Quote:
Originally Posted by deckofficer
David,
Can you fit 10.7" cells (plus terminal bolts) in you battery space? If they won't fit the 200 a-hr cells aren't that much more in cost.
(12) 200 a-hr is $2772, so about $600 more for a cell that fits standing upright and has 5 a-hr more per cell.
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OKIDOKI.
A few issues rather unsurprisingly.
One we have 11.25” of height available BUT only around 24” x 24” of footprint.
Looking at the 195Ah 3.2V 10C Power Style, LiFePO4
Lithium Prismatic Batteries, HiPower LiFePO4 Li-Ion EV Battery, 7.2L * 2.8W * 10.7H in
We don’t have a big issue with the height BUT if I wanted to set them out as follows.
FOUR Banks of 195Ah connected in parallel to give me 780 Ah. I cant connect them physically as left to right groups of four cells
[] [] [] [] [] cells 1-4......[] [] [] [] cells 5-8.....
[] [] [] [] cells 9-12......[] [] [] [] cells13 -16
AND have the parallel to series interconnection in the middle of each four cell group as that would need almost 12” by 30”
[ c1 ] [ c5 ] [ c9 ] [ c13 ]
[ c2 ] [ c6 ] [ c10 ] [ c14 ]
[ c3 ] [ c7 ] [ c11 ] [ c15 ]
[ c4 ] [ c8 ] [ c12 ] [ c16 ]
NOW IF I have going from left to right two groups of eight cells BUT still with only four cells interconnected in a parallel way.
Can I have OR does any one see issues with the following configuration?.
[] [] [] [] cells 1-4 G1......and to the right [] [] [] [] cells 5-8 G2.....
and below
[] [] [] [] cells 13-16 G4......and to the right [] [] [] [] cells 9 -12 G3
[ c1 ] [ c5 ]
[ c2 ] [ c6 ]
[ c3 ] [ c7 ]
[ c4 ] [ c8 ]
[ c13 ] [ c9 ]
[ c14 ] [ c10]
[ c15 ] [ c11]
[ c16 ] [ c12]
Group one is connected to group two with a mid cell interconnection and group two is connected to group three from bottom the cell to the top cell and group three is connected middle cell to group four, the POSITIVE is off group one and NEGATIVE is off group four to give me my 12+volts.
That seems to be a possible way of getting the 195Ah cells into the space I have.
I do have the identical space on the other side of the
boat so could I split the battery physically into two six volt
parts one on the port side one on the starboard side. BUT would the 6 to 8 feet interconnection
cables screw up the whole thing?
Of course I can or could use 100Ah cells and then I don't have any issues at all (apart from the cost ones) as they are much thinner and not as tall I could even get 32 x 100 Ah cells in to give me 800Ah as they are only 6” x 2.75” x 8.25” so they would fit in in that first described as above - logical physical arrangement quite easily. However if I was going to be happy with 500Ah I could have only 20 cells 600 Ah 24 cells or even 700Ah with 28 cells. At the moment in the morning we are never down more than 60Ah assuming we cook more using the
electrical devices and do that in the evening and not have a hot lunch when we are running off of the solar I cant see how we would be more than 200 Ah down even if we used the inverter to heat our hot
water tank for hot showers (that we could do during the day(sun up time) on a timer when the solar was 'finished charging the batteries) . So really as LiFeP04 will give me more usable amps vis a vis a FLA/GEL/AGM battery bank of the same capacity 500/600Ah could be more available Ah than we would ever need based on current usage. Of course having more available Ah means we can do more from the solar/wind/LiFeP04/inverter system maybe an A/C
watermaker
Question One. One is told that one should not mix FLA Gel and AGM batteries of various ages..........does this also apply to LiFeP04 batteries? This is quite critical as if we can, we could start with a lower Ah system and grow it as we find we need to, OR do we need to plan for the future and grow into an initially bigger Ah Battery.
Question Two, LiFeP04 Battery retention. It seems that these batteries need restrained on their long edge to stop them bulging under charge. How critical is this? Is this related to charge rates? Would a custom fit say 1/4” thick GRP
Battery Box be 'enough' or would I need to put strengthening 'stiffening' ribs in/on it? and of course I would want to add a lid to protect all these many cell interconnections from an accidental short.
Question Three, What about a small say 40/60 Ah system for
engine start?
Question Four. I have already downloaded 90+ pages of the 236 page thread and intend to download all of them ….. then I will filter out all the stuff that I don’t want. Would it be acceptable to create my own mini edited 'short' version of replies that I feel are important and create some sort of composite document {with acknowledgements of course} of what I see as important and valuable posts/information and then post here as an attachment?
Enough for now methinks