Power supplies for quick, silent NINJA charging

[swbluto]

Pretty good ideas for cooling laptop power supplies:

http://superuser.com/questions/317736/how-can-i-cool-down-a-laptop-power-supply

I would simply put a pen under each end of the PSU. Just getting it up off the floor should help immensely.

My suggestion would be to get a laptop cooler that is larger than your laptop and then lay the adapter next to your laptop

Hmmm... laptop coolers seem like they'd work well (Laptops are designed to burn off all the power they use, so something like 90watts at peak, while power supplies are designed to be at least 85% efficient, so they generate 10-20 watts at max). Wonder if there's any 'quiet' ones? (Like, possibly a cooler with a huge, slow moving fan.)

Apparently there are! Fan spins at a presumably quiet 1100 RPM.

http://www.newegg.com/Product/Product.aspx?Item=N82E16834998051

Might need to still limit the current with a cheap resistor if the power supply is a "non current limiting" supply. (In my testing, the lenovo power supplies do current limiting, but I don't know about the chinese ones. I honestly don't see why not, it's as simple as a current sense resistor, maybe a voltage amplifier and the appropriate MCU algorithm.)

 

[bowlofsalad]

The amount of cubic feet per minute "CFM" you are going to get out of those fans won't be much, I am not saying that it's worthless or pointless, I am sure it'll make a difference, but I imagine finding a way to use larger fans at slower RPMS might serve you better.

 

[jkbrigman]

What about using a laptop power supply to power an R/C balance charger dedicated to every 6s chunk of the pack? (or whatever way you'd want to conveniently divide the pack...)
Then you can let the R/C charger worry about the voltage regulation and get all the charging data the R/C charger can offer. It almost doesn't matter what voltage the power supply provides...

That's what I use (Powering an RC balancer with a laptop power supply). Works like a charm. It's not 'silent', however, with the noisy RC balancer's hi-speed fan but it works.

I tried a laptop supply with my iCharger and wasn't happy - it wouldn't drive the iCharger very well, overheated and eventually quit working. It was a decent IBM-spec laptop supply, too.

But: hey, I'm into this idea of using multiple laptop supplies in series for a kind of bulk charge. I'm interested in giving it a try...especially since I can easily divide my pack into 6S "chunks".

JKB

 

[999zip999]

Swbluto I reread your thread and what cells and battery are you wanting to charge ?

 

[swbluto]

What about using a laptop power supply to power an R/C balance charger dedicated to every 6s chunk of the pack? (or whatever way you'd want to conveniently divide the pack...)
Then you can let the R/C charger worry about the voltage regulation and get all the charging data the R/C charger can offer. It almost doesn't matter what voltage the power supply provides...

That's what I use (Powering an RC balancer with a laptop power supply). Works like a charm. It's not 'silent', however, with the noisy RC balancer's hi-speed fan but it works.

I tried a laptop supply with my iCharger and wasn't happy - it wouldn't drive the iCharger very well, overheated and eventually quit working. It was a decent IBM-spec laptop supply, too.

Oh, yeah, there are limitations. On my 50watt turnigy balancer with which I use a 16V 4.5A 72W IBM laptop power supply, the charge current is limited to 1.5A instead of the full 2.0A that it seems possible of, but it's a small compromise. I'm not using a 50 watt balancer on my 1000wh pack to break world records or anything.

Does make me wonder, however. The laptop power supply is rated at 72W but the balancer can only output 24v*1.5 = 36watts. Almost makes me think the laptop power supply really isn't capable of sustaining 4.5 amps on average... maybe 3-3.5amps... maybe 4.5 amps is the peak load? I won't jump to conclusions - I should do some testing and measure the current before making judgments. I can do that today... hmmm.... well... I'll get the test results in an hour or so and bring it back to you guys.

 

[swbluto]

Swbluto I reread your thread and what cells and battery are you wanting to charge ?

6s lipo packs. I configure them in series for a higher voltage with a switch and I flip the switch to parallel the batteries for bulk charging at 6s. Laptop power supplies designed to charge 6s li-ion battery packs seems to be promising...

 

[swbluto]

Did some testing using my 16v 4.5 amp IBM laptop charger and 50w turnigy balancer. It appears the balancer is easily bulk charging the batteries at 2.0 amps this time -- interesting, when I tried before, the charger would immediately cutout. I wonder if balance charging is limited to 1.5A but bulk charging is limited to 2A?

The output measured from the laptop power supply was 3.32 amps and 16.4 volts. Doesn't appear to be nearing it's realistic current limit since the output voltage is holding steady.

It's been running for 5 minutes and the laptop charger has reached a temperature within 10 degrees above room temperature. Doesn't feel 'warm' or even 'lukewarm'.

Going to take another temp measurement at 12:15, 30 minutes after the charger commenced.

EDIT:

30 minutes later at 3.32 amps and the temperature on the laptop power supply is lukewarm, probably somewhere between 80 and 90 degrees fahrenheit (Room temperature is 70 degrees).

I'd imagine at 4.5 amps, the power supply's full rating, that the power supply would probably get very warm/hot, but not too hot to the touch.

I wouldn't begin to speculate the thermal performance on the cheap chinese power supplies, but it seems like most would be manageable with adequate cooling. Well enough designed ones might not even need anymore cooling than using pencils to suspend the power supply into the air. Would have to do testing to verify.

 

[Tinto]

Swbluto I reread your thread and what cells and battery are you wanting to charge ?

6s lipo packs. I configure them in series for a higher voltage with a switch and I flip the switch to parallel the batteries for bulk charging at 6s. Laptop power supplies designed to charge 6s li-ion battery packs seems to be promising...

Do you have a photo or diagram of your setup - the switching component in particular?
I'm keen to understand the "switch to parallel" approach as that would make charging a much simpler connection than my current disassembly of EC5 and the series cable.

 

[swbluto]

Swbluto I reread your thread and what cells and battery are you wanting to charge ?

6s lipo packs. I configure them in series for a higher voltage with a switch and I flip the switch to parallel the batteries for bulk charging at 6s. Laptop power supplies designed to charge 6s li-ion battery packs seems to be promising...

Do you have a photo or diagram of your setup - the switching component in particular?
I'm keen to understand the "switch to parallel" approach as that would make charging a much simpler connection than my current disassembly of EC5 and the series cable.

Sure. There's a switch diagram at http://endless-sphere.com/forums/viewtopic.php?f=16&t=50232 for converting between 2s1p and 1s2p (Allows me to switch between 48v and 24v with two separate lipo packs).

Might be able to get more complex setups by compounding switches, though I'd imagine one could easily run into short-circuiting issues with a naive approach.

 

[petedude2lu3]

what gets me about these products is they take more volume than a motor controller, and you really need one at EACH destination, PLUS one to carry! Why aren't motor controllers doubly functional as chargers? Chargers and Ctrl'ers both have power transistors, they just need a few more to switchmode.

 

[grindz145]

+1 for the HLG series, That's what I use and I've been super happy. Outlined here: http://endless-sphere.com/forums/viewtopic.php?f=14&t=50744&p=750827&hilit=meanwell+hlg+240#p750827

 

[amberwolf]

Is this the one?

http://endless-sphere.com/forums/viewtopic.php?f=14&t=27199&start=325

Unfortunatley I don't think it is; I think one of the phrases used in the thread was "bad boy" charger, or something like that. I think that one of the chargers was being built from other stuff and I thought one was from scratch, but it's been so long I don't recall the details, as I didn't need to use the idea myself.

I also think that someone was going to use one of the LED PSUs from MeanWell for this, but not sure if it's the same thread.


Oh, also: Grin Tech / ebikes.ca has those new fanless chargers available. I don't remember the thread title but there's a thread as well as being on their news page. Might be in the most recent "trip thread" by JustinLE.


FWIW, you could use any of the higher power existing chargers with fans, making htem fanless, if you were to modify them for better heat dissipation. Larger heatsinks with much more surface area, possibly with a very slow fan (12V fan on 5V, for instance) just to keep *some* air moving over / thru the heatsink(s). Open the casing ends for pass-thru passive ventilation, as large a single hole as you can manage. Add little heatsinks glued to individual hot components inside. Or pot the whole thing in heat-conductive material, which will also make it survive the vibrations of being carried around better (this is what htey do to many powerchair chargers that are built into the chairs).

 

[nicobie]

You might check with Grin. When I last talked to Justin at the Makers Faire he showed me the prototype of his new charger that he will be selling soon. Its a variable voltage one with built in amp hour meter and can be run in series for 100+ V. Fully potted for mobile use and very small form factor.

 

[swbluto]

Is this the one?

http://endless-sphere.com/forums/viewtopic.php?f=14&t=27199&start=325

Unfortunatley I don't think it is; I think one of the phrases used in the thread was "bad boy" charger, or something like that. I think that one of the chargers was being built from other stuff and I thought one was from scratch, but it's been so long I don't recall the details, as I didn't need to use the idea myself.

I also think that someone was going to use one of the LED PSUs from MeanWell for this, but not sure if it's the same thread.


Oh, also: Grin Tech / ebikes.ca has those new fanless chargers available. I don't remember the thread title but there's a thread as well as being on their news page. Might be in the most recent "trip thread" by JustinLE.


FWIW, you could use any of the higher power existing chargers with fans, making htem fanless, if you were to modify them for better heat dissipation. Larger heatsinks with much more surface area, possibly with a very slow fan (12V fan on 5V, for instance) just to keep *some* air moving over / thru the heatsink(s). Open the casing ends for pass-thru passive ventilation, as large a single hole as you can manage. Add little heatsinks glued to individual hot components inside. Or pot the whole thing in heat-conductive material, which will also make it survive the vibrations of being carried around better (this is what htey do to many powerchair chargers that are built into the chairs).

Ok, I googled using the search query 'site:endless-sphere.com liveforphysics badboy charger lipo' and found some interesting threads with ideas being thrown around but nothing actually fully materialized.

"Dirty Power stealing charger"
http://endless-sphere.com/forums/viewtopic.php?f=14&t=19658

"DIY ebike Chargers"(Contains a compendium of DIY charger links on ES upto Nov 2011)
http://endless-sphere.com/forums/viewtopic.php?f=14&t=34078

 

[cal3thousand]

I'm just waiting for Justin's Satiator. No need to figure this out, there's a genius on the job.

 

[swbluto]

What about using a laptop power supply to power an R/C balance charger dedicated to every 6s chunk of the pack? (or whatever way you'd want to conveniently divide the pack...)
Then you can let the R/C charger worry about the voltage regulation and get all the charging data the R/C charger can offer. It almost doesn't matter what voltage the power supply provides...

That's what I use (Powering an RC balancer with a laptop power supply). Works like a charm. It's not 'silent', however, with the noisy RC balancer's hi-speed fan but it works.

I tried a laptop supply with my iCharger and wasn't happy - it wouldn't drive the iCharger very well, overheated and eventually quit working. It was a decent IBM-spec laptop supply, too.

But: hey, I'm into this idea of using multiple laptop supplies in series for a kind of bulk charge. I'm interested in giving it a try...especially since I can easily divide my pack into 6S "chunks".

JKB

Do you know which iCharger you have? It seems like the ones I'm seeing on google are rated for 250w/300w and laptop supplies are usually in the 50w-100w range, so it wouldn't surprise me if a laptop supply would be inadequate if you're using one of those 250w/300w ones. It works well for my 50w turnigy balancer.

So, do you know if the IBM laptop supply didn't limit the current at 4.5A (Or whatever its designated limit is)? I thought most legit laptop supplies limited current so they wouldn't 'quit working' from prolonged overheating, but I wouldn't know about all models.

 

[swbluto]

I'm just waiting for Justin's Satiator. No need to figure this out, there's a genius on the job.

Do you have a link? Sounds interesting!

 

[Holocene]

Do you have a link? Sounds interesting!

Hi swbluto,

Read the comment Chargers by justin_le on Sat May 11, 2013

 

[jkbrigman]

Re: Justin's "Satiator" - I left the last comment in that thread seeking an update on the Satiator. No word yet. Please prove me wrong. I'd buy one of those today.

 

[bowlofsalad]

Do you have a link? Sounds interesting!

Hi swbluto,

Read the comment Chargers by justin_le on Sat May 11, 2013

Very nice share, thanks, I am glad to say I am a customer of his : P. If only it had the ability to balance cells.

 

[jkbrigman]

Do you know which iCharger you have? It seems like the ones I'm seeing on google are rated for 250w/300w and laptop supplies are usually in the 50w-100w range, so it wouldn't surprise me if a laptop supply would be inadequate if you're using one of those 250w/300w ones. It works well for my 50w turnigy balancer.

So, do you know if the IBM laptop supply didn't limit the current at 4.5A (Or whatever its designated limit is)? I thought most legit laptop supplies limited current so they wouldn't 'quit working' from prolonged overheating, but I wouldn't know about all models.

Hey swbluto - I have the iCharger 106B+ and I love it. You are right, 250W, but it works like a champeen with my 150 watt 10A/15v Lambda open-frame switching power supply. The iCharger is pretty smart - you can *tell* it how much current to pull from the power supply in Amps. The iCharger has TWO input power ports: a 5mm/2.1mm jack that's limited to 6 amps and dual banana plugs that can handle up to 10 amps.

You are right, your 50w Turnigy balancer would be quite happy with the kind of laptop brick supply you have been talking about.

I found another laptop power supply, going to give it a try tonight with the iCharger, a Lenovo 90Watt "20V" supply. I'll first use it to feed the iCharger106B+ (to see if the last laptop supply I used was just ready to give up the ghost). Then I'll try it as a standalone "bulk" charger for 6S. I'll edit this posting with the results.

 

[cal3thousand]

Do you have a link? Sounds interesting!

Hi swbluto,

Read the comment Chargers by justin_le on Sat May 11, 2013

Very nice share, thanks, I am glad to say I am a customer of his : P. If only it had the ability to balance cells.

^That's the key part it's missing. Someone needs to develop and piggy-back balancer for these things.

 

[swbluto]

Hi swbluto,

Read the comment Chargers by justin_le on Sat May 11, 2013

Very nice share, thanks, I am glad to say I am a customer of his : P. If only it had the ability to balance cells.

^That's the key part it's missing. Someone needs to develop and piggy-back balancer for these things.

If you need a quick, silent bulk charger for a journey, I honestly think balancing should be one of the last things to be concerned about. Sure, I guess, bring along a balancer so the batteries can take their sweet time to balance every 10-20 cycles or so, but I wouldn't be concerned about balancing when I'm stopping in the coffee shop for 30-50 minutes for a quick charge.

Ideally, one of these SATIATOR chargers would be used with a BMS that does balancing, like the ping BMS or other balancing BMSs. If you're using lipo, absent the appropriate BMS, it's pretty common to use a balancer being powered by a bulk-source for balancing, anyhoo.

 

[swbluto]

I found another laptop power supply, going to give it a try tonight with the iCharger, a Lenovo 90Watt "20V" supply. I'll first use it to feed the iCharger106B+ (to see if the last laptop supply I used was just ready to give up the ghost). Then I'll try it as a standalone "bulk" charger for 6S. I'll edit this posting with the results.

It'd be pretty awesome if they could be used to directly charge 6s lipo like I suspect. Eager to see the results!

Btw, just want to give you some heads up in the laptop world. It seems like the laptop's quality of the ThinkPads went down after IBM sold it to Lenovo, as they replaced metal hinges with plastic ones and they just cheapened it all around; I'm suspecting that, similarly, the quality of the Lenovo laptop power supplies *might* have decreased a bit over the original IBM power supplies. If that's the case, then assuming overheating is a problem, one of the most important things with the cheaper power supplies is to limit current somehow to reduce heat, usually by increasing resistance. Maybe adding a cheap power resistor, a bulb, etc.

If only the laptop power supply supplied a simple rectified AC signal, you could increase impedance with an inductor and incur little additional energy losses. (Not that energy losses are a "big deal", just so long as they're not happening too much in the power supply)

I'm not exactly sure how to appropriately model the circuit for charging a battery in my TINA simulator, but my simulation seems to suggest an additional resistor between 50mOhm and 200mOhm would good enough for a lipo pack with an internal resistance between 50mOhm and 100mOhm to limit the charge current between 2-3amps per laptop power supply. This would probably require further testing to get the best value.

Good news about that is that 200mOhm would only generate (I^2*R) 3amp^2*.2=1.8watts of heat would should be easy enough for a cheap 5w power resistor to handle.

EDIT: I think my simulation was too simplistic. If you increase the load resistance, the power supply might increase the output voltage to maintain a steady current, which would be self-defeating. This will definitely require further testing given the laptop power supply is an active source with unknown charge characteristics. A 5w (Or maybe 25w) pot would probably prove useful in testing.

 

[bowlofsalad]

If you need a quick, silent bulk charger for a journey, I honestly think balancing should be one of the last things to be concerned about. Sure, I guess, bring along a balancer so the batteries can take their sweet time to balance every 10-20 cycles or so, but I wouldn't be concerned about balancing when I'm stopping in the coffee shop for 30-50 minutes for a quick charge.

Ideally, one of these SATIATOR chargers would be used with a BMS that does balancing, like the ping BMS or other balancing BMSs. If you're using lipo, absent the appropriate BMS, it's pretty common to use a balancer being powered by a bulk-source for balancing, anyhoo.

I am not sure why you'd make it sound as though something such as an RC chargers ability to always balance cells or the use of a BMS to always balance cells while charging isn't a wonderful thing. Not all packs have perfectly matched cells, and that can cause issues even before 10-20 charges. I am not saying that even with those kinds of ideas that you shouldn't routinely check balance to make sure things are working well and so on, but the idea of always having a self balancing setup would be golden.

What is this "balancer being powered by a bulk-source for balancing" you speak of?