PSU - Info

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PSU - Info

Postby expresso » 18 Oct 2017, 22:30

Lets use this section to talk about PSU units - lets post links to the units we are using - talk about whats good or not - and why each is using what they are etc, -

i am using two units i got from ebay -they work fine - these are 75A models - one is 24V and another 12V -

looking to be ready to purchase another 24V in case one goes bad - the ones i find are in the $200 range and higher -

https://www.ebay.com/itm/New-Turnigy-Re ... 0009.m1982

with this model - says 23A output - but 350Watts - to me that dosnt add up - i am using my 12V at 75A and i do about 19A maybe 20A max if i raise the limit on the PL 8 - so how can this unit above give me 23A at 350 Watts ?

http://www.buddyrc.com/charging-systems ... upply.html

More to choose from -

lets add links to PSU so we can just come to this page and look up the units

this is what i am using now - ebay

https://www.ebay.com/itm/JUICE-BOX-Powe ... 0290.m3507

and i have the 12V version but mines were 75A - now they are relisted after being missing for some time and they are now 60A -
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Re: PSU - Info

Postby Gnomatic » 19 Oct 2017, 03:13

You have one 12v 75A PSU and one 24v 75A PSU. Both 75A. Your 24v can charge with more amps because the PL8 is only drawing half the amps out of that psu compared to your 12v. The PL8 has a limit on how many amps it can draw.

I've looked at this one.

https://www.ebay.com/itm/rc-power-suppl ... 36043adce6

and have this one(which has given me issues and am looking for another)

http://www.lipoconnectionsolutions.com/ ... 5FMAPL.htm
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Re: PSU - Info

Postby Burgerman » 19 Oct 2017, 03:42

I use an old laptop power supply when charging small batteries, 19V.
And a 480 watt 20A 24V cheap ebay supply for next to bed for slower charge: Similar http://www.ebay.co.uk/itm/DC-5V-12V-24V ... 1KGFx_J79Q

And I charge from chairs (via andersons) at 12 or 24V for quadcopter or to charge vehicle, to start it etc.

Or from 2x bench excellent stable power supplies 30V 40A each http://www.wheelchairdriver.com/BM3-con ... arging.jpg
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Re: PSU - Info

Postby expresso » 19 Oct 2017, 04:11

http://www.usastore.revolectrix.com/Pro ... wer-Supply

this model - with a few others i seen that can adjust Volts and have 3 extra plugs to connect more chargers

but this one above - its 50A - the Main outputs - does that mean - i can run my PL 8 off the Main ones and use 50A - while still using the smaller ones at 10A each all together or combined Amps between all of them ?

i know its most likley combined but just to be sure i understand - maybe a unit that gives me more options could be useful - i could leave both chargers connected to one PSU this way - something for the future to think about - how best to keep it simple and do more at once -
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Re: PSU - Info

Postby shirley_hkg » 19 Oct 2017, 04:16

My next PSU .

SIEMENS GR60

7---65V , 0----120A 6Kw , weight 28Kg . :fencing

£150.00
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Re: PSU - Info

Postby expresso » 19 Oct 2017, 04:16

https://www.ebay.com/itm/222679133682?ul_noapp=true

just relized - or just came to mind - i knew it had two connections just didnt think i would need or want them - but this is my 24V unit - my 12V also has two connections - mines are 75A - on the 24V -

so if i connect both my chargers on the 24V unit - i can saftely charge two chairs at 30A each ? since its 75A - if thats the case - i can make longer charge cables - in the future - organize the chargers - stack them somehow - one PSU - i can vision it - dont think i am not in a rush to need everything done at once same time - but would be fun
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Re: PSU - Info

Postby shirley_hkg » 19 Oct 2017, 04:29

cheers
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Re: PSU - Info

Postby expresso » 19 Oct 2017, 04:49

https://www.ebay.com/i/322267542492?chn=ps&dispItem=1

Can be used for Cell and Amp monitor - color screen - XT 60 on it also - interesting -
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Re: PSU - Info

Postby sad_vampire » 19 Oct 2017, 10:03

I use a SKYRC eFuel 1200w, 50A PSU, 15-30V

https://www.flyingtech.co.uk/accessorie ... cd-display
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Re: PSU - Info

Postby Gnomatic » 19 Oct 2017, 15:49

expresso wrote:
so if i connect both my chargers on the 24V unit - i can saftely charge two chairs at 30A each ? since its 75A - if thats the case - i can make longer charge cables - in the future - organize the chargers - stack them somehow - one PSU - i can vision it - dont think i am not in a rush to need everything done at once same time - but would be fun


You could run both chargers and get 30A out of each charging. PSU would be working twice as hard, buy since its rated @75A it should have enough headroom.
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Re: PSU - Info

Postby expresso » 19 Oct 2017, 15:56

Gnomatic wrote:
expresso wrote:
so if i connect both my chargers on the 24V unit - i can saftely charge two chairs at 30A each ? since its 75A - if thats the case - i can make longer charge cables - in the future - organize the chargers - stack them somehow - one PSU - i can vision it - dont think i am not in a rush to need everything done at once same time - but would be fun


You could run both chargers and get 30A out of each charging. PSU would be working twice as hard, buy since its rated @75A it should have enough headroom.



nice good to know - - now with the 12V PSU - i am not sure what that was rated at when i purchased it - i like to say 75A - but it may not be - with that one - what would be the max for each output ?

if i charge at 19A to 20A max - i leave it at 15A charging with this 12V - unless i up the charger a bit - it may give me a bit more - but dont want to max everything out just for a few extra Amps -

so with the 12V - 9A each would be the max then - if i am correct ?
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Re: PSU - Info

Postby expresso » 19 Oct 2017, 16:00

sad_vampire wrote:I use a SKYRC eFuel 1200w, 50A PSU, 15-30V

https://www.flyingtech.co.uk/accessorie ... cd-display


i like this one also - at some point - maybe one of these or silimar may come in handy for me - as long as my Ebay models are working and they still make them - its the least expensive option with two outputs and 60A now -

but i like having one plug also and compact - i like having those extra 10A outputs also -

now with this unit - if you connected all those outputs - the Main 50A - and the other 3 all at the same time - how much can you pull from the Main then ? 20A max and 10A for the other 3 for a total of 50A ?
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Re: PSU - Info

Postby Gnomatic » 19 Oct 2017, 16:27

expresso wrote:nice good to know - - now with the 12V PSU - i am not sure what that was rated at when i purchased it - i like to say 75A - but it may not be - with that one - what would be the max for each output ?

if i charge at 19A to 20A max - i leave it at 15A charging with this 12V - unless i up the charger a bit - it may give me a bit more - but dont want to max everything out just for a few extra Amps -

so with the 12V - 9A each would be the max then - if i am correct ?


Something like that, maybe a bit more. The PL8 can only handle 60A current from the supply. So your 12v PSU has to send twice the amps to the PL8 compared to your 24v PSU, for the PL8 to charge at the the same output. That's why you can't charge at 30A or 40A with your 12v PSU, but you can with your 24v.
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Re: PSU - Info

Postby expresso » 19 Oct 2017, 17:00

i think i have my PL 8 set for 50A in the settings - i figure not to max it or stree it too much - would it be a good idea to raise it to the Max 60A on the Charger end ?
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Re: PSU - Info

Postby Gnomatic » 19 Oct 2017, 18:58

You might be able to charge at higher amps with your 12v PSU than you're able to now.
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Re: PSU - Info

Postby expresso » 19 Oct 2017, 19:33

Gnomatic wrote:You might be able to charge at higher amps with your 12v PSU than you're able to now.


its Ok as it is - but - is it Ok then you think to put the charger PL 8 to Max Amps in the settings so its able to pull the Max - is going to stress it ?

i think i have both of mines at 50A -

what does everyone keep there PL 8 at ?
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Re: PSU - Info

Postby sad_vampire » 19 Oct 2017, 21:25

expresso wrote:
sad_vampire wrote:I use a SKYRC eFuel 1200w, 50A PSU, 15-30V

https://www.flyingtech.co.uk/accessorie ... cd-display


i like this one also - at some point - maybe one of these or silimar may come in handy for me - as long as my Ebay models are working and they still make them - its the least expensive option with two outputs and 60A now -

but i like having one plug also and compact - i like having those extra 10A outputs also -

now with this unit - if you connected all those outputs - the Main 50A - and the other 3 all at the same time - how much can you pull from the Main then ? 20A max and 10A for the other 3 for a total of 50A ?


Well, you can't use them all at full power at the same time, the unit is 1200w.

If you set it to 30V you can only pull a maximum of 40A anyway. At 24V you get the full 50A.

It won't let you run the PL8 at full power, but it's still enough to be reasonably quick, & the unit is a reasonable size so I can take it on my holidays.

Just one of the many possible solutions.
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Re: PSU - Info

Postby expresso » 20 Oct 2017, 00:35

i dont understand this PSU stuff much - i would think 30V would give you more -

I just Maxed out my PL 8 to 60A with the 12V PSU and isnt worth doing - i get 22A max charging out of it - and screams like a mother F..ker -

i will put it back to 50A once i am done charging - and charge at 15A - works fine - i can get 19A with the charger at 50A - but again screams -
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Re: PSU - Info

Postby Burgerman » 20 Oct 2017, 01:38

Its kinder to the power supply, and the charger to use more volts and less amps if you worry about things going bang, efficiency, noise, melting cables etc.
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Re: PSU - Info

Postby expresso » 20 Oct 2017, 01:57

so is 50A on the charger PL 8 - OK - leave it there ? or lower ?
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Re: PSU - Info

Postby Burgerman » 20 Oct 2017, 02:18

You can do it. I would set whatever I needed to do.

Heres calcs/charts, they are pessimistic. You get accurate results if you add 1v to the power supply (because 3.65 per cell is the minimum):

Calculator 1 -- At what current can I charge using my existing power supply?
http://www.revolectrix.com/PL8_Calc_1.htm

Calculator 2 -- What kind of power supply do I need to charge my LiPo at a current I specify?
http://www.revolectrix.com/PL8_Calc_2.htm

Calculator 3 -- What is the max DISCHARGE current for my pack?
http://www.revolectrix.com/PL8_Calc_3.htm
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Re: PSU - Info

Postby snaker » 20 Oct 2017, 02:30

expresso wrote:so is 50A on the charger PL 8 - OK - leave it there ? or lower ?

That depends on the PSU quality. A good server PSU works fine at 80% of its nominal Apms rating. So if your PSU is 75A rating, it can work at 80% x 75 = 60A therefore you can set 60A on PL8. But it is the case of high quality server PSU. Normal PSU usually works much less efficiently than 80%. I think you can set the Apms in the Suply tab to 60A but only set charging amps in the Preset lower than the one that makes the PSU scream.
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Re: PSU - Info

Postby Burgerman » 20 Oct 2017, 02:32

Thats not actually true. I use a 20A power supply on 20A every night. And my 40A supply at its 41A maxed out on my bench regularly for 6 or 7 years or so. Unlessthe server supply is less powerful than it is claimed?

He actually means setting the input current on the PL8 lower. Which is kinder to the charger. 60A on small components, and thin wires on the PL8 makes a lot of stress and heat and more likely to fail. Its less efficient too. Its always better to use say 24V at 30A than 12V at 60A which allows the same basic charge power/Amps for efficiency reasons too. Unless you are charging a small 2 or 4 cell battery.
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Re: PSU - Info

Postby expresso » 20 Oct 2017, 16:02

I was just curious - i put my PL 8 Back to 50A on the supply - i can use 15A charging with this 12V PSU and its fine - not screaming etc, - if i try to push it for more charging Amps - then it gets stressed to the Max - and you only get a few more Amps charging out of it - not a big deal -

i got this 12V PSU as a back up really to have - $50 when i got it - and it works fine - i may just get another 24V and put this aside or just leave it till it dosnt work - either way - depends on the day - how i feel :D
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Re: PSU - Info

Postby Gnomatic » 20 Oct 2017, 17:17

Burgerman wrote:Unlessthe server supply is less powerful than it is claimed?



Efficiency ratings on a server PSU just mean how good the PSU is at converting wall power into its load power. For example, an 80 Plus Bronze rated PSU has to be above 82% efficient at 100% of its rated load. Like many other things, headroom is a good thing when selecting a PSU. Server PSU's will last longer if they're used below their rated maximum.

The other thing with these repurposed server PSU's several of us are using, is they were pulled from 5 or 6yr old servers. They've likely seen heavy use during that time and are less efficient than when they were new. It's also tough to find one with any kind of warranty more than 90 days. I had one fail on me in less than 9 months of use. I have another that's just a couple months old and I'm not confident in it lasting long. I hope to find a decent deal on a good bench PSU someday..
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Re: PSU - Info

Postby expresso » 20 Oct 2017, 17:58

Sorry to hear that - your PSU failed and not up to spec - since i recommended them i belieave - and in my case - i could be lucky - i have 2 of them - and both so far - working fine - but your right - warranty wise is very short -

cost wise is about half of a new unit - but may be worth getting a new unit with your experince with these - i am thinking of getting another Ebay model 24V now - but not ruling out a new unit either - i like a small unit that the new ones are and with one cable - but most are at 50A max also - - still good - means you cant charge at 40A but 35A should be fine
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Re: PSU - Info

Postby Gnomatic » 20 Oct 2017, 18:50

expresso wrote:Sorry to hear that - your PSU failed and not up to spec - since i recommended them i belieave - and in my case - i could be lucky - i have 2 of them - and both so far - working fine - but your right - warranty wise is very short -

cost wise is about half of a new unit - but may be worth getting a new unit with your experince with these - i am thinking of getting another Ebay model 24V now - but not ruling out a new unit either - i like a small unit that the new ones are and with one cable - but most are at 50A max also - - still good - means you cant charge at 40A but 35A should be fine


I'm not mad or anything. I knew what I was getting. And if I were to get another server based PSU, I'd probably get it from Strick. If I don't find a bench one there's an eFuel unit rated 15v-30v up to 50A. I like that the voltage is adjustable.
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Re: PSU - Info

Postby Burgerman » 20 Oct 2017, 19:08

If you get a bench supply, you can charge lead directly too. Set to say 25A and 28.2 or 29.4V and you have a CC/CV charger. I do it all the time. Leave on for 5 or 6 hours.
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Re: PSU - Info

Postby expresso » 20 Oct 2017, 23:13

eFuel unit rated 15v-30v up to 50A. I like that the voltage is adjustable.
Gnomatic

i like that also but what benefit is it to have that voltage adjustment option over the same one without ?

i think i like to get one now 24V - either another Juice box - Ebay - or a new unit -

http://www.usastore.revolectrix.com/Pro ... wer-Supply

which would be better ?

http://www.hobbywow.com/en-skyrc-efuel- ... gINefD_BwE
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Re: PSU - Info

Postby Burgerman » 21 Oct 2017, 10:04

A voltage adjustment allows you to set a different voktage in the event you haveany boost/buck transition issues. Or allows you to charge a lead battery directly, 12 or 24V at high amps, etc. Or test motors, run things on the bench, etc.
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