80Ah ADD ON build

[expresso]

I added some of that fire proof tape on all the exposed metal areas - then i covered it all with tape also - leaving just the diodes bodies exposed to breath

[Burgerman]

Electricity doesn't care if the wires are ugly

[expresso]

made another cable with a fuse also which i never done before on my ADD ONs - but its a good idea and these fuse holders are small - i like them - and cheap - i used a 50A on her pack - i will add them to my packs also- i have 50A and 60A fuses for these holders - i went with 50A for her pack to be safer - if it turns out to be too low - i will swap them to 60A - on my packs i will use 60A and see how that works out -


i was checking on my new Cells - the screws i received with them dont go all the way down - turns out i have plenty of headway screws which fit fine and are a bit shorter - i will use the headway screws instead - will still need a washer or two - flat and lock on some of them -

[expresso]

Headway screws

[expresso]

the other problem i may have with those connectors - they may not fit after i add some silicone sheet between the cells - i have to see - i hope i can get them to fit - would be easier for me - and i will use double connectors on each one - along with a lock washer - i have them already - they are not the ones shirley posted -

i may get those instead or use what i have which are the lock washers, screws and flat washer that come with the headway cells - i have a ton of them left over.

i will start to charge one maybe tomorrow or on Sunday and try to do one a day - at 10A a hour charge - - will take about 8 hours for each cell - they are 3V - rated down to 2.5V as cut off - at 3V they are basically empty - the cells themselves are very nice - and the blue wrapping isnt bad - i bet they are fine just as they are with nothing in between - But just in case - i feel better adding a thin sheet of silicone - like i did with the previous 60ah cells -

i like that they are thinner - 16 of these would fit in group 24 size box and give you 160ah -

this will be 80ah ADD ON - which isnt bad consider its more than a group 24 lead is - will almost double once installed on 100ah lithium chair - 180ah would be total if all goes well

[expresso]

Electricity doesn't care if the wires are ugly

- we see how 2 diodes work out sooner or later - if it works - thats great - if not - i replace it with one and thats it - one is good for sure - that we know and at least 1 should be used on a ADD ON with Lead combined chair - if ADD ON is going to be used with lithium also - if all lithium - then NO diode is needed.

[Scooterman]

they are 3V - rated down to 2.5V as cut off - at 3V they are basically empty - the cells themselves are very nice - and the blue wrapping isnt bad - i bet they are fine just as they are with nothing in between - But just in case - i feel better adding a thin sheet of silicone

Just for clarification, you state the cells are rated at 3v, is that a typo?

Don't you mean 3.2v?

Also re charging lifepo4 and other battery technologies. When charging at high amps do the cells heat up much? I thinking would not some plastic spacers rather than sheet insulation be better between the cells to allow for a bit air flow between cells?

NB: The above are questions not criticisms, I'm just trying to understand that's all.

[Scooterman]

Just for clarification is this where the diode is placed?

[Scooterman]

I just got my new 80ah Cells - not bad looking

Please can I ask if the cells are a brand or generic? Also can I ask approximately how much $$$$$ they were per cell?

Please don'y think I'm being nosy, it's just that when I've got my head round lithium and had a practice with some of these that I've ordered https://www.ebay.co.uk/itm/8pcs-AA-IFR-14500-3-2V-600mAh-LiFePO4-Rechargeable-Li-ion-Torch-Battery-Flat-Top/223056380544?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I plan to order 16 x 80Ah-90Ah-(or whatever will fit) prismatic cells.

[expresso]

they are 3V - rated down to 2.5V as cut off - at 3V they are basically empty - the cells themselves are very nice - and the blue wrapping isnt bad - i bet they are fine just as they are with nothing in between - But just in case - i feel better adding a thin sheet of silicone

Just for clarification, you state the cells are rated at 3v, is that a typo?

Don't you mean 3.2v?

Also re charging lifepo4 and other battery technologies. When charging at high amps do the cells heat up much? I thinking would not some plastic spacers rather than sheet insulation be better between the cells to allow for a bit air flow between cells?

NB: The above are questions not criticisms, I'm just trying to understand that's all.

Hi - the cells are 3.2v LifePO4 Cells - 3v is the Volt i have received them at. - when they get shipped - they dont ship them full - these cells were drained before shipping and they show 3v when i checked - 10A charging is not very fast at all when you consider its a 80Ah Cell - that will take about 8 hours each cell to recharge at 10A a hour.

the reason for the silicone or thin rubber sheet i will add between each Cell - is to be sure they dont touch or rub each other. the cells are wrapped already but to be safer i add something myself - since they are just a shell and the only protection is the wrapping they arrive in. -

[expresso]

Just for clarification is this where the diode is placed?

BM can explain this better - i took it from him - the diode only flows one way and it can only be placed in that one direction. depends what diode it used - you would have to first know which direction is correct and then place it in line in the correct fashion. in my case with the diode i used - recommeded by BM - i placed it the way he told me since i wasnt sure which direction either.

my diode has 3 spike ends and that end is the direction of the flow - discharging direction out of the pack is the direction the 3 spike end of my diode is facing. - hope that makes some sense - if not BM or someone will explain it better than me - i am just like you learning as i go

[Scooterman]

Expresso - thank you for answering my questions.

[Burgerman]

Yes, and now you know what a diode does!

[Scooterman]

Yes, and now you know what a diode does!

I never realised that diodes have an internal resistance. But I suppose going by that all semi-conductors do. Just as copper wire, batteries and everything else electrical/electronic does.

And that's where super-conductors come in!!!

see, I'm learning all the time, (with your help)

EDIT: RE the diode I should have probably said drops voltage across it. Because as you said the voltage drop stays constant over a wide current range whereas with a resistor is doesn't VD = I x R. And that is why a diode is used and not resistor.

[Burgerman]

Well pretty constant across a rtange of currents. You need to select the right diode!

[expresso]

and its ON - first Cell - you have to be careful - Chinesse are a bit backwards - the Black on the Cell is the Positive Post - go figure - you would think make Black the Neg. side - or color code the top posts - so you have to check your Cells - they can all be different - no standard they follow -

i will add some Red Tape on the Black side to remind me just in case - i think everyone else in the world sees Black as Neg. -

[Scooterman]

Well pretty constant across a rtange of currents. You need to select the right diode!

Understood

[Scooterman]

and its ON - first Cell - you have to be careful - Chinesse are a bit backwards - the Black on the Cell is the Positive Post - go figure - you would think make Black the Neg. side - or color code the top posts - so you have to check your Cells - they can all be different - no standard they follow -

i will add some Red Tape on the Black side to remind me just in case - i think everyone else in the world sees Black as Neg. -

[Burgerman]

Dont forget that the case/shell is also connected to a terminal. And so there needs to be some kind of non conducting material between every one. And bottom/sides of the whole thing once assembled.

[Scooterman]

Dont forget that the case/shell is also connected to a terminal. And so there needs to be some kind of non conducting material between every one. And bottom/sides of the whole thing once assembled.

What would you recommend BM? Expresso mentions silicone, I thought perhaps rubber? EDIT: I suppose it doesn't really matter...

[expresso]

Dont forget that the case/shell is also connected to a terminal. And so there needs to be some kind of non conducting material between every one. And bottom/sides of the whole thing once assembled.

i basically just added a sheet between the Cells that would be touching each other - i didnt cover the sides completly on my 60ah Cells - i added tape on the bottom and some of the fire proof tape on top etc, - but not the sides - mines sit in a plastic shoe box so nothing can short it out there for sure -

these new 80ah Cells seem to be wrapped a bit better also - with a bottom sheet and top - seems to be cardboard material - - i may leave it and just tape it across the bottom once all connected together in the end -

i started the first Cell charge - BUT i left my laptop on its own power which it went to sleep and i didnt get the full recording of the charge on graphs - hours later when i received it - i stopped it and made sure to use outlet power on my laptop and started it again -

here is the last and only graph i have from this first Charge -

[expresso]

these Cells and also the previous 60ah Cells are rated down to 2.5v cut off -

what i am realizing now is that they shows the specs in Ah size for Each Cell - lets say 60ah - and now 80ah etc, - But i dont think these Cells in actual use - we may not get that Ah out of them because we should stop when it hits 3V or 2.9V - to be on the safe side and never go low enough to damage them -

but they show specs of Ah size of the Cells based on the fact of discharging down to there cut off limit of 2.5V - i dont feel i will get the full 80ah of these or any of the Cells unless discharging down to 2.5V - i expect to get about 70ah out this pack once all done and will discharge to see what the Real Usable Ah i will end up with.

its the same with my previous 60ah Cells - i got about 55ah out of them - i dont expect this to be any different and at least i hope to have 70ah to 75ah when all said and down - i be fine with that . if this is a pattern of how they get there full Ah specs - then that means - try to get a 100ah Cell and hope to get 90ah out of them at least.

i can say with the previous 60ah Cells - so far they are fine and do the job - it keep me mobile last summer - without that 60ah pack - i would have been very limited to just lead alone and that means going no where - so i am not complaining - in the long term - that we have to wait and see how they hold up - we talk about 5 years 8 years - 10 to 15 years on full packs - i dont really know for sure since i havnt had them that long to say - i believe Shirley and BM had lithium packs long enough to say they should last a very good amount of time.

i am on my third summer with lithium - ADD ONs and one Full pack so far - next summer would be my 4th - i did have my full pack chair down most of this summer - motors died on me - so didnt get to use it much this summer - reason for rushing to get the 60ah pack made and used all summer instead. still got me 36 miles with one diode on a charge. i take that over lead any day

[Burgerman]

these Cells and also the previous 60ah Cells are rated down to 2.5v cut off -

Do that, and the self discharge rate will increase. They say 2.5 because that way you get best measured Ah. But its too low.

2.9v best lowest ever level in service.
2.7v best level in testing for Ah. NOT OFTEN!

Dont do 2.5 or you may regret it.

these Cells and also the previous 60ah Cells are rated down to 2.5v cut off -

what i am realizing now is that they shows the specs in Ah size for Each Cell - lets say 60ah - and now 80ah etc, - But i dont think these Cells in actual use - we may not get that Ah out of them because we should stop when it hits 3V or 2.9V - to be on the safe side and never go low enough to damage them -

but they show specs of Ah size of the Cells based on the fact of discharging down to there cut off limit of 2.5V - i dont feel i will get the full 80ah of these or any of the Cells unless discharging down to 2.5V - i expect to get about 70ah out this pack once all done and will discharge to see what the Real Usable Ah i will end up with.

Correct. Thats the chinese for you. Headways actually do what it says on the tin mostly. At 2.9V.

[expresso]

yes headways are still top of the line if you want the best quality - but limited with how much you can fit - i dont have a problem with the Cells i am using - now i know what to expect and wont be disappointed - i wont go below 2.9v when pack is built and test discharge just to find out what the actually real Ah is at 2.9v

when this pack is going to be in actual use on the chair - i will make another Volt meter - with longer cable - to keep it connected and watch the end mostly - once i find out the lowest Volt i should go. and match that with my JS battery number - to have an idea - this is going on the Bounder so - according to there battery manual i shouldnt go down to number 3 at most before the BMS will kick in and stop it -

my goal if this works out is - get a solid 40 miles out of the bounder with this ADD ON and never get below number 5 on the JS number while having a safe end Volt. at that time - end of day etc, - thats what i hope i will be able to do - not sure if i make it but we try. this extra 80ah HAS to Help somewhat for sure - how much is the question yet to know.

next summer will be the real test to know for sure.

[Burgerman]

Lower speed gearing makes a huge difference to range. And the other things.

[expresso]

Lower speed gearing makes a huge difference to range. And the other things.

after i test it this way to get an idea - thats the plan - i am going to use it first this way to see what it can do Range wise - so i have an idea either way and can only get better once i lower the gearing to 10mph will be the first stop - thats my plan i will be able to know better next summer when i can compare to my friends chair who will have 10 on his -

also reason i will try 10 first i would only need the rear sprocket different and of course different size chain - but i wont have to touch the motor sprocket - means dont have to remove the braking etc, - less for the tech to do and less of anything going wrong - should be very simple - remove wheel - remove chain - remove sprocket -

i am sure 4 bolts only - then replace sprocket - replace chain - put the wheel back on - then i can compare how big a difference it will gain me in range and hills etc, - and last but not least - IF that is not enough - i can go lower to 9mph - thats the lowest i can go with my motors - in which case - i would then need to just replace the motor sprocket - and of course different chain again - but the rear wont need to be touched - so to me it makes sense to do the rear only first giving me 10mph which may be just right for me.

we see - it get worked out sooner or later - after next summer - i will have it where its just right for me - both power and range - i will use the speed as much as i can first before i start to slow it down - we see - worst case theres always that plug and play 48V option - thats a real unplug JS - plug in new one - unplug PM - plug in New one - thats it - and make a new 48v battery -

no other chair has so many options like this - the Con. its expensive - so may not be with in reach - never know - you live once - if that ever happened - i would lower it down to the lowest at 9mph - giving me about 18mph

[expresso]

so far Cell 2 is doing well on recharging and its still going over 70ah returned - need about another hour to finish - so maybe there is 80ah in there after all - we see - if all the rest are the same as this one - i would say the first Cell is the same - it was my laptop that stopped recording and no way to know how much was returned.

feeling a bit better now about these 80ah Cells - 6 more to go -

[Burgerman]

The amount returned isn't telling you capacity accurately. Recharging efficiency varies. The amount you discharge DOES!

[expresso]

Oh Ok - still feel better to see more going in even if some is lost to heat - i hold my breath then till its built and recharged fully as a 24v pack - then do a full discharge leaving it going day and night till its done on its own - no stopping - and hope for the best

pretty sure i need to make cables to connect them - those connectors i dont think will fit - reach once i add the silicone sheet in between cells - there were tight just close enough with nothing in between - dont see it working out with them - too bad would have made it easier for me -

[Burgerman]

Lithium is also the opposite to lead in that discharging them warms them up. So instead of getting less Ah at higher discharge rates, you can get more. Usually about 1C gives the highest Ah out. So you will need to discharge at 60A to do that... Theres not this much difference though. Maybe 3 or 4%. But warmer gives better performance. Test the same pack at 5C instead of room temperature and get less. But not massively.

So when they claim that Ah figure, they do 3 things. They quote it at say 1C (if thats the best rate for that cell, and they quote it at 25 centigrade. And they discharge it to 2.5V.

So if you test at 20C room temp, and at say a few amps, with the PL8, and to 2.7V, you will get a little less. Maybe 3 or 4Ah.