PINNED - Lithium battery conversion/info

[Mark]

It would be nice if the Hyperion charger (having been preset to the charge regime we want for our particular battery pack) could then be started remotely by an accessible push button. The Hyperion could then be tucked away somewhere under the seat and all the problems of connector type and life for balance would disappear, since the balance leads would be short and always connected. Or have I missed something? - It wouldn't be the first time !

I suppose the bluetooth mod might offer a way forward if the windows software could be made to run on an Android smartphone. I wonder if there are any Android windows emulators?

Even with lead-acid (which I am still using) I would like to have a Hyperion charger on board so a single Anderson input connector on the chair would allow charging from any 12 - 30 volt dc source. Unfortunately without remote control, the only place I could mount it would be vertically just below the front edge of the seat, i.e. behind my legs. Would need a mirror to see what button I was pressing and what the display showed, and might get some funny looks poking about down there.

Just had another thought..... Doesn't the Hyperion manual say that you must connect the input supply to the Hyperion BEFORE connecting the output to the battery to be charged, so perhaps it wouldn't tolerate being permanently connected to the w/c battery?

[stevelawiw]

Hi Mark, I've had my Hyperion permanently connected to my chair for about six months now, I've had no problems so far. It's mounted under the seat at the front so I can see it if I lean forward. For indoor charging I just plug in a single anderson connector from my 24v psu and press the far right hyperion button and off it goes, for in car charging the same applies, a single hyperion connection and press the same button twice. Although I can slide the Hyperion out and peer down to see the display, I find that with the audible beeps signalling successful charge start, and monitoring the negative ah drain on my cycle analyst I know it's working ok.

[Burgerman]

I turned you all into geeks

[stevelawiw]

Your right BM, it's ALL your fault!

[Mark]

Hi Steve and many thanks for the info.

I was just very wary of having the Hyperion always connected to the battery pack when no charge source was connected. Two reasons really.... The instructions that came with my 1420i say don't do this on more than one page, and indeed it is the first item in a list of "Cautions" on the first page ! The second reason is that I already have had a failure of a 1420i after a software download (but that was probably co-incidence) and it was replaced under guarantee (eventually). As they are expensive I was reluctant to risk it.

As a Scientist (Research Physicist - now retired) I always quote that "an ounce of practice is worth a ton of theory" (although you still have to understand the theory!) so many thanks for sharing your experience. It also sounds as if the underseat position is quite practical. I wonder if a hinged mounting would work well so that you could hinge it forward and see the screen if necessary?

Are you using Lead Acid batteries and what model is your Hyperion?

If I do this I'll probably buy a second Hyperion for general charging. Once you've had one, it is difficult to imagine life without it.

[Burgerman]

You better be quick, they are out of production.

[Mark]

You better be quick, they are out of production.

What have they replaced the 1420i with?

[Burgerman]

No idea yet. Hobby stuff comes and goes fast.

[stevelawiw]

I'm using the 1420i and I have 105ah LiFePO4 batteries. I'm sure a hinge could work, I used a homemade slider so that the charger is out of harms way tucked up under the seat base when not in use.

[Burgerman]

Do you read how many Ah returned on charge?

How many Ah per mile? Per average day?

[stevelawiw]

Ah returned on charge 70 - 90, average Ah per mile 4.96, which has worsened since I've started using my electric chair around the house more instead of my manual one, it used to be about 3.6 when just used outdoors

[Mark]

Thanks for the info Steve. You're the first person I recall who has successfully mounted the Hyperion on their chair permanently connected to the battery, so I now have a bit more confidence to do the same.
BM, cheapest price I can find on the net for the 1420i at present is 130 GBP which is what I previously paid, so I expect if a replacement model comes out remaining 1420i stock could be available at a discount. Of course, depending on the new model facilites and spec, I might decide to get that instead. Thanks for the (inside?) info.

[Burgerman]

Ah per mile 4.96

it used to be about 3.6 outdoors only

That's terrible!

Just shows how much worse indoor/turning is compared to long straight footpaths...

That would be only around 9 miles range on lead batteries! Or 22 with lithium (for indoor).
Or 13 outdoors with lead, and 30 with lithium. Based on your 108Ah Lithium battery.

Still not great, you must have bad streets and funny angles or cambers and lots of turning. I use less Ah per mile on average by about 36 percent. And I am fat...

I suspect that if you tested that on a more flat area, on long roads etc at full speed you would get about 45 to 50 miles.

[shirley_hkg]

LED + Buzzer low voltage alarm triggered at 2.7V , is good for non-BMS user.

It sells $1.50

[Burgerman]

I would need 13 of those!

[ex-Gooserider]

Glad to hear of folks doing an on-board mount of the Hyperion, but I have to admit that I'd be concerned about doing that... I don't know how solidly the inside components are mounted so vibration and bumping around could be a concern. More importantly, I'd be worried about weather - the front panel doesn't look to bad for waterproofing, but you have two vent fans, and a LOT of ventilation slots, and no visible sealing around the connectors...

If I was guessing, I'd say the IP rating on the Hyperion is around IP30 or "Protected from tools and wires greater than 2.5 millimeters. Not protected from liquids." By comparison, the joystick pods are around IP 64 or 65, at least IP 63, but probably not 67 or 68 (which allow for submersion)
IP63 Protected from total dust ingress. Protected from water spray less than 60 degrees from vertical.
IP64 Protected from total dust ingress. Protected from water spray from any direction.
IP65 Protected from total dust ingress. Protected from low pressure water jets from any direction.
IP66 Protected from total dust ingress. Protected from high pressure water jets from any direction.

ex-Gooserider

[stevelawiw]

If I worried about everything that COULD go wrong I wouldn't get out of bed in the morning!

[Mark]

Good points ex-Gooserider but when I had the covers off my Hyperion it looked a reasonable well-designed and constructed pcb and the odd bit of (fresh - not salty) water wouldn't cause any harm. I was more worried that the instructions state that you must apply the supply voltage before connecting a battery to the output and permanent mounting leaves the battery permanently connected unless you introduce extra switching. The fact that Steve has done so without problems for some time gives me more confidence in this.

[Burgerman]

There is a big capacitor in there that is fed an output voltage via a high value resistor from the supply, so it charges slowly. Plug in the output to a battery first and it takes hundreds of amps as it charges instantly. Leaving it connected shouldn't cause an issue.

[Mark]

There is a big capacitor in there that is fed an output voltage via a high value resistor from the supply, so it charges slowly. Plug in the output to a battery first and it takes hundreds of amps as it charges instantly. Leaving it connected shouldn't cause an issue.

So where is the damage potential? Is it that the capacitor is connected to the output via a thin pcb track that will act like a fuse and burn-out with the capacitor inrush current? Or are they worried that the powerchair's (or other device's) charging fuse is going to blow ?

Wonder what this large capacitor is for? Is it because these are primarily designed to charge Li batteries ? I'm baffled, but with more knowledge should be able to avoid damage to the Hyperion.

I think there were also references in the instructions that the USB lead must be plugged in after everything else, but your bluetooth mod would eliminate that risk. Pity no Android software available to drive the Hyperion. It would be good to be able to initate charge from ones smartphone since most of us probably always have a phone on us .

[Burgerman]

Dunno why but when you do it there's a loud crack at 45v... And I killed a mosfet and it went short circuit on one about 2 years back.

Connecting the power to the Hyperion first pre charges it to 50v! Although this shown on the screen but isn't "available" on the output as current.

[steves1977uk]

Was just wondering if the 40152S cells will take the M6x8 Allen type of screws since I have the screw tab type in mine.

Does anyone know if the Allen type will fit assuming there the same as the 38120S?

Steve

[Burgerman]

They are all m6 I think.

[steves1977uk]

Ok thanks BM

[ex-Gooserider]

Note that as well as the screw diameter / pitch, you also need to worry about the length - one terminal has a pressure relief valve at the bottom of the screw hold which can be jammed closed by a to-long screw, and both can be damaged if an over length screw is driven to far into the terminal in an effort to make it seat...

However I'd expect the same size to work with any of the Headway cells - so if 8mm is the right length for one, it should be fine for all... IIRC BM said he used M6 x 8mm on his pack somewhere in his build notes, so should be OK.

If I was really feeling paranoid, I'd do a test fit to see if a screw would make up all the way with no busbar or other hardware under it, and no excess force. If so then It should be golden...

ex-Gooserider

[shirley_hkg]

Due to limited space, I have to use Li-ion 3.7V cells in a 50Ah auxiliary pack. These are SAMSUNG 18650 @2600 mah.

Very good and uniform quality, that they balance very well on the first charge.



The original welding workmanship is the best ever met, with copper strip as media.





BM, will it be more stable and safer for transportation to discharge it to certain level and what's the suitable SOC ?

Regards.

[Burgerman]

Anywhere from 40 to 70 percent is where lithium should be stored for safety or long life.

[steves1977uk]

Whats the max amps I can charge a 8S 5P pack? I'm using 15Ah cells, the Headway 40152S ones. I've set up the Powerlab 8 to charge at 3.6v and balance at 3.3v, also I assume where it asks for the pack capacity in mAh, I've set this to 75000 which is 75Ah for the total pack.

Thanks,

Steve

[Burgerman]

They are 5C charge, 10C discharge.

So if its an 85Ah pack, you can charge at 85 x 5 = 425Amps max. But you will need your own power station to do that!

I don't think any charger, at full power is going to worry it!

SET to max Amps, 28.8v (3.600v per cell) and to 85Amp capacity.
Untick the time limit box, and set to "continue" rather than stop, and 100 percent.

Set it to balance at 3.600v. Setting it to balance at 3.3v will not balance the pack at all, just the opposite..

[steves1977uk]

Hi BM,

Here's how the PL8 Charger is set up:-


























As you can see the balance voltage doesn't go above 3.30 on the A123 preset which I've customised for the Headway Cells. There are other presets for LiPo cells, but these are all generalised but allows a higher balance voltage. Should I customise one of those presets instead?

Thanks,

Steve