Power Supply for PowerLab8 v2

[Burgerman]

Ideally, you want 6mm squared. But a fraction less or bigger is fine.

Add a 60A fuse in the pos lead near the battery,or bolted to it. That should ideally be a midi fuse. eBay...

Then even charging at 12A it will charge more completely and around 2 hours faster due to the lack of high resistance bus cable, and connectors inc the XLR.

But you can easily charge a set of AGMs at 30A or more. I charge both lithium and lead at 40A regardless. Although technically the recommended max for gel is 24A. But its a safety thing in case you have a large block of batteries on a boat or solar storage. So go to 30A without worry. Odyssey say as much as you can is beneficial. So 40A...

[Burgerman]

https://www.ebay.co.uk/itm/PAIR-SB50-AM ... rk:22:pf:0
There are several sizes of terminals. These are correct.

https://www.ebay.co.uk/itm/10M-coil-50- ... rk:17:pf:0
Cable 6mm2

https://www.ebay.co.uk/itm/Copper-Tube- ... 1006.m3226
Choose 6mm2 (4mm)
6MM hole...
Pack 10.

https://www.ebay.co.uk/itm/MIDI-STRIP-L ... :rk:2:pf:0
Choose holder.
Choose 50 or 60A fuse.

[jefferso]

Thanks, that's super helpful.

I got these for the XLR plugin. Will they be ok for the Anderson too? for connecting to the PL8.
https://www.ebay.co.uk/itm/292613499639

[shirley_hkg]

I have some extra 2mm diameter stranded cable, but for 20 or 30A, I'd need more robust cable, correct?

Simply use 2 stranded pairs and you'll have 4m㎡ cables .
Use what you have .

[jefferso]

Simply use 2 stranded pairs and you'll have 4m㎡ cables .
Use what you have .

Do you mean a pair together for positive and a pair together for negative?
The 2 core 2mm Thinwall cable showed as rated for 25Amp for 12V on the ebay page, so using both cores for each side should allow for 50A?
I have 2 meters of that cable, so I'm not sure if it's enough to route it sensibly from the battery posts to the side. There's no advantage to making them the same length each side is there?

[Burgerman]

No.

[jefferso]

But a single silicone diode or 2x shottky will. Which I cant spell, would give either .7 or .5V APPROX drop depending on diode / load/curve you choose. All depending on what you need to do. The reverse diode should always be a single low drop one of course.

For correcting the voltage on a 12A 28.8v charger for Gel, would these diodes potentially work?
Either two of the Schottky in series, or one of the Silicon?

https://www.ebay.co.uk/itm/5-x-HY-Elect ... 2610036449

https://www.ebay.co.uk/itm/P6KE30A-Sili ... 3533398358

For the reverse diode, is using a matching diode the best, or one with the lowest possible voltage drop?

[Burgerman]

Low drop for the return diode.

As for 2 low drop types, or one silicone diode, it depends how the charger responds. But I would expect the .7V drop would be best if a little too much. So since they are cheap you can also try 2x low drop ones. Be sure to use ones with higher Amp rating than the charger.

At the last part of CV where the battery voltage is highest, just before you get the green light the volts should be 28 to 28.2V. A diode doesn't drop a fixed amount quite, as they have a little resistance so it will gradually climb a fraction as the charge becomes complete.

If that charger has float too, you better measure that as well. Because while most are 13.8 and some are 13.6 you will be dropping this as well. And instead of waiting till around 1000thC or around 6 to 8 hours, they end charge at about 1A or so, (not fully charged) and rely on the float to finish the charge over the next 8 hours... So its important to know what the charger actually does.

[jefferso]

(26 May 2018, Re: To Buy a PL8 - Accessories, attachment: "Lead MK GEL 12A Max With XLR plg.PS8.zip")
viewtopic.php?f=2&t=7925&start=30#p119575

In this preset, in the "Fuel" tab, it shows pack capacity as 74000 mAh. Does that affect anything? It says "Use Fuel Table" "No" so I'm guessing not. But is it correct? If it's 2 12v 74Ah batteries, wouldn't the pack capacity be 148Ah?

[Burgerman]

2x 12V 74Ah batteries connected in series to give 24V is now a 24V 74Ah battery. If connected in parallel you would then have a 12V battery with double the Ah.

In that tab, the capacity (fuel) is almost meaningless. It works quite well with LiPo but not at all with LiFePO4, or very vaguely with lead. Better to set to no.

[jefferso]

That makes sense, thanks.

My Permobil C500 has two XLR receptacles, one under the joystick, and one on the side of the chair. Is the 12A limit for charging with the XLR more for the typical plug that goes in the controller?

The one on the side of the chair is much closer to the batteries and has more substantial cables. Right now, when I'm charging at 12A with the PL8, the XLR plug and cable do not seem to get warm at all. Could I potentially charge at 15A or higher? Or is it the actual XLR internal connection that is the limit?

Here's what the side plug looks like with the cover off.

[Burgerman]

You may get away with 15 on that. Although the tech limit on those connectors is 12A.

You wont do much harm trying that on that connector alone. Dont do it via a joystick pod.

[shirley_hkg]

The one on the side of the chair is much closer to the batteries and has more substantial cables. Right now, when I'm charging at 12A with the PL8, the XLR plug and cable do not seem to get warm at all.

It's the contact between pins that matters , not the wires yet .

15A ? My experience said NO

[flagman1776]

If you want to fast charge your chair with your PL8, why not install an Anderson SB 50 socket direct wired to your batteries. I'm assuming you are using lead acid batteries. I'm sure BM could set you up with a charging profile. it's just a power plug, when the charger is unplugged so no one needs to know if you are concerned about service technicians. You'd need a pigtail for the PL8 with the same SB 50.

[jefferso]

If you want to fast charge your chair with your PL8, why not install an Anderson SB 50 socket direct wired to your batteries.

Yes, that's on my to-do list. Using MK gel batteries in a Permobil C500s.

I got all the parts from BM recommendations, viewtopic.php?f=2&t=8401&start=60#p129261, and just need time and assistance to solder the connections and fuses and banana clips for the PL8. I also have to figure out what path the cable will take physically, and whether I will have to cut a notch or make a hole in the plastic shroud to let the cable with the SB50 dangle out.

But I figured it would be good to know if the lower XLR plug could take more than 12A in the mean time. I'm leaning towards not trying more than 12 with the XLR since it won't gain too much.

[flagman1776]

The Anderson SB 50 connector is drilled for mounting screws. BM has fixed mounted the chair side. Yes, locating the connector conveniently & dressing the wires needs access which you might not have when you are sitting in it.

You haven't put your general location in your signature... on this International forum, it might be easier to help if we knew where you are.

[Burgerman]

All my chairs, have 12 or/and 24v anderson connectors. lithium and lead. As does my electric bed, all my solar system panels and solar inverters, and wiring at various voltages, drills, mower, 12 and 24v to 240vac inverters, van, gf's car, chargers on input and outputs (8 in total), dummy loads, power supplies (5 of them), power polisher, 12v soldering irons, generators (2) and a bunch of other stuff. All grey. Everything can run on, off, and connect to anything else. It offers massive flexibility. I have long and short anderson extension cables. And 12v and 24v "double" ends for series and parallel connection.

In other words I can run inverters to get 240v while outdoors or in a power cut to work beds, or freezers, and keep the central heating on, lights, etc. I can use them to charge one chair from another, charge my van, all by PL8 or direct connection to start a vehicle. E.G. a mile from my home here: http://www.wheelchairdriver.com/gopro/starter.mp4 (2 on the chair and a parallel 12V supply connection used to start the dead van here) Remember that this also CHARGES your chair very fast once an engine is running. So can be used to rescue you if you run out of power on your travels.

It means I can plug tools and drills, lawn mowers, strimmers, grinders, drills, hedge trimmer etc either at 12, 24, or 240V either directly, or via an inverter, or via a PL8 from my chair to do work outdoors or in, or if no power. I can start my van, and connect to an anderson either under the wheelarch, or under the dashboard, to power the house via an inverter. Or to charge a chair as I drive, or to power or charge anything like a generator. It allows me to charge and power my hobby stuff on the airfeild, as well as allows the van to charge the chair as I drive home... Flexibility!

[jefferso]

That's my goal, to get lots of interconnectivity with Anderson plugs eventually. And to mount it nicely on the side of the chair. But I got the materials weeks ago and still haven't started. That video is great. It would be reassuring while travelling to have that 12/24 Anderson setup and be able to get a fast charge from a vehicle. Though with MK Gel batteries, I'd have to be pretty recently charged to offer to help someone start their vehicle.

To answer flagman1776's question, I live in the UK in London. My Permobil is from the U.S. That shouldn't matter I would think, especially from a Swedish company, but somehow in the UK I've ended up with the wrong parts because of some part number differences. Or maybe they were just using that as an excuse for ordering the wrong thing.

[ex-Gooserider]

I agree with everything BM says about how to wire the chair / van / etc... However I think that for a lot of things the SB-50 size connector is really overkill, and using it makes life a bit more difficult as it can be a pain to make small wire connections into those pins...

I have found it easier to use the smaller PP 15/30/45 series for everything but the main battery power leads on the chair and van - they are about 1/4 the size, and the pins are sized to match the wire you'd use for a given load... Essentially they work for anything that uses AWG 10 down to AWG 18.

I added a pair on the 24V terminals of my battery jumper block, so I have a direct hookup for charging at 24V, or can use it to run my 'cordless' drill (if it has a cord that connects to my powerchair instead of the wall, it's still cordless right??? )

ex-Gooserider

[Burgerman]

Though with MK Gel batteries, I'd have to be pretty recently charged to offer to help someone start their vehicle.

Those are not great as vehicle starters.

But also remember that if you connect via the way I do mine, you get a choice of both series 24V and parallel at 12V. If you use the Parallel setup, then you are starting a vehicle from TWO 74Ah MK's. Thats the same as having a massive 148Ah battery. So you have double the cranking Amps you think you do. So it will easily start a car/van.
More reasons http://www.wheelchairdriver.com/wheelch ... ectors.htm



Shows 12V parallel connection adapter and the connector loop needed to drive.


Shows 24V connection...


I plug mine into my van from the driving position too, so when I start my van I have THREE batteries doing the job. 2 on the chair, 1 where it normally lives on the van. Even if its dead, it still starts. Then I start motor, and the vans 100A alternator charges all 3 batteries at 14.4V as I drive. The lowest battery charges the fastest. After around half an hour driving all are quite well charged and are at CV. And you are now safe to drive for 8 hours non stop. Current drops away naturally as they charge.

CABLE with 12V PARALLEL adapter to charge from, or start the van!


CHARGING AT 49A as I drive here:


CHAIR CABLES, ALL SOLDERED:


FITTING


VAN INSIDE CONNECTOR IN DASHBOARD. Allows direct charging lead. Or lithium charging via PL8. Or van starting!


ANOTHER EXTERNAL CONNECTOR (so I can charge a chair in the sun, connect my PL8 to charge a quad-copter or plane, or another chair. Or so I can start the van, or lower the ramp to enter if battery is flat... Or to plug in an inverter to power 240V stuff like vacuum cleaner/polisher or an over winter float charger.)



DETAILS: http://www.wheelchairdriver.com/faster- ... arging.htm

[Burgerman]

ALL my chairs, have the same setup.
Here, 12 / 24V setup installed on my Storm 4 chair with the drive loop plugged in.
That loop is also useful when storing the chair as once removed, the battery is totally disconnected from the chairs control system. So can be stored 3 to 4 months without charging if already 100% full.

Want some power while in a chair? 2KW mains AC 240V available here from your chair or van.

[jefferso]

If I don't go out, and just use the chair inside, and to power my vent, it seems to take 26 to 31 Ah to recharge it (up to 46 Ah one time when I went out), according to the PL8. A few times I let it charge until it stopped and it took 10 or more hours with the 12A charge. It seemed to only go down to around 200mA, so maybe it was eventually timing out with the 8 hour limit.

I kept wondering why it didn't seem to go down to 100mA and eventually thought of my 24/12v dc converter for my vent on the back of my chair. Even though the vent is off when the chair is charging, it must have been drawing something because it had a little LED on.

When it was charging CV at about 340mA I got my helper to unplug the the XLR cable from the chair to the 24/12v adapter, and the amps went down to 200mA.
So maybe all these years I've been charging my chair while that thing draws about 140mA.
Now when I charge the chair, I get that unplugged. It seems to take 4 to 6 hours for the PL8 to finish the charge and stop itself.

I've had these batteries for about 3 months. Could charging them with that constant small draw have long term consequences?

I also wondered how much current just having the chair on might draw. When the chair was drawing about 400mA at CV, I turned it on, and then the PL8 showed about 850mA, then back to around 400mA when I turned off the chair again. The chair powers itself off after 10 minutes, so I never thought about it before, but now I figure I might as well make sure it's off as soon as charging starts.

[Burgerman]

Heres what happens.

You can choose to let the PL8 charge for, 8hours CV limit. And or Total charge length limit. You can also choose at what point the charge terminates.

Batteries DISCONNECTED to anything (no small drain from any device or the chair itself).
100mA is actually a quite safe limit. For 70Ah batteries a 70mA limit is actually better.
Unless your batteries are a bit sulfated, in which case it might take 2 days CV to desulfate them. Or a CC 500mA charge, with a 15.2V limit for say 12 hours a few times after charge ends.

Now...
With a normal chair, no vent, and the power turned OFF there will still be anything from 6 to 20mA drain happening all the time. At least thats what I measured here. Hence the higher 100mA termination for safety. Designed to allow for that. Its also why you must disconnect a battery cable or unplug the battery if storing the chair. When switched ON, the control system, joystick pod etc take from 100mA to 300mA depending on make, modules etc. The chair will STILL fully charge in this case or with your 140mA drain. But will go the full 8 hours as you discovered. Effectively you are not stopping the charge when full, but relying on the 8 hour limit instead.

So what happens when residual load is higher than termination current?
You get the usual CC stage. Then you will get 8 hours at CV since it wont ever be able to fall to the low enough limit as you have a load on the battery. That wont hurt. But if the chair is not heavily discharged, it will stay at CV too long. Thats better than not long enough. So, it might be better to drop say .2V from the charge voltage if you continue to do that.

You might also like to look at this thread where I am recovering and then testing 2 Optima batteries (in parallel, so its one big 12V battery with double the 68Ah capacity so a 138Ah batt, as far as the charger is concerned).
viewtopic.php?f=2&t=8552

Might be dull, but also worth a slow read.
Your battery should not need any restoration. And will not be damaged. It may be well charged if its doing a full 8 hours CV stage. But best to remove load, and allow it to end sooner, naturally, if you can. Since unless its heavily discharged 8 hours is a little too long. The idea is that the 100mA point will turn it off at the correct point, dep on how discharged it was. A full discharge takes 8 hours CV to end. A slight discharge doesn't need that long. You might want to lower yours to say 85mA based on the 4 to 6 hours.

[jefferso]

Thanks a lot for that explanation. I read that thread about the resurrection of the Optimas so was getting more of an understanding about how the sulfation happens and can be dealt with.

[Burgerman]

I just started on an old unknown set of MKs, that came fitted to a brushless invacare chair. They have been maintaied at 26.7V most of the last 2 years so should be good to go. Will fully charge, then count out Ah to the same 10.2V (20.4V) in series via XLR. So I can see if they are worth keeping or otherwise.

[Mechniki]

Hmm! Clamp meter, now I see how you check current. Erm! Does the PL 8 also check current?

[Burgerman]

Of course. Discharging a set of MK Gel 73.4Ah GRP24 batteries here to determine the ACCURATE CONDITION.

The PL8 graphs and records it as you charge or discharge. Amps and Volts and time. And capacity taken out or returned. And lots of other things.

For e.g. This screenshot shows that the MK batteries are in series, and have been discharging for a little under 5 hours.
At 4A continuously. Thats a slow discharge at approx the 18 hour rate. So I would expect to get 71Ah out when it hits 10.2V. As per spec. IF 100% as new.

This shows:
The battery has been discharging for 4 hours 50 mins 09 seconds...
That the AVERAGE cell is down to 1.999V
That the pack voltage is 12.01V per battery or 24.01V.
That so far 19,180mAh or 19.18Ah has been removed.
That the target discharge rate is 4.00A
That its actually charging at 4.01A
That the supply voltage is 21.96V
That discharge watts are 96
That supply current is 0.0A (since its discharging)
Then it graphs Volts V time, Amps V time, cell volts, and amps, individually over time for lithium, returned Ah over time, resistance per cell over time, etc. Also graphs loaded and unloaded supply or current over time.

[Burgerman]

And one look at this shows why lead batteries are crap. And gel are worse than odyssey.

Its down to 12V where your lights warning light start telling you its dead, after a slow 4A discharge for under 5 hours. Its not actually anywhere near dead, you are seeing the voltage depression caused by loading a gel battery. If I stop discharging it, will rise from its depressed 12v to 12.8V after say 16 hours... And so you get a full set of battery level light back.

[jefferso]

I ordered one of these Victron Energy Blue Smart IP22 Charger 24/12 chargers as a travel charger:

https://www.batterymegastore.co.uk/vict ... 42002.html

It's not cheap, but it's light and small compared to similar 12A chargers and it already has a euro plug if I go to Europe (slight annoyance to take a euro -> UK adapter for travel not in Europe, but not a big deal).

It has screw terminals so had to solder an XLR cable and put the bare ends into the terminals.

It has bluetooth so I can monitor the charge on my phone or laptop with the VictronConnect app.

The only trouble is, it's the wrong voltage for the Lead profile. It's got 28.8 and 29.4 v settings at 6 and 12A. It also has a Li-ion profile which does 28.4v which is closer to the 28.2v I need for the gel batteries. I will try to charge with the Li-ion setting and watch the graph to see what it does.

I might also make another XLR cable with diodes in line to get closer to 28.2 with the lead setting. I guess having the 29.4v option might be helpful if the diodes drop too much for the 28.8v setting.

[Burgerman]

Set to lithium it will likely only do CC, then some CV and turn off. So the battery willl not be full...

Set to 14.4V it will upset the batteries... So the diode thing may help, but it also drops the float voltage. So you might want to monitor to see what it actualy does.

Remember that the 14.1V or 28.2V thing is the highest voltage allowed. At room temp 20C or 68F. In summer temps above 20C where your battery will be a few degrees warmer than ambient after use, and will stay warmer as you charge then thats too high. It actually says that the extremes at room temperature are 13.8 to 14.1V and the ideal voltage is 13.95! Since we only have overnight we choose to be at the top limit. To ensure a full charge with least damage.

Theres a MK chart here: https://www.intercel.eu/media/datasheet ... ochure.pdf

Screenshot of that here: