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Opie91 · 20-11-2013, 06:25

LifePO4 goes airborne in a substantial way:

True Blue Power Announces Advanced Lithium-ion Batteries | Aero-News Network

True Blue Power® | Aircraft Inverters, Batteries and Emergency Power Supplies

Lithium Iron Phosphate Battery Technology | A123 Systems

hellosailor · 20-11-2013, 11:18

http://www.crainsdetroit.com/article...f-a123-systems#

Despite A123's technology they went belly-up bankrupt and took a big piece of US development money with them. Apparently the Chinese think they can make a success of the same products despite the fact that A123 could not do so previously.

Lower energy density than other lithium chemistries, versus arguably higher safety. That should still appeal to some markets.

Wraith_Mac · 20-11-2013, 19:51

LOL, 'Stalking horse bids' are not exactly going belly up, indeed nothing like it.
The A123 media releases from 2012 and 2013 paint a broader picture of what really happened.
http://www.a123systems.com/f68f383b-...ses-detail.htm
A123s are marketed [their website] mainly for power [Hi C] use, overkill for house banks IMO.
Mac

deckofficer · 20-11-2013, 19:54

Quote:

Originally Posted by Wraith_Mac

LOL, 'Stalking horse bids' are not exactly going belly up, indeed nothing like it.
The A123 media releases from 2012 and 2013 paint a broader picture of what really happened.
http://www.a123systems.com/f68f383b-...ses-detail.htm
A123s are marketed [their website] mainly for power [Hi C] use, overkill for house banks IMO.
Mac

Yep, those cells were the darlings of the EV racing crowd.

Opie91 · 21-11-2013, 05:41

Quote:

Originally Posted by deckofficer

Yep, those cells were the darlings of the EV racing crowd.

Not suggesting anyone should use these in a boat, just pointing out that LiFePO4 has made it into aviation with a decent sized battery. As far as I can tell this is the first successful attempt to use this technology as a main ship battery.

Besides Mid-Continent Instrument Co. is a reputable aviation supplier which should speak well for LiFePO4.

senormechanico · 21-11-2013, 08:43

A bit OT, but an interesting read.

Super Capacitors are sneaking up on batteries:

http://www.mouser.com/applications/n...tent=articlerm

deckofficer · 27-11-2013, 10:09

In this group I probably have the smallest LiFePO4 bank, so it would be easier for me to rack up the cycles than others. Since my trusty 25 year old Trace 2012 inverter is 400 miles from my current location and heavy to boot, I bought another 2000 watt inverter that weighs 1/6 as much (8 lbs) and will be handy to use. I should be able to rack up 5 cycles and charges per day during the winter. The new inverter has a low battery alarm that sounds off at 11.5 volts, so when the alarm sounds I turn off the 1500 watt heater and record the time that it ran. Since yesterday have cycled 7 times, resting cell voltage at start is 3.38 volts. Voltage after 59 minutes of powering the space heater and low voltage alarm is 2.95 volts. Then charge at 50 amps for a bit over 2 hours and repeat. I made life easy on me by connecting (2) Anderson plugs to the inverter, one for the battery bank and the other for the charger. 3 years ago I got hit with a snow storm that knocked out power for 5 days. I have a pellet stove for heat but it needs 120 VAC to run the fire box blower and distribution fan and also the pellet auger. Also needed to power the refrigerator, lights at night, etc. I did this by running a small generator 24/7 and going through all the gas I had in jerry cans and most of the gas in the hot rod. I'll be ready if it happens again, that is why I placed (2) Anderson connectors on the inverter as that will allow me to swap out a depleted bank for a charged bank without turning off the inverter. I calculate the load of the fridge and pellet stove to be low enough that each bank will run for 10~12 hours, so instead of 24/7 generator run time it will be reduced to about 4 hours per day for charging the banks. Plus I lost a little heat from the house running the AC cord from the generator on the back deck through a sliding glass door into the house. Won't need to do that for the next power outage.

Charging at 49.4 amps.

**Cotemar** · 27-11-2013, 10:45

deckofficer,

Is their any way to fast charge these LifePO4 batteries in less than 4 hours?

deckofficer · 27-11-2013, 11:08

The batteries have no problem with fast charging, I just have a 50 amp charger so it takes me 2 hours. They can be charged in 20 minutes if I had a 300 amp charger. My main purpose is to prove that they have a cycle life of 2000 cycles before dropping to 80% of rated capacity. I will try and cycle at least 5 times a day on this one bank. My feelings are since the manufacturer's were so conservative in their a-hr rating, I'm betting their cycle life claims were also conservative. Instead of waiting 10 years to find out from others using them in the field, I hope to find out in 2 years.

**Cotemar** · 27-11-2013, 11:47

I have LifePO4 batteries in my self balancing electric unicycle. The LifePO4 batteries allow me to go 12 miles at 12 MPH on one charge.

The fast charger tops the battery off in 45 minutes.

It's a personal thrill rides that allow me to cover the islands I visit without getting all sweaty on a bike. It easier and lighter to carry in the dinghy.

deckofficer · 27-11-2013, 12:49

I've seen those on the Internet. Since your no Spring chicken like me, how long did it take to master it? Also, do you have any sore muscles after extended rides?

**Cotemar** · 27-11-2013, 13:04

Quote:

Originally Posted by deckofficer

I've seen those on the Internet. Since your no Spring chicken like me, how long did it take to master it? Also, do you have any sore muscles after extended rides?

I did my first fifteen minutes of practice in my home hallway going back and forth using the walls for support then coasting out into my living room.

Needed more room, so I did 45 minutes in my driveway.
I only needed one hour before feeling comfortable going onto my street for a spin.

The users manual says that it should take three hours practice before going out into the street.

You have to be prepared for everyone stopping their cars and talking to you. They attract a lot of attention.

Riding the Solowheel to work - every days obstacle course - YouTube

deckofficer · 27-11-2013, 13:15

Any muscles get sore from long rides?

deckofficer · 27-11-2013, 13:25

This is why I like 48 volt battery banks for heavy inverter loads. Running 1500 watts at 12 volts is pulling 125 amps and no matter how short your leads are, they will get hot along with the 50 amp Anderson connectors and each cell connector on the bank. To continue these cycle tests I have positioned the battery, cable and connectors behind the inverter so that the (3) fans on the inverter that cycle 50% of the time will help cool everything that is getting hot from repeated cycles. If I was running at 48 VDC then the amp draw would be 31 amps and that would be a fraction of the heat.

It also appears LiFePO4 cells like to be cycled a bit. First off, these cells were already 3 years old when I got them. I top and bottomed balanced them and then cycled them about 5 times and then they sat unused for another year. The first cycle yesterday saw 57 minutes powering the 1500 watt heater before the low voltage of 11.5 volts alarm sounded. By the end of yesterday's cycles it increased to 59 minutes before alarm. Today that trend is still going and the last cycle went 62 minutes.

You just have to love these LiFePO4 cells. My 4 year old 100 a-hr cells deliver 125 amps for 1 hour and 2 minutes with 20% remaining. This would be hard to believe if I wasn't seeing it first hand, plus I'm staying warm.