LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[roetter]

Originally Posted by deckofficer

roetter,

My guess is with as many gray days that you have had, your pleased with the performance of your (8) 700 a-hr Balqon discount cells?

Grinning from ear to ear.

[deckofficer]

Originally Posted by roetter

Grinning from ear to ear.

Yep, it is a huge step up in performance going from lead to lithium.

My next project has me researching for the next step in lithium performance and since there is no forum for electric aircraft, I thought I'd pose my ideas here for constructive feedback. I can count on one hand the number of companies that offer an electric plane. It appears to me that for battery selection these companies have simply chosen the highest energy density that also has the highest C rate for discharge. Take off and climb out does require a lot of power vs cruise speed so I understand their logic, but the price of these pouch cells that fit the criteria is sky high, no pun intended. On a simple powered trike with a hang glider wing the battery bank cost is $8500 for 5.6 kwh. I have experience with the Winston cells and 5.6 kwh is $1900, big difference. But the Winston cells are 36% heavier (which is a big deal when flying), and only have a 3 C discharge rate, not quite enough for a strong take off and climb. In defense of the Winston cells they have a cycle life of 2000 cycles (@80% DOD) and the expensive pouch cells used in the aircraft only has a 700 cycle life. In my search to find a battery with high C and decent energy density I have come across Headway 40152S 15ah LiFePO4 cell. This cell is a 3.2 volt LiFePO4 that is rated at 15 a-hr and 10 C. 480 grams and a 2000 cycle life, so a bit heavier than the pouch cell but lighter than the Winstons that I have now.

Has anyone here used the Headway 40152S 15ah LiFePO4 Cells?

http://www.evassemble.com/index.php?...roducts_id=175

[T1 Terry]

Hi Bob,
Be prepared for a number of duds, the solder tab type will give you less grief, if you do the soldering. The spot welding done by most of these mobs leaves a lot to be desired. I bought a LiFeP04 power assisted push bike with a 20 Ah battery pack, it ran out of puff after a very short time. I pulled it pieces (as you do) and discovered less than half the cells at each end of the pack (18 cell in parallel x 8 in series) were actually attached vie the spot weld. A repair using the trusty soldering iron and stripped out copper from 6mm auto cable seems to have it back up and running sweetly.
What about building a pack using 18650 cylindrical cells/ If you want serious discharge rates http://www.hobbyking.com/hobbyking/store/__16575__A123_3_3VB_Lithium_Ion_2300mAh_Single_Cel l_Battery.html or a cheaper to give you capacity to by building enough discharge rate http://dx.com/p/18650-rechargeable-lithium-lifepo4-battery-1350mah-5105 this is for 2 cells and bulk gets a better discount.

Now, where can you buy a microlight trike with electric propulsion? A microlight is on my bucket/wishlist, lithium powered would be nearly too much to resist

T1 Terry

[deckofficer]

T1 Terry, we share some of the same interests.

I'll research your suggestions, thanks. Do they have better specs than my link? I plan to go with the threaded ends for using buss bars to make a 32S3P pack. That would be 96 volt (102.4 volt) 45 a-hr bank. Total 96 cells at 480 grams, 101 lbs and good for 10 C discharge (450 amp), for a cost of $2283 for 4.7 kwhr bank.

The other choice is use the cells they use, 5.6 kwhr for $8500. This pack is 23 lbs lighter. But it only has a 700 cycle life.

Here is one link to electric aircraft, Randall has a electric trike, and single seat electric Moni electric glider and a SLA two place electric.
ElectraFlyer.com - The World Famous ElectraFlyer-C

This company uses, as all the others do, 2 stroke engines in their ultralight offerings but I feel their Aerolite 103 is a perfect candidate for electric propulsion.
Aerolite103

[deckofficer]

T1 Terry,

I'm familiar with the A123 cells and that $7.99 is a great price, but to build a 4.7 kwhr pack would be $5023. It is 4 lbs lighter though.

$5730 would be the cost using 18650 cells and 2 lbs lighter.

So far the winner is http://www.evassemble.com/index.php?...roducts_id=175

[gael]

What about building a pack using 18650 cylindrical cells/ If you want serious discharge rates http://www.hobbyking.com/hobbyking/store/__16575__A123_3_3VB_Lithium_Ion_2300mAh_Single_Cel l_Battery.html or a cheaper to give you capacity to by building enough discharge rate http

[/QUOTE]
Hi Terry,
Sharing the same "curiosity"... I have in mind the TESLA car battery packs are build with xxxxxx cylindrical cells ( I read that somewhere) and I suspect with Lithium Cobalt technology. Did you heard something like that??

rgds
Gael

[CharlieJ]

gael-
A house bank does not need "serious discharge rates" so what advantages would there be in building a bank using 18650 cells in lieu of prismatics that we are using?

[goboatingnow]

Originally Posted by gael

What about building a pack using 18650 cylindrical cells/ If you want serious discharge rates http://www.hobbyking.com/hobbyking/store/__16575__A123_3_3VB_Lithium_Ion_2300mAh_Single_Cel l_Battery.html or a cheaper to give you capacity to by building enough discharge rate http

Hi Terry,
Sharing the same "curiosity"... I have in mind the TESLA car battery packs are build with xxxxxx cylindrical cells ( I read that somewhere) and I suspect with Lithium Cobalt technology. Did you heard something like that??

rgds
Gael[/QUOTE]

Tesla is using the 18650 form factor , but the cells are quite exotic anode and cathode variants produced for tesla by Panasonic.

Having done a lot of work on 18650 cells , there's no advantage to them for boats. Large prismatics are better space wise and you don't have to worry about the durability of all those interconnects.

Dave

[Badsanta]

I find this all very interesting. But confusing with such a large posting. Can I buy a replacement for my house bank or do I have to buy all the bits and put them together?

Sent from my SPH-L710 using Cruisers Sailing Forum mobile app

[goboatingnow]

Originally Posted by Badsanta

I find this all very interesting. But confusing with such a large posting. Can I buy a replacement for my house bank or do I have to buy all the bits and put them together?

Sent from my SPH-L710 using Cruisers Sailing Forum mobile app

Buy all the bits , understand them , and then put it all together

Dave

[gael]

Tesla is using the 18650 form factor , but the cells are quite exotic anode and cathode variants produced for tesla by Panasonic.

Having done a lot of work on 18650 cells , there's no advantage to them for boats. Large prismatics are better space wise and you don't have to worry about the durability of all those interconnects.

Dave[/QUOTE]

Hi Dave,
I have my prismatic CALB cells in place since 2010 et very happy with this set up. As long we are planning for regular service or short power pulse this is the best approach.
I'm a now looking to replace all the propane installation for cooking and for propulsion. Is it efficient in term of weigth??

rgds
gael

[gael]

Originally Posted by CharlieJ

gael-
A house bank does not need "serious discharge rates" so what advantages would there be in building a bank using 18650 cells in lieu of prismatics that we are using?

Hi Charlie,
Sorry I miss your reply..; but just rsponded to Dave for a same question.
rgds
gael

[Cotemar]

Originally Posted by gael

I have my prismatic CALB cells in place since 2010 et very happy with this set up. As long we are planning for regular service or short power pulse this is the best approach.
I'm a now looking to replace all the propane installation for cooking and for propulsion. Is it efficient in term of weigth??

I was wondering the same thing about these LifePO4 battery banks.
Would a LifePO4 400ah house battery bank with a Victron Multi-Plus Inverter/ Charger
be able to support the use of two of these portable induction cooktops at the same time?

[goboatingnow]

Originally Posted by gael

Tesla is using the 18650 form factor , but the cells are quite exotic anode and cathode variants produced for tesla by Panasonic.

Having done a lot of work on 18650 cells , there's no advantage to them for boats. Large prismatics are better space wise and you don't have to worry about the durability of all those interconnects.

Dave

Hi Dave,
I have my prismatic CALB cells in place since 2010 et very happy with this set up. As long we are planning for regular service or short power pulse this is the best approach.
I'm a now looking to replace all the propane installation for cooking and for propulsion. Is it efficient in term of weigth??

rgds
gael[/QUOTE]

Yes it's close to the most efficient there is on a readily available format
Dave

[campr]

The Nuwave2 uses 1300W according to their FAQ (Induction Cooktop | Buy Cooktops | FAQ - NuWavePIC.com) at maximum setting. Using around 90% conversion efficiency from your 12V->110V inverters, this would render you needing ~ 2860W or around 220A at 13V. Since the 400Ah cells support 3C current, (1200A), this should certainly be possible. Expect ~ 1.5 hours of cooking time with topped-up batteries.

What would interest me more, is if there were 12V DC induction cookers. Why waste efficiency going to 110V or 220V

You might want to read this for the pro's and con's: http://theboatgalley.com/induction-cooktop-on-boat/

Also interesting watching:

http://www.youtube.com/watch?v=yXSjl8DFaf0