NASA BM-1 Battery Monitor

Discussion in 'Motorhome Chat' started by pablomc, Feb 17, 2013.

  1. pablomc

    pablomc Funster Life Member

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    Need to buy a BM-2 (as I now have a 2.5KW inverter :Eeek:), so selling the BM-1 I have (never installed or used). Offering here before I put on ebay. :BigGrin:


    For anyone who does not know the difference, the BM-1 is rated up to 100 ams and the BM-2 to 200amps.
     
  2. pappajohn

    pappajohn Funster Life Member

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    asking price ?
     
  3. pablomc

    pablomc Funster Life Member

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    Thinking £85 including P&P.
     
  4. G8WVW

    G8WVW Read Only Funster

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    BM1 excellent. Have one myself.

    2.5KVA inverter; crikey!
     
  5. manda3000gt

    manda3000gt Funster

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    Did you buy a Sterling inverter ? Pure sine or modified ?
     
  6. pablomc

    pablomc Funster Life Member

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    Yes Sterling procombi pure sine wave. Got it off ebay. :Smile:
     
    Last edited: Feb 17, 2013
  7. manda3000gt

    manda3000gt Funster

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  8. Wildman

    Wildman Read Only Funster

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    my existing Solar regulator shows charge rate, discharge rate and battery Voltage or % charge what is the differance please.
     
  9. MicknPat

    MicknPat Funster

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    Simply, what does the BM-2 do that the BM-1 doesn't?

    I have a BM-1 still in its box waiting for good weather and someone ( one of my sons) to crawl under the RV to route and secure the wiring between the batteries and the BM-1 monitor. :Smile:
     
  10. pablomc

    pablomc Funster Life Member

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    :thumb:
     
  11. Terry

    Terry Funster

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    £100 ish :BigGrin:

    But the blurb says it can handle from 5 to 650 amps :Smile:What on earth are you running to want 2.5kw--must be overkill :Eeek::BigGrin:
    terry
     
  12. MicknPat

    MicknPat Funster

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    Sorry about that Pablomc, I'm no electrician nor do I fully read the postings. :Sad:

    So have I goofed in buying a BM-1 to connect to the 4x 6 volt 232 Amp hour house batteries that are connected in series so giving (if I understand it correctly) 12 volt 464 AH?

    Thanks :thumb:
     
  13. pablomc

    pablomc Funster Life Member

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    Nope overall rating does not matter, it's if you intend to pull a high current in excess of 100 Amps from them.

    So if you only ever pull say 20 amps max then no biggy, but if you have an inverter then there is potential to draw a lot more depending on the inverter size. E.g. when I tested mine with the wife's hair dryer it was pulling 165amps :Eeek:.

    If you don't have an inverter, then don't worry the BM-1 will be more than adequate. :BigGrin:
     
  14. pablomc

    pablomc Funster Life Member

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    BTW if you have 4 X 6 volt batteries then they should be wired as pairs in series then those two pairs in parallel for 12 volts. If you wire them all in series you will have 24 volts and if all in parallel 6 volts. If in doubt ask. :thumb:
     
    Last edited: Feb 18, 2013
  15. pablomc

    pablomc Funster Life Member

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    See the previous post re the rating. :thumb:

    Re the 2.5 better to have too much than too little. :Tongue1: :Laughing:
     
  16. pappajohn

    pappajohn Funster Life Member

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    only drawback with a large inverter, it will use more power when idle...ie: on standby with nowt plugged in... than a litte 'un so really needs turning off completely when not in use.
     
  17. MicknPat

    MicknPat Funster

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    Looking at the pdf schematic from Fleetwood for our RV the connections go like this.

    Battery 1. + to battery 3 + inverter etc
    - to battery 2 +

    Battery 2. + to battery 1 -
    - to battery 4 -

    Battery 3. + to battery 1+
    - to battery 4+

    Battery 4. + to battery 3-
    - to battery 2- and ground

    Doesn't those connections make is part serial part parallel ? All Greek to me :Smile:

    thanks :thumb:
     
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  18. Techno

    Techno Funster Life Member

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    The bigger Sterlings come with remote switch to place where convenient.My inverter is in the garage
    [​IMG]
     
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  19. pablomc

    pablomc Funster Life Member

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    0.4A in power save mode and 1.8 A in on mode, or as described by Techno100 can be switched off at the remote panel. :Smile:
     
  20. jb0371

    jb0371 Read Only Funster

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    If its still for sale can I have first dibs on it, away in the van till tomorrow so internet a bit touch and go at the minute
     
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