Go Back  DoItYourself.com Community Forums > Electrical, AC & DC. Electronic Equipment and Computers > Electrical - AC & DC
Reload this Page >

Building DC adapter to replace battery back on paint sprayer

Building DC adapter to replace battery back on paint sprayer

Reply

  #1  
Old 03-21-16, 09:02 PM
Member
Thread Starter
Join Date: Oct 2014
Posts: 79
Building DC adapter to replace battery back on paint sprayer

I have a Graco Proshot 2 handheld paint sprayer which has two faulty batteries. I want to gut one of the batteries and use the battery casing to house a DC converter so I can plug the battery pack into the sprayer but it will run on regular wall power.

The battery specs are 20v 2.4AH 43.2WH

Any links to an DIY power adapter instructions?
 
Sponsored Links
  #2  
Old 03-21-16, 09:11 PM
Member
Join Date: Nov 2015
Posts: 687
I would recommend against it because power tools like that usually pulls high current from the battery. This means, you will need a thick cable to compensate for voltage drop and to handle high current.
If you are able to find a small enough power supply, you are better off attaching power supply to the sprayer or inside battery and running AC power to the tool.

You will need 20V power supply and probably around 5A output. You tool won't be pulling constant 5A, but motor will pull high current on start. If there is a battery protection circuit, will need more modification. How to bypass that will depend on the tool design and may require some reverse engineering.

Best way really is just getting new batteries or repacking them with new cells.
 
  #3  
Old 03-21-16, 10:18 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: NJ - USA
Posts: 43,492
The battery specs are 20v 2.4AH 43.2WH
Is that the two batteries added together ?
Each battery is 10v ? Each battery is 20v ?

20v is a strange battery pack voltage.
 
  #4  
Old 03-22-16, 12:05 AM
Member
Thread Starter
Join Date: Oct 2014
Posts: 79
Where can I get new cells?

I'm not sure if I follow what you're saying or if you understand what I'm saying.

I want to take one of the batteries, remove the cells from the battery casing, and put a DC adapter in the old battery housing. That way I don't have to modify the spraying gun and it can still use a regular battery in the future.

With my modded one, it will have a plug that will allow an extension cord to hook up with it.
 
  #5  
Old 03-22-16, 12:09 AM
Member
Thread Starter
Join Date: Oct 2014
Posts: 79
Those are the specs, per battery. Same one as this one:

Graco 20V Lithium ion Battery 16D558 for Truecoat Proshot Sprayers 17C930 | eBay
 
  #6  
Old 03-22-16, 05:29 AM
Member
Join Date: Nov 2015
Posts: 687
If it is using Li-Ion battery, chances are there is a protection circuit in the tool as well.
Open the tool and if there is any sort of IC inside the tool, simply supplying 20V power won't work.

You can buy Li-Ion cells on eBay (many are fake Chinese cells, so don't go too cheap). Disassemble the battery and replace cells.
For the size of the cell, you will have to disassemble the battery pack to fine out, but most uses 18650 cells.
Most cells require spot welding, but there are some with taps already welded on. This is what you want to buy. That way you can solder cells with soldering iron instead of using special spot welder.
 
  #7  
Old 03-22-16, 09:49 AM
Member
Thread Starter
Join Date: Oct 2014
Posts: 79
There is a protection circuit, or something in there: you can see a gooped over IC on the sprayer near the battery connector.

Why won't supplying 20V 2.5MAH work?
 
  #8  
Old 03-22-16, 10:09 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: NJ - USA
Posts: 43,492
That's 2.5A (amps).

I've never seen a 20vdc power supply. I've seen variable ones.

Something like this may work...
Amazon.com: 20V AC / DC Power Adapter with Power Cord

I want to take one of the batteries, remove the cells from the battery casing, and put a DC adapter in the old battery housing.
I don't see that happening.
 
  #9  
Old 03-22-16, 10:52 AM
Member
Thread Starter
Join Date: Oct 2014
Posts: 79
You don't see that happening cause of size constraints? Of the battery enclosure? I already removed the cells. I thought about ordering new cells but for the price, a new battery is just a little more.

This battery has 10 cells.
 
  #10  
Old 03-22-16, 10:54 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: NJ - USA
Posts: 43,492
Mostly size constraints..... unless you build a custom switching supply with no big transformer.

Yes..... 10 x 2v cells = 20v.
 
  #11  
Old 03-22-16, 11:57 AM
Member
Join Date: May 2015
Location: USA
Posts: 3,138
You would really need to measure the actual DC current drawn at full load to size any off-line power supply. Ampere Hours capacity doesn't tell you what current is needed, only the capacity of the battery.

I too, doubt there will be room in there for a full power supply with sufficient power output. Your best bet is probably an external supply and run DC to the unit.

Acopian (and lots of others) makes a variety of 20 volt supplies in lots of form factors, but you need to the know the full load current: 20v (volt) Power Supplies | Acopian Power Supplies
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'