200Ah Pack

[Burgerman]

Thats not bad. Remember that if a back is just 1% out of balance, that means its 2 full Ah out if its a 200A pack.
If its a 20Ah pack with the same 2% out of blance, its only 0.2Ah out of balance.

So with a fixed 1000mA or 1A balance capability, that a massive difference on recharge for the balance time/graph.

200Ah pack, takes 2 hours to rebalance.
20Ah pack, only takes 12 mins.

If that was balanced with a 100mA capability BMS it would take 10x longer!
So 20Ah battery pack thats 1% out, Balanced by BMS will take 2 hours. But a 200Ah pack would take a rediculous 2o hours at CV to balance up.

So the larger the pack, the worse the graph will look. For a very large pack that doesent look at all bad. And will likely get better over the next dozen cycles or so till it all matches. But if you only charge every 3 months then expect the next few charges to look terrible! Because all the cells self discharge at different rates for 3 months. In use, it will not do that. So will get MORE balanced.

[expresso]

It won't be used for a long while. I can either recharge it every few months or more often to keep it more balanced. I see next summer if my new chair was ordered etc. If nothing by then. I can just try to swap it out of the other chair use it there. But I will use the bounder the most in the summer I can't complain it's the largest I will have inside a chair and will never really use it all. Not Goin to do 70 miles all the time

[Scooterman]

Espresso - Is that the first 16 cell pack you've made?

What's your opinion of using 16 cells?

My existing pack is 16 cells but new pack will be 8 cells. Personally I don't like wiring up 16 cells, it's awkward, a lot of connections.

But of course currently 16 are needed to pack max Ah into 2 x grp24 space.

[expresso]

yes its the first 16 cell pack - at the time i was looking for cells - i found these that are thin in width - size was right - 100ah cells - but really closer to 175ah to 180ah in practice - and price was good - i ordered 8 to see if they would fit etc, i figure worse case i make another ADD ON but it fitted so i ordered 8 more to just try it -

i agree using 16 is more of a pain with the wiring and connections - if the buss bar were used - it would have been nicer in apperance - and that was my first intention - to use them - i can get them Nickel treated if i want now - but i used the wire instead much neater with the smaller wire for connecting two cells now -

i was hoping to have a chair to stick it in this summer - but thats not going to happen now - so it may just sit there for another year - or swap it into my 646 in the summer just to test it - depends how i feel - since no one i know here is interested enough to want a pack - i guess its just me with lithium that finds it amazing to have

i never go back to lead - if i ever have to do it again or another one for what ever reason - i would try using just 8 cells - would have given me the same Ah - and less work etc, - if cost was good enough - i got a good price on these so i went with them -

[Burgerman]

Funny isnt it.
Up until recently, we all used 70Ah lead, that only gives 35 to 40Ah usable then we stop. And it takes 10 to 16 hours to recharge.

Now we are worried about the difference between 175Ah and 200Ah usable Ah...
Its because we like round numbers. The reality is that we get 4 times as much range with some left over regardless. over 4x the range maybe 5. For years rather than monhs before it deteriorates. maybe 5 to 10x te service life.

[expresso]

i agree - my 646 is running off 150ah - and i have yet to use it all on any given day - bounder 180ah - can get 70 miles on that heavy chair - at the very least anyone should fit at least 150ah pack - anything more is better but most likely wont be needed - since many cells now can get easy 175ah using just 8 cells

i would shoot for 8 cells in the future - by then we may have 200ah cells that fit only 8 in the box - i say 150ah is the Min. that can work fine - 646 chair with 150ah headways - will be 6 years this coming summer - and i am not worried about it - also used copper ring terminals my first pack - didnt know better then

just to say its still working fine even with copper - now i would do it different but if its not broken - i wont touch it - i havnt even opened that battery box to look at it for years - which is what i like -

[Scooterman]

I've ordered 8 x 150Ah cells, but me and my chair are very lightweight combination, and 8 saves about 10kg over 16, but imho that's not a reason to go for 8.

[expresso]

150ah is more than enough - you should be able to do easy 50 miles - no worries - of course - you want to always test your limits - each user chair combo is different - all my chairs run high speed so i use alot more battery than the avg. 6mph chair - and even then i cant use it all up in a day -

since i know i have so much - i tend to just ride as far as i can - use up the day 5 - 6 hours riding easy - but not many do that so 99% of users wont matter much after 150ah -

what cells did you get - have a link to them ?

[Scooterman]

These expresso https://www.aliexpress.com/item/4000224208689.html

The price tends to fluctuate a bit but not too much, I paid £613. Not sure how much that is in USD, just under $800 I think???

[expresso]

yeah have to search - i just seen a set for $600 - with shipping - then i find others for $800

i found some 195ah cells also - its all about the cost - sometimes its cheaper to get 16 cells - with more Ah - then 8 -

at this point any 8 cells at least 150ah is great

[Burgerman]

https://www.aliexpress.com/item/4000343 ... b201603_55


http://m.rj-lithium.com/sale-11530426-p ... f-car.html

[expresso]

https://www.aliexpress.com/item/4000259 ... 2e0exedbnx

if i seen these first - i would have taken them

[Burgerman]

Or https://www.aliexpress.com/item/3304029 ... 7e23c8e547

These cells claim to be 205Ah, same size.

Or 210
https://www.aliexpress.com/item/3297625 ... b201603_55

[expresso]

its a bit different in size - a few mm difference - its pushing the limits of a grp 24 size - would need a chair that has some wiggle room -

how much can they fit in the same size Cell - not long ago - 100ah was the best that can be found that fits - now its double - there must be a limit how much they can fit in the same size ?

i would even use those buss bars - which are not bare copper limit is 173mm - now you may have some minor room to make 175mm fit - but depends on the chair - sometimes thats enough to not fit - and be stuck with the cells -

i have yet to test fit my new pack - i had to cut the battery try lip on one side - since it didnt fit perfect in the tray - but i have that wiggle room just enough - front or back - but not the sides - so i should be able to make it fit in a 646 chair

[Burgerman]

https://www.aliexpress.com/item/3301996 ... 0f042f7034

200ah 1k delivered to your door. Yes you must measure to be sure. These will fit my salsa I think without any issues.

As time goes on the capacity gets bigger. Price and size stays the same. But its now easy to fit 150 to 200Ah in place of a stock grp24. Making the lead brick 70Ah drop in replaceents look even sillier.

You can get 5x the range, and a decade of service life, for 2x the price of a set of MKs that you throw away yearly.

[expresso]

lets see when others are going to wake up finally - and just dont even bother with lead - 150ah without question can fit - at the very least - that should be the min. if you have a grp 24 size to fill - but for not much more in cost you can get 200ah - so makes no sense to even think of lead - use 8 cells - cant get any easier

when will the industry see this - at least another 10 years before they may show some interest - - at least bounder did it - and been doing it for years now - like it or not - only one who has the balls to do it - small pack for the chair - but still better than lead - avg. user is fine - more active user - not enough for me.

[Burgerman]

Yes. Unfortunately they are a bit left behind at 100Ah but its a start.

[Scooterman]

https://www.aliexpress.com/item/33019962665.html?spm=a2g0o.detail.1000013.7.7ce354d3NjOqr3&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.146401.0&scm_id=1007.13339.146401.0&scm-url=1007.13339.146401.0&pvid=1436b33c-2785-42a1-a214-020f042f7034

Two nasty bolt heads intrude into front of salsa battery compartment, where it's bolted to frame tube

But I think you know about that and suggested flat head bolts. I've got a couple of low profile m8 coach bolts in nut & bolt box and will grind square flats off just under mushroom head. They'll do

Espresso - do you find building lithium packs is addictive? It's practical and technical and not oily so best sort of project

[stevelawiw]

Espresso - do you find building lithium packs is addictive? It's practical and technical and not oily so best sort of project

And on top of the satisfation of a job well done you increase your quality of life - more range = less worry about getting stuck somewhere, and you're not so tied to the charger

[Burgerman]

Thats easy to fix.
Flat head bolts.

You can also recess them. Fit a bolt from the inside. Fit a LARGE nut as a big donut over the other side centralised by taping over the bolt threadded side. Fit a big washer or anything with an 8mm hole that covers that big nut. (Actually I use a big socket instead). Add a nut on top. Now tighten it up and it will deform the front of the battery box and the bolt head gets hidden. A least enough to hide the flat head bolt completely.

[Scooterman]

That’s a really clever idea BM, i’ve never heard of that before. I will store store it in My memory bank, aka brain.

But I do wonder whether it will be a struggle with the salsa’s battery compartment. It looks to be about 16 SWG? With a blowtorch help or doesn’t it get hot enough?

[Scooterman]

Maybe you’re deform method using a conventional bolt, then replacing it with a flat headed bolt?

[Scooterman]

Ah I see what do you mean by using a large socket instead of a doughnut size nut which I don’t have. With a socket you need a longer bolt but I’ve got long bolts

[Burgerman]

Any bolt, but normal hex is OK, and you shouldnt need to heat it. You only need 3mm to cover the head on a flat head bolt.

[Scooterman]

Any bolt, but normal hex is OK, and you shouldnt need to heat it. You only need 3mm to cover the head on a flat head bolt.

[Burgerman]

Dunno how thick that metal is, but it works easy on a car body. If all else fails, weld the flat head bolt to the outside of the box.

[Scooterman]

It It pretty thick perhaps 10 gauge?

But I'm doing away with the salsa's two hinged back plates and having just the outer back plate which the controller is bolted too. I will make my own out plate out of a scrap of sheet/plate steel, and will gain me about 20mm on length so my mushroom coach bolts will be fine.

[Burgerman]

Lost track, which cells?

[expresso]

Yes. Unfortunately they are a bit left behind at 100Ah but its a start.

yes true but still the only manufactor who does it - been doing it - - the others should all follow you would think - but since bounder is a very different kind of chair than most users want - but till now they never had a Class 3 chair covered - so maybe it will help them - insurance wise - still the vendors wont really push bounder

they rather give you a pride chair - mid or rear wheel drive etc, and make you feel you got the best of the best - most dont know any better -

[expresso]

Espresso - do you find building lithium packs is addictive? It's practical and technical and not oily so best sort of project [/quote]

yes it is addictive - i enjoy doing it and always learn something new - or make different mistakes which i then improve on etc, - this may be my last one for a while i believe - i done both my outdoor chairs full - indoor chair has lead and not touching it - never leaves the house - and my back up now is the combo chair lead and ADD ON which i dont use much at all now -

so will be lending out that ADD ON to my friend with a bounder also - so he can do long trips also - but problem is - he dosnt know how to charge it etc, - hes all plug and play or forget it - so i have to take the ADD On back after its used and charge it for him to use on the next ride - we see how thats going to work out this summer

i dont have any more chairs to make lithium - and its going on 6 years this summer - - i would have though others would have wanted at least an ADD ON - but no - i guess its just me - everyone has no problem spending 1K on iphone - but complain about the cost of lithium and charger etc, how the times have changed