BCU-NEV-XXC MANUAL
1.0
Disconnect one of the signal wires between the cell modules. The red LED on the BCU will flash
After a delay of about 10 seconds the relay will switch off. Switching on the charger at this time
should have no effect, that is, it will not switch on. Switch the charger off at the wall and reconnect
the signal wire.
Reset the BCU by switching OFF/ON again.
Switch on the charger, it should now work. Charge until the battery is full and the charger switches
off. If the BCU switches off then an overcharge has been attempted. Reset and recharge while
watching the battery closely.
The battery should now be ready for use.
General Charging Tips
Once the battery pack is balanced it can be used and charged as required. Occasional partial
recharges are acceptable but should not be commonplace or the balance of the battery may be
affected.
If there is a battery error the BCU will terminate charging. This may not be serious if the battery is
slightly out of balance after a few partial charges or deep discharges. However if it persists it may
be necessary to check the battery.
If the battery has been discharged to a point where one or more of the cells is below 2.5V the BCU
will disconnect the battery. In this case reset the BCU by switching OFF/ON and recharge
immediately.
If the BCU keeps terminating charging not do not persist or worse battery damage may result.
Check the battery and charge individual cells if required using a small current (1A max).
About Lithium Iron Phosphate Batteries
A “battery” is made up of “cells”. Each cell is an individual unit that cannot be split into a lower
voltage component.
LFP cells have a nominal voltage of 3.2-3.4V. This is the voltage that the cells drop back to when at
rest. They will stay around 3.2V until about 90% discharged when the voltage will begin to
decrease until fully discharged at 2.5V. It is highly recommended to discharge less than 80% of the
cells total Amp Hour capacity. This will help to maximize the cell life.
LFP cells may be connected in “series” (+ to – to + etc) to obtain a higher nominal voltage. This
creates a “battery”. They may also be connected in “parallel” (+ to +, - to -) to increase the Ah
capacity. Under no circumstances should cells or a battery be short circuited, that is the +
connected directly to the – to create a loop. This will damage the cells and most likely the operator
also.
Under no circumstances should the cell voltage be allowed to fall below 2.5V for a sustained
period. Permanent damage will result. It is possible that this situation may occur if the battery is
allowed to stand for a long time (ie. months). In this situation the BMS will not allow recharge
because a cell is outside the safe range. To try and rectify the problem a small 4.5V 300mAh DC
plug pack type power supply can be applied to individual cells one at a time until the cell voltages
rise above 2.5V and the BMS will allow normal charging to commence. Care must be taken with
the first few charges as the battery may be severely unbalanced.
PAGE OF
15
17