% discharge. The figures need to be lowered for any practical application.
LiFePO4 can handle total discharge without degradation (it does require a per-cell low voltage disconnect to do it though).
No explosive gasses generated whilst charging. Also, unlike some earlier Lithium technologies, the newer LiFePO4 won't randomly turn into incendiary devices.
With their much lighter weight, hiding them in the roof cavity may be an option, whereas lead acid are too heavy to do this.
Amanda[ Parent ]
From memory, Lipo technologies is well known to have less than 400 life cycles of duty. The cells have a nominal voltage of around 3.7v. It has been up until now, however, had the best charge rates and discharge rates. However, it needs a very controlled charge rate and temperature or fire or worse explosions can result. This is the technology of cellphones and laptops.
Nicad has a great discharge rate and charge rate, relatively robust, and long cycle life--1000 cycles. A nominal voltage of 1.2v. The problems have been primarily toxicity of cadmium and capacity (less capacity than NiMH and Lipo).
NiMH have good capacity (less than Lipo), relatively non toxic, relatively robust, much more so than Lipo but less than Nicad--500 cycles. Also 1.2v LSD (Low Self Discharge) NiMH, also sometimes call NiOOH. This version of the NiMH cell have less capacity than NiMH but have low self discharge, longer life than a plain NiMH cell around 1000 cycles. Also 1.2v nominal
LiFePo4 are the new technology. 3.3v nominal. A very robust technology. Much more robust the Lipo, even greater charge discharge rates than Lipo. Greater cycle life than all of the above technologies 1000-3000 cycle life (manufacturers vary in quality and also DoD (Depth of Discharge) does have an impact on the life cycle). Relatively non-toxic.
So, as you can see, there is a big difference to your cellphone battery with this new technology. There are currently quite large intellectual property battles going on with the new LiFePo4 technology. Personally, I'm waiting for the smoke to settle. While I wait I am happy with my eneloop LSD cells, they are great.[ Parent ]
