PINNED - Lithium battery conversion/info

[Burgerman]

To charge from a car, to your lifepo4 any capacity, you need either a NON BALANCED LIFE profile, or a LEAD profile set to 28.80V. In both cases you would stop charging well before it was near full. You could then use that to charge LEAD AGM or Lithium Phosphate to about 3/4 or more full safely.

I can do that if you want.

[Burgerman]

if i need a different Preset for charging from my chair to a friends chair which has LEAD -

You made me this one for Lead - i can use this preset for charging a LEAD chair - its at 20A - can i up that to 25A ?

Or more.

[Burgerman]

I have the Chair set to cut off at 22V - in the programming settings - is that still fine to leave it there when using the ADD ON also connected to the chair -

i would think so but who knows i may be missing something -

Yes... But don't go that far!

[expresso]

To charge from a car, to your lifepo4 any capacity, you need either a NON BALANCED LIFE profile, or a LEAD profile set to 28.80V. In both cases you would stop charging well before it was near full. You could then use that to charge LEAD AGM or Lithium Phosphate to about 3/4 or more full safely.

I can do that if you want.

Ok i would want one of those presets for me in case - you did make me one for MK Gel - i posted it for you to look it over and see if thats good or else Yes make me a good one

[expresso]

if i need a different Preset for charging from my chair to a friends chair which has LEAD -

You made me this one for Lead - i can use this preset for charging a LEAD chair - its at 20A - can i up that to 25A ?

Or more.

these would be MK GeL kind - 73ah - if cheap AGM - 20A max i think

[expresso]

I have the Chair set to cut off at 22V - in the programming settings - is that still fine to leave it there when using the ADD ON also connected to the chair -

i would think so but who knows i may be missing something -

Yes... But don't go that far!

Ok i leave it there - 40 miles is good for the 105ah - with the 140ah - i wont do more than 50 total

[expresso]

i may be thinking of doing this tomorrow morning - if it looks ok - suppose to rain till about 10am - i would like to leave at that time or not much later

so i can be back before dark - being a sunday - they may be a few people around - unlike weekdays most working -

[Burgerman]

At 50 miles there should be some reserve based on previous measurements. If you do 50 that's already further than I ever did.

[expresso]

At 50 miles there should be some reserve based on previous measurements. If you do 50 that's already further than I ever did.

it may be less than that - i dont know how far it takes to go along that stretch under the bridge and around up again and back home -


the other day i went to the start of it - and i think it said close to 15 miles not sure - i turned back since i wasnt expected to go that far that day - just went to see how to get there -

i looked it over at google maps - it may just be 40 miles total - all i know i made it back and it was 28 miles - but i never started down the path -

[expresso]

i will use My tracks the app to track it - and save it to google drive - video it also

[expresso]

https://www.google.com/maps/place/Henry ... 73.9450863


over this bridge - make a right and go all the way to the end of road - make right and follow the henry hudson dr down to the water and ride it back under the bride keep going till i can get back up to the main road and back to bridge and home

[shirley_hkg]

How can you recharge @35A , if PL8 is powered by a car's 12V ?


JUST FOR YOUR INFORMATION :
We are all using TOP BALANCE APPROACH in our LiFePO4 so far , instead of bottom balancing .

@24V you are very likely to have over discharged ONE of your 8 cells already .

@22V , I promise you have to replace half of your pack .

Trust me . You need only ONE TRY to kill your battery .

USE YOUR CELL MONITOR when you are loosing the 25.2V comfort zone .

[Burgerman]

22V is a loaded figure. He doesn't want it cutting out on a curb etc. So should happen as he accelerates or turns etc. At least I think it is. So should not be a problem. I presume it will cut out under load and so the unloaded voltage will be a couple of volts higher. If set to 24, it may drop to that point as he climbs a curb. So start behaving like a problematic BMS as the battery gets lower? Possibly setting 23 and testing with a low battery is in order?

But in any case on all of my 3 packs the lowest cell group drops within just .3Ah of the highest group. Extremely close. So shouldn't be a problem at least with a good pack. And he shouldnt be going there anyway! As already mentioned... And really should be using the cell monitor you sent him to monitor all cells individually if he goes this low.

Trust me . You need only ONE TRY to kill your battery .

USE YOUR CELL MONITOR when you are loosing the 25.2V comfort zone .

That would be great. I suggested it. He wont!

[Burgerman]

:( How can you recharge @35A , if PL8 is powered by a car's 12V ?

You wont get quite get full power but it doesent matter if its set to 35 or 40A.

http://www.revolectrix.com/pl8_calculat ... Calc_1.htm

The program above wont let you choose 3.1 or 3.2V but gives an idea. [i](You can choose 14.4 and 6S with 4.2Vpc you get the correct initial charging voltage for lifepo4). And in fact efficiency is higher than its worst case shown, so you actually see more than the Amps displayed here. It shows 29.6 Amps. Reality is just over 30A in my van if battery is low.

He will be using the 35A setting. Or 40 if I do a new balance free profile. It will charge at about 30A or more initially as the cells are 3.1V (or less) initially. And stay around 27A until they start to climb up to 3.35V (or above) towards the end. If he charged them FULLY to 3.65V it would then drop to 25A at the end. Based on the alternator maintained 14.4V INPUT level, from a cars charging system, and the charge curve on the LiFeP04.

So you could set it to 30A without any/much affect on the charge time. But then if a fire/police vehicle or some commercial vehicle with 24V battery system turns up, he would be limited to 30A instead of 35A or 40A and increase the waiting time. The PL8 will limit current automatically to match the supply without a problem. Setting it to max Amps is fine.

[shirley_hkg]

22V is a loaded figure. He doesn't want it cutting out on a curb etc. So should happen as he accelerates or turns etc. At least I think it is. So should not be a problem. I presume it will cut out under load and so the unloaded voltage will be a couple of volts higher. If set to 24, it may drop to that point as he climbs a curb. So start behaving like a problematic BMS as the battery gets lower? Possibly setting 23 and testing with a low battery is in order?

But in any case on all of my 3 packs the lowest cell group drops within just .3Ah of the highest group. Extremely close. So shouldn't be a problem at least with a good pack. And he shouldnt be going there anyway! As already mentioned... And really should be using the cell monitor you sent him to monitor all cells individually if he goes this low.

I recalled that you've spent months in sorting out the capacity of each cell. I know that will make a huge difference at the empty end .
However, neither of us has the endeavor to do this capacity equalization process .

I USUALLY get the lowest at 2.9V , while the others remain 3.1XX volt .

My A123 pouch cells are rated 5C continueos . With my wife on the trolly behind me , I lost only 0.15V on crusing , 0.3X and 0.4X on start and going up ramp of footbridge respectively .

Your Headways may even out perform mine . The voltage drop is deem to be no more than that of mine .

So, BE CAREFUL NOT TO OVER DISCHARGE .

[Burgerman]

I am. I keep a tiny cell voltage monitor on me. If I go far enough to actually see a noticeable drop in voltage, I monitor it. The problem is that Expresso won't do it. Says its too complicated or too hard to reach.

So instead we do this.
Check distance, GPS. Monitor volts and Ah returned AFTER the trip. So based on what we know, he can do 40 miles with some reserve. And 50 miles with some more in reserve with add on. And there should be no problem unless he starts testing that reserve!!!

[expresso]

I am. I keep a tiny cell voltage monitor on me. If I go far enough to actually see a noticeable drop in voltage, I monitor it. The problem is that Expresso won't do it. Says its too complicated or too hard to reach.

So instead we do this.
Check distance, GPS. Monitor volts and Ah returned AFTER the trip. So based on what we know, he can do 40 miles with some reserve. And 50 miles with some more in reserve with add on. And there should be no problem unless he starts testing that reserve!!!

thats correct - i wont do it because i dont see a way for me to check the Cell monitor when i am out alone anyway - i cant keep it attached to the pack because it will drain it ? so thats out of the question - plus i have to take out the pack and redo the wiring even if i could do that part -

i wont be able to attach it - and disconnect it anyway - i dont see how i can do it - but if someone comes up with a way that i see is doable - i do it -

when i did the 40 miles - then recharged - it was at i believe 25.6V - or 26.2V - dont recall - have to check back i

i wont overdo the 40 miles - on the 105Ah pack - and or 50 with the Add On -

i am charging the ADD on right now alone - and going to make the trip today - i should make it to the bridge and over into NJ with just the ADD ON pack - about 12 miles

then i have another 40 miles left to use and get home - thinking it over - i dont think i will use over 40 on this trip today -

well see -

[expresso]

I checked - at 39 miles - it was 25.6V


i wont over do 40 miles - with the ADD ON i wont over do 50 miles - i may not even need the ADD ON today - i am just taking it so i dont overdrain the Cells

the ADD On is really my reserve today - i think i can do this in 40 miles

[expresso]

by the way - the ADD ON 36ah pack - does a great job - charges nicely - smooth one line - even with the Lead combined charging

MUCH Better than with the BMS at the beginning - i am sure if i had kept the BMS for the ADD On - the graphs would have been all over the Map like me

[steves1977uk]

I am. I keep a tiny cell voltage monitor on me. If I go far enough to actually see a noticeable drop in voltage, I monitor it. The problem is that Expresso won't do it. Says its too complicated or too hard to reach.

So instead we do this.
Check distance, GPS. Monitor volts and Ah returned AFTER the trip. So based on what we know, he can do 40 miles with some reserve. And 50 miles with some more in reserve with add on. And there should be no problem unless he starts testing that reserve!!!

thats correct - i wont do it because i dont see a way for me to check the Cell monitor when i am out alone anyway - i cant keep it attached to the pack because it will drain it ? so thats out of the question - plus i have to take out the pack and redo the wiring even if i could do that part -

i wont be able to attach it - and disconnect it anyway - i dont see how i can do it - but if someone comes up with a way that i see is doable - i do it -

when i did the 40 miles - then recharged - it was at i believe 25.6V - or 26.2V - dont recall - have to check back i

i wont overdo the 40 miles - on the 105Ah pack - and or 50 with the Add On -

i am charging the ADD on right now alone - and going to make the trip today - i should make it to the bridge and over into NJ with just the ADD ON pack - about 12 miles

then i have another 40 miles left to use and get home - thinking it over - i dont think i will use over 40 on this trip today -

well see -

I have a similar one like this in a black case expresso... http://www.ebay.co.uk/itm/1-8S-Lipo-Vol ... SwMtxXsR~3

The wiring is tucked under my seat, although I haven't used it in ages. I keep the cell checker in a bumbag which I take with me when I go out, and if I ever needed to check the SoC (State-of-Charge), I'd get my Mum or Carer to plug it in just to keep an eye on the cells if ever there was a low one.

Steve

[expresso]

@Steve - i have a cell monitor that Shirley got me when he got me the BMS also - its great if it can be left on and i can mount it where i can see it when in my chair alone etc, - but since it will drain the battery if left on - it cant work for me if i have to plug it in to check and unplug etc, -

i am alone on these trips - even if i was with a friend if he ever does the ADD On like mines - he cant help either - the way i am doing now seems to work fine -

i know my limit with the 105ah pack - 40 miles - i have yet to do more than 40 miles in one trip - which i managed to do today - i have the 36ah ADD ON attached but turns out i could have done without it also - i didnt explore much since i was there to just test a route i planned to do and it worked out fine - actually it was only 30 miles

seeing that - and it was still early - i kept going around the freedom tower and around - over another bridge to Brooklyn and back - i was trying to use the miles to hit 40 which i managed -

but the trip i planned to do - turned out to be 30 miles - so that means if i had just the 105ah pack and did it - i had another 5 miles to explore going out more - and still make it back -

the ADD on would have given me another 10 miles to explore before heading back - will post results later - charging the 105ah now - will charge up ADD ON tomorrow morning . i checked both volts - both read 26.3V now i want to see how much Ah i put back

[expresso]

How can you recharge @35A , if PL8 is powered by a car's 12V ?


JUST FOR YOUR INFORMATION :
We are all using TOP BALANCE APPROACH in our LiFePO4 so far , instead of bottom balancing .

@24V you are very likely to have over discharged ONE of your 8 cells already .

@22V , I promise you have to replace half of your pack .

Trust me . You need only ONE TRY to kill your battery .

USE YOUR CELL MONITOR when you are loosing the 25.2V comfort zone .

Hi Shirley - - i didnt actually realize that i would be charging from a 12V battery if i ever needed to do that - i didnt know i could have done it this way - since i though i needed a 24V source to charge - BM says it can be done and i believe him

i will get the parts needed - cables , wires etc, - make sure the PL 8 is set to do this in the Supply section - use a Preset Non balancing that BM will make for me - a
and only would do a fast one hour charge if this ever was needed - will not fully charge this way - when your stuck - dead - bottom charge will be just fine

when i get home - Fully charge correctly - i dont think i will ever reach that low in Volts - i have the cut off in the Rnet set to 22V - in the event i ever get that far down - it would cut off - and save the batteries from getting too low -

but at 40 miles on the 105ah pack - Volts are 25.6V so will never get that low - today with the ADD ON attached - 140ah - 40 miles - Volts were 26.3V even better
and having the extra weight did feel good for wheelies more and traction -

[expresso]

BM - this is how my supply section is set up - is this Ok to leave alone - if i wanted to charge from 12V car battery etc - ?

is there a better way i can use a Cell monitor - that i can do myself from in the chair alone ? maybe run wires from the pack all the way up to my seat and use that to plug in and out as needed ?

just rather not have to add more wiring than i really need - its been working so far with watching the Miles on my joystick and using that to keep it in check -

what do think ?

[expresso]

this is how my chair looked with the ADD ON - i really dont like how it looks this way - but its worth it when you need the extra juice

first time i actually used it this way - and it works - thats all that matters

[expresso]

before and after distance -


140ah chair

[expresso]

results from charging - this was 40 miles but had the 36ah ADD on also - 140ah -

normally this would be closer to 95ah returned if i had only the 105ah pack - now its only 70ah returned - when i charge the ADD ON tomorrow - i bet it used about 24ah of the 36ah -

[LROBBINS]

Expresso,

instead of plugging and unplugging, you can wire in a switch to do the same thing.

[expresso]

Expresso,

instead of plugging and unplugging, you can wire in a switch to do the same thing.

which means what excatly - i have a cell monitor that i got from Shirley - but never did anything with it - if theres a way i can wire it and leave it alone - not draining my battery in the OFF postion - then when i want to see it - turn it ON - check and turn it Off again -

that i can look into - i would do it during the winter when i take it out to replace the main power wires - i need more details about this -

thinking of you - i got these fresh - and are amazing you know these for sure

[Burgerman]

I am eating a stale mass produced bread bun with a slab of generic cheese when you posted that...

[expresso]

I am eating a stale mass produced bread bun with a slab of generic cheese when you posted that...

if you were closer - i send you some - they are so good when fresh and still warm - i have 2 left will have in a bit -