60ah ADD ON build with Pictures

[expresso]

ok i am hoping it gets better after a few discharges and recharging - it seems to be one cell thats a bit lower on the discharging so far - Cell 3 - i will check it in a few hours - stop it - and restart when i get home - then recharge tomorrow .

i just feel cheated some from the seller - - this shows - its not easy finding a good Cell the way i did - headways seem to be the best bet still in getting a quality Cell -

[Burgerman]

Problem is you dont know the manufacturer, the history,, or anything. Theres plenty of horror stories from china. Reslling failed or warrantied cells, and reshelling old ones etc. Best to buy a known source, with plenty of users with tests etc.

[expresso]

Problem is you dont know the manufacturer, the history,, or anything. Theres plenty of horror stories from china. Reslling failed or warrantied cells, and reshelling old ones etc. Best to buy a known source, with plenty of users with tests etc.

yes very true -

question - how bad can it be if i got 8 more headways to add to my 30ah pack which i used last summer ? mixing new to used - they werent used the whole year - i say a good 4 months total - i am thinking of getting 8 more to make the most of the space -

[Burgerman]

It will be fine.

[expresso]

thanks - i think i may do that anyway - that was my first plan then i used 8 to make 2 12v packs and made it 30ah instead - i can fit another 8 - might as well make use of the space - i hope to get this 60ah going and in use - then work on the 30ah to add 8 more - at least i know what i am buying this time

about to go check on the discharge in a few min. and head out for a while - i am sure it wont be a good graph at least with that one Cell 3

[expresso]

if it stays this way - may not be too bad - will recharge when i get home and do it again tomorrow -

what do you think of this ?

[Burgerman]

Keep going for a bit. 6 or 7 hours. Or a full discharge. See what it does.

[expresso]

I will continue over the weekend discharge till 2.9v. And see then recharge.

[Gnomatic]

I will continue over the weekend discharge till 2.9v. And see then recharge.

This is good, no need to panic. And you'll get an idea of your pack's actual capacity to within safe voltage limits And who knows, maybe the graphs tighten up a bit over time.

[expresso]

if it stays this way the whole way or most of the way - shouldnt be too bad - its a few off of the rest - Cell 3

being so close - i wonder if it is the connector i made - if i should make a new one just for this Cell maybe ?

[snaker]

I see these discharging graphs are so good. The cell 3 is just a bit weaker than the rest. Fit it to the chair and

[expresso]

maybe just maybe they may be alright -

will continue it tomorrow till i reach 2.9V

[Burgerman]

Keep going... In an ideal world you will get about 55Ah, and all will end reasonably close. But one will always drop first.

[shirley_hkg]

Keep going... In an ideal world you will get about 55Ah, and all will end reasonably close. But one will always drop first.

I bet he will get 50Ah from this pack .

[Burgerman]

Well the only way to get more will be to discharge to a lower voltage which isnt a great idea.

[shirley_hkg]

Everybody should know the cutoff voltage of their packs . They vary a lot .

Mine shouldn't go below 25.1V .

[Burgerman]

givebeer
I bet he will get 50Ah from this pack .

shirley_hkg

Maybe if its old? Impedance would worry me more, cell 3 looks higher than the others. At the start at least.

[expresso]

yes its good to do this at the start of a pack to know what it can do - and know the cut off Volt etc,

restarted the discharging and looking much better - i should know by tomorrow what it puts back in the end how many Ah - i hope at least 50ah and more

[expresso]

Being that this is an ADD ON pack - i am disappointed if in fact these cells are OLD USED or just crap - but i would be more upset and pissed if i did the whole chair with unknown used cells !! - even if you can save half the cost - it may not be worth it - the work - since i am no expert - its easier and safer for me to use NEW CELLS for a full chair pack - costing double i am sure - but done right - lasts and worth it -

i was almost considering doing a full chair with these kind of cells - instead i will add 8 more headways to my 30ah ADD ON and then have a 150ah Headway pack -

i still hope this 60ah ADD ON will give me that extra range i am expecting to get - i am going say 30 miles give or take - limited still but for a backup chair with lead - cant complain

[Burgerman]

Why stop and restart?

[expresso]

Why stop and restart?

i went to bed - and i am going out in few - but i wont stop it now - its going and should take hours still - i think - i wont be out for long - i should get this done discharging today for sure and then maybe even recharge it later when i get back

i have the preset set to 2.9V - when the first Cell hits 2.9V - it will stop discharging ? i dont have to manually stop it ?

also i noticed Cell 3 started to go off course again by a digit or two - lower than the rest of the line - so that may be the weakest Cell that i need to watch - but if its only a digit or two - wont be bad since most of the pack will be close enough - IF it stays more or less the same once i start using it -

[Burgerman]

i have the preset set to 2.9V - when the first Cell hits 2.9V - it will stop discharging ?

yep!

i dont have to manually stop it ?

nope!

But you are now missing the first part of the graph which will make the drop at the end by the first cell look worse than it is.

As it is you would get another 3 or 4Ah if you discharged it lower on most cells, but we know that and its unwise to test that far. So a healthy 60Ah pack will give about 55Ah doing it how you are. A less than healthy one with a cell thats less than perfect will stop sooner, as soon as the worst cell ssees 2.9V.

[expresso]

ok all done discharging and Cell 3 is the worse of the bunch - - dosnt seem that much off - but we see how that translate in real usage -

will recharge it up till its done - i am pretty confident now that i can get 55ah back in this pack - maybe i can make some use of this ADD ON after all

[Gnomatic]

I think it will be fine.

[Burgerman]

Its not how much you put back, its how much you took out that matters. So... How much did you take out? That was what we were waiting to find out!

Those cells are close enough to the same. Dont take it below 3.1V unloaded in use. Measure while sitting still. Thats the point you stop!

[expresso]

I think it will be fine.

i hope this will have to take me thru this summer - my only chair - till about sept.

[expresso]

Its not how much you put back, its how much you took out that matters. So... How much did you take out? That was what we were waiting to find out!

Those cells are close enough to the same. Dont take it below 3.1V unloaded in use. Measure while sitting still. Thats the point you stop!

OH i see - Ok - i figured it was about 58.9Ah taken out - i stopped and started the discharge 3 times over the course -

i started it - then when i went out - i stopped it - because i wanted to see it - then i started it again yesterday and stopped it when i went to bed.

today was the last one -

i added up the Cap. out from the graph screen shots - and came up with that number

today was 21.5ah Cap out

yesterday 12.7ah Cap out and also

yesterday 24.7ah Cap out -

58.9ah - can that be correct - sounds great giving that one cell is a bit weaker - maybe i will make a new connector just for that cell to see - before i start to use it next week - i will put it on the chair Monday - i can change that out easily now its out in the open -

maybe worth a shot ?

[expresso]

this was the morning charge yesterday - i stopped it when i went out - if i knew i could have left it - i would have - i wasnt sure -

[expresso]

this one is the next one i restarted when i got home yesterday and then the one for today when all done

now i am recharging

[Burgerman]

So you discharged about 48Ah. And a couple extra if you had kept going to their 2.5 limit. So about 50Ah max.

You have 60Ah cells, sold as 60Ah there then. Still not bad for an addon. The chinese tend to inflate the figures a bit because they think that people cant measure it with accuracy and a bms, dumb charger. So sellers get away with it.