Better batteries than these C5004XXXFO Batteries 12Volt 18Ah

[shirley_hkg]

FYI, I put one good battery with one bad battery…

Still lasting me

It's a bad bet .

[Burgerman]

FYI, I put one good battery with one bad battery…

Still lasting me

Depends on your definitions.
Put one good with one bad can still mean in parallel or in series. In parallel thats the best option. If you must connect good and old together. In series, thats really bad...

And still lasting means what?
Can you still wheelie up that ramp? You said not. So you have already seen some deterioration, and if its enough to feel its quite severe. As I say, to find out how much they have deteriorated is not easy. You must measure both ac impedance, and accurately measure Ah in controlled conditions and graph the output to compare specs to new. The PL8 can do this if you know what you are actually doing. But with 4 batteries to charge, discharge, and recharge it will take around 6 days.

[jehan]

don't have a choice…

I do have a new set of 4 batteries… these are E bike batteries (Chinese)… last time I used them was 6 months ago with a mobility charger from another chair…Will start balancing the new set in a couple of days

Do you know of a reliable source for the headway cells…ev assemble is not replying on email… Should I take a chance and order with them? I need 34 cells 12 AH headways lifepo4

the other option is http://eclipsebikes.com/product_info.php?products_id=91 ......anyone have experience with them?

[shirley_hkg]

Make sure your chair WORKS with only ONE 24V supply , before going lithium .

It will be complicated if it doesn't ..

[jehan]

FYI, I put one good battery with one bad battery…

Still lasting me the full day without any problems

so, for last night's charge I reduce the voltage from 2.365 V per cell to 2.360 V per cell and it still didn't get down to the termination voltage of 40 MAH.…

It was stuck at 0.069 AH compared to the previous days of 0.067 AH .

The only thing that happened is that it finished charging an hour earlier and continued for 3 hours till the 8 hour timeout.

Capture.JPG

What should I do?… Go down some more on the voltage

i dont think you saw this post....please asvise on voktage, termination settings

[Burgerman]

jehan wrote:
FYI, I put one good battery with one bad battery…

Which tells us nothing! I presumed you meant in parallel, shirley presumed you meant in series...

Still lasting me the full day without any problems

Which also tells us nothing. How many Ah or how much voltage drop under load is that???

so, for last night's charge I reduce the voltage from 2.365 V per cell to 2.360 V per cell and it still didn't get down to the termination voltage of 40 MAH.…

Thats such a small difference that you wont tell. Reduce it to 2.35 and try.

It was stuck at 0.069 AH compared to the previous days of 0.067 AH .

It may just be that theo old battery never reaches a low mA level. It may be that those specific batteries at the temperature they are at, need less volts. It may be that you put old and new in series so one battery (the old high impedance one) will be over voltage, and the other, will be lower voltage and so both will be ruined. But no proper specs mean guesswork. Either way its 30C in my room. My batteries feel warmer. So I will be charging at 14.2V instead of 14.7.

The only thing that happened is that it finished charging an hour earlier and continued for 3 hours till the 8 hour timeout.

Which isnt possible. if it finished earlier, after 3 hours, then the thing has done. How can it then continue???

What should I do?… Go down some more on the voltage

Its difficult to tell what you ARE doing already. So the answer is maybe.

[jehan]

sorry for not being clear …

I have connected one used battery with one new battery in series.

I have 2 sets of those which are connected in parallel.

It's been about 5 days now that I've been running like this… Should I change to putting the new batteries together in parallel and then connecting in series the old batteries? this is still my temporary set… I have another fresh set of 4 batteries which I've yet to balance charge before installing.

last night, I brought the voltage down to 2.355 V per cell in the lowest the charge amperage got to was 43 MAH… Still triggering the timeout of 8 hours. Will try 2.350 V tonight

These batteries are lastingly the whole day and even at 25.4 V (which is the lowest so far when I put it to charge at night), it climbs ramps without stuttering. previously (with my temporary set) at 25.7 V it would struggle to go up ramps.

I need to find a source for the headways…will try evassemble one more time… Have you switched to any other batteries?

[shirley_hkg]

Let's say you have 2 sets of batteries IN YOUR WIRING DIAGRAM . One on the left and the other on the right .

It'd be better to put 2 new batteries TOGETHER on one side , and the old batt on the other side .

[shirley_hkg]

I need to find a source for the headways…will try evassemble one more time… Have you switched to any other batteries?

We tend to switch to rectangular cells . They accommodate more AMP hours .



https://www.wheelchairdriver.com/board/ ... &start=120

[jehan]

thanks Shirley

sorry I made a mistake here

Should I change to putting the new batteries together in parallel and then connecting in series the old batteries

Meant to say connect the new batteries together in series and then connect with the old batteries in parallel as you've just mentioned.

It'd be better to put 2 new batteries TOGETHER on one side , and the old batt on the other side .

[shirley_hkg]

Meant to say connect the new batteries together in series and then connect with the old batteries in parallel as you've just mentioned.

That's right .

[Burgerman]

Still wont last because the new batteries take most of the load due to lower impedance and they were already far too small as a healthy 36Ah pair. So those will soon deteriorate to match the old ruined ones. And unless the two old ones are in the same state of deterioration, charging at 24V will still overvolt one set and undervolt the other because of differeing impedance... Its months if you are lucky rather than years.

[jehan]

thanks Shirley,BM,

so,On the new set of 4 batteries,please advise on…

1. parallel charge the set of 4 batteries for 2 days (with a power supply)at 13.5 V? spec sheet says float is 13.8 .... but I don't think my power supply can do more than 13.5 V

2.nightly charge with the PL8. Charging at 28.8 V and terminations set to 50 MAH (48 AH battery pack)? spec sheet mentions cyclical a bit higher at 29.2 V

new set of 4 batteries (Chinese)

planning to have the lithium in place in about 3 months. I need to make this existing set in the chair and the fresh set last till then.... Shouldn't be a problem… Considering they lasted longer without half as much correct care.

I had a look at the sinology cells … Will post about that in this thread by funky keyboard who has converted lithium on the same wheelchair as mine.
http://www.wheelchairdriver.com/board/viewtopic.php?f=2&t=1960&hilit=lifestand+LSC+lithium&start=60

[Burgerman]

Those are even worse than the ones you have. Max discharge current is just enough for a decent headlamp at a miserable 18A, its not adequate for a chair. Your chair can take TWO HUNDRED Amps at times.
Will it drive? Yes very badly. And it will hurt a lot them doing so

Max charge current 3A??? Seriuously? Odyssey RECOMMEND their own 30A charger for their 18Ah battery.
Those batteries are hopeless for a powerchair. And a 13.8V float is OK for 12H max to finish a charge. BUT it will cook them longer term.

Lets do a quick compare...
Odyssey 18Ah battery PC6255 450 CYCLES
FOUR HUNDRED AND FIFTY Amps for 10 seconds pulse
FOUR HUNDRED Cranking Amps
THREE HUNDRED and FIFTY Marine Cranking Amps.

Compared to 18A max allowed...

Do you understand the difference between a decent battery anbd a crap one?

[Burgerman]

Its not about lasting, itr wont even steer properly.

1. parallel charge the set of 4 batteries for 2 days (with a power supply)at 13.5 V?

YES.

spec sheet says float is 13.8 .... but I don't think my power supply can do more than 13.5 V

No it does not! It says FLOAT CHARGE as in uising a 13.8 to 14.1V charger to charge the battery and disconnect. Old chargers work this way because they do not measure current or have timers so you just use a CV of a lesser voltage and leave for 16 hours.

2.nightly charge with the PL8. Charging at 28.8 V and terminations set to 50 MAH (48 AH battery pack)? spec sheet mentions cyclical a bit higher at 29.2 V

For a proper charger that will end at the correct time, then all four 18Ah in parallel, set to anything from 14.4 to 14.7V V no float needed. 8 hour limit and 100mA termination at 20c. It will likely run to 8 hours. Thats fine.
Or 13.3 to 13.4V for a couple of days.

IN USE you charge at 29.4V ant termination 8 hours or 50mA. As long as the batteries arte 20C or less.

[jehan]

thanks a lot but BM, I'll manage with these till we can get the lithium's up and running

[Burgerman]

Unlikely.
Green batteries in your image have Max discharge 18A? So if both your parallel batteries are healthy you have just 36A Maximum limit...

This is a current (Amps) real time measurement taken from the left motor alone on a typical 6mph chair.
So you must double this figure for your 2 motors. As you will see its super easy to reach 100A. (200A for BOTH)

http://www.wheelchairdriver.com/gopro/motoramps.mp4

[jehan]

but I've used a green set like that and it worked really well for 6 months… These are 24 AH so that's 48 AH

The 18 aH ones I have now didn't even last 4 months.

My usage is all in the house and in the garden… The furthest I go from the house is 2 KM

I don't want to be caught with my pants down… So switching to lithium.

How do airlines treat the lithium?… Do they need to be disconnected or removed from the wheelchair for air travel?

[Burgerman]

Several things. I dont have experience, but the rules say its OK. Airlines either dont seem too concerned. Or refuse them as they dont know the rumes. Technically OK, ANY CAPACITY, IF they are permananty installed in the chair. And only requires the chair to be deactivated.

But they get confused and start mixing this up with removable lithium batteries as used on travel chairs. And so can be difficult if you tell them. Thares a few here that flew all over the world though without issue. They didnt bother telling anyone.

[biscuit]

If your wheelchair is normal your batteries are probably 12V each and wired in series to give 24V. Then you have the same amount of Ah as each battery, so like I've got 2x 17Ah batteries in my Vienna giving me a total of, wait for it, 17Ah. (As they are lead pigs, of course I can only use them for about an hour before they need a breather.)

Airlines don't care what is allowed, they don't want to think about the risk of a fire on board their plane. They do not tell you this until it's to late to deal with it. So I would not trust them with lithium batteries.

[jehan]

thank you biscuit, BM,

Just as an exercise, I'm going to call a few airlines to get some feedback

I know a friend who took a powered 3rd wheel to America and back with his wheelchair… You know the one that attaches to the front of the wheelchair and makes it like a trike


he didn't have any problems on either end… But the lithium was sealed in an aluminum casing and probably not too large

[LROBBINS]

That 3rd wheel has a removable battery and the rules for them are different - they can't be larger than a certain size and they must be removed and put in the overhead bins. Non-removable lithium batteries are not size-limited and they must not be removed. They must be electrically disconnected (not necessary physically disconnecting the battery cables - just a switch, key lock, free-wheel interlock or unplugging a control cable - the important thing is that the chair can non be unintentionally turned on. The last IATA regulations I read (and the FAA regulations are the same) did, however, leave it to the discretion of the pilot to refuse to carry a lithium-powered chair (why, I have no idea, nor can I understand why there is no distinction made between safe LiFePO4 and other Li chemistries). Perhaps the experience of airline people having trouble for years dealing with the difference between "sealed non-spillable" and "wet" batteries made the committee not want to tax their smallish brains.

[Burgerman]

Perhaps the experience of airline people having trouble for years dealing with the difference between "sealed non-spillable" and "wet" batteries made the committee not want to tax their smallish brains.

Now you sound like me!

[jehan]

Dear BM,

I've got a set of 4 NEW lead batteries lying in a sealed carton box which I haven't used for a month,

how do I keep them in good shape till I need them?… Thanks

[Burgerman]

Charge properly, in parallel as one 12V battery, put them somewhere cool. Recharge every 2 to 4 weeks.
or
Put them in parallel, on a permanant 13.3V float, indefinitely.