12volt hairdryer/microwave solution.

Discussion in 'Tech/Mech General' started by Snowbird, Jun 27, 2012.

  1. Snowbird

    Snowbird Funster Life Member

    Joined:
    Apr 24, 2009
    Messages:
    10,141
    Likes Received:
    16,400
    Location:
    Liverpool.
    Have come up with a solution regarding the proverbial "How to run a hairdryer/microwave from 12volt" problem. We hardly ever use campsites as we don't need hookups, but there has been a problem recently that I never had before, and that is the damned hairdryer. All our appliances are 12volt and we have adequate solar/wind generator to recharge the leisure batteries. Having purchased a 3000 watt inverter at Hagers bring and buy I was wondering what to do with this monster. In a flash the solution to the hairdryer came to me.
    So I have a battery completely separate from the leisure batteries which the inverter is coupled too, with a remote on/off switch and the same gizmo I have keeping my engine battery topped up with any excess power from the solars.
    How it works is this...Once it detects that the leisure batters are up to 13.6volts the relay opens and feeds any power the solars produce into another battery bank. Thereby only charging the second bank after the first is full. Once the relay detects that the leisures have dropped below 12.5volts it switches off.
    My reasoning behind all this is that there is no chance of the main leisure batteries deep discharging and leaving me with no power.
    OK the big inverter will not run for long on full power but it will run the hairdryer long enough for herself and will cook a FB pie in the halogen oven...even though I wouldn't touch a FB pie with a big stick.
    These relays are available on evilbay at £18-99 each, so if your worried about flattening your main leisure batteries with an inverter, this is the way to go.
     

    Attached Files:

  2. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,941
    Likes Received:
    14,014
    Location:
    UK
    If it is a relay connecting the two batteries together ensure that it and the cables are rated to the full load of the inverter.

    If you power up the hairdryer while this relay is closed it will pull half its power or there abouts from the main leisure batteries via this relay.

    If it is not rated high enough at best you will get a blown fuse at worst a fire.

    Sorry if you already know this and have taken it into account...
     
    • Like Like x 1
  3. Snowbird

    Snowbird Funster Life Member

    Joined:
    Apr 24, 2009
    Messages:
    10,141
    Likes Received:
    16,400
    Location:
    Liverpool.
    Thanks for that Gromett,:thumb: I did think about that but there must be something in the box of tricks that stops that happening as there would be a similar situation when the starter motor is engaged to start the engine. I have had one of these gizmos attached to my engine battery for some time now and it seems to work OK. Will of course keep an eye on it when the battery is fully charged to see if anything gets warm.
     
  4. Snowbird

    Snowbird Funster Life Member

    Joined:
    Apr 24, 2009
    Messages:
    10,141
    Likes Received:
    16,400
    Location:
    Liverpool.
    OK, Panic over, I couldn't wait to see if Gromett was right, so plugged the hairdryer in and all was well after 10 minutes. There must be something in that gizmo to stop the inverter from feeding through it. :thumb:
     
  5. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,941
    Likes Received:
    14,014
    Location:
    UK
    The engine battery one will only engage if the battery is fully charged and the engine is running. A full 12v battery at rest will be at something like 12.8V if memory serves. When the alternator is charging this goes up to about 13.8V. It is this that will cause the relay to close.

    If the vehicle battery is low and the leisure battery is full the relay will remain open so there is no chance of the vehicle trying to start off the leisure battery.

    However in your situation, it is possible for the main leisure battery to be on charge and at 14.5 volts when you start the hairdryer. The relay would be closed due to the 14.5 Volts when you apply the high load to the second battery.

    Grrr, I am not explaining this very clearly am I??

    The current flow in the existing system goes from the high load side (alternator/starter motor) to the low load side (leisure battery)

    In your addition the current will be flowing from the low load side to the high load side (hair dryer.)

    Bahh. I think you had better wait for someone who is better at explaining these things. I understand these things but I am crap at explaining/teaching unless I have a bit of paper in front of me to draw what I mean:Doh:
     
    • Like Like x 1
  6. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,941
    Likes Received:
    14,014
    Location:
    UK
    Ok, I was typing while you were replying.

    When you tested did you have the van on Hookup and the charger working?
     
    • Like Like x 1
  7. Snowbird

    Snowbird Funster Life Member

    Joined:
    Apr 24, 2009
    Messages:
    10,141
    Likes Received:
    16,400
    Location:
    Liverpool.
    No, we never have hookup. The only charging is done by the solar panels. The main leisure bank is full and so is the engine battery through the other split charge gizmo.
    The battery that's connected to the inverter is now being brought up to full charge via the relay from the main leisure bank.
    I cant get into the gizmo to see what's in there as its all sealed up so haven't a clue how they have done it.
     
  8. JJ

    JJ Funster

    Joined:
    May 1, 2008
    Messages:
    14,561
    Likes Received:
    25,731
    Location:
    Quinta Majay, Pinheiro Bordalo, Portugal
    What are you two like?

    I bought a 12 volt hair dryer at a show and it dries my hair really fast... No inverter... No separate battery bank... No bother...

    JJ
     
    Last edited: Jun 27, 2012
    • Like Like x 1
  9. mick noe

    mick noe Funster

    Joined:
    Apr 14, 2009
    Messages:
    610
    Likes Received:
    508
    Location:
    near Boston Lincolnshire
    I believe that you and I are similarly follicularly(spelling?) chalanged... a HAIR DRYER:Rofl1::Rofl1::Rofl1::Rofl1:
     
    • Like Like x 1
  10. JJ

    JJ Funster

    Joined:
    May 1, 2008
    Messages:
    14,561
    Likes Received:
    25,731
    Location:
    Quinta Majay, Pinheiro Bordalo, Portugal
    Excuse me Mick... I have no idea what you are talking about...

    True... sometimes I choose to wear my hair on the short side... :Wink:

    JJ :Cool:
     
    • Like Like x 2
  11. Carol

    Carol Funster Life Member

    Joined:
    Oct 2, 2007
    Messages:
    10,357
    Likes Received:
    14,785
    Location:
    North Wales.
    Hi Dave, I always use my 12v hairdryer no problem, always wash my hair in the morning so the power I use is soon put back in via the solar so no problem, maybe the 12v is a bit slower but hey ho, no hurry. when we are in the van.:Smile:
     
    • Like Like x 1
  12. Snowbird

    Snowbird Funster Life Member

    Joined:
    Apr 24, 2009
    Messages:
    10,141
    Likes Received:
    16,400
    Location:
    Liverpool.
    Ahah, Well its not just the hairdryer. I must tell the truth, I cannot start the day without my coffee, and I don't mean instant. When I had the RVs it was no problem, I fired up my 5K Onan Genny and put the Sensio machine on. Now I can do it from 12volt without annoying the neighbours. Herself has tried the 12 volt hairdryers and they dont work for her.
    Anything to please a lady.
     
    • Like Like x 1
  13. motor roamin

    motor roamin Funster

    Joined:
    May 23, 2010
    Messages:
    1,535
    Likes Received:
    785
    Location:
    Leicester
    Ah I am with you on the coffee Dave.......I have bought a stove top perc in the USA brilliant not the quickest but as good as any perculator....can't beat fresh brewed columbian:thumb: :Rofl1: If I run the 8k onan for coffee she tells me that has cost £6 no mention of when I put it on for her hair dryer :RollEyes:

    All the best Rick
     
    • Like Like x 1
  14. Snowbird

    Snowbird Funster Life Member

    Joined:
    Apr 24, 2009
    Messages:
    10,141
    Likes Received:
    16,400
    Location:
    Liverpool.
    Hi Rick, Am up at 6-30 every morning. Dont do a damned thing till 9-30 only drink Columbian or Brazilian. Dont touch the stuff after 10 AM. I must admit I did miss it whilst away last winter. Job done now though :thumb:.
     
  15. motor roamin

    motor roamin Funster

    Joined:
    May 23, 2010
    Messages:
    1,535
    Likes Received:
    785
    Location:
    Leicester
    I get through about 3 pots a day on my own :RollEyes: :Rofl1:
     
    • Like Like x 1
  16. Gooney

    Gooney Funster

    Joined:
    Jun 2, 2010
    Messages:
    4,759
    Likes Received:
    7,774
    Location:
    Flintshire
    No hair?
     
    • Like Like x 1
  17. TheBig1

    TheBig1 Funster Life Member

    Joined:
    Nov 27, 2011
    Messages:
    7,224
    Likes Received:
    9,611
    Location:
    Dorset
    You do realise there is another good and often free way of drying hair????

    do what my old dog used to do and stick your head out of the open window as your being driven down the road. for safety reasons dont try to drive at the same time :Rofl1::Rofl1::Rofl1::Rofl1:
     
    • Like Like x 1
  18. Snowbird

    Snowbird Funster Life Member

    Joined:
    Apr 24, 2009
    Messages:
    10,141
    Likes Received:
    16,400
    Location:
    Liverpool.
    Its not realy as simple as that. These hairdryer thingys meen nothing to me, its something to do with streighteners and making it curl under instead of over :Eeek:.
    Obviously a woman thing :Rofl1:
     
Loading...

Share This Page