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

[mcarling]

Originally Posted by Cotemar

What should I set my boat battery charger to ? See attached settings.

I would choose Profile C.

[deckofficer]

Cotemar,

The real pros have discussed this a lot on this thread. My choice for 4 cells in series would have the charger done at 14.6 volts or 3.65 volts per cell. If over time balance becomes an issue, I'll push it up closer the 4.0 Volt max that Winston states, until balance between cells is on again, then back to the lower setting.

[deckofficer]

I was just contacted by a gentleman named Doug because he was unable to join the forum (reg problems). He wants to use the cells in his RV, which I think is a good application. He was concerned about shipping costs, since the retailers all seem to wooden crate the batteries. My shipping costs were included in the purchase price. Is this the case with others?

Also, for anyone that might be jumping on these clearance cells from Balqon and are concerned about shipping times, your welcome to drop my name as the guy that it took 3 1/2 months to receive the cells.

Bob Lemke

[Cotemar]

Originally Posted by deckofficer

Cotemar,

The real pros have discussed this a lot on this thread. My choice for 4 cells in series would have the charger done at 14.6 volts or 3.65 volts per cell. If over time balance becomes an issue, I'll push it up closer the 4.0 Volt max that Winston states, until balance between cells is on again, then back to the lower setting.

OK 14.6 volts, so would that be Setting "D" on my charger?

I have it set on "D" now, because I have 3 Lead (Calcium) batteries.

[deckofficer]

Originally Posted by Cotemar

OK 14.6 volts, so would that be Setting "D" on my charger?

I have it set on "D" now, because I have 3 Lead (Calcium) batteries.

Please don't go just by me on this. This thread has a lot of experienced users of these cells that also have a solid understanding of batteries and chargers. I haven't had the chance to even cycle mine yet. All my cells from Balqon read 3.32 volts except one at 3.31. I would say they are well balanced as they still read the same two weeks later.

[senormechanico]

I've set my 200 aH lithiums for 14.4 and 13.8V on my BlueSky MPPT.
Same for shore power, but I've never even plugged in the boat since last February.
My alternator has a single adjustment point which I set as low as possible, 14.3V.
Batteries are perfectly happy with that.

[deckofficer]

senormechanico, thank you for jumping in with that. I'm curious what state of charge the factory gives them. What is you DOD % when you cells read 3.32 volts?

[Cotemar]

Originally Posted by deckofficer

Please don't go just by me on this. This thread has a lot of experienced users of these cells that also have a solid understanding of batteries and chargers. I haven't had the chance to even cycle mine yet. All my cells from Balqon read 3.32 volts except one at 3.31. I would say they are well balanced as they still read the same two weeks later.

OK, maybe "T1 Terry" will chime in.

I know the basics and would really like to change out my 3 x 100ah Lead Calcium battery bank.

[deckofficer]

Originally Posted by Cotemar

OK, maybe "T1 Terry" will chime in.

I know the basics and would really like to change out my 3 x 100ah Lead Calcium battery bank.

Terry T1 is a good source. This I feel comfortable saying though, with the difference in DOD of you old batteries, you might find the deepest discounted batteries in the Balqon sale to do a fine job replacing you 300 a-hr bank, and that would be the 165 a-hr cell at the 44% discount of $99.

[downunder]

Originally Posted by deckofficer

Terry T1 is a good source. This I feel comfortable saying though, with the difference in DOD of you old batteries, you might find the deepest discounted batteries in the Balqon sale to do a fine job replacing you 300 a-hr bank, and that would be the 165 a-hr cell at the 44% discount of $99.

DO,

I expect Cotemar is also taking the opportunity to increase the capacity of his bank at the same time on his 36ft cat.

[mcarling]

Originally Posted by deckofficer

you might find the deepest discounted batteries in the Balqon sale to do a fine job replacing you 300 a-hr bank, and that would be the 165 a-hr cell at the 44% discount of $99.

I agree. 160AH lithium phosphate should be as capable as 300AH lead calcium, as well as weighing a small fraction, lasting a few times as long, safer, and more environmentally friendly. At $400, it's hard to beat.

[Cotemar]

Originally Posted by downunder

DO,

I expect Cotemar is also taking the opportunity to increase the capacity of his bank at the same time on his 36ft cat.

Yes, Absolutely.
I have 460 watts of solar, but no place to store it for those cloudy days.

[mcarling]

One could get 8x of the 160AH batteries for a 320AH 12V bank for $792 or 4x of the 400AH batteries for a 400AH 12V bank for $1032. The best deal per AH would be 4x of the 1000AH batteries for $2080, which should store roughly about 3 sunny days' output from 460 watts of solar. The latter should be about the same weight as the existing 300AH lead calcium bank.

[deckofficer]

This is something I feel comfortable on, and my choice for any voltage application is to size the cells in a single series string. Less chance of balance issues than a series/parallel configuration to reach desired capacity.

Sorry mcarling, I sure don't mean to question you, as I hate when I'm on the receiving end, but I think the guys better versed on this than me will chime in. I could be wrong, but all the off grid homesites I've done prior to lithium, I'd use single lead acid wet cells at 2 volts and do a single series string for the home. These 2 volt cells I used ranged in size from 700 a-hr to 2500 a-hr.

[mcarling]

No offense taken. I also prefer to keep things simple, but I wouldn't hesitate to use 8x 160AH rather than 4x 400AH for the lower price per AH if 320 total was sufficient or I was trying to keep the weight down. If you open a lithium phosphate cell (I don't recommend it), you'll find the internal organization to be in parallel. So, I'm not uncomfortable with paralleling pairs of cells before assembling a string in series.