Digital Mobile Charge
Digital Mobile Charge
Advanced Electronic In-Transit 4-Stage Alternator to Battery Charger
Owner’s Manual and Installation Guide
130 Amp Alternator to Battery
80 Amp Alternator to Battery
Part Number
12V Advanced In-Transit 4-Stage Charger
24V Advanced In-Transit 4-Stage Charger
Your Satisfaction is Important to us. Do Not return this Product to the Retailer or
Dealer for any service or warranty requirements. Please call our Customer Care
Department line at 1-800-824-0524 from 8 am to 5 pm (Eastern Time) for warranty,
service or installation assistance you may need. Thank you.
Please save and read all safety, operating and installation instructions before
Installing or applying power to your Digital Mobile Charge.
Table Of Contents
Table of Contents
page 2
Product Overview
page 3
Details of Operation
page 3
General Safety Instructions
page 4
Personal Safety Precautions
page 4
Installation Warnings
page 5
Positioning Battery Type Switch
page 6
page 6
Additional Features
page 7
Figure #1, Simple Install
page 8
Figure #2, Complete Install
page 9
Wire Gauge Charts
page 10
Description of LED’s
page 11
Start up and Test Procedure
page 12
Customer Service and Warranty
page 13
Digital Mobile Charge Overview:
On Board Solutions’ Alternator to Battery Digital Mobile Charger is a combined split
charge diode system and a voltage amplifier. The unit is comprised of one alternator
input and two battery bank outputs. The output marked starter battery is a straight
channel through a diode which has no boost function as it is the channel that must be
connected to the boat/vehicle engine system; most vehicles E.C.U. (engine control unit)
cannot deal with a high input voltage because this would set off alarms in the E.C.U.
Additionally, the Digital Mobile Charge ensures at all times that the power required to run
the primary system of the vehicle or boat engine is not affected. The engine start battery
is constantly monitored and receives top charging priority. The engine start battery
cannot discharge through this system, even in the event of a unit failure.
The solution: The Digital Mobile Charger pulls the voltage down and allows the
alternator to output at it maximum capability and then amplifies the voltage from 13 to
14.8 volts for 12V models (26V to 29.6V for 24V models) and the surplus power created
by fooling the alternator is amplified into a higher voltage by the Digital Mobile Charge.
This amplified output is used to charge a secondary battery bank using a totally isolated
digitally controlled 4 step charging curve.
In summary, the Digital Mobile Charge provides your extra battery system a charge that
is approximately 5 times faster than could be achieved in using the vehicles alternator.
This provides in transit charging of extra battery banks and increases the life of the
batteries by de-sulphating them. The Digital Mobile Charge provides the same utility as
an advanced regulator, a zero loss battery isolator, and a 4 step battery charger.
Details of Operation:
The Digital Mobile Charge begins operation by monitoring the engine start battery. The
unit will not start until the battery voltage exceeds approximately 13 volts for 12v models
(26v for 24v models), then waits for 2.5 minutes to ensure that some charge is placed
quickly into the engine start battery. After that, the Digital Mobile Charge pulls the engine
battery down to no less than 13 volts for 12v models (26v for 24v models), which
enables the engine battery to still receive a small charge and ensures the alternator
works at its full potential.
Additionally, to further ensure the engine battery is O.K., every 20 minutes the Digital
Mobile Charge stops for 3 minutes, allowing the engine start battery to be charged
exclusively by the alternator. After the 3 minutes, the Digital Mobile Charge resumes
battery bank charging by pulling down the engine start battery to 13 volts for 12v models
(26v for 24v models) and so continues the charging cycle. After a period of time,
calculated by the software, when the battery bank batteries are full, the system will float
the batteries at 14 volts for 12v models (28v for 24v models); all while ensuring the
viability of the engine battery comes first.
Other features included in this system are an alternator temp sensor, a remote battery
temp sensor and a fully automatic sleep sensor, which switches the unit off when the
engine has stopped. (Please See the Additional Features Section on page 7 in this
manual for more detail on these features)
General Safety Instructions:
Before connecting your batteries, read all instructions and
cautionary markings on the battery charger and batteries.
CAUTION - To reduce the risk of injury; charge only lead acid type
rechargeable batteries (lead acid, gel cell and AGM). Other types of
batteries may burst, causing personal injury.
Use of attachments not recommended or sold by On Board Solutions or
Professional Mariner, LLC may result in a risk of fire, electrical shock or
personal injury.
Do not operate the charger if it has received a sharp blow, direct hit of
force, dropped or otherwise damaged in any way.
Do not disassemble the charger. Call the factory directly when service or
repair is required.
Incorrect assembly may result in risk of electrical shock or fire.
To reduce risk of battery explosion, follow these instructions and those
published by the Battery manufacturer, and of any equipment you intend to
use in the vicinity of a battery. Review all cautionary markings and labels.
Personal Safety Precautions
1. Someone should be within the range of your voice or close enough to come to
your aid when installing this product or working near lead acid batteries.
2. Wear complete eye protection and protective clothing. Avoid touching eyes while
working on or with batteries. Have plenty of soap and water nearby in case of battery
acid comes in contact with skin, clothing or eyes.
3. If battery acid comes in contact with skin or clothing, wash immediately with soap
and water. If acid enters the eye (s) flood eye (s) with running water for at least 10
minutes and get medical attention immediately.
4. Never smoke or allow a spark or a flame in the vicinity of a battery or engine.
5. Be extra cautious to reduce the risk of dropping a metal tool onto a battery. It may
spark or short-circuit the battery or other electrical parts that may cause an explosion.
6. Remove all personal metal items such as rings, bracelets, necklaces, watches and
jewelry when working near a battery. A battery can produce a short circuit high
enough to weld a ring or any metal, causing serious burns.
Installation WarningsSet the unit as you would any other high power battery charger; fit it near the batteries in
a cool, dry and well-ventilated space to ensure the unit has the ability to dissipate the
heat it will generate. Do not place directly above or below the batteries.
WARNING: Electrical Shock and Fire HazardsOn Board Solutions and ProMariner recommend all wiring is done by qualified
personnel. Disconnect all power sources to prevent accidental shock. It is the installer’s
responsibility to ensure compliance with all the applicable installation codes and
WARNING: Fire HazardDo not cover or obstruct the ventilation openings. Do not install this equipment in a
compartment with limited airflow; Overheating may result.
WARNING: Low Voltage - Electrical burn and spark hazard. Disconnect battery power
before servicing.
WARNING: Be sure the area around the charger and batteries is well ventilated while
the batteries are being charged.
WARNING: Add distilled water in each cell until electrolyte reaches levels specified by
the battery manufacturer. This helps purge excessive gases from cells. Do not overfill.
Always carefully follow manufacturer's recharging instructions.
WARNING: Study all manufacturer’s specific precautions, such as removing or not
removing cell caps while charging, in addition to rates of charge.
WARNING: Clean battery terminals with full eye protection to prevent corrosion from
coming in contact with eyes.
WARNING: If necessary to remove a battery from this charger, always remove
grounded terminal from battery first. Make sure all accessories are off, as to not cause
an arc.
Positioning Battery Type Selector Switch:
Program the battery type into the unit. Do so by positioning the battery type dip switches
on the unit to the appropriate battery type.
There are 4 possible battery type selections:
Non-Sealed Lead Acid Battery (Orange LED)
Exide Gel Battery (Green LED)
Gel Battery (All others except Exide) (Green Flashing LED for 10 times)
AGM Battery (Red LED)
Understanding Battery Types
There are three primary types of batteries in the marketplace today; Flooded
(Lead Acid), AGM (Absorbed Glass Mat) and GEL cell (Gelled Electrolyte LeadAcid). Traditionally, the most common type of batteries used are Flooded (Lead
Acid batteries).
Almost all GEL cell batteries will state that they are GEL cell on the battery case
or labels. (Shown below) are typical battery voltages at absorption and float
Battery Type
Flooded (Lead Acid)
AGM (Absorbed
Glass Mat)
GEL cell
12V Charging
14.6 Absorption,
13.3 Float
14.4 Absorption,
13.3 Float
14.1 Absorption,
13.8 Float
24V Charging
29.2 Absorption,
26.6 Float
28.8 Absorption,
26.6 Float
28.2 Absorption,
27.6 Float
Battery Information
Water filled (with or without
Removable caps)
NOTE: AGM (Absorbed Glass Mat) batteries are not GEL (Gelled Electrolyte Lead-Acid) batteries. AGM
batteries are charged at the same charging profile as Flooded (Lead Acid).
***If you are still unsure as to what kind of battery you have, we recommend that you contact the
manufacturer of the battery.
Installation of the Unit:
1) Connect the main alternator output to the center stud marked alternator input, then connect
the domestic battery to the domestic stud. Connect the engine battery to the stud marked starter
battery. Please ensure that the cable used can carry the full current of the alternator. Please see
Cable Size Charts for 12v and 24v models on page #10.
NOTE: Cable protection fuses or breakers must be used within 7” of the alternator and 7”
of the battery.
2) The unit has a smaller negative wire which requires a # 6 AWG cable and should be
connected directly to the alternator negative at the alternator case or negative engine stud.
3) If you already have a split charger diode, then the three positive cables are already there.
Simply replace the diode with this unit and connect the negative. Please see the basic
installation drawing.
Additional Features:
Battery Temp Sensor: Simply connect the ring end of one of the enclosed
temperature sensor to a battery terminal post (neg. or pos.) Be sure not to crush
the temp sensor which is enclosed inside the yellow ring terminal. Connect the
wire end of the temp sensor to the 2 small terminals marked battery temp on the
Digital Mobile Charge. Simply push the small lever down and insert one wire into
each side. There is no polarity on these wires. The output voltage will be reduced
in the event the battery temperature increases.
If the battery exceeds 50 degrees Celsius, the Digital Mobile Charge will switch
off, as a major battery failure may have occurred. (It is important to note that the
straight path from the alternator is still connected which means if the problem
which has caused your batteries to overheat if the failure of your standard
regulator in the alternator, the Digital Mobile Charge will be able to warn you with
an illumination of the “High Alternator Voltage” LED, but it will not be able to stop
it, as it is a component in the alternator. Please take this warning seriously and
have your alternator or alternator’s regulator serviced.
Alternator high temp disengage: This is another supplied temperature sensor
which should be connected to your alternator output post (b+) and will disengage
the Digital Mobile Charge in the event the alternator reaches 100 deg Celsius. A
warning LED will illuminate when the alternator reaches the threshold
temperature. When the alternator cools to 80 degrees Celsius, the system
automatically reengages and continues charging.
Battery Bank Voltage Monitoring: As a standard feature, this unit senses all
the control voltages at the unit. However, if you want to sense the voltage at the
domestic battery bank directly to overcome the voltage drop in the cable run,
then simply connect a cable from the domestic sense connection directly to the
domestic battery.
Starter Solenoid: Some alternators cannot work if there is no voltage on their
main B+ terminal. This voltage fires up the alternator. This is easy to see
because when you fit a split charge diode there is no feed on the B+ which in turn
means that the engine will start, but that the alternator may not work.
If this is the case, the way to overcome this is to use the starter solenoid feed.
This is a simple feed that connects the terminal on the starter motor and which
only becomes live when the starter motor bendix is engaged (i.e. the first two
seconds of having the ignition key fully on). Then when the starter is disengaged,
the point becomes dead. What actually happens is that a 12 volt feed is sent to
the alternator B+ terminal for the starter duration and the alternator will engage.
Low alternator regulator adjustment for 12V unit: (standard set switch 1 off)
Most 12V regulators come as standard between about 13.8 and 14.4 volts. If the
standard regulator is not within its limits and has a low voltage performance of
below 13.8v, the unit may not work as well as it could. By switching on the switch
number 1 on the regulation voltage, the engine battery is dropped from 13v to
12.8 volts, which in turn improves the boost effect from the unit. Warning: Do not
do this unless you have the above-described problem as this could result in a low
engine start battery performance.
Figure #1- Simple Installation
Figure #2- Complete Installation
AWG Wire Gauge Chart for 12V and 24V-
Description of LED’s found on Unit:
1) FAST CHARGE: Green: This should be on from start up (slow flash shows unit is on
but on rest mode for the first 2.5 minutes upon start-up and approx. every 20 min after)
and shows that the alternator should be working at it's maximum. This LED should
remain on until the Float Mode LED comes on and signals the high charge rate is
2) ABSORPTION CHARGE: Yellow: Timer Activated: This LED comes on when the
voltage reaches about 13.9 - 14 volts (27.8v – 28v for 24v models). The software will
calculate the timing for the Absorption Charge and depending on how long it took to turn
on will dictate how long the timing cycle will remain on. This will vary from 1 - 6 hours.
This light will remain on until the Absorption Charge is over.
3) FLOAT MODE: Green Float Mode LED: This indicates that Absorption charge cycles
are now over and should remain on after all the high charge lights are out. The system is
now running at a Float rate, which is a maintenance charge rate.
4) LOW BATTERY VOLTAGE: Orange: Low Voltage Warning: This is simply saying
that there is low voltage at the main battery bank and has no active function. For
information only, this usually indicates a defective alternator, or perhaps a defective
main battery.
5) HIGH BATTERY VOLTS / TEMP: Red Dual Information LED. This LED has two
functions and shows a Red Flashing LED when the battery temperature sensor has
picked up a temperature in excess of 50 deg C at its source (where ever you have fitted
it) this will trip the unit until it has been reset. Please find the fault before resetting.
If the LED is on permanent Red, it means there is high voltage present at the
output battery (or battery bank) being charged. This solid Red LED will warn you
and switch off the charging. This LED indicates that either the Digital Mobile Charge has
failed and was overcharging your battery bank, or you have some other charging source
on your output battery bank which is overcharging the batteries and the Digital Mobile
Charge senses the current which triggers the warning.
6) BATTERY TYPE- Tri Colored LED: This simply displays the battery type that the user
has set the Battery Type Switch to:
Non-Sealed Lead Acid Battery (Orange LED)
Exide Gel Battery (Green LED)
Gel Battery (All others except Exide) (Green Flashing LED for 10 times)
AGM Battery (Red LED)
7) HIGH ALTERNATOR VOLTAGE: Specifically, this LED means that your alternators
own regulator has failed and the alternator can now run unregulated with the possibility
of overcharging damaging your batteries.
8) ALTERNATOR TEMP- Yellow: This monitors the temperature of the alternator and
disengages the unit in the event of the alternator reaching 90 deg C, which waits for the
alternator to cool down then automatically re-engages.
9) UNIT FAILURE: Red: This LED will give an indication in the event of a total unit
Start-up and Test Procedure:
As soon as the unit is connected it senses the output voltage from the alternator,
so when the alternator starts up, it will turn on the Digital Mobile Charge. Upon
start up, the top battery type LED will illuminate yellow, red, green, or yellow
flashing depending on the battery type selected, and the Fast Charge LED ( 3
down ) will begin flashing slowly. This green LED slow flashes to shows that the
unit is working but is inactive for the first 2.5 min. with the intention of allowing the
engine start battery to recover a little.
After about 2.5 min. the Fast Charge green LED will stop flashing and change to
a continuous green light, indicating the unit has begun charging. This high
current output to the domestic battery bank will continue in cycles of
approximately 20 minutes on and 3 minutes off to ensure the engine start battery
is always maintained.
Once the domestic battery bank reaches a certain voltage (depending on the
battery type setting but between 13.5-14v for 12v models or 27v-28v for 24v
models), the Absorption LED will illuminate and the high rate of charging will
continue for a period of time calculated by the Digital Mobile Charge (between 16 hours). This time period is determined by what battery type you have selected
and the state of discharge of the domestic battery bank. The rest period
continues to be 3 minutes off for every 20 minutes off. After the calculated
amount of time is over, the unit drops to float at 13.5-13.8 Volts for 12v models or
27v - 27.6v for 24v models (dependent on battery selector switch) with no switch
off period. A Float LED indication tells the operator the domestic battery bank is
charged and is being held at a maintenance voltage.
The Digital Mobile Charge will attempt to hold the battery voltage at the above
described Float range. If current is demanded, the Digital Mobile Charge will try
to meet that demand and keep the domestic battery bank at float between 13.513.8 Volts (27v -27.6v).
If on start-up nothing happens, then:
1) Test the alternator voltage. It should be about 13.8 volts for 12v systems, but if
it isn't then please check the user installed inline fuses. If you are still
experiencing problems, please call 1-800-824-0524 as the unit may be defective.
2) If the alternator voltage is below 10 volts, then the alternator is either
defective, or it may not be working because it needs 12 volts on the B+ terminal
for it to work successfully. To check if this is the case, simply short for a couple of
seconds a length of wire between the alternator output connection and one of the
battery positive terminals in order to provide 12 volts up the alternator cable. If
the alternator starts charging, then install the start sense wire as shown in Figure
#2, (The Complete Installation Diagram).
Customer Service & Warranty:
We are committed to customer satisfaction and value your business. If at any
time during the warranty period you experience a problem with your new Digital
Mobile Charge, simply call us at 1-800-824-0524 during standard business hours
(8:30 AM – 5 PM Eastern Time) for Technical Support.
Each product is guaranteed against defects in material and workmanship to the original consumer
in normal use for two full years from the date of purchase. On Board Solutions and Professional
Mariner, LLC at its Discretion, will repair or replace free of charge any defects in material or
The following Conditions apply:
• Warranty is calculated from date of manufacture if not registered within two weeks
of sale.
• Warranty void if damage occurs due to negligent repairs.
• Customer is responsible for returning the product to On Board Solutions and
Professional Mariner, LLC. inbound shipping costs must be prepaid.
• This warranty does not cover blemishes due to normal wear and tear or damages
caused by accidents, abuse alterations or misuse.
Purchase or other acceptance of the product shall be on the condition and agreement that On
Board Solutions and Professional Mariner SHALL NOT BE LIABLE FOR INCIDENTAL OR
CONSEQUENTIAL DAMAGES OF ANY KIND. (Some states do not allow the exclusion or
limitation of consequential damages, so the above limitations may not apply to you.) This
warranty is made in lieu of all other obligations or liabilities on the part of Onboard Solutions and
Professional Mariner. Additionally, On Board Solutions and Professional Mariner neither assumes
nor authorizes any person for any obligation or liability in connection with the sale of this product.
To make a claim under warranty, call Factory Service at 1-800-824-0524. Follow the company’s
return policy, which will be provided by the company. On Board Solutions and Professional
Mariner will make its best effort to repair or replace the product, if found to be defective within the
terms of the warranty, within 30 days after return of the product to the company. On Board
Solutions and Professional Mariner will ship the repaired or replaced product back to the
Please contact Customer Service for additional assistance. This warranty provides to you specific
legal rights and you may also have other rights, which vary from state to state. This warranty is in
lieu of all other, expressed or implied.
Please Register your product with the enclosed warranty card, or online at
Factory Service Center
Service Phone: 1-800-824-0524
200 International Drive, Suite 195
Portsmouth, NH 03801
Phone: (603) 433-4440
Fax: (603) 433-4442
Visit us on the web at:
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