Replace 14V NICad with wallwart

Discussion in 'General Electronics Chat' started by mcgyvr, Oct 4, 2012.

  1. mcgyvr

    Thread Starter AAC Fanatic!

    Oct 15, 2009
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    Got a device (battery powered terminal crimping machine) that uses a 14V NiCad (listed as 2 amp) battery. I tried powering this device with a 14V benchtop power supply or with a 14V regulated wallwart (3.5A) and it was barely working (like it had almost NO power).. ?? any ideas why.. polarities were correct.. The device basically has a small hydraulic ram inside it.
     
  2. gerty

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    Aug 30, 2007
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    Sounds like not enough current. Battery powered tools usually draw high currents for short periods. I tried using a 12v Makita drill with a 10 amp powersupply. It ran fine untill I loaded the drill by pressing on it. The supply had a amp meter on it and I pegged 10 amps easily.
     
  3. mcgyvr

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    Thats sort of what I thought.. My benchtop power supply is capable of 60V@3A (180W) though so thats why I tried that when the 14V 3.5A wasn't cutting it.. I thought for sure that would do it..
     
  4. mcgyvr

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    Just tried the benchtop supply again.. This time watching the volt and current meter.
    As soon as I pull the trigger it drops to 3.5V (from 14.0) and current reads 1.75A
     
  5. crutschow

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    Mar 14, 2008
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    You said the power supply is rated at 3A so it should read that with a maximum load. You apparently have the current limit turned down.

    Edit: Could you use the NiCds to supply the high current to power the machine and just use the wallwart to continuously charge the battery at a trickle charge?
     
  6. mcgyvr

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    yeah not sure whats going on there either.. I just switched it to constant current mode now with the leads shorted and its set at 3A CC. Switched it back to CV and when I hook it to the crimper again it drops to 3.5V @1.75A.. Its a cheap-o Protek 6003L benchtop supply. ??

    Gonna try it now on the big expensive sorenson supply (up to 60V @ 70 Amps I believe)
     
  7. mcgyvr

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    Just hooked it up to the smaller Sorenson we have (50V @ 8A max) because the bigger one isn't wired up right now and it actually almost worked.. As the crimp tooling was closing it was pulling 6A @14V but then during the actual final crimping it maxed that one out too. No wonder the batteries go so quick.. :)

    anyone know where to find a cheap (sub $100) 14V @ 15A or 20A supply?

    might just have to go with this http://www.mpja.com/15V-15A-Linear-Power-Supply-IHF15-15/productinfo/6618+PS/
     
  8. bountyhunter

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    Sep 7, 2009
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    A cheap solution would be a 12V motorcycle battery with your power supply as a charger. They are about 15 A-hr ballpark, put out tons of current and cost about $35 - $50.

    Another solution is one of the cheapo units used to power CB radios or similar. I recall they put out 12V at pretty high current.

    Ebay would be the place to look.

    http://www.ebay.com/itm/Astron-RS-1...omm_Device_Power_Supplies&hash=item4abcb94deb
     
    Last edited: Oct 4, 2012
  9. mcgyvr

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    might have to try that astron unit..
    We might just ditch the whole hand-held crimper and go to a full hydraulic unit with separate remote vice mount crimp heads. The cycle time is the killer though.. The handheld units are like a 5 second cycle time which is faster than the big hydraulic crimpers..
     
  10. crutschow

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    If you can get by with 12V, a high power computer ATX type power supply may work such as this. They are relatively cheap.
     
    Last edited: Oct 4, 2012
  11. mcgyvr

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    Thanks for the help.. I'm good to go.
    I just couldn't imagine that sucker needing 10+ amps so was a little caught off guard thinking maybe there was more to it than it really is.
     
  12. Audioguru

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    Dec 20, 2007
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    You read the label on the battery wrong. You said it is 2A but actually it is 2Ah.
    It can supply 20A or more for a short time (which your machine needs) and is rated to supply 0.2A for 10 hours.
     
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