Would you fellas be able to help with how to link my batteries in series for my 72v Ford Think?
My idea was to have 24 LifePo4 in series, but not sure how exactly to arrange them and where to have the four factory Ford Think battery cables connected.
I am running a BMS and a DeltaQ re-programmed for lithium (Algorithm #53, cuts off at 87.588 volts).
I have attached a photo of how my lithium batteries current sit in the cart, waiting to be wired up.
Any help would be greatly appreciated.
Can you give a little background on these cells? Did you buy them as an assembled pack? or as individual cells and you put them together?
Did you get connection bars as part of this kit?
What BMS are you planning to use?
What is your range of mechanical skills? Are you able to fabricate, bend, shape, and massage metals into useful shapes?
What tools and supplies do you have at your workshop?
The reason I ask these odd questions is they will direct responses towards the best path on how to finish this pack.
Now the meaty bits.
Can you still break these packs apart?
Before you do that, I need you to verify that the cells are gathered up properly.
What I am seeing is the order seems to be messed up in row two. (Judging by the stickers next to the burst discs)
The entire top row needs to be flipped also. (Not as one row, but each cell).
The bottom pack appears to be arranged in a useful order. (if you want to use it as an example).
Hopefully you have a meter to verify how these are all arranged.
If you CAN still break these cells up and rearrange them I can offer up a suggestion to make these go together with bars and one cable to connect the two packs.
I am also seeing an odd artifact on the bottom left cell. Was that one dropped? It appears it have a smashed in corner.
And what cells are these?
Are you sure the PeakV is ok going up to 3.64pcell?
They are new individual cells 3.2v 102ah LifePo4 (Charge voltage capable of 2.5~3.65v). I assembled them (created the case) to fit into my Ford Think/ space available. I do have bus bars and am capable of making custom bars if needed. I have already purchased/plan to use a Daly Smart BMS rated for 24s LifePo4 at 500amps. I am sure there are better BMS out there, but I already have this one.
I also had my DeltaQ charger reprogrammed for lithium, using algorithm #53 for 87.55 volts, should the BMS fail to cut it off.) NOTE: I also have other algorithms available to use for different cutoff voltage, #67=73.8v, #128=82.08v, #211=83.16v, #163=85.5v, etc)
The Ford Think has four cables that connect to the original batteries to the cart. Two ( + & -) went to the a fuse 400amp fuse. The other two (+ & -) went to the contactor/switch.
If I can get a basic drawing of how to configure and bus link my cells to include the four cables that go to the cart; it would be much appreciated.
Thank you for offering to help.
There is no damage to the cells. Only the decals peeling off. I have attached a side view for better perspective.
Example of 72v I had planned to use.
Ok- Looks like a good design. Are you using polyethelene sheets for the sides? I see the top label coming up now.
Inwo strongly suggests to not install the fuse in the middle of the pack. If for some reason it should blow, disconnect, or have a bad connection, it would probably smoke your BMS because it has it’s own monitoring leads still attached. You can put the big fuse at one end or the other and it will be outside the BMS.
My view- I still have a concern about how you oriented a few of your cells in the far pack. Looking at the tops I see a square that seems to be consistently oriented next to a specific terminal(guessing Pos). There is also a scan code on one end of the blue packages(guessing Neg). On the terminals I see a tan and a black base which clearly indicates polarity of each cell.
In your latest side view pic the cells in the closer group are stacked with a proper path to connect via bars. No problem.
In the far off pack I clearly see two negative posts next to each other and with what I see there are 3 Pos terminals next to that.
If using bars, this current arrangement will not work as desired. I also see that in the isometric view the bars are hooked up on the packs in the same wonky pattern. Where did this pic come from?
DONT copy that plan!!
Thank you Inwo. So basically in series like the photo depicts, with one series end terminal (-) to fuse and the other series end terminal (+) to the contactor/switch?
Like this?
Thank you AssyRequired. Would you be willing to provide me an overhead drawing/sketch of how you recommend to orient the cells and bars?
Sure, if it helps. This is only one way to do it. If main batt cables are happier if routed to another post let me know.
Make sure you rearrange the cells. Note that most in the upper pack are not correct. Red dot should be positive on the cell. Verify with your meter and keep track of color code on the post.
Excellent! Thank you.
