MNHydrovolt Hydrometer Manual Link

As has been mentioned here previously, MidNite is importing the Hydrovolt Hydrometer. This has been expensive for state-side folks to have shipped to the USA. Recently MidNite has added this easy-to-read and accurate Hydrometer to its catalog Below is a link to the manual for any interested:

http://www.midnitesolar.com/pdfs/Hyvolt-e.pdf

They do spec the accuracy, and how to use info. Vic
Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.

Comments

  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    Re: MNHydrovolt Hydrometer Manual Link

    I wonder if NAWS is going to sell them? Or, perhaps, someone in Canada?
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link

    Hi NorthGuy,

    We COULD ask Wind - Sun if they would entertain selling the MNHydrovolt.

    There may be a reseller in Canada that sells the MN line that would be willing to carry them.

    MidNite Solar was kind enough to sell some to me directly, and a few others that have mentioned it on this board.

    As a derailment of this Thread, IMHO the Brady Hydros are not good. And the micro job that W - S now carries belongs in the TRASH. There is SO much Surface Tension due to the diameter ratio twix the inner float max diameter vs the outer tube's inner diameter, that it reads +/-- 20 - 50 points differently on each pull from the same cell. And this variation is not going in a single direction it swings erratically.

    Again, in my opinion, having a Brady Hydrometer is WORSE than having NO hydro at all. Perhaps the newly offered micro model is really designed for thinner liquids, like Wine or grain alcohol ... dunno but it is useless for 1.265-ish SG H2SO4. Back to regular programming. Opinions, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    Vic wrote: »
    Recently MidNite has added this easy-to-read and accurate Hydrometer to its catalog Below is a link to the manual for any interested:
    http://www.midnitesolar.com/pdfs/Hyvolt-e.pdf

    Thanks for the heads-up, Vic. I'm very happy with my Hydrovolt and I didn't even know it had a manual.
    Its the first hydrometer I have ever used that could give repeatable measurements of 0.005

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link

    I have been using a Refractometer for some time now. unless someone knows something I do not know (very possible) I can't understand why anyone would want to use a hydrometer any more having to deal with temperature correction, keeping it perfectly level, air bubbles, etc.

    You can get a specific gravity Refractometer on Amazon for $20 for the plastic ones and $50 for the metal ones.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link

    Hi jcheil,

    If the Hydrometer is rinsed several times after each measuring session, there should not be any air bubbles inside the Hydro. Temperature compensation can often be ignored when the electrolyte is +/-- 5 or so degrees C of specified temp.

    And, as I read it, Refractometers need to be calibrated for each measuring session.

    Hydros often have 2 - 3 point repeatability and readability.

    EDIT: However, I have never used a Refractometer, perhaps would love them after using one. Just my opinions.
    Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    Re: MNHydrovolt Hydrometer Manual Link

    I contacted the Hydrovolt manufacturer to see if they had a Canadian distributer. They forwarded my request on to Midnite, who, in turn, gave me the name of their Canadian distributer. Unfortunately, the Canadian distributer told me that they didn't carry the Hydrovolt. I haven't contacted Midnite yet to see if they have anyone else on their Canadian distribution system.

    I use a refractometer to measure the salinity of my marine aquariums. They are extremely accurate and much easier to use than hydrometers. HOWEVER, they must be calibrated on a regular basis using a reference solution that is close to the refractive index of the target solution. The refractometer reading will drift over time, especially if subjected to extreme temperature swings. Failure to properly calibrate them will result in meaningless and potentially highly inaccurate readings. I've looked at battery refracs from various online sources and have yet to see a calibration fluid available for sale.
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    Rybren wrote: »
    I've looked at battery refracs from various online sources and have yet to see a calibration fluid available for sale.

    Use battery acid of known SG for calibration. Perhaps a battery dealer will sell you a half pint which will last you several lifetimes.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    Vic wrote: »
    And, as I read it, Refractometers need to be calibrated for each measuring session.
    Vic

    You may be saying the same thing I am thinking, but just in case, you only need to calibrate it (with a drop of distilled water and turning a small screw) one time before you take samples from ALL of the cells. You do not need to calibrate it each time before each cell. And realistically, if you are just looking for an imbalance between cells, you don't even need to calibrate it.

    I check calibration on mine each month when I take readings and I think in the year that I have used one I have only had to adjust the calibration maybe 2 times and even then it was only out by .005

    I would seriously suggest trying one. I would find it hard to believe that anyone would want to go back to a hydrometer after using one. I know I would not! This is the one I use. It is the higher quality (metal) one, only because I like better quality when it comes to any tool.

    http://www.amazon.com/gp/product/B000HTNODE/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    Rybren wrote: »
    I've looked at battery refracs from various online sources and have yet to see a calibration fluid available for sale.

    In the case of your salinity ones, your are correct in that you would need a calibration fluid that had a specific and known salinity of an exact proportion.

    For SG/Coolant refractometers you simply use a drop of distilled water - which is why IMO they are the perfect for the task of measuring SG.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    jcheil wrote: »
    For SG/Coolant refractometers you simply use a drop of distilled water - which is why IMO they are the perfect for the task of measuring SG.

    I have never seen a battery/coolant refractometer that could be calibrated with distilled water. Distilled water is too far out of the measurement range of any battery/coolant refractometer that I know about.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    jcheil wrote: »
    For SG/Coolant refractometers you simply use a drop of distilled water - which is why IMO they are the perfect for the task of measuring SG.

    I beg to differ. Refractometers work based on the principle of measuring the refractive index of a solution. The refractive index of distilled water is significantly different from that of battery acid. If you calibrate your refrac using distilled water, it will not give an accurate reading. It may be close, but it will not be correct. Whether the accuracy is "good enough" is up to you. However, if all you want to know is the delta between cells, then I agree that using distilled water to calibrate is fine, as all of your readings will be off by the same amount.

    FWIW, most marine refracs will also tell you that you can use distilled water for calibration. They are also misleading. I've done multiple calibration checks between using distilled water and a 35ppt salinity calibration standard, and there can be significant differences.

    In case anyone is interested, here is a great article on Refracs written by Dr. Randy Holmes-Farley, a PhD in chemistry.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    vtmaps wrote: »
    I have never seen a battery/coolant refractometer that could be calibrated with distilled water. Distilled water is too far out of the measurement range of any battery/coolant refractometer that I know about.

    --vtMaps

    I have no idea really, I just read instructions and thats what it says, right in the documents.
    And so far, the few times I compared it to a hydrometer it was "right on". YMMV
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link

    Distilled water should read "1.000". Most hydrometers/refractometers may not go this low, starting instead at "1.100". If the measuring device has the range to read 1.000 and you set it for that with distilled water that would be accurate calibration.

    Otherwise you need a liquid with a known SG within the range of the instrument. Glycerine, for example, is 1.263 and should be easy to get.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    Distilled water should read "1.000". Most hydrometers/refractometers may not go this low, starting instead at "1.100". If the measuring device has the range to read 1.000 and you set it for that with distilled water that would be accurate calibration.

    Otherwise you need a liquid with a known SG within the range of the instrument. Glycerine, for example, is 1.263 and should be easy to get.

    That explains why it works for mine because the one I have starts at 1.00 and with a drop of distilled water on it you calibrate it to the 1.00 reading. It is, like I said, specifically designed for SG so I would think they would have thought of that.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    Distilled water should read "1.000". Most hydrometers/refractometers may not go this low, starting instead at "1.100". If the measuring device has the range to read 1.000 and you set it for that with distilled water that would be accurate calibration.

    Otherwise you need a liquid with a known SG within the range of the instrument. Glycerine, for example, is 1.263 and should be easy to get.

    If the Refrac was brand new, had no manufacturing defects, and was perfectly calibrated at the factory, using distilled water would probably be close-enough, but not perfect. One bump in shipping or handling, and I wouldn't count on that water calibration.

    While the SG of Distilled Water may be 1.000, the Refractive Index is 1.3330. Note that a refractometer doesn't measure SG. It measures the refractive index, and the markings on the scale within the eyepiece is based on a relationship table between the RI and SG for the fluid that the device was designed for. Using any fluid other than what the device was designed for, even if it is at the desired SG, will not be accurate. Will it be good enough for government work? Maybe. Will it be as accurate as using the proper calibration fluid? Nope.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link

    People who have batteries that need the SG read usually also have distilled water for filling same.
    Ergo any company with half a brain would make their device so that it can be calibrated with distilled water. A measuring device does not have to be calibrated by the substance it is used to measure, only against a 'known value'. It does not matter if you express this as specific gravity or as refractive index.

    Hence jcheil's experience.
  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    Re: MNHydrovolt Hydrometer Manual Link

    I'll make one last attempt at explaining my reasoning as to why using distilled water is not the best choice for calibration, then I'll shut up.

    Refractometers measure the Refractive Index of a solution, and that RI gets translated to a SG reading on the scale inside the device. The translation between the two isn't straightforward nor is it consistent between fluids, ie, I can't use my saltwater refrac to determine the SG of my battery acid because the RI to SG scaling on my saltwater refrac is based on the RI of saltwater and not battery acid.

    When the scaling of a refrac is off for whatever reason (and most are off) - manufacturing defect, mishandling, temperature changes, etc, the further you get from the calibration point, the further off your reading gets. So, if you can only calibrate the refrac at a single point, you want that calibration point to be as close to the RI of the fluid being measured as possible.

    Ideally, you'd want two calibration points - one for the zero point, and one to determine the slope of the line (Think of the equation for a straight line - y=mx+b) We could use distilled water for the zero point calibration, but we'd need a proper calibration fluid to get the slope right. This way, the accuracy will be consistent along the entire slope of the scale.

    Think of a bathroom scale. If I make a bathroom scale that reads zero when nothing is on it, but I put the numbers on the scale 1.1 lbs apart instead of 1lb apart, then the more you weigh the further off you will be. 1 lb will show up as 1.1. 10lbs will show 11. 100 lbs will show 110.

    That sounds silly for a bathroom scale, but with refractometers it is all too often the case.

    So, to sum up, can you use distilled water to calibrate? Sure. Will it be accurate? It depends on the accuracy of the slope. If the slope is perfect, then the reading will be correct. However, if the slope is incorrect, then the reading will be off by some unknown number; the variance may be small or it may be large, you have no way of knowing when using water. Will the refrac maintain it's slope and accuracy over time? Probably not, that's why we need to calibrate them.

    Why is using a calibration fluid better than distilled water? Two reasons: 1) The fluid has the same RI to SG relationship as the refrac and 2) Because the calibration point is closer to the RI of the fluid being measured, any errors in the slope will be minimised (the further you get from the calibration point, the further off your reading gets)

    Ref: Dr. Randy H-F and Dr.Andy (disc1)
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    Rybren wrote: »
    Refractometers measure the Refractive Index of a solution, and that RI gets translated to a SG reading on the scale inside the device. The translation between the two isn't straightforward nor is it consistent between fluids, ie, I can't use my saltwater refrac to determine the SG of my battery acid because the RI to SG scaling on my saltwater refrac is based on the RI of saltwater and not battery acid.

    Correct, but that is why we/I use a refractometer SPECIFICALLY designed (and scaled) to measure the SG of battery electrolyte. Of course if you used the incorrect "tool" you would receive an incorrect "result". So your statement doesn't really have any bearing on the point because we are not trying to use a "screwdriver" as a "hammer".
    Rybren wrote: »
    When the scaling of a refrac is off for whatever reason (and most are off) - manufacturing defect, mishandling, temperature changes, etc, the further you get from the calibration point, the further off your reading gets. So, if you can only calibrate the refrac at a single point, you want that calibration point to be as close to the RI of the fluid being measured as possible.

    Ideally, you'd want two calibration points - one for the zero point, and one to determine the slope of the line (Think of the equation for a straight line - y=mx+b) We could use distilled water for the zero point calibration, but we'd need a proper calibration fluid to get the slope right. This way, the accuracy will be consistent along the entire slope of the scale.

    I have to say No, IMO the "slope" is done by the manufacturer to "design" the instrument and the scale on the instrument. Once they define it, the scaling "factor" of the device can't be "off". Sure the "printed" scale "marks" on the device could be off if they designed it wrong, but realistically the scale will start from the bottom end and go to the top end in equal gradients. The manufacturer would have done exactly what they tell us to do for 1.00 calibration. The used distilled water to define the low 1.00 mark and then they would have used a known 1.40 (or whatever the high mark is) electrolyte to determine the high mark and then simply equally divided the points between those marks to produce the "printed scale" on the device which becomes the permanent SCALE of the device.

    Sure if there was a "generic" refractometer, then you could calibrate it yourself on BOTH the low and high sides and then create your own gradiant scale (slope) between those two points. But we are not doing that. We are using a tool that was specifically designed with the slope for SG from a known low point to a known high point. And when we calibrate it we simply move those points (equally) up or down to match ONE of those values, and since distilled water is 1.00 that is the easiest point to calibrate against. The points inbetween the low and high will never change.
    Rybren wrote: »
    Why is using a calibration fluid better than distilled water? Two reasons: 1) The fluid has the same RI to SG relationship as the refrac and 2) Because the calibration point is closer to the RI of the fluid being measured, any errors in the slope will be minimised (the further you get from the calibration point, the further off your reading gets)

    It doesn't matter that RI and SG are two different units of measure. The fact is that they both have an EQUAL proportional relationship to each other along both of those scales. If they did not, then your argument would be correct.

    And I did read that entire article you posted a link to and found it very interesting, however it is not an apples to apples comparison to what we are talking about. In your article, the refractometers are being used to measure salinity, which in that case shows that it needs precision out to 4 and 5 decimal places and seems to have a RI much higher than distilled water. I can understand needing a calibration fluid for THOSE devices because the manufacturer would have to be able to create a scale factor with a much larger range, not to mention granularity, to produce those desired results. That large of a range would not likely fit on the optics of such a small device and if they did, the gradients would be so close together to get to 5 decimal places that they would likely be unreadable.

    Like a regular thermometer for example. I can have one that is physically 6 inches long that can have a temperature range of 0-212 and another that is the same length that can do only 0-50 but in much more precise increments.

    So yes, use the wrong tool and you get the wrong results. But use the properly designed tool for the job and get the right results. And that is what we/I are using for measuring SG - a SG properly designed tool.

    Sorry, not trying to argue. And I certainly do not know everything.
    You have some good points, but I just don't think they apply to the refracs specifically designed for SG.
    So if you want, I agree to disagree.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • Ralph Day
    Ralph Day Solar Expert Posts: 1,020 ✭✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link

    I thought a refractometer would be ideal for checking battery sg. It is...but only if you have an sg 1.265 as the datum (at least for the one I purchased). So, I check the sg with my hydrometer, put some in a baby food bottle when it's 1.265 and use that as my calibration source. Haven't done that in a while. I went back to the old hydrometer since it was the ultimate say in sg level.

    Ralph
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: MNHydrovolt Hydrometer Manual Link
    Ralph Day wrote: »
    I thought a refractometer would be ideal for checking battery sg. It is...but only if you have an sg 1.265 as the datum (at least for the one I purchased). So, I check the sg with my hydrometer, put some in a baby food bottle when it's 1.265 and use that as my calibration source. Haven't done that in a while. I went back to the old hydrometer since it was the ultimate say in sg level.

    Ralph

    Yeah the one I got (in the link) is great because the scale starts at 1.00 so you can just use distilled water.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html