lithium battery power on lifestand LSC?

[funkykeyboard]

Yes. Fully charge and balance.

Then choose discharge, at max rate, to the lowest figure it allows. They will take some time, best watched on a PC. Read off capacity and watch to see if all cells end at the same time or close.

That will give you a 100 percent capacity reading. You can do that 1000 times with these cells right down to 100 percent! So its not harmful.

Then fully charge and balance as normal to 3.600v per cell. You will get exactly the same Ah back in as you took out within .2 of an Ah.

just to doublecheck everything. Here you say

After you do all of the above post. And read this carefully it should charge fine.

However.
DONT choose DISCHARGE or BALANCE with a LiFePO4 pack. That will UNBALANCE the pack.
DONT charge it as a LIPO battery. That will seriously damage the cells.
ALWAYS charge only, and this balances the pack at the end.

But it cant do this if they are say 10 percent different. Well it could, but it would take around 2 to 3 days...
This is why you fully charge each cell or parallel groups of cells individually first after you assemble the pack.

Then you will get something that looks like this below:

mine is the LiFePO4 pack. So is it okay to discharge?

You say "Then choose discharge, at max rate, to the lowest figure it allows. " It being the charger? Discharge to the lowest figure the charger allows?

[Burgerman]

Yes. Its not only a charger. Its a tool. Allows all kinds of things. But measuring battery capacity, and allowing you to view individual cell capacity and a curve on a graph is extremely useful.

But at the END of discharge the stupid charger will try to balance the pack. This is OK for small hobby packs but not good for a big LiFePO4 pack in a powerchair.

Watch it discharge on your PC. When a single cell reaches the 2.7v or whatever you set, the discharge will end. Then click stop or it will try to balance. You only want balance at the TOP at full charge. Not when discharged. Work around is to unplug balance cable. But then you cant see individual cells. So just tell it to stop at the end with your mouse! The cells will not all empty together. The worst ones will get discharged first. This is why its useful to watch on a PC so you can see whats going on.

[Burgerman]

THIS is what you will see if you DISCHARGE a fully charged balanced healthy battery. Here I am discharging my BM3 battery, and almost 12Ah removed so far.

Graph shows initial voltage drop, then all cells (13 displayed) are within 5000ths of a volt... See yellow square, graph, and other data.

Eventually this graph will suddenly drop at the end. But the software is limited to 65Ah, although charger/discharger will keep going for about 18 hours. Known Programming bug. This wont affect you.

This way you can see if any cells drop off early, and measure actual capacity as you discharge or charge it. Manually STOP it when it ends. Or it will start to balance cells automatically. You do not want it to do this.

[funkykeyboard]

My memory is not good on this. I will discuss it through with my electrician on Monday, and even try to provide some pictures.

To my memory, which could be faulty, the problem wasn't at the Anderson connection. The problem was the wire running from the charger. I think there was some kind of shorting going on. That's why I wanted a picture of the full set up, from charger to Anderson connector.

Anyway, I try and get a proper picture of what I had, and see if we can throw some light on the situation.


[As I say, it is difficult when you don't know exactly what you're talking about)

back to this problem. I'm guessing the way the PA's are pulling them out are loosening the soldering.

Can anybody provide me with a picture of their setup right through from the Anderson plug to the charger. It's the cable setup I want to look at. Think there may have been a problem with the way my guy did it. There may be a more simple methodology than we used.

Going to talk it through with him tomorrow.

[Burgerman]

You need proper solder joints. Proper connections. VERY TIGHT connections where the cells are all connected. Its easy to miss one. If you get any of it wrong you will see endless balance and charge problems. You must get this right and understand whats going on.

[Burgerman]

I just used Anderson from the 4mm connectors on the charger with a 20 amp fuse. For charge lead. Its literally unbreakable.

For balance I used a custom made lead with 2x 8 pin standard connectors at the charger and 1x 15 pin one at the chair. Actually a OBD2 plug/socket.

Shown here (charge lead) in shorter form and no fuse. You NEED a fuse... Or if you pull 4mm connections out of charger and they touch there will be smoke! As the battery is on the chair end.

[ex-Gooserider]

Shown here (charge lead) in shorter form and no fuse. You NEED a fuse... Or if you pull 4mm connections out of charger and they touch there will be smoke! As the battery is on the chair end.

Maybe I'm overly paranoid, but seems to me like this is an excellent reason why I'd be very tempted to replace those banana jacks w/ a set of 45A Andersons while I had the unit opened up to do the Bluetooth mod that you've mentioned elsewhere... Seems like it would be much safer and avoid risking fuses... (besides banana jacks are really not designed as serious power connections, they are more intended as data carriers)

BTW, I recently obtained a few USB Bluetooth modules in a cruft swap - rather than opening up the unit to solder in one of the cheap chinese modules, would one of these work? (I'd need an adapter since the Hyperion uses a mini-USB, and the dongles are USB "A" style, but that's trivial...)

ex-Gooserider

[Burgerman]

I don't think so.

[Burgerman]

Those 4mm connectors or even smaller ones but 3.5mm are used all over for 30 or 40 amp chargers, same on inverters. And on board model planes at 100 amps plus. And on the 40 amp professional quality bench power supply. In fact its the same on the 50 amp ones. They are actually very good at high currents. Lots of surface area and gold plated.

And millions of hobbyists and others use these for chargers and other similar applications every day. I suspect they learn by sparks not to do it! I am just aware of it so take care. Nandol on the other hand may blow up a few carers.

[Burgerman]

Even on the 100 amp version...

http://www.farnell.com/datasheets/424942.pdf

That's 5x as much as the Hyperion.

I charge my chair at 45 amps from mine at full power most days. Cables get warm, connectors don't get any hotter.

[LROBBINS]

Maybe you could use some epoxy+flox to build a bridge between the two bullet connectors. If they come out, they at least won't be able to touch each other.
Ciao,
Lenny

[ex-Gooserider]

Maybe you could use some epoxy+flox to build a bridge between the two bullet connectors. If they come out, they at least won't be able to touch each other.
Ciao,
Lenny

Even easier, if the Hyperion sockets are spaced at the standard spacing (I haven't checked) is to simply buy a "double banana" plug - any good electronics supply house should have them - I even have some triple bananas in my supply collection. However that still leaves the issue of having the potentially live contacts exposed... IMHO one of the big advantages of the Andersons is that they protect the contacts so that it is all but impossible to (accidentally) short them out...

(Note that at least in the US, meter leads are required to use "shielded" banana plugs, which unfortunately don't work with the "3-way binder" sockets on most power supplies, and aren't even reliably compatible with different meters...)

ex-Gooserider

[Burgerman]

http://www.ebay.com/itm/20PCS-Screw-Typ ... 0831521449

[funkykeyboard]

Yes it is the balance cable we had problems with, touching each other, creating smoke and sparks that's why he moved to the silver ones that are on the back of my chair now. The silver ones we use there, eliminate that problem.

[Burgerman]

One per battery? What are they?

[ex-Gooserider]

http://www.ebay.com/itm/20PCS-Screw-Type-Solderless-Dual-Banana-Plug-Speaker-Connector-for-Amplifier-JS9-/150831521449

Exactly the item type I was thinking of - just haven't checked to see if the socket spacing on the Hyperion is right for those to fit... Looked OK from eyeballing, but really needs to have a fit test...

That said, I see two problems with that style of plug, though it is in some ways an improvement over separate bananas...

1. While it prevents the exposed ends from shorting to each other, it does nothing to prevent shorts if the plug lands on a metal surface...

2. The plug is a single color (red or black - i've also seen other colors rarely, but never molded in multi-color) and is NOT polarized in any way, so unless being very careful to use appropriate wire colors, marking, etc. it would be very easy to plug it in backwards...

Anderson's solve both problems - the contacts are well protected, and the design is inherently polarized so that you can't plug them in backwards...

ex-Gooserider

[Burgerman]

Well if you use one red and one black wire the colour of the actual plug doesn't matter a lot. And the hyperion will just tell you its polarity is wrong.

A fuse will protect against both terminals touching a bare metal surface. So it should be OK. Don't know about the spacing. That spacing was primarily for hi-fi speakers. But as you say it looks correct.

[flagman1776]

It would be cleaner with an Anderson style socket built in but I am going to do the mid cord adaptation like BM. I don't anticipate removing the banana plugs for anything... might glue or tape it in place. In my opinion, it would be improved with a locking connector.

[ex-Gooserider]

I don't know just what the original was for the double-banana spacing, but my experience has been that it is pretty much a standard on any kind of bench equipment that I've ever dealt with that uses banana jacks or three-way binder posts for input / output connections - from power supplies to low tech O-scopes, and other meters....

If getting a set of banana jacks or binder posts for making equipment of any sort, it is often just as cheap to buy them in a package with a single mounting base - which makes for a nice neat panel, and handles the insulation of the posts as part of the assembly. Those are (far as I know) ALWAYS on double banana spacing. It seems like one of the few things where there is a "standard" that really IS standard...

(Usually it's a case of standards being wonderful, especially because there are so many to choose from.... )

My van's been in the shop this week so I haven't been able to get to the Asylum where both my Hyperion and my double banana supply are sitting, but I should be getting it back tomorrow, and as soon as I get in I'll check to see if the spacing is actually right...

ex-Gooserider

[funkykeyboard]

Okay, still sticking with these plug sockets for the lithium batteries and Hyperion charger.


don't ask me to explain this more clearly, as this is all I could understand from how the electrician explained it.

On the lead there was a wire left over. Somehow, as the charge was proceeding, there was some kind of build up which tricked the charger into thinking there was another cell, so the charger stopped charging. He sorted this wire out, and now everything appears to be hunky dory again.

[Burgerman]

He means he wired it wrong!

There are 2 balance connectors on the charger. A and B.
A does cells 1 to 7.
B does cells 8 to 14.

Each connector has 8 wires... Because with 7 cells there are one at each end, and 6 in the middles at each cell connection point.

You have 8 cells...

So you have a choice of 4 to each connector, (4 cells so 5 wires each 12v "pack" of 4)
Or...
7 cells to A connector, and one cell to B connector. The B, still needs 2 wires... And one of those also goes to the A connector.

I just read this and it will only make sense if you personally are wiring it...

[funkykeyboard]

Yes. Fully charge and balance.

Then choose discharge, at max rate, to the lowest figure it allows. They will take some time, best watched on a PC. Read off capacity and watch to see if all cells end at the same time or close.

That will give you a 100 percent capacity reading. You can do that 1000 times with these cells right down to 100 percent! So its not harmful.

Then fully charge and balance as normal to 3.600v per cell. You will get exactly the same Ah back in as you took out within .2 of an Ah.

okay this is the next project. Here is the cells; "32 x 12Ah Headway LifePo4 cells". You say it will take some time, less than 12 hours?
I could always sit still for the day, discharging them. Then I could get pushed through and put them on charge overnight.

What software would I need on my laptop to watch the process? Just plug a USB from the laptop to the charger?

[Burgerman]

Hyperion charger and software.

Charge fully, and don't sit in it or move it.

Then discharge to 2.5v per cell, at 5 amps. Will take about 10 hours. Read Ah and be there at the end so you can click STOP or it will try and balance cells at the bottom which you don't want.

Read Ah, recharge fully at full power to 3.600v, read Ah again... Recharge will take less than three hours.

[funkykeyboard]

Okay, I've acquired a power supply which should be usable. What is the absolute cheapest charger I could couple to the power supply to charge my wheelchair?

This is just going to be for quick charge's, top up charge, placed somewhere conveniently in my living area. (My Hyperion charger, and Fusion power supply will be used for night time charging.)

Went out yesterday, and in the middle of doing a lot of stopping and starting at shops, pubs, and restaurants I managed to do about 8.2 miles. Checked the charger this morning, and it had charged about 30,003. My original capacity with the batteries was 48,000 (80% of which would be 38,400). I now need to work out what my actual capacity is at present, then I will have a rough idea how many miles I can do without damaging the lithium batteries.

Thanks in anticipation, funky keyboard

[Burgerman]

Power supply? 12 or 24 volts? Amps?

You should only use 1 charger. Each one will balance at a slightly different level. Use the hyperion, it does it right.

The distance you travel is RELATED to how much charge you use. But it may be completely wrong. You need to monitor the battery voltage. 8 miles, 30Ah sounds a bit bad.

In reality you used about 2/3rds of it turning, and shuffling about, and about 1/3rd of it covering distance. And this varies.

[funkykeyboard]

Power supply? 12 or 24 volts? Amps?

You should only use 1 charger. Each one will balance at a slightly different level. Use the hyperion, it does it right.

The distance you travel is RELATED to how much charge you use. But it may be completely wrong. You need to monitor the battery voltage. 8 miles, 30Ah sounds a bit bad.

In reality you used about 2/3rds of it turning, and shuffling about, and about 1/3rd of it covering distance. And this varies.

yeah, not in the fractional way you gave, but that's what I figured.

I have done about 4 miles in the past, and it's only took about 4000 ah. So I figured it must be in large part due to the manoeuvring usage, rather than the straight mileage. I did avoid standing up that day, so as to not skew the reading. I might try another one with a straight run, just a comparison.






Just to doublecheck. I will always use the Hyperion charger to do the long charger at night time. It's just using that in the day, is a bit inaccessible.. So to be clear, I'm only proposing to use the 2nd charger for the odd power-up here and there, where I have been out and about, and need a quick boost. You know like when you charge your chair whilst in the car? Do you use another Hyperion in the car?

[Burgerman]

No use ONE charger. With a big pack, and a small hobby charger it can take hours to rebalance a pack even if the voltage is just a tiny bit different to what the charger expects.. And there's no guarantee how different the balance voltage calibration will be.

The hyperions are very very accurate, bet even they vary between different chargers by a few hundredths of a volt. Other makes can be drastically different. You will cause balance issues swapping between chargers.

[funkykeyboard]

No use ONE charger. With a big pack, and a small hobby charger it can take hours to rebalance a pack even if the voltage is just a tiny bit different to what the charger expects.. And there's no guarantee how different the balance voltage calibration will be.

The hyperions are very very accurate, bet even they vary between different chargers by a few hundredths of a volt. Other makes can be drastically different. You will cause balance issues swapping between chargers.

Thankyou for your advice

[jehan]

hello, I'm looking to convert the lifestand LSC 3 to lithium.

From reading this thread, it looks like funky keyboard built 4 x 8S headway 12 AH and made a 24 V 48 AH pack?

are headways still the way to go for this application?

and if funky keyboard sees this post, I'd like to know how it's working out for him

thanks

[Burgerman]

They work. But theres a multitude of lithium prismatic cells coming out of china for a few years now that may allow more Ah in the same space that you have available.