- Megapulse specification
- How long a battery can power Megapulse without being recharged
- Reading the LEDs (Mk3, Mk4)
- Changing between the LO / HI / WW modes
- Interpreting the battery load test results (Mk3, Mk4)
- Megapulse battery test function (PDF)
- Which mode should I use?
- Installation notes
- Simple AM radio test to see if Megapulse is operating
- Reviving a dying battery
- Battery technology in a nutshell
- Battery maintenance (flooded cell, golf car)
- Issues with small sealed/flooded lead acid batteries
- Notes on charging lead acid batteries
- Applying an equalization charge
- Table of key voltages for lead-acid batteries
- Table of SOC (state of charge) vs voltage for lead-acid batteries
- Dimensions and shipping weights
- Mounting dimensions
Reading the LEDs (Mk3, Mk4)
- On powering up:
ACTION LED COLOUR LED RESPONSE 1 Power on start up test: red & green LEDs 3 secs, alternating 2 Which mode (LO, HI) set: green LED = LO
red LED = HI
1 sec, steady
- Continuous indication while running:
ACTION LED COLOUR LED RESPONSE 3 Battery voltage check: red + green LEDs 1 sec both, every 30 secs 4 Battery load test result: green LED = pass
red LED = fail
Mk.3: 3 quick flashes, every sec
Mk.4: 1 quick flash, every sec
Changing the LO / HI / WW mode
- Megapulse Mk4:
ACTION LED COLOUR LED RESPONSE 5 Place magnet on spot marked 'Magnet', then
check LEDs for which mode has been set
wait 1 sec red LED = HI / WW set
green LED = LO set
6 Remove then replace magnet
to cycle through modes
wait 1 sec green (or red) LED flashing 7 Remove magnet to activate mode change - Now at step 4 above
- Megapulse Mk3: As above; no WW (Window) mode, only applies to 12v & 24v models
- Megapulse Mk2: As Mk3, but instead of magnet use slider switch to set mode
Interpreting the battery load test results (Mk3, Mk4)
- LED readout (12v, 24v models):
- If voltage drops >2v after load test, red LED flashes
- Action required: check battery and connections
- Otherwise green LED flashes
- Results of last load test will be displayed until the next load test done
- LED readout (6v, 36v, 48v models):
- Battery voltage low, red LED flashes
- Action required: recharge battery
- Otherwise green LED flashes
- When is the load test performed?
- Immediately after power-up
- Every 24 hours from the time of power-up or reset
- To force an immediate test, disconnect then reconnect Megapulse.
For a true reading, ensure the battery has not been charged during the last few hours.
- The load test will not be done:
- If the battery is on charge (voltage exceeds threshold)
- If the battery has recently been on charge (voltage still exceeds threshold)
- Checking a possibly sulphated battery:
- Do not put the battery on charge before testing
- If the battery has been recently charged, allow the battery to settle for 4 - 8 hours before testing
- NOTE: The green LED will always be on while the battery is under charge (no load tests performed)
Which mode should I use?
|LO:|| Default setting. Switches off when battery 80% discharged.|
Suitable for most petrol/diesel vehicles, UPS and solar/wind applications.
|HI:|| Switches off when battery is not being charged.|
Suitable for most electric vehicles, UPS applications. (Golf car mode)
|WW:||Switches off when battery is being charged, or is 80% discharged. (Aircraft mode)|
|NOTE:||Batteries that lie idle for long periods should be left on trickle charge (e.g. 100mA) with Megapulse in LO mode. This keeps Megapulse operating and minimizes battery deterioration.|
Table showing the battery voltage < below & above > which Megapulse Mk.4 switches off:
|Battery voltage||LO voltage||HI voltage||WW voltage|
|6v||< 5.3v||< 6.4v||-|
|12v||< 10.5v||< 12.8v||> 12.8v|
|24v||< 21.0v||< 25.6v||> 25.6v|
|36v||< 32.0v||< 38.4v||-|
|48v||< 42.5v||< 51.2v||-|
Simple operational test
- Required: portable AM radio tuning the MW band (0.5 - 1.6 MHz)
This test is useful as a way to check that Megapulse is operating when the unit is difficult to access.
Tune around 1.4 MHz, selecting a spot where there is no broadcast station, and listen for the pulse noise produced by Megapulse.
Hold the radio within 1.5m of where the Megapulse unit is mounted. Slightly vary the tuning to find the loudest reception of the noise signal. Every 30 seconds, the noise will stop for 1 second while Megapulse performs a battery voltage measurement. This characteristic period of silence will ensure the noise signal you are listening to is being produced by Megapulse, and not some other source.
Click here for a .wav example of noise from a Mk.4 Megapulse picked up on a cheap portable radio. Note the one-second silent period that occurs in the middle of this recording. You may or may not hear the whistle evident on this recording, just the 'background' noise.
Issues with sealed/flooded lead acid batteries
- It has been found that the small sealed lead-acid batteries similar to that shown on the left can be easily damaged in normal use. These types of battery are commonly found powering golf trolleys, gate motors, alarm systems etc.
Our experience leads us to believe these batteries are very intolerant of overcharging - even continuous charging at voltages recommended by the manufacturers - which can lead to loss of capacity after a period of months. The damage that progressively increases over time does not appear reversible.
These types of battery generally cannot be revived, once the performance has seriously deteriorated.
The good news is that, using Megapulse and a simple timer, the performance of new batteries can be maintained for substantially longer periods: 2 - 3 years is not unusual. More details of the method can be downloaded here.
Notes on charging lead acid batteries
- The following graph shows the relationship between the open-circuit voltage of a flooded-cell lead-acid battery (for a 12v battery and 48v battery bank) and its state of charge:
- While the voltage is temperature-dependent, this is negligible compared to the more significant variation between different makes and types of lead-acid battery, which can amount to 0.5v in some cases. Therefore the above chart is a rough guide only.
The following tables summarize all the important voltages when dealing with lead-acid batteries. It must be noted that the voltages shown are typical of the battery types. The construction of a battery will affect these voltages, resulting in different recommendations by different manufacturers.
Hybrid lead-acid battery
Lead-calcium / silver calcium lead-acid battery
VRLA lead-acid battery
AGM lead-acid battery
The best charger for a battery that is cycled through periods of charge and discharge is a multistage 'smart' charger which typically operates as follows:
- Bulk charge: high current charging to quickly reach about 90% of battery capacity
- Absorption charge: constant voltage decreasing current up to 100% of battery capacity
- Float charge: lower voltage low current charging to keep the battery at 100% capacity
- Equalization charge: see notes here
Batteries can be kept permanently on charge at the float voltage without damage.
A lead-acid battery is approximately 75% efficient, meaning it takes about 1.3 times more power to replace the charge that has been taken out of the battery during use.
How long a battery can power Megapulse without being recharged
- If possible, a battery should not be discharged beyond 50% SOC. In other words, assume 50% of the Ah in a battery is available to power Megapulse between charges.
(Should the battery be discharged down to 20% of its Ah rating, Megapulse will automatically power down to prevent the battery being damaged by complete discharge. Of course, the battery will require recharging before further use. Megapulse will automatically restart while the battery is being recharged..)
The following table shows the typical maximum time between charges for a 12v battery fitted to a vehicle.
- Column 1 defines a range of battery capacities.
- Column 2 assumes the only load is a Megapulse unit, and ignores the battery self-discharge rate.
- Column 3 assumes a typical vehicle 'key-off' load of 20mA plus a Megapulse unit.
- Column 4 assumes a typical vehicle 'key-off' load of 40mA satellite tracking unit, plus a Megapulse unit.
- The data for both the Mk.4 and Mk.5 Megapulse models are shown in columns 2, 3, 4.
- Time period shown is the time taken for a fully-charged battery in new condition to reach 50% SOC.
- The Ah capacity of an ageing battery (without Megapulse protection) decreases, which should be taken into account.
- Where a battery stands for periods exceeding those shown, a trickle charger or solar panel should be used to keep the battery fully charged.
It should be noted that where a battery discharges faster than expected, the problem is likely to be additional loads that have not been taken into account.
Shipping information and dimensions
|DESCRIPTION||SIZE (mm)||WEIGHT (kg)|
|Megapulse Mk.5 unit:||92 x 52 x 17||0.120|
|Megapulse Mk.4 unit:||100 x 58 x 21||0.182|
|Megapulse filter unit:||130 x 85 x 30||0.212|
|Megapulse Mk.5 unit: (shipping weight)||155 x 135 x 22||0.174|
|Megapulse Mk.4 unit: (shipping weight)||200 x 135 x 40||0.248|
|Megapulse filter: (shipping weight)||150 x 135 x 40||0.276|
- NOTE: Dimensions subject to change without notice.
|Megapulse Mk.5 mounting hole (4mm dia) spacing:||78 x 38|
|Megapulse Mk.4 mounting hole (3.5mm dia) spacing:||85 x 40|
|Megapulse filter mounting hole (4mm dia) spacing:||60 x 80|
|Megapulse pos / neg cable length (approx):||470 / 470|
|Megapulse cable lug int. dia.:||8|
|Megapulse filter screw terminal dia.:||6|
|Megapulse filter terminal spanner size:||10|