hi All Battery Cell Layout question
- Thread starter billym1967
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If you look at the Youtube video, you'll see slots in the strips. they're very important, especially as you need to weld one strip on top of another. they force the current to go down through the layers. Without them, the current will take the shortest route through the strip from one electrode to the other without welding. Use a Dremmel with a cutting disc to plunge slots in your strips.
ok, but why in the second link, does he not use slots. so am i right in saying if there is 1 on the bottom the strip on top needs the slot.
I recongise the voice in that video, is he the guy who works with Paul at Em3ev ?
SO MUCH POWER - POWER
Doesn't he make it look easy in the video though. Also I notice he uses the handheld spotwelder attachment which has me thinking about that 3s lipo handheld spotwelder.
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The cell can is all negative from bottom to the top rim with only the top centre being positive, the only bit that stops a potential short when welding the strip/bus bar on the positive end is the pvc shrink wrap. Adding an extra insulator to the positive end just ensures a extra bot of safety and all for about 50 or 60p's worth of expense.
thanks - so holed stips for the = and - connections and insulators on all the +.
so the only bit i'm struggling with and ive added some pictures with numbers. so ive done the 5 + together and the 5 -. so i connect = to - on each of the 5. so the second picture the 1st 4 are done. in the second picture how and what do i do to connection between 1 an 4. and do i insulate it to make sure it dosnt connect to 2 and 3.
so the only bit i'm struggling with and ive added some pictures with numbers. so ive done the 5 + together and the 5 -. so i connect = to - on each of the 5. so the second picture the 1st 4 are done. in the second picture how and what do i do to connection between 1 an 4. and do i insulate it to make sure it dosnt connect to 2 and 3.
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You can connect all 10 of those cells together without any fear of shorting them out. I would use longer strips rather than lots of short ones to cut down on the number of welds. Then move on to the next group of 10 making sure you don't connect or cross over the first group.
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Grind awat the plastic guides with a Dremmel when you want the strips to go at a different angle.
I agree with post #28 if you are able to use a longer continuous strips and remove some plastic away if needed.
In the second pic cells marked 1,2,3 & 3 if you want to you could link cell 1 with one long strip and will aslo triangulate that last cell to discharge more evenly.
On 2 & 3 you can reduce the welds by one by having a continuous strip reducing stack height and possible bad welds.
Whilst working to prevent mishaps cover the cells you are not working on with a cardboard template and a bit of tape , cut up old cereal packs might help prevent accidental shorting if you drop misplace a piece of nickel. Also sometimes you can't help but may be lay your wrist /lower arm across the top, it will stop the buzz/tingling you will receive from bridging the cell ends.
In the second pic cells marked 1,2,3 & 3 if you want to you could link cell 1 with one long strip and will aslo triangulate that last cell to discharge more evenly.
On 2 & 3 you can reduce the welds by one by having a continuous strip reducing stack height and possible bad welds.
Whilst working to prevent mishaps cover the cells you are not working on with a cardboard template and a bit of tape , cut up old cereal packs might help prevent accidental shorting if you drop misplace a piece of nickel. Also sometimes you can't help but may be lay your wrist /lower arm across the top, it will stop the buzz/tingling you will receive from bridging the cell ends.
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so ive built my first battery. not a neat as i would have like. so before finishing i decided to test charge it. and it wouldnt charge green light stayed on.
now i think i may have mad a boob, i dint charge the cells before buliding and its only reading 35v, so could my problem be the cells are to low for the charge. at the moment i'm trying out my new spot welder, which also has a charger. gonna see if i push some vauts in, weather it might then charge.
now i think i may have mad a boob, i dint charge the cells before buliding and its only reading 35v, so could my problem be the cells are to low for the charge. at the moment i'm trying out my new spot welder, which also has a charger. gonna see if i push some vauts in, weather it might then charge.
Assuming you have wired up a bms, double check all cell string voltages. At 35v it should charge if they are all fairly equal.
so me being impatient, while i was waiting for bits a had a mess with my new cell charger. i part charged 4 cells. so when ive just checked the strings. 9 measure 3.53v but the 10th is 3.93vs. is that the problem and how do i put it right thanks
A higher voltage like that can prevent the bms switching.
You need to manually discharge the high string with a drain source and monitor it down to near the others, wire up some car headlamp bulbs in parallel.
You need to manually discharge the high string with a drain source and monitor it down to near the others, wire up some car headlamp bulbs in parallel.
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In order for it not to charge, one cell needs to be at 4.2v or above, or one cell needs to be below 3v. Your problem must be somewhere else. If you want to balance the 10th cell, use a 6v light bulb ton drain it down. A 5w one should be about right.
all sorted. it was the BMS board. it was a bit diffrent to the last one i fitted. the 1st black wire on the others ive had is a negitive. on the board last night its number 1 on the 10 charging. so i put all 10 wires 1 wrong. moved them and all was good. thanks for the help
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Please keep us updated with how you get on with this battery, how it performs, how long it lasts and any reliability issues. That will help people, who want to do a similar project.
hi, so its finished and charging. its 11.6a 40 cell. ive learned loads duering the build. would i build another. the answer is yes, im going to but not in a case as i found it very chewy. the next one i build will be in shrink rap.
i watched a you tub vidoe on building one in a case and he made it look easy. my skill level i would say is pretty good and as i said it was a chew nad i would only recommend very experienced builders to do it. when its charged i will update on the voltage total, but being sony cells im hoping it will be good and have a good life.
thanks for the help and i havent added internal pics as i'm not over joyed with how it looks. the next one i build i will add pictures.
i watched a you tub vidoe on building one in a case and he made it look easy. my skill level i would say is pretty good and as i said it was a chew nad i would only recommend very experienced builders to do it. when its charged i will update on the voltage total, but being sony cells im hoping it will be good and have a good life.
thanks for the help and i havent added internal pics as i'm not over joyed with how it looks. the next one i build i will add pictures.