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Discussion Starter · #1 ·
later on when i buy a good charger to charge both nimh and nicads..

i dont want to run the charger off a 12v car batt..

so what sort of power supply thing would i need, how do they work,? do they plug into a powerpoint,??



Nismo
 

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all r/c tracks have powerpoints i think


hmm yeah


lol your avatar


hahaa


man thats going 10kph and your wheel falls off


 

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nismospeed said:
later on when i buy a good charger to charge both nimh and nicads..
i dont want to run the charger off a 12v car batt..
so what sort of power supply thing would i need, how do they work,? do they plug into a powerpoint,??

Yep they take 240V AC from powerpoint and gives you 12V DC (sometimes a little more is good eg 13.8V DC).


Powersupply needs to be able to pump AT LEAST enough current that your battery charger does your cells at. eg if you charge at 5A, your PSU needs to supply the 12V juice at 5A or better.


The higher the current capability the better, but of course the units get bigger/heavier in size and more expensive.


A good powersupply will be fully regulated and be compliant with all power authorities eg "CE mark". Fancier ones might have meters or digital readouts to tell you what voltage & current is drawn, but these are fancy extras.





Don't don't don't don't ever be tempted to convert an ex-PC's PSU for use as a charger PSU.


(Not unless you're a qualified electrical engineer registered with the IEEE... even then I would have to ask 'who' before I'd trust half their work hahaha)


The risks aren't worth it.
 

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jay car sell switchmode power supplies for around the 100 buckmark. i run one. it puts out 12.5 amps at 12-13volt
 
G

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Discussion Starter · #8 ·
ok

nice

i think i might pick one up later, as i dont really like using 12v
batts, after i ger a powersupply i think illonly use 12v when goen out
for a while at a carpark



Nismo
 

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I use this charger, theMRC SuperBrain 969 Pro. It was recommended by the Dr Doug TXT-1 and Savage FAQ's as Highly Recommended..
Can charge two packs at the same time, charge at 4.5A (max), discharge
on the A channel whilst charge on the B channel and it has the ability
to do peak detection for NiCd and NiMh. AND it comes with an AC 110-240v 5Apowersupply</font> as well as 12v leads.It only cost me $99.99US from Tower. It may not be the best charger in the world, but it does everything I've wanted it to do, and hasn't died on me yet.
Only issue I've had with it is when it's charging the fan can be a little noisy at night.
Edited by: jerrah
 

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MRC Super Brain 969 Pro Series specs
FEATURES: AC/DC delta peak charger with patented MicroPeak Technology
Dual independent outputs for added versatility
Discharge function allows you to get the most out of your batteries
Large LCD screen shows: battery voltage, charge rate, peak threshold,
capacity, number of cells in pack, & elapsed time
Charges NiCd & NiMH batteries, Lithium, and Lead Acid
For 1-8 cells any capacity battery
Selectable charge rate with 0.1 amp increments
Selectable delta peak voltage thresholds in 5mV increments
Cooling fan keeps components cool for continuous charging
12-bit Analog-to-Digital converter greatly improves
measurement resolution
Digital Signal Processing filters out noise and improves
voltage accuracy
Standard battery connectors (TAM)
** Will charge 2 batteries at the same time **
INCLUDES: One 969 Pro Super Brain charging unit
One DC power converter, AC powered (wall powered)
One AC cord for converter
One DC cord w/alligator clips, for use with a 12V power source
One charge cord w/banana clips, to utilize Channel A charge jacks
One Instruction book



REQUIRES: AC 120V power source, such as a wall outlet
DC 12V power supply if needed in the field or track



SPECS: 969 case size: 3.75" x 6" x 1.375" (96mm x 152mm x 35mm)
969 Channel A specs: Cell range: 1-8 cells
Charge rate: 0.20 to 4.5 amps
Discharge rate: 0.20 to 3.0 amps
969 Channel B specs: Cell range: 1-8 cells
Charge rate: 0.20 to 4.5 amps
No Discharge
DC Power Supply case size: 5" x 2.75" x 1.5</pre>
 

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An external powersupply is handy as you can run other 12V stuff off it eg CB radios, fans etc.


Gotta be careful with the switchmode supplies... some don't have very good filtering (voltage regulation) and some are dodgy on their specs. If your current draw requirements has occasional spikes some switchmodes can't keep up and its better to have a 'real' big transformer instead.





This jaycrap one is quite popular with the newbies, ok for running 1 charger.



<TABLE cellSpacing=0 cellPadding=2 width="100%">
<T>
<TR>
<TD class= width="72%" bgColor=#f2f2f2>STOCK-CODE: MP3072 </TD>
<TD class= align=right width="28%" bgColor=#f2f2f2>RRP: $109.50 </TD></TR>
<TR bgColor=#d0e0e8>
<TD colSpan=2>
<TABLE cellSpacing=0 cellPadding=0 width="100%">
<T>
<TR>
<TD class=>Qty 1+ $109.50</TD>
<TD class= align=middle>Qty 3+ $97.95 </TD>
<TD class= align=right>Qty 6+ $86.95 </TD></TR></T></TABLE></TD></TR>
<TR>
<TD class= vAlign=top colSpan=2>13.8V 5A Regulated Power Supply

- Output current: Continuous: 5A- 50% duty cycle: 7A- Surge: 9A- Voltage regulation: (of rated output) <2%- Ripple voltage: <3mV- Recommended fuse: 1.5A- Safety approval number: N16511. </TD></TR></T></TABLE>


javascript MM_openBrWindow'ShowLarg...lbars,resizable,toolbar,width=460,height=500'


or they've got bigger ones too:



<TABLE cellSpacing=0 cellPadding=2 width="100%">
<T>
<TR>
<TD class= width="72%" bgColor=#f2f2f2>STOCK-CODE: MP3074 </TD>
<TD class= align=right width="28%" bgColor=#f2f2f2>RRP: $169.50 </TD></TR>
<TR bgColor=#d0e0e8>
<TD colSpan=2>
<TABLE cellSpacing=0 cellPadding=0 width="100%">
<T>
<TR>
<TD class=>Qty 1+ $169.50</TD>
<TD class= align=middle>Qty 3+ $152.95 </TD>
<TD class= align=right>Qty 6+ $135.95 </TD></TR></T></TABLE></TD></TR>
<TR>
<TD class= vAlign=top colSpan=2>13.8V 10A Regulated Power Supply

- Output current: Continuous: 10A- 50% duty cycle: 12A- Surge: 15A- Voltage regulation: <1% (of rated output)- Ripple voltage: <1mV- Recommended</TD></TR></T></TABLE>



<TABLE cellSpacing=0 cellPadding=2 width="100%">
<T>
<TR>
<TD class= width="72%" bgColor=#f2f2f2>STOCK-CODE: MP3075 </TD>
<TD class= align=right width="28%" bgColor=#f2f2f2>RRP: $189.50 </TD></TR>
<TR bgColor=#d0e0e8>
<TD colSpan=2>
<TABLE cellSpacing=0 cellPadding=0 width="100%">
<T>
<TR>
<TD class=>Qty 1+ $189.50</TD>
<TD class= align=middle>Qty 3+ $170.95 </TD>
<TD class= align=right>Qty 6+ $151.95 </TD></TR></T></TABLE></TD></TR>
<TR>
<TD class= vAlign=top colSpan=2>13.8V 15A Regulated Power Supply

- Output current: Continuous: 15A- 50% duty cycle: 17A- Surge: 20A- Voltage regulation: <1% (of rated output)- Ripple voltage:<1mV- Recommended </TD></TR></T></TABLE>





this one looks pretty good...




<TABLE cellSpacing=0 cellPadding=2 width="100%">
<T>
<TR>
<TD class= width="72%" bgColor=#f2f2f2>STOCK-CODE: MP3090 - On Special </TD>
<TD class= align=right width="28%" bgColor=#f2f2f2>RRP: $399.00 </TD></TR>
<TR bgColor=#d0e0e8>
<TD colSpan=2>
<TABLE cellSpacing=0 cellPadding=0 width="100%">
<T>
<TR>
<TD class=>Qty 1+ $349.00</TD>
<TD class= align=middle>Qty 2+ $315.00 </TD>
<TD class= align=right>Qty 4+ $279.00 </TD></TR></T></TABLE></TD></TR>
<TR>
<TD class= vAlign=top colSpan=2>


3V to 15 Volt DC 40 Amp Regulated Switchmode Laboratory Power Supply

This high powered switch mode power supply will deliver up to 40 amps. It has a variable output voltage from 3 to 15VDC, or it can be fixed at 13.8VDC


javascript MM_openBrWindow'ShowLarg...lbars,resizable,toolbar,width=460,height=500'</TD></TR></T></TABLE>





These ones... technically they're meant to be built into projects etc.


We don't like seeing them on pit tables as they're too risky & dangerous... high chance you'll drop a screw or allenkey into the big cage holes.
The 240V terminals are exposed, too close to the 12/24V outputs (on the same terminal block!!?) and the case needs to be either double-insulated or grounded.





They're one step better than using recycled PC PSUs but most clubs won't allow their use... hard to find a qualified electrician to sign off certification that's its 'safe'.


(Uncertified electrical gear voids the club's public liability insurance.)
 

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Zoomer, I've read that Electric guys like charging at high amps, but a
40A power supply seems alot.
I presume this is to run multiple
chargers, but what would you normally charge your batteries at? What
benefit is there to charge them at 5A+?

Wouldn't they get really hot?
 
G

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Discussion Starter · #15 ·
i think by what i have posted on here earlyier,

charging at slow amps aka 2amps, will make your batts last longer, but
wilkl punchless, and like you running a dead battery for 20mins or so

charging at 5amps would give you a lot of punch but decrease the life of the battery
 

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nismospeed said:
so charging at 5amps would give you a lot of punch but decrease the life of the battery
What is the ideal trade off rate? I wouldn't want my batteries to die
before their time, but then everyone wants punchy performance.




Superbrain 969 from the previous page can charge at 4.5A (two batteries
at 4.5A if you charge off a 12v battery) off the included transformer
and works fine off the wall. The transformer maxes out at 5A.... Not
10A unfortunately, but the charger is still very cheap for all the
things it can do!
I've cycled a few NiCd's using the discharger
function and managed to get better performance/run times out of my
batteries.
 

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nismospeed said:
wouldnt charging 2 batts at same time overheat the supernova???


It's a Superbrain - not supernova. The whole bottom of the charger is a
heatsink, and it has a fan on top which keeps the temps down. It's
designed to charge two batteries at once, and has the jacks in it to do
it. The heatsink pumps out a fair amount of heat, but it has thermal
overload protection which is supposed to kick in if it gets above a
certain point. Has never kicked in for me? I charge two at a time
regularly. Basically seems like two chargers in one, and each channel
is controlled independently through the LCD screen. You can stop one
whilst the other keeps charging and start another battery.
 
G

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Discussion Starter · #19 ·
ahh whoops,

was thinking of different charger

wow that charger sounds awesome...

only prob is i cant get anything from overseas....no credit card or paypal..bugger..

that charger sounds cool..

and that will run off the 240v and 12v....
 

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jerrah said:
Zoomer, I've read that Electric guys like charging at high amps, but a 40A power supply seems alot.
I presume this is to run multiple chargers, but what would you normally charge your batteries at? What benefit is there to charge them at 5A+? Wouldn't they get really hot?

Yeah 40A PSU has far more than enough to run 2 chargers... have seen them hang off up to 6 at one desk. But being a switchmode its quite compact and light, and that grey one is one of the few that actually work well for RC charging at that level.


Serious racers will have 2 chargers, discharger, fans, motor lathe, motor run-in checker etc etc hooked up. Usually need about 25A to be comfortable. 40A will let you run a little portable car fridge off it if you wanted to...



Why moreis good? Well some users are daddys whose kid/s race too so they need 3-4+ chargers going together. Others are the generous types with friends who leach their 12V juice off them... haha you know what I mean.





Racers charge their 3300 NiMHs @ 5-6A for good punch & runtime. More is excessive & bad for cells; less is low on punch & just takes too long.


3300s shouldn't get hot whilst charging at 5A if they're good "RC" cells with low Internal Resistance.


However they will get hot if overcharged... and at 5A you've only got a very small window of error. That's where a good charger is priceless.
 
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