Thanks for the comments, I am based in Cambridgeshire. There are not a lot of us in the UK.Idontwanttopedal wrote:Hi nice build where in uk are you I'm in Essex. I'm thinking of turning my zx6r b1h into ev and the gearbox seleted two get at once at 60mph. I kept it up but totalled gearbox. Got one prob with my build planing on doing work out only get around 30ah
Hi John,John in CR wrote:Do you already have your batteries? With a pack that size consisting of cells of a chemistry where an issue with 1 cell can cause a thermal runaway of the entire pack in less than a minute, be sure you understand the precautions required. It boils down to making sure no faulty cells make it into the pack, and make sure each cell can neither be discharged to too low a voltage or charged to too high a voltage, and they will serve you well.
Can't wait to see pics.
Hi John,John in CR wrote:Before you reorder think about doing only 2 bus bars, your positive and negative...less cost, less work, less weight, less risk of a short. Simply plug the packs to each other in series. Your balancing board will create the parallel structure for you that you need at the cell level, not the Turnigy pack level. The bus bars in the middle of the pack don't accomplish anything.
The motorcycle section of the forum doesn't get a lot of action. Before proceeding I think you should have the guys in the battery section go over your pack and offer suggestions about how to best set up to monitor and protect your pack, as well as make it convenience to balance.
Hi John,John in CR wrote:I wish I had read your thread sooner.
I like the new plan better because you can also more safely have the packs "prove" themselves with use by running the pack with only the ends of the strings paralleled. With that many packs you are almost certain to have some duds, or at least some with a significantly weaker cell. The reason I say it's safer is because If you force each pack at a parallel level to have an identical voltage, then a low cell has to be has its effect spread over the 4 other cells verses 19 other cells without the bus bar.
eg. Let's say there's a bad cell whose voltage ends up 0.5V low . That puts you overcharging the other 5 cells even if you were charging only to 4.15V . With only 2 bus bars, the effect is spread over 19 cells, so instead of a too high 4.25V charge, they end up a safe 4.18V. With that many packs you obviously won't individually balance charge each pack on each cycle, and if you go with full parallel structure at the cell level, the bad cell remains hidden. Cell level paralleling and monitoring is safest, but it forces you to test the packs under load before the pack is assembled in order to sort out the weak packs. I have no means of doing that, so I test with conservative real world use. After 10-20 shallow cycles, those which stay in perfect balance are trusted enough for cell level parallel structure and weak packs removed.
I've had a brand new unused pack flameout while sitting undisturbed for a month, so I treat them like fire bombs until they have proven themselves in use, so there's just no way I'm letting a weak pack hide inside my pack. Each has to prove worthy.
Hi pendragon8000 as requested the pics keep coming, I have been ordering cables and battery terminals and working on the cable arrangement for my prototype battery box, some pictures below. Notice the terminals are too short in the picture below so I have ordered some 50mm ones.pendragon8000 wrote:Keep the pics coming .looks great.