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Compaselect HydroVolt


Compaselect HydroVolt battery hydrometer, a great hydrometer for a very modest price

SKU: COM-181-100 Categories: , Tags: , ,

The Swiss-designed HYDROVOLT battery tester is a heavy-duty, chemical-resistant hydrometer which is direct reading and with build-in temperature compensation accurate at all electrolyte temperatures. Its advanced design incorporates important practical features which simplify battery service as never before; this is the easiest-to-use hydrometer out there. It is also very accurate, beating out any turkey-baster type, and equaling much more expensive refractometers. We at Solacity use a HydroVolt hydrometer ourselves to keep tabs on our forklift battery!

It is a very good idea to take regular hydrometer readings of your flooded lead-acid battery cells. In particular right after a full charge, when it is easy to see if you have a problem with sulphating. Specific gravity readings with a hydrometer are the only accurate way to see what is happening inside your (expensive) deep cycle batteries, and are a way to catch issues when they can still be corrected, before they become a problem.

Regular (say once-every-two-months) hydrometer readings, and keeping a log of those readings for each cell (number the cells with a Sharpy) will also go a long way if it is ever necessary to make a warranty claim with a battery manufacturer. You will stand much stronger when you can show with a log that the battery was maintained well, but despite that a cell just went ‘bad’, it happens.

The HydroVolt is identical to MidNite Solar’s ‘MNHydrometer’ product. Solacity just imports them directly from the manufacturer in Europe, we do not get them from MidNite Solar.


  • Handy compact size for use with hard-to-get-at batteries
  • Large, easy-to-read scale with quick-check coloured sectors
  • Readings independent of vertical positioning of instrument
  • Fast, bubble-free intake of fluid sample
  • Automatic air-lock prevents fluid loss and air bleed
  • Unrivalled automatic temperature compensation and measuring accuracy
  • Sturdy, shock-resistant materials, noncorrosive throughout


For the modest price this is truly the best hydrometer out there, and a must-buy for anyone with flooded lead-acid batteries!



Mnfr. model


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