Cellwatch Frontier System Installation & User Manual
Section I – Installation Guide-33
2. Avoid fixing the DCM onto metalwork. Electrical noise can be radiated from the metalwork even
if the frame is grounded and this can cause reading variations within the DCM.
3. Always place the DCM tab washers next to the battery post or strap. Never place any stainless-
steel material between the battery post and the tab washer. Stainless steel is very resistive and
may offset ohmic value readings.
4. Beware if a DCM is installed across a battery breaker or an open jumper between two cells. If
the battery voltage is greater than 80V, opening the breaker could potentially damage the DCM.
Always keep in mind the minimum operating specs for the type of DCM you are working with.
Non-activated DCM 5 units operate at 4.5-60V while activated DCM 5 and DCM 5T units operate
at 4.5-80V. DCM6-L units operate at 4-12V and DCM6-H units operate at 12-80V.
5. Always dress excess DCM wire in ‘sticks’ and not coils. Carefully fold the wires back on
themselves and avoid creating loops. Loops create inductors that can cause variability in
readings at low ohmic values.
6. Avoid grouping brown and white power leads with sense leads. Keeping power and sense leads
separated reduces the risk of cross talk between the power and sense leads.
Preparing the Battery
There are a few basic steps that should be taken into consideration when preparing to tab the battery
and install the DCMs. While the 3M™ Dual Lock™ fasteners on the DCM will not harm the battery, some
users prefer that DCMs are mounted to another surface, often Panduit or Plexiglas covers. NDSL also
offers a DCM with DIN rail mounting capabilities as an alternative way to mount DCMs. Dual Lock™
fasteners provided can be used on other surfaces such as Plexiglas or fiberglass suspended above or
close to the batteries. DCMs should not be installed on the metalwork of the cabinet, rack, or stack.
The best placement for a DCM is often on the cells or container(s) it is connected to.
Tabbing the Battery
Several ring tab washer sizes are available to match the majority of termination bolt sizes. These are
3/16” (5 mm.), 1/4” (6.3 mm.), 5/16” (8 mm.), 3/8” (10 mm.), and ½” (12 mm.). Tab washers are
provided as they are less likely to fall away from the battery and can be torqued to manufacturer
specifications. Make sure you have the correct size for the cells you are monitoring by checking battery
manufacturer specifications for bolt sizing.
For accurate readings, particularly on low ohmic value cells or containers, connect
the DCMs to the tin plated (lead-free) copper and brass tab washers provided by
NDSL.
Note: Stainless steel tab washers or dual tab washers should not be used unless by prior agreement
with NDSL. Stainless steel and dual tab washers may generate higher ohmic readings due to the
higher resistance of the metals and/or common resistances.
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