Yacht Devices NMEA 2000 YDBM-01 User manual

User Manual
NMEA 2000 Battery Monitor YDBM-01
also covers models
YDBM-01N, YDBM-01R
Firmware version
1.00
2021

© 2021 Yacht Devices Ltd. Document YDBM-01-002. December 2, 2021. Web: http://www.yachtd.com/
NMEA 2000 Battery Monitor is certied by the National Marine Electronics
Association.
NMEA 2000® is a registered trademark of the National Marine Electronics
Association. SeaTalk NG is a registered trademark of Raymarine UK Limited.
Garmin® is a registered trademark of Garmin Ltd.

Contents
Introduction 4
Warranty and Technical Support 5
I. Product Specications 6
II. MicroSD Slot and Card Compatibility 8
III. Understanding the Basics 9
IV. Typical Use of the Device 12
V. Choosing a Shunt 18
VI. Installation and Connection of Device 20
VII. LED Signals 23
VIII. Quick Setup List 25
IX. Device Conguration and Settings 26
X. Battery Synchronization 48
XI. NMEA 2000 Digital Switching Support 53
XII. Firmware Updates 56
Appendix А. Troubleshooting 57
Appendix B. Supported NMEA 2000 Messages 60
Appendix C. Example of Conguration File 62
Package Contents
Device 1 pc.
This Manual 1 pc.
Stickers for MicroSD slot sealing 6 pc.
MicroSD card Not supplied
NMEA 2000 Cable Not supplied
External shunt Not supplied

— 4 —
Introduction
This Manual contains information on how to install, congure and operate the Yacht Devices
NMEA 2000 Battery Monitor YDBM-01 (hereinafter the Device). The Device is intended for use
in NMEA 2000 marine electronics networks.
The Battery Monitor is primarily designed for monitoring a marine battery. However, you can use
the Device with any single DC source (i.e. alternator, wind generator, etc.) or load (windlass, refrigerator, etc.).
This capability increases both marine safety and sailing comfort by giving you full information about
on-board DC sources and consumers.
To operate as intended, the Battery Monitor requires an appropriate external shunt, shunts in the range
from 5A to 1200A are widely available. The Device should be properly wired and congured.
At the minimum, you should specify drop voltage and maximum current for connected shunt. In addition,
you can specify battery parameters such as nominal capacity and voltage, chemistry, etc.
Current and voltage measurement data, and, in case of batteries, calculated data (state of charge, consumed
ampere-hours, battery time remaining) are output to an NMEA 2000 network. The data can be displayed
on MFDs or instrument displays, and is available to all other devices within the NMEA 2000 network.
Current and voltage data measured by the Device, as well as battery case temperature data supplied
by an external NMEA 2000 sensor, and calculated data like state of charge, can be used to manage channels
of an NMEA 2000 digital switching system, and/or trigger a digital alarm unit compatible with standard
NMEA 2000 PGNs 127501/127502. For example, you can congure the Battery Monitor to automatically
raise a sound alert about low battery charge, or to turn some equipment on or off, or to start a genset
to recharge the battery (see IX.3 and Section XI).
The Device incorporates a MicroSD card slot which allows using a standard FAT-formatted card
to program the Device and update its rmware. For programming only, you may also use PC software
with an appropriate NMEA 2000 gateway (from ActiSense, Maretron or Yacht Devices; see IX.2),
or an MFD that supports installation description strings.
Thank you for purchasing the Battery Monitor, and Bon Voyage!

— 5 —
Warranty and Technical Support
1. The Device warranty is valid for two years from the date of purchase. If a Device was purchased
in a retail store, the sales receipt may be requested when applying for a warranty claim.
2. The Device warranty is terminated in case of violation of the instructions in this Manual, case integrity
breach, or repair or modication of the Device without the manufacturer’s written permission.
3. If a warranty request is accepted, the defective Device must be sent to the manufacturer.
4. The warranty liabilities include repair and/or replacement of the goods and do not include the cost
of equipment installation and conguration, or shipping of the defective Device to the manufacturer.
5. Responsibility of the manufacturer in case of any damage as a consequence of the Device’s operation
or installation is limited to the Device cost.
6. The manufacturer is not responsible for any errors and inaccuracies in guides and instructions
of other companies.
7. The Device requires no maintenance. The Device’s case is non-dismountable.
8. In the event of a failure, please refer to Appendix A before contacting technical support.
9. The manufacturer accepts applications under warranty and provides technical support only
via e-mail or from authorized dealers.
10.The contact details of the manufacturer and a list of the authorized dealers are published
on the website: http://www.yachtd.com/.

— 6 —
I. Product Specifications
Figure 1. Drawings of YDBM-01N (left) and YDMB-01R (right)
Most of our Devices are supplied with different types of NMEA 2000 connectors. Models containing «R»
in the sufx of the model name are equipped with NMEA 2000 connectors, and are compatible
with Raymarine SeaTalk NG. Models containing N in the sufx are equipped with NMEA 2000 Micro Male
connectors. You can connect the Device directly to a backbone, without a drop cable.

— 7 —
Device parameter Value Unit
Supply voltage (from NMEA 2000 interface) 7..16 V
Consumption current (NMEA 2000 interface), average 50 mA
Load Equivalency Number 2 LEN
External shunt rated current 5..2500 A
External shunt’s nominal voltage drop (recommended) 75 mV
Shunt voltage measurement range -50..50 mV
Current measurement accuracy (1) ±0.5 %
Voltage measurement accuracy 0.1 V
Maximum allowed DC voltage on inputs (with respect to GND input) 40 V
Breakdown voltage between NMEA 2000 network interface and inputs 2500 VRMS
Device case length (without connector) 54 mm
Weight 60 g
Operating temperature range -20..55 °С
Note 1: (1) not accounting for shunt accuracy which is typically ±0.25% or ±0.5%, and ±20 – 25
ppm/°C for temperature drift.
Yacht Devices Ltd declares that this product is compliant with the essential requirements of EMC
directive 2004/108/EC.
Dispose of this product in accordance with the WEEE Directive. Do not dispose of electronic refuse
with domestic or industrial waste.

— 8 —
II. MicroSD Slot and Card Compatibility
The Device has a slot for a MicroSD card that allows you to congure the Device (refer to Section IX)
and update the rmware (refer to Section XII).
When you nish conguring the Device, we recommend sealing the card slot with the sticker that
is supplied with the Device, or with a piece of tape to prevent water from entering the Device through
the slot.
The Device slot has a springloaded «push-push» mechanism that ensures proper card xation.
Improper loading or unloading (withdrawing your nger too quickly, or not pushing until
it clicks) may result in the unexpected ejection of the card from the slot. To avoid possible
injury, damage or loss, please insert and eject the card with caution.
The Device supports MicroSD memory cards of all sizes and classes. The card must be formatted
on a personal computer before it can be used in the Device. The Device supports the following le systems:
FAT (FAT12, FAT16, MS-DOS), and FAT32. It does not support exFAT, NTFS, or any other le systems.
Be careful when inserting the MicroSD card into the Device. The card should be inserted with the label
side toward the LED.
Figure 1. Device with a MicroSD card installed (pin side on the left, label side on the right)

— 9 —
III. Understanding the Basics
The primary use of the Device is to monitor battery voltage, current, temperature (via an external
temperature sensor) and a number of calculated parameters, such as state of charge and consumed ampere-
hours, via MFDs, instrument displays, PCs or mobile gadgets connected to an NMEA 2000 network.
The Device has three input wires which may be connected to a marine battery or other DC source
(see Figure 1 in Section I) using an appropriate external shunt (purchased separately). The Device
is capable of measuring both current and voltage. Both positive and negative amperage is measured.
Negative values indicate battery discharge, positive indicate charging.
To report battery status and perform more accurate calculations, the Device requires battery temperature
provided by an external NMEA 2000 thermometer, for example, Yacht Devices' Digital Thermometer
YDTC-13.
Calculations of state of charge (SoC), consumed ampere-hours, time remaining and state of health
(SoH) are based on Lead Acid or Lithium-ion batteries. Further information will primarily relate
to these battery types. NiCad and NiMH batteries have signicant memory and self-discharge effects,
etc. which are not taken into account in calculations. Use of NiCad and NiMH batteries with the Device
will decrease the accuracy of the calculations. Calculations can be turned off (see CALCS parameter
or YD:CALCS command in Section IX), and the Device may be used to monitor battery voltage, current
and temperature (with an external temperature sensor).
To obtain results for SoC, consumed ampere-hours, time remaining, SoH calculations usable, you have
to specify the battery’s characteristics, such as nominal voltage and capacity, in Device settings.
If the capacity value is rated for a discharge rate other than 20 hours, you must specify the latter
as the NOMINAL_RATE parameter value (see Section IX).
Since the Device is powered from the NMEA 2000 network, the Battery Monitor must be permanently
connected to both the network and the monitored battery/DC source. This is a proven way to obtain
credible values of state of charge, consumed ampere-hours and time remaining. Otherwise, you can rely
only on voltage, current and temperature readings.

— 10 —
To power off your NMEA 2000 network without breaking the Device’s connection to the battery, you may
need a dedicated hardware solution, for instance, a Garmin NMEA 2000 Power Isolator (part number
010-11580-00). With such a device, you can place the Battery Monitor and other NMEA 2000 devices
in different network segments, each of which can be powered off separately.
The Device is intended to measure battery voltage and current, continuously monitor battery charging and
discharge, and calculate battery status data. An ideal battery always gives and takes 100% of its energy
without any loss. In real-world conditions, the amount of energy available from a battery heavily depends
on the discharge rate and, to a lesser extent, on the battery’s temperature. The charging process, as well,
is not 100% efcient.
Figure 1. Typical capacity vs. temperature graph.
The Device accounts for charge efciency and battery temperature (if working with an external temperature
sensor), and the discharge rate (via the so-called Peukert’s exponent, see Section IX). Consumed
ampere-hours is compensated for charge efciency only, and state of charge (SoC) is compensated
for charge efciency, temperature and Peukert efciency.
40
60
80
100
120
-40 -30 -20 -10 010 20 30 40
Capacity, %
Temperature, °С
Example of capacity vs temperature

— 11 —
Battery manufacturers normally specify maximum permitted depth of discharge values for their products.
Depth of discharge (DoD) is the percentage of capacity removed from the fully charged battery. DoD
is the inverse of state of charge (SoC + DoD = 100%).
Figure 2. Typical cycle life (the number charge/discharge cycles before battery's performance
has been signicantly reduced) vs. Depth of Discharge
Discharging below the specied DoD limit would damage the battery and decrease its expected lifespan
(commonly expressed as state of health — SoH). The purpose of monitoring battery’s state of charge
is to keep it from discharging deeper than permitted, and thus extend its operational life.
10,05
10,5
10,95
11,4
11,85
12,3
12,75
0
500
1000
1500
2000
2500
020 40 60 80 100 120
Voltage, V
# of cycles
Depth of Discharge, %
Example of Depth of Discharge vs Cycle Life for 12V
Lead-Acid Battery

— 12 —
IV. Typical Use of the Device
The cases below do not comprise a comprehensive list of possible uses of the Device. They just give
an overview of the Battery Monitor’s capabilities in a number of real-life applications.
1. Monitoring of batteries on modern and legacy MFDs
Figure 1. Battery state as displayed on a Raymarine Axiom MFD

— 13 —
For compatibility with legacy displays, the Device sends measurement data in PGN 127508
«Battery Status» (with voltage, current and case temperature data only) which is supported by most
NMEA 2000 displays on the market. On the Figure 1 above, State of Charge (SoC) and Time Till Zero
Charge (TTZ) from PGN 127506 «DC Detailed Status» are also shown.
2. Monitor solar panels and wind generators
Though the NMEA 2000 standard distinguishes between different types of power sources, the vast majority
of modern MFDs are still incapable of monitoring solar panels and wind generators: they are shown
as ordinary batteries. However, we believe that as these alternative power sources become more popular,
MFD manufacturers will upgrade their solutions to let them handle the full range of data that the Battery
Monitor supplies. In the Device’s settings, you can congure DC source type as battery, solar cell, wind
generator, alternator or DC converter (see Section IX).
3. Receive alerts on battery’s State of Charge
If the battery SoC falls below the pre-specied threshold, it may decrease battery lifespan or even fail
to perform a vital action, i.e. start an engine, feed navigation lights or run a bilge pump.
Using Digital Switching commands, the Device can be programmed to automatically detect an insufciently
state of charge, and turn on a specied DS channel in a specied bank (see IX.3 and Section XI for details).
YD:SS1 ON <40 0 0 1
In this example, the rule turns ON Channel #1 at the DS Bank #0 when the calculated SoC value
momentarily drops below 40%.

— 14 —
Figure 2. Basic digital switching system that provides alerts on battery’s SoC
If the vessel has an NMEA 2000 Alarm Button (see XI.2) congured for bank #0 (see Figure 2), the rule
will trigger an audio alert. The Alarm Button allows uploading of custom alarm signals or voice messages.
4. Turn on a genset to recharge the battery
On a sailing journey, there might be a lot of reasons to sail motorless. During such periods, an unexpected
discharge of a starter battery may become a very unwelcome surprise. Even if you have top rated deep cycle
batteries from a reputable brand, you need to keep an eye on their state of charge.

— 15 —
Let’s congure a rule that is triggered if a battery voltage falls below the specied limit (in this case, 11.5 V)
for longer than a specied period of time:
YD:SV1 ON <11.5 30 0 1
If you have an Alarm Button congured (see XI.2), you can receive an audible notication when the rule
is triggered.
If your charging equipment is not capable to initiate recharging automatically, you may use the Device’s
Digital Switching commands to activate, e.g., a genset. In this case, you may require a dedicated genset
start circuit. On the Figure 3, the Circuit Control (see XI.1) is used to close the contacts of the genset’s
starting circuit.
You may need an additional rule to release the starter when a genset is on (voltage is above 12 Volts
for more than 5 seconds):
YD:SV1 OFF >12 5 0 1

— 16 —
Figure 3. Simple digital switching solution to automatically start a genset on low battery voltage
5. Discover a specic behaviour of a DC load
In normal conditions, a bilge pump is rarely seen in operation. If it consumes current continuously,
this may be a sign of hull leakage or other major problems. If the bilge pump feeding circuit is connected
to a properly programmed Battery Monitor, you may apply the following rule:
YD:SC1 ON <-0.2 1200 0 1

— 17 —
The rule switches on DS channel #1 at bank #0 when the pump is continuously switched on
(i.e. is consuming more than 0.2 amperes) for more than 20 minutes (1200 seconds). Negative current
value means that the DC load is discharging the battery.

— 18 —
V. Choosing a Shunt
A shunt is a precision resistor, with a low resistance value, used for current measurement. Shunts
in the range from 5A to 1200A are widely available. Another important parameter of the shunt, besides
current, is the voltage drop at maximum load. Typical voltage drop value is 75 mV, but 50 mV and 100 mV
shunts are also available.
Figure 1. A typical shunt appearance
The Battery Monitor measures voltage drop across a shunt in the range of -50..50 mV. This means that,
with the use of a shunt of a greater voltage drop than 50mV, the maximum measured current value
will be less than the shunt’s rated current. For 75 mV and 100mV shunts, the decrease will be,
respectively, 65% and 50%. For instance, with a 75 mV / 10 A shunt, the maximum measured current
will be approximately 6.5 A. In case of a 100 mV / 100 A shunt, the maximum measured current
will be approximately 50 A. Please take this into account when choosing a shunt.

— 19 —
Moreover, due to safety concerns for continuous operation, it is recommended in IEEE standards to keep
the maximum amperage in a connected circuit below two-thirds (2/3) of the shunt’s rated current.
We recommend using a 75 mV shunt and selecting a current rating that takes into consideration
that maximum current of you system should be less than 65% of the shunt’s rated current. This provides
for electrical safety, and accounts for the Device’s 50 mV limitation. For example, if the maximum amperage
in your system is 60 A, a 75 mV / 100 A rated shunt will be sufcient.

— 20 —
VI. Installation and Connection of Device
The Device requires no maintenance. The Device’s case is not waterproof; please avoid installing the Device
in a location where it can be ooded or sprayed by water, or get wet in rain. To minimize any possible water
damage, we recommend that you cover the MicroSD card slot with a supplied sealing sticker when the slot
is not used.
1. Connecting to monitored batteries / DC circuits
The Device is designed to work with a standard 75 mV shunt (not supplied) with no limits for rated current
(shunts in the range from 5A to 1200A are widely available). If necessary, you may use a shunt with
a nominal voltage drop of 50 or 100 mV, however, with some trade-offs (see Section V). You have to specify
the shunt's rated current and nominal voltage drop in Device's settings, as well as battery's nominal voltage,
capacity and discharge rate.
When making connections, refer to the diagram below (see Figure 1 on the next page).
Make sure to use a marine grade power cable with proper voltage, current, temperature, and water/oil
resistance ratings.
Proper choice of wire gauge is also important: the voltage drop in cables that connect the positive terminal
of the battery to the shunt, and the ground wire of the Device to the negative terminal of the battery
directly affects the measurement accuracy. Determine the amperage in your circuit noting the lengths
of the cables. Assistance in choosing the optimal wire gauge for the lowest possible voltage drop
may be found on the Web.
Please note that the Device readings will be non-zero when the Device is not connected to the shunt
and the battery or when the Device is connected only to the shunt and not connected to the battery.
To prevent the Device from being damaged, NEVER leave any of the Battery Monitor’s red
or blue wires unconnected. If you have not installed a shunt, and use the Device
for measuring battery voltage, connect both wires to the positive terminal of the battery.