60ah ADD ON build with Pictures

[Burgerman]

All good.

I wouldnt go any further though. That 2.5V per cell is really extreme. You CAN do it, with care, and not do too much damage. But it means 2.5 lowest under load. As you drive, or turn, the voltage drops, and comes back. So 2.9V may well be 2.5V as you work the cell hard. And instantly recover as you stop to look. So its best to stay away from the bit where the cell volt starts to drop like a rock.

I flew a quadcopter away about 3 miles one day. And noticed in my goggles, that its battery was a little low. I JUST mad it back over the water (sea) as the voltage was dropping off a cliff, and I landed rapidly. That was a new battery pack. It went in the bin ruined. Voltage too low once. Was enough to total it. £50 wasted...

[expresso]

yeah your right - 2.9v should be the lowest i should go - i wanted to push it a bit since i know that Cell 3 is weak - i figure let me see - but i wont do it anyway

i may be getting an replacement Cell - if i do - and its better than what i have there now - i will replace it during the winter time - even if i only get 30 miles out this pack in its current state - its still pretty amazing for just an ADD ON -

OK i did the Diode Cable - it looks like crap - but its done - i tried to cover any exposed metal from the diode - reason for tape and heatshrink and leave the Body of the diode uncovered -

i hope this is safe this way and will connect it tomorrow - may use it tomorrow but wont be doing 30 miles just in case - not sure how i can test this unless i push it to 35 miles or more -

any other way to know if this is working other than pushing it to 35 mile plus ?

[expresso]

reason for the SB50 end and XT90 end - is i am using the very first Cable i made for an ADD ON - for my first ADD ON i made 36ah - back then i had the SB50 on the pack and Chair etc, -

i have since went to using XT90 on my packs - and Cable - but since i had this cable made this way already - i just made an adapter extension this way -

i have to just replace whats there now with this new one with Diode inline - - whats there now is the same setup adapter cable without the diode

in a way its good - if it should not work or fail - i can just go right back to the way it is now - only problem is if it fails when i am outside - then i may be stuck

thats my worry about this diode thing - another part in the middle that can fail and leave me with no Juice -

what are the ODDS of that happening ? or anything with the diode etc,

thanks

[expresso]

After recharge - if Cell 3 ends up being replaced - and the diode ends up working out - then i can say 35 miles with no problem and end it at 2.9V also

maybe a bit more than 35 miles - will vary between rides - 30 miles for sure on any day -

[Burgerman]

Test it, see if it works. If it works, then turning hard left, right, left, right, for a minute or two and it will either get warm, or it will get hot. If its going to fail thats will do it. without even leaving your room.

It will also let us know if heat will be a problem. If it doesent even get a tiny bit warm, then you may have it in the wrong way around and your lithium battery will not get discharged at all.

Now. Provided its correct, when you charge the battery, you will need to increase the voltage a little. To match. Because the voltage reaching the lead battery when on charge will be slightly less. So. Charge at 3.570V per cell. That gives us 8x 3.57V = 28.56V to the batteries from the charger which then has a approx .25V diode drop to your MKs.

So to be sure these estimates are correct, while its actually charging at CV and low amps near the end, measure the two charge pins in the empty XLR socket with your multimeter. It should read 28.2V plus or minus a tiny bit.

[expresso]

Ok its on there now - - i checked it with the volt meter connected to the pack and it shows the correct volts so i know its working -

i ran the chair up and down my hall way and turning in my home etc, - my girl checked it - its warm - not HOT that you cant touch it - she says its warm but can hold her finger on it and not get burned etc, - so thats a good sign so far -

i will go out for a short fast run today - and see what i get back how it is - i cant check it when outside of course - but i will disconnect it when i get back and check it with the volt meter again to make sure its still working and flowing at least -


about the charging - i dont think i have to up the volts on charging because my charge cable is not the same cable as the ADD ON CABLE going to the chair with the Diode on it -

when i charge with the SubD cable - etc , that cable dosnt have the diode on it - when i make my packs - i always make two sets of cables - one for just charging with 12AWG wire etc,

the ADD ON Cable with the diode gets 10AWG wire - the diode dosnt see any charging which is good it think - dosnt get over used for no reason

not sure what i can figure out today for a short ride - i would have to push it to 35 miles or more to see if it makes any difference i would think -

thats for another day - i wont see many hills on todays ride - it wont be pushed too hard today - about 8 to 10 miles more or less i may hit a steep short hill or two -

well see when i get back - if it fails i can still make it home on a 10 mile ride on lead alone - so far its working

[expresso]

Ok looks like it held up today - it was very hot outside today - i ran it a good 13 miles and did a few hills - a bridge - cant say how hot it got during use but once home i disconnected it again and checked - was fine 26.4V -

if i get a good day - i may try for 35 miles just to see what it did or does etc. - recharging now - i am guessing it should be 28ah used for 13 miles

i may be wrong - but its a guess based on my last run of 33 miles and 85ah returned -

[Burgerman]

Doesent work as simple as that. Isnt life a bitch!

The CV part, est the last CV few hours on both Lead, or lithium, can take much more power and is less efficient. So while you can put back say 2Ah per mile for eg as you begin to charge, that can be 4Ah per mile or worse towards the end.

So measuring what you put BACK doesent tell us a great deal about if it helped.

What will happen is that as you drive the chair, thinks the lithium is .25V lower. So battery lights will drop out sooner, and more lead gets used up. But not that much.

[expresso]

Ok so i shouldnt worry too much if i notice the battery lights drop sooner than expected - its still going on CV - but already 32AH returned more than i guessed

if i feel good tomorrow and it dosnt rain - i may try for 35 miles - - if the diode does its job - 35 miles should be easy to reach - not bad for 60ah pack with one weak Cell holding it back -

normally i dont loose a light on battery JS till about 26 miles give or take - before i may notice one green light out - - its down hill from there - cant be too far once that happens -

but now it may go out sooner but not to worry ?

[Burgerman]

A little. Take the lithium monitor, and watch that one.

[expresso]

A little. Take the lithium monitor, and watch that one.

Dont have a monitor - the one i made never worked out - - i have a volt meter for pack volts from the XLR - i bring that alone and can just check volts - 24.5 more or less seems to be the limit - i have done 24.2v and still good 2.9v - so it varies a few

[expresso]

Ok i reached my limit with this 60ah Pack - Cell 3 is holding me back - i can easily get 40 miles out of this Once i replace Cell 3 -

but even as is - its amazing - i got 36.7 Miles with the diode in place - which made a big difference - easy an extra 5 Miles - which is all i needed to do the same trip i used to take with my 646se with 105ah lithium -

this chair is the quickie P222se - its a light chair compared to my 646se- it has no seat lift - just tilt - light front end - because of all this - its giving me great range with the 60ah pack -

why didnt we discuss this diode before ? today again was very hot out - 90s and humid and i ran it all day up hills down hills - non stop - i made it all the way home with all my green lights - about 32 miles - so i kept going close to home till the green light went out - wasnt much longer -

i will say 37 miles - since i didnt start my GPS right away when i went out - i figure half a mile was lost before i started the app -

i no longer feel too limited now - and once i get a new Cell to replace Cell 3- 40 miles would be easy and safe - as long as this diode holds up - and it was fine when i got home -

and this Diode is what about half a volt less its sucking from the pack ? if using a 1 volt diode - could get even more at the expense of the Lead - but this is fine as is -

[expresso]

the only thing that holds me back on this chair is the light front end - cant do much hills - will get me stuck on the way up the hill -

i was debated doing the whole chair lithium - but i see how great it is with just the 60ah ADD ON - i dont feel the need to do the extra work - New chair coming in a month - 646se being repaired in a few weeks - new motors -- this will be my Back up to my Backup Chair

and i want to make another ADD ON for my new chair - 100ah lithium isnt enough - i want to make another 80ah ADD ON - giving me 180ah on new chair - 150ah on 646se chair and this 60ah ADD ON combined chair -

i think its worth while adding a Diode if you have a combined ADD ON setup - easy enough to do - and the gains are very good i think

[Burgerman]

There are no 1 volt diodes. And each varies its volt drip depending on load.

So a basic silicone based diode will start at about .65 volt drop with no load. Then depending on which diode you select, the volt drop changes as the amps increase.

And a Schottky diode starts at about .25 drop... And again this increases with load depending on spec, but when you slow down or stop, the difference is again .25 volts...

I chose that one quite carefully to get the desired effect. High enough volts to be safe, correct amount of forward voltage drop, high enough max current to be safe and not fail, and big enough physically to dissapate enough heat. All of it guestimates, but reasonably safe ones. If you want a bit more range a silicone diode or 2 of those that you have (one in each wire (neg and pos) or 2 in series bolted together will do that and use more lead power. At the moment you are using just over 1/2 of your lead. Another diode, and your display in the photo will read .25 less at the end of your drive. Maybe 40 miles.

I never tried this you are the alpha and beta tester! But it seems to do as I expected. When you charge the PAIR of batteries, it will do the same. So you should really need to increase the charge voltage to the lithium. But for reasons I dont understand you tell me not.

Anyway pleased it worked properly.

[Burgerman]

Different diode types. Ignore the pics, they come in many shapes and designs!

Read the link page below, you are using a 100A capable, 100V max, 0.25V volt drop Schottky diode.
You can replace that with a similar spec Si (silicone) diode to get .65V drop approx. It will get twice as hot.

https://www.elprocus.com/types-of-diode ... lications/

[expresso]

Ok - i am not looking to get the last drop of it - its fine as it is really - even without the diode but with it - i get an extra 5 miles more or less and just what i need to reach the spot where i used to go with the other chair - - i dont feel limited now - i can do what i used to and go where i used to before and not worry about it -

adding another one in the Neg. line would give me double the effect ? thats interesting - not going to try it - but good to know - if i get the itch one day - maybe i order a few more - and do it just to see - winter time project

about the charging - I dont need to add more voltage to the charging because its not charging thru the diode cable -

the charge cable is direct to the battery pack - NO DIODE is in line with the charging cable - so i dont see the need to rasie the voltage - unless i am missing something -

the Cable - wire with the diode inline is separate from the charge cable - - i always make my packs with two sets of cabling - one set for charging balancing with the SubD - another set of cable wiring going to the chair lead -

when charging its not using the cable with the diode - no need to change anything with the charging preset - - - correct me if i am missing something - i could be wrong -

it held up well today - 37 miles with high heat temps outside - 90s humid - hills non stop - its robust - time will tell but if it didnt fail today - good chance it will hold up over time -

i think this is something everyone should consider when doing an ADD ON with Lead - if they want the most out of it - - or else its fine without also -

i know i needed at least 34 - 36 miles to do the ride i always did before - and i was just a bit short of that without the diode in place -

the diode changed everything - i feel comfortable now going that far like i used to and make it home again - Given it never fails in use over time -

you can check volt meter ever so often to keep an eye on it - if you notice big changes - or your green lighst on JS go out much sooner than normal - then you know it may have failed

i can say for sure - it was about 33 or 34 miles before first green light went out on my JS - i was pretty much home then - blocks away - compared to before without the diode - first green light or two went out about 26 to 27 miles and i was about 4 or 5 miles away from home -

this diode gave me just the extra bit i needed - about 5 miles - - once i replace Cell 3 in the winter - if all goes well 40 miles will be the safe distance and about Max for this chair setup -

and all from a 60ah lithium ADD ON with Diode in line - anyone can do it - if i can - you can

[expresso]

Done charging -

almost 90ah returned - i am curious now - will order two more diodes - same kind and make another cable with both diodes - one each line pos and neg.

Neg. diode facing the other way ?

with a replacement Cell for Cell 3 -- two diodes in line - i think i can get 100ah out of this total - maybe 45 miles - wont know till next year when i change Cell 3 -

[Burgerman]

Neg. diode facing the other way ?

Yep.

Next year? Remember that lead, and lithium dont stay at 100% they all get worse over calender time and cycles. So you may have lost a little by next year, and then gained some back with the extra diode... So its not so simple. And you dont always get the same miles per Ah on each trip. Its a bit like the guy who thinks he gets better MPG in his car because he does some placebo action like changing to a different engine oil or something. Testimonial, and unscientific unmeasured controlled parameter testing of MPG or Miles Per Ah are not accurate. Or repeatable. Even if it feels that way!

[expresso]

Ok - it cant hurt either way - may end up having Cell 3 replaced by next year also - either way its a good thing to use the diode if someone wants the Max out of there setup -

[Burgerman]

So we have another winner!

[expresso]

[expresso]

BM - I think i got it what you were saying about adjusting the preset to charge with the diode in place - it just hit me last night for some reason - your correct - since the ADD ON cable with the diode in line is going to the Lead - your saying the diode will affect it the same way when charging as it does when its discharging -

therefore adjusting the preset to about 3.55V instead of 3.25V should offset it enough ? i was thrown off because i was thinking of the 60ah pack itself - not realizing that the ADD ON Cable going to the chair which in turn is charging the lead - thats where the diode is - took a while but it just hit me last night for some reason

So yes in that case - i need to up the charge volts to offset it -

Would 3.55V do the trick ? or higher ?

Another Question now since i may make another cable with Two diodes in line - IN that case - if using MK Gel with two diodes in line - i would then charge at 3.6V to offset the diodes ?

Also what if a chair is using AGM batteries with an ADD ON - with Two diodes in line - would 3.6V charging be enough to get those AGM's full - ?

thanks - took a while - but i got it now what you were saying

[Burgerman]

3.600V x8 is perfect for AGM. 28.80V.
3.600V x8 less .25 Diode is 28.65V which is too high for gel but also fine for AGM.

3.650V x8 is OK for Lithium, 29.20V too much for some lead, OK for some inc odyssey.
3.650V x8 is OK for lithium, and with 2 diodes, so .5V less than 29.20V so 28.70V and OK for AGM.


3.550V x8 is 28.4V so a little low for AGM. But a little high for Gel.
3.550V x8 less .25 Diode is 28.15V so perfect for Gel.

3.590 is ok for lithium, and OK for GEL bricks, with 2 diodes at 28.20V

Fine tune with Voltmeter in the XLR socket holes... At CV.

[expresso]

Ok got it - will adjust according to what will be used - at the moment - its now has AGM - so i will adjust the preset - no diode -

the pack may be moved over to her new chair which may have MK Gel - if it does - then i leave it alone the preset

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Another question - a bit off topic -

the vendor changed out the batteries - BUT they connected the ADD ON Cable on ONE BATTERY ONLY - unknown to her - the Cable from the lithium ADD ON was connected to the lead Cable - it make a buzzing sound and got hot fast - it was a Sec. she disconnected it -

did that damage anything ? i just went to check what was wrong - and thats what i found - they connected the cable to one battery - showing 12.9V - the ADD ON cable shows correct 26.7V - we will fix it Wed. - -

is there something i can check with the PL 8 for the lithium if it did any damage there - i would think not - it was a split sec. and was disconnected -

what do you think ?

[expresso]

banghead

3.600V x8 is perfect for AGM. 28.80V.
3.600V x8 less .25 Diode is 28.65V which is too high for gel but also fine for AGM.

3.650V x8 is OK for Lithium, 29.20V too much for some lead, OK for some inc odyssey.
3.650V x8 is OK for lithium, and with 2 diodes, so .5V less than 29.20V so 28.70V and OK for AGM.


3.550V x8 is 28.4V so a little low for AGM. But a little high for Gel.
3.550V x8 less .25 Diode is 28.15V so perfect for Gel.

3.590 is ok for lithium, and OK for GEL bricks, with 2 diodes at 28.20V

Fine tune with Voltmeter in the XLR socket holes... At CV.

i was thrown off being that i charge with a separate cable for the pack - but didnt take into effect the cable going to the Lead which is being charged also with the diode in line - wasnt sure if it was working during discharging only - so i guess its works period all the time - diode in line -

hey - at least i got it - in my sleep weeks later

[expresso]

I got another question - about andersons - quick one

i dont have it in front of me and wont know till i get my new chair - but the Anderson they use shows 120A - 600V - would that be the SB50 or SB75 model - - i feel its the larger SB75 with those numbers - ?

[Burgerman]

No idea, but the 50A ones we use are 50A HOT SWAP, so designed to be capable of plugging in, out at up to 50A 1000s of times with arc damage not being a problem. The 50A ones are capable if a couple of hundred amps continually or more for a few seconds without a problem. And probably a thousand amps for a second.

i was thrown off being that i charge with a separate cable for the pack - but didnt take into effect the cable going to the Lead which is being charged also with the diode in line - wasnt sure if it was working during discharging only - so i guess its works period all the time - diode in line -

hey - at least i got it - in my sleep weeks later

It works any time that the current flows towards the lead battery. So as you empty the lead, or as you charge the lithium. It doesent allow power back the opposite way. So you could charge the lead at 50V and not damage or charge the lithium at all. Its like a one way valve.

[expresso]

It doesent allow power back the opposite way.

Ok this is what i was thinking but got it confused - i was assuming the diode is working during the discharging stage - - so when charging - isnt it going backwards then ? putting it back in rather than pulling it out ?

i wasnt sure of that - but my mistake was thinking i am charging with the Sub D connector and no diode inline there - so i though i was by passing it all together - - the pack it is - but the lead is still being affected - i didnt get it then - but thats why this place is a great place to learn

[Burgerman]

Yes. You get there in the end.

Learning is fun. If I dont learn stuff every day I would go mad. I honestly think I understand how almost everything in the world I live in works. At least at the basic level. If I ever find ANYTHING that I dont understand it drives me mental. To the point where if I cant figure it out I will spend good money, buy one, or whatever it takes to take apart and find out...

I dont give a monkeys about anything touchy feely, soaps, ball games, or any of the multitude of things the vast majority seem to waste most of their time on. I watch the odd science or physics documentary, on TV in the background, but those are all dumbed down to the point of being almost unwatchable. So TV is basically dead to me. I dont actually own one, apart from the perfect OLED one used just as a PC monitor. I would rather study science, physics etc online than waste my life on TV.

This all started when I was a kid. When 9, I once used my pocket money to buy toothpaste. And a box cutter. I HAD to know how it came out stripy. My mum thought I was crazy. She may be right. I learned a LOT from building and designing model planes, building engines, etc as a kid. Including building a Kart from my dads petrol lawnmower. And 101 other things. I am still as bad at 58. I cant buy anything today without taking it apart to make it work better.

[expresso]

thats great you are that way - not only for yourself -- you help alot of others like me - i dont do TV much - just to sleep - watching space Docs. etc, - music pandora when in am home on Computer - always have it going in the background - i do enjoy with my Girls here - spanish shows - its interesting - and the girls are usually hot -

anyway - what do you think of this - this happened today - i was called and went to check -


Another question - a bit off topic -

the vendor changed out the batteries - BUT they connected the ADD ON Cable on ONE BATTERY ONLY - unknown to her - the Cable from the lithium ADD ON was connected to the lead Cable - it make a buzzing sound and got hot fast - it was a Sec. she disconnected it -

did that damage anything ? i just went to check what was wrong - and thats what i found - they connected the cable to one battery - showing 12.9V - the ADD ON cable shows correct 26.7V - we will fix it Wed. - -

is there something i can check with the PL 8 for the lithium if it did any damage there - i would think not - it was a split sec. and was disconnected -

what do you think ?