12V motor / battery questions.....

Discussion in 'The Projects Forum' started by Walter4, Aug 14, 2013.

  1. Walter4

    Thread Starter New Member

    Aug 14, 2013
    3
    0
    I have a daily use for a DeWalt sized power tool that is a simple transfer pump that runs on a rechargeable battery. Unfortunately, nobody makes such a tool (that I know of) and I want to make my own, and possibly one or two extras.

    I need to transfer a non corosive, non flamable liquid at 35psi or so, once a day, every two days or so. About a gallon's worth, and what I have in mind is the perfect solution, but I'm not sure about the electrics of it.

    The fuel pump below is the ideal solution (build, pressure, size, etc...) but I'm trying to figure out a battery solution that's easy to carry. I'm hoping to go with something small, since it only will run 30-60 seconds tops each use/day, and I can easily charge it in the meantime.

    The inefficiency, cost, wear, etc... these are not issues for me, as the convenience would really outweigh those, plus as with any invention, once I have something that works, I will think and discover new solutions to streamline it or make it more efficient or better in some other way as time goes on and as i use it.

    Any advice on why or why not I should use one of the battery solutions below, or if I even can, or if I need some conversion of something (besides termal ends, of course) or any other solutions I'm open and very glad for.

    To me, 12V is 12V, and this is where I'm hoping to benefit from your experience and knowlege. Thanks in advance for your time! :)

    [​IMG]

    [​IMG]

    (By the way, the pictures were just made in Windows Paint with stuff I grabbed from Ebay; just to give you a clearer idea of what I was thinking of using, and the info that I know about each. After posting, it looked too much like I post this all over the internet, and I only used it for this one forum, I'm just trying to make the most of the few minutes time I might be getting from someone who knows their electrics. I use forums a lot, but am new to this one as of the time I posted this, and just wanted to mention it. :D )
     
    Last edited: Aug 14, 2013
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,552
    2,374
    Have you considered an automotive gas tank pump?
    AFAIK the gas runs over the motor itself, so I am not sure how other liquids would react, but a visit to the local wrecker would not cost much to experiment?
    For power you could also look at a 12v Gell Cell as used in standby emergency or EXIT lighting signs.
    Especially for short term usage.
    Max.
     
  3. LDC3

    Active Member

    Apr 27, 2013
    920
    160
  4. wayneh

    Expert

    Sep 9, 2010
    12,136
    3,054
    I use one of those and it works fine, although it seems to require priming, at least wetting. If you've already got a drill handy, this would be a quick solution. I leave the hoses I use attached all the time, so it's ready to go in seconds.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,552
    2,374
    But will they sustain the 35lbs/sq-in required?
    Max.
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,136
    3,054
    Good point. Almost certainly not.

    I wonder if that's ∆P that the pump must develop, or just the pressure of operation.

    Anyway, my battery recommendation is to get the one that will be easiest to recharge with equipment you already own. Each battery chemistry requires a different charging strategy, and you don't want to buy another charger if you don't have to.
     
  7. wayneh

    Expert

    Sep 9, 2010
    12,136
    3,054
    Actually there are some out there that could be candidates.

    Here and here, for instance. Depends on the details.

    Here's a fancy one.
     
  8. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,770
    970
    There are tons of DC powered pumps out there.

    But yes the pressure specification above must be clarified to give any good answers..
     
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,552
    2,374
    I know the average 12vdc auto fuel pump will typically operate up to 50lbs/sq, I am not sure what method they use, It could be a gear pump?
    Max.
     
  10. #12

    Expert

    Nov 30, 2010
    16,304
    6,814
    If you see a bypass line connected to an over pressure valve, it would be a gear pump. Those are constant flow rate and can produce very high pressures if there is no way for the excess mass to escape.
     
    Walter4 likes this.
  11. Walter4

    Thread Starter New Member

    Aug 14, 2013
    3
    0
    Thanks guys, I KNEW this was a good forum once I found it... it used to be you had to rely on whatever the guy at the NAPA counter told you, and hope he had as much real knowledge on the subject as he pretended to. Now with the internet and forums you can really reach some thinkers.... this is great.

    As for the pump, the electric fuel pump is really the absolute ideal pump- quiet, small in/out hose sizes, and though most are usually 12psi or so, the racing/high pressure pumps are around 40psi, which is absolutely ideal. So as far as the pump/transfer issue goes, that pump is definitely the way I want to go. I just dont want to burn one out by hooking it up to one of those batteries to see if it will work or not.

    I'm looking for the best way to run that particular pump for a minute or so every day or so, without carrying around a big car battery... I dont want to ruin a pump and/or the battery by trial and error, you know?

    Thanks for all the input so far! It's much appreciated. :D
     
  12. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,552
    2,374
    As long as you don't put any more than 12vdc on a 12v motor, it does not matter where the battery power comes from, If only running for the time you mention, IMO a Gell Cell would do the job, I use one that is 5 1/2" x 4" x 2" and weighs around 2lbs.
    Max.
     
    Walter4 likes this.
  13. LDC3

    Active Member

    Apr 27, 2013
    920
    160
    Since you are only running it for a few minutes a day up to 5 times a week, a gel cell would probably work for several weeks before becoming discharged. So, it would probably be better to charge it every weekend.
     
    Walter4 likes this.
  14. Walter4

    Thread Starter New Member

    Aug 14, 2013
    3
    0
    Nice! This not only is what I was hoping, but also addresses my greatest fear.... So hooking up a motor that's meant for a 12v automotive system to a 12v DeWalt or Gel battery won't hurt the motor, it then just becomes an issue of how long it will last? (since I can charge the unit on the shelf where I'd store it everyday, especially with the DeWalt charger, I can always just put the battery on charge while not using the unit).
     
  15. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,552
    2,374
    Correct!
    Max.
     
    Walter4 likes this.
Loading...