Power supplies for quick, silent NINJA charging

swbluto

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Hey, does anyone know what the most powerful, relatively compact and quiet chargers are? I'm presuming it'd be of SMPS technology, but can't think of any particularly powerful ones.

I'm wondering because it'd be quite cool to pop into the library/coffee-shop/etc. and charge your portable battery in 30 minutes and be on the road (My lipo battery is in a laptop case so I can carry it around). Would make those long-distance journeys a lot more feasible, with the greater amount of charging opportunities you'd have with a quiet charger. (I'm not charging my batteries with the noisy fan on my RC balance charger in the library, lol.)

Here's a few ideas, a little on the expensive side, though.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817151099

Just put two of these 400w fanless badboys' 12v outputs in series, and you have something like 800watts of 24volt charging power for 6s lipos. So, it's totally possible to have quiet high-power charging, just costs a cool ~$250. (Which is pretty cheap compared to how much my 50watt charger cost me, watt-per-watt. Lab power supplies are much more expensive, too.)

Wonder if you could parallel 24v laptop power supplies on ebay? Maybe one could parallel 10 of those laptop power supplies to get 700 watts of quiet charging power, total cost being $120ish. Might have to use a diode, hmmm... (Of course, maybe the power supply comes with its own internal diode?)

http://www.ebay.com/itm/15V-24V-65W...=Laptop_Adapters_Chargers&hash=item27c7bf844a

Still looking for more ideas, possibly cheaper ones if possible. Maybe ones with an adjustable voltage output for fine-tuning, and not just stuck at "24v" [When they say 24v, I'm not sure if they really mean 24.6v or what for the float voltage] (You could pair these chargers up with a methods lipo protection unit for quick, easy and safe bulk charging. I'd, personally, just watch the charging with a voltmeter but some may not feel so comfortable with that setup, lol.)
 
There's a thread a year or two old, maybe more, about this basic idea. A few chargers were recommended, and at least one was developed and tested, though I don't recall the results. I know Liveforphysics posted to it, and probably Methods, so you could search their posts about that.
 
amberwolf said:
There's a thread a year or two old, maybe more, about this basic idea. A few chargers were recommended, and at least one was developed and tested, though I don't recall the results. I know Liveforphysics posted to it, and probably Methods, so you could search their posts about that.

I suspect you may have relatively advanced visual memory, so I wonder, do you remember any particular words or phrases used in the thread? Might make a google search for the thread a whole lot faster.

Actually, got the gears turning already.

Google query: site:http://endless-sphere.com liveforphysics methods quiet charger

Will try that and variations thereof if that doesn't work!
 
I have about 15 DPS-670 670w fanless server 12v PSUs all you need is something to current limit.
 
icecube57 said:
I have about 15 DPS-670 670w fanless server 12v PSUs all you need is something to current limit.
Would a charger setting be effective in current limiting or do you need to do stuff to the Powersupply?
otherDoc
 
docnjoj said:
icecube57 said:
I have about 15 DPS-670 670w fanless server 12v PSUs all you need is something to current limit.
Would a charger setting be effective in current limiting or do you need to do stuff to the Powersupply?
otherDoc

You might need a lightbulb, lol. (You shouldn't need a particularly powerful one to limit it to ... what is that... 50 amps? Might even need to parallel lightbulbs. Getting the highest current possible from the power supply might be tricky business, however, but you can probably get pretty close to 'good enough' with enough bulbs and experimentation.)

Presumably the fanless server PSU he has doesn't have built-in current limiting which seems kind of strange but not impossible.
 
Unless you have a huge pack or one with a very high C-rate, it's harmful and potentially catastrophic to charge too quickly.
 
xenodius said:
Unless you have a huge pack or one with a very high C-rate, it's harmful and potentially catastrophic to charge too quickly.

Assuming for most of your trips, you're charging at home at a slow rate, that's not a problem.

It's just that when you're out there and you need to charge somewhere and you're waiting for the charge to finish, many people are willing to sacrifice a cycle or two to get it done in 30 minutes. Waiting for 4 hours for the charging to finish is no fun. (And in places like coffee shops or restaurants, can become a bit awkward)

Ideally, this kind of charging would be used on long-distance trips where you don't want to buy $1000+ worth of batteries to get between places and be forced to charge at night somewhere where there's a plug.

(The higher quality lipos can be charged in 30 minutes.)
 
cwah said:
Why would I burn my house or my charger? I don't get it. Doesn't the charger charge up to the designed current?

This is assuming you are using a lipo pack, but if you charged the pack at a radically higher rate or over charged the pack, it would surely light on fire.

endless-sphere.com/forums/viewtopic.php?f=14&t=52560 This thread looks interesting for charging.
 
bowlofsalad said:
cwah said:
Why would I burn my house or my charger? I don't get it. Doesn't the charger charge up to the designed current?

This is assuming you are using a lipo pack, but if you charged the pack at a radically higher rate or over charged the pack, it would surely light on fire.

endless-sphere.com/forums/viewtopic.php?f=14&t=52560 This thread looks interesting for charging.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=52560

That's more of a viking, not a ninja.

(6.6kw active fan cooling so pretty loud)

Although, I do wonder, if you limited the power output of a 6.6kw power supply combo to 800 watt, would the fans trigger?

Hmmm... for $1200... I'm not sure I'm going to try it, lol.
 
The Delta-Q QuiQ chargers are rated for 1kw and are fanless. They go for about $500 retail, though I see some going for a bit less via ebay auctions.

etecq.jpg
 
Seems like the 20V IBM Lenovo laptop power supplies might have a float voltage upto 25 volts or thereabouts.

This ebay auction lists the x60e adapter as a "25 volt" power supply even though it has a 20v nominal rating, so I'm suspecting that's the Open-Circuit/Float voltage.

http://www.ebay.com/itm/For-IBM-LEN...=Laptop_Adapters_Chargers&hash=item4853a532ce

Title: For IBM LENOVO X60e Laptop 65W 25V AC Power Adapter

Seeing that most adapters seem to be 19v and seem to go upto 24volts or so, I'm suspecting most of the 20v laptop power supplies may go upto 25 volts. Confirmation of that requires further investigation and testing.

Here's a 90w 20v model for $10.65. It's also designed as an IBM/Lenovo power supply.

http://www.ebay.com/itm/20V-NEW-Lap...=Laptop_Adapters_Chargers&hash=item43b8aee52d

Personally, it wouldn't surprise me if these lenovo laptops using '20 volt power supplies' have 6s li-ion batteries. That might be a pretty easy way to confirm they can charge 6s batteries... hmm...

Let's check the batteries!

http://www.amazon.com/Lenovo-Original-Genuine-ThinkPad-40Y6799/dp/B000EQW5SA

Aha! It's a "LENOVO 6CELL PRIMARY NOTEBOOK BATTERY 41+". I think it's probably safe to say these 20v laptop power supplies could be used to bulk charge 6s lipo batteries silently, quickly and cheaply.

I do wonder why they rate the power supplies at 20V as 20/6 = 3.333, which has no obvious significance when it comes to li-ion voltages. Hmmmm... do the electronics run at 20volts, but yet the batteries can be directly charged upto 100% at 25v?
 
Here's the cheapest chinese knockoff 20v 90w laptop power supply I could find on ebay, price is $8.20. Might want to buy one (Check the voltage), or two(See if they can parallel), for testing before ordering hundreds. :wink:

http://www.ebay.com/itm/Laptop-Batt...=Laptop_Adapters_Chargers&hash=item58a26054dd

Checking out eBay, it seems the going price for new 20v 90w genuine 'brand name' laptop power supplies (Lenovo,IBM,Dell,etc.) is around $25-27, shipped.
 
swbluto, I like where you are going with this. Laptop supplies aren't very durable (they can overheat easily) but if they are cheap, it's not the end of the world to buy extras.
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...

JKB
 
You could probably easily limit the current to limit heating by adding resistance (Possibly a lightbulb, maybe a cheap 5-10ohm power resistor), and/or probably add a passive heatsink of some sort to improve reliability. Don't know of the best passive-cooling heatsink nor cheapest for these guys, but it seems possible.

I'd think the 'official power supplies' would probably be more durable assuming they came with builtin thermal limiting of some sort. Some(Most?) of the cheap chinese knockoffs probably do away with these 'extras'.

jkbrigman said:
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.
 
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