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  1. capta

    capta

    Joined Jun 4, 2009
    2,941 posts, 1,024 likes
    Pearson 530
    na Admiralty Bay, Bequia SVG
    I've got this great Blue Sea battery monitor @ the chart table, but the old analog meters on the Bass panel are just not as exact and easy to read as the new digital meters. I've found these cool and inexpensive digital ones (see below) that I'd like to try, just for kicks.
    Do I need to parallel the shunts for these meters and the one for the Blue Sea meter, or can I run them in series? They aren't as important (accuracy wise) as the Blue Sea meter, so if I lose a bit of accuracy, no sweat.
    Thanks.

    dc meter.jpg
     


  2. LeslieTroyer

    LeslieTroyer

    Joined May 20, 2016
    2,343 posts, 1,030 likes
    Catalina 36 MK1
    US Everett, WA
    I’d try parallel. These are just voltage meters, that use voltage drop caused by current running thru the shunt.
    Usually 500mv/100A IIRC.
     


  3. Davidasailor26

    Davidasailor26

    Joined May 17, 2004
    1,551 posts, 365 likes
    Beneteau Oceanis 37 LE
    US Havre de Grace
    You don't want shunts in parallel. If you do that each one will only see a fraction of the total amperage. In series should work fine, as long as the meter for the "higher" shunt can handle its low sense line being as much as 50mV above true ground. I don't know the specs of those meters but I'd imagine they could handle that small difference.
     


    uncledom likes this.
  4. dlochner

    dlochner

    Joined Jan 11, 2014
    3,287 posts, 1,487 likes
    Sabre 362
    113 US Fair Haven, NY
    Parallel would not be the way to go, as it will make both shunts inaccurate. Can you piggy back the new meter on the existing shunt?
     


  5. Maine Sail

    Maine Sail Moderator

    Joined Feb 6, 1998
    10,867 posts, 699 likes
    Canadian Sailcraft 36T
    US Casco Bay, ME
    You may want to consider the inexpensive, easy to install, more accurate and simple Blue Sea 1733 OLED volt meter. You already know current from the Blue Sea. The 1733 is also waterproof so it can even be mounted in a cockpit. I have a few of those eBay/Amazon China specials, bought them for simple shop use, and they are horribly inaccurate.
     


  6. LeslieTroyer

    LeslieTroyer

    Joined May 20, 2016
    2,343 posts, 1,030 likes
    Catalina 36 MK1
    US Everett, WA
    No you dont parallel the shunt - parallel the output of one shunt. Stacking them end to end to end just generates heat. These meters have very high impedance so it won’t effect accuracy much if it’s even measurable.
     


  7. Davidasailor26

    Davidasailor26

    Joined May 17, 2004
    1,551 posts, 365 likes
    Beneteau Oceanis 37 LE
    US Havre de Grace
    That's probably true as long as they both have the same resistance.
     


  8. sailcrazy1

    sailcrazy1

    Joined Sep 29, 2012
    8 posts, 2 likes
    Taswell 43 Center Cockpit
    US currently the eastern Carrib
    If they're "China Specials"from ebay etc...Be sure they work before you go to the trouble. I bought a similar set last year, ran the wires and mounted them, only to find out they did not work. Not learning my own lesson, I bought some amp meters this year...they don't work either! From now on I buy only known, quality-made meters.
     


    capta likes this.
  9. capta

    capta

    Joined Jun 4, 2009
    2,941 posts, 1,024 likes
    Pearson 530
    na Admiralty Bay, Bequia SVG
    I'm not looking for extreme accuracy, I have that on the Blue Sea M2 @ the chart table. Just something that will replace the analog meters in the panel in the galley, so the cook can see what's going on while she's cooking, charging and loading the genset (on an ac meter).
    Anyway, thanks for the replies and I will be sure to test them before installation.
     


  10. abarrow

    abarrow

    Joined Jul 14, 2014
    16 posts, 0 likes
    Beneteau Oceanus 390
    MX Puerto Vallarta
    Test it first, but I'm confident you can just put both meters across the original shunt. As a previous poster said, these meters are high impedance volt meters - meaning they will not effect what you are reading by putting them there. Think of them like a simple handheld volt meter. It won't effect the accuracy of either meter. Just be sure your Chinese meter is designed for an external shunt (some low current models have internal shunts).
     


  11. jlp0217

    jlp0217

    Joined Jun 27, 2014
    105 posts, 13 likes
    Jeanneau Moorings International 50
    US Everett
    Shunts are specified by their max current and voltage drop (full scale voltage). 50 & 100 mv full scale drop are common.
    you can parallel multilpe meters on a single shunt as long as the shunt rating (drop) is the same. The meter measures the voltage drop across the shumt and displays it on an AMP scale. Never parallel shunts, series is ok, Nobody is going to miss 0.1 or 0.05 volts in a circuit running at 30, 50, 100 or 200 amps. and actual drop is proportional to acutal current.
     


    LloydB, jssailem and capta like this.
  12. Mechone

    Mechone

    Joined Mar 20, 2016
    132 posts, 32 likes
    Beneteau 351
    ca WYC Whitby
    Look at microlog dmm3 or dmm4 ,have on my boat works great ,made in Canada not china and are cheap
     


    capta likes this.
  13. capta

    capta

    Joined Jun 4, 2009
    2,941 posts, 1,024 likes
    Pearson 530
    na Admiralty Bay, Bequia SVG
    Thanks, but I'm more interested in a -100 to a +100 amp indication, not just a one-way circuit, which these are. They also dislay everything with no scrolling, which is a huge plus for us.
    I'm going to try these cheapos, first off the Blue Sea shunt then it's own shunt if that doesn't work. They will fit nicely in the Bass panel we have and it's just for fun. If they work and last, cool, if not I'm out a very few bucks and an hour of wiring. I'll keep my fingers crossed.
     


    Last edited: Mar 19, 2019 at 2:34 PM
  14. Mechone

    Mechone

    Joined Mar 20, 2016
    132 posts, 32 likes
    Beneteau 351
    ca WYC Whitby
    Are you sure about that??Charge and discharge current monitoring (with shunt kits, see below):
    The Microlog DMM-3 / DMM-4 System will also monitor the intensity (Amperes) of incoming current from charging equipment such as alternators, wind generators or solar panels and/or, current consumed in your boat or RV. You can measure just charging or just discharging current if you prefer; or NET current circulation to your House bank, your choice. Charging current will be represented with a "+" sign and discharging current with a "–" sign.The instrument measures the slight potential difference between shunt terminals and translate this measurement in Amperes (Shunt is needed and optional, see below).
    I bought the cheap china unit for my A/c bass panel with current measuring however ,I haven't installed it as I really don't want to cut a hole and then have it fail leaving a mess
     


    Last edited: Mar 19, 2019 at 2:32 PM
  15. jlp0217

    jlp0217

    Joined Jun 27, 2014
    105 posts, 13 likes
    Jeanneau Moorings International 50
    US Everett
    I use the cheap Chinese ammeters to measure my alternator outputs, and Volt/AMP meters for my AC input (they use a coil around the hot wire). I have had good luck with them except the one ammeter I blew by reversing the +sense and +12V wires. I think they were less than $10 with shunts, maybe $20, $5 without. They have lasted several years so far. Accuracy compares with my victron battery monitors. What I want to know is whether my alts are producing 5 amps or 50, +- 10% is good enough..
     


    capta likes this.
  16. capta

    capta

    Joined Jun 4, 2009
    2,941 posts, 1,024 likes
    Pearson 530
    na Admiralty Bay, Bequia SVG
    Ok, sorry. I just quickly read the blurb on the page beside the pic and missed that, since I already have ordered the others. I'll make a note and if these fail, those are next on the list. But I really want a full-time multi-display, not a meter that I must scroll through.
     


  17. Brian D

    Brian D Moderator

    Joined Feb 17, 2006
    4,330 posts, 978 likes
    Lancer 27PS
    US MCB Camp Pendleton, Ca KF6BL
    Don't forget to have a jar nearby. If the smoke is released, the product will stop working. The jar is there just in case smoke is released. Capture the smoke and send both jar/smoke and product to Mainesail. He can put the smoke back in... I think. ;)
     


    kappykaplan likes this.
  18. kappykaplan

    kappykaplan

    Joined May 1, 2011
    926 posts, 173 likes
    Pearson 37
    US Lusby MD


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