How do I add/remove batteries?

There will come a time when you will need to change your batteries. This may be due to the batteries wearing down due to usage or could be because you want more out of the system. Whatever the case may be there are a few rules to follow to ensure that the changeover is as smooth as possible and limit the chance of damage to your system. 

Before purchasing a battery, check whether that battery type is supported by your Battery Management System. Not all batteries are compatible with all models.

Disconnection Steps:

1. Turn off your charger at the mains, or remove the mains lead from the vehicle.
2. Identify where your main charger/battery fuses are and remove them. 
3. If you have a separate solar regulator, identify and remove the fuse for this also. 
4. If you have a BatteryPlus35 mk1 remove the Bat+, and Bat- cables from the bottom right side of the unit. If you have a thick, black cable on Negative Output 1 (first cable on the left), remove this also.
5. Undo the Negative terminal on the battery. If you have more than one battery, undo all Negatives at this time. It may be worth labelling where these were connected, particularly if you have a BC300 or another kind of monitor attached.
6. Once all negative lines are removed, it is safe to remove the Positive terminal connections, taking care not to touch your socket/spanner to the chassis or negative terminals. In tight situations, it can be helpful to cover the terminals after removing the connections or using something like a piece of cardboard to protect the chassis from the tools. 

If you are removing the batteries for testing or failure you can now use most items in the van as normal by plugging the mains back in. All BMPRO Battery Management Systems are able to act as power supplies in this manner. This will only work for circuits 1-14, anything connected directly to the battery cannot be powered in this manner.

When it comes time to reconnect the batteries, simply follow the same steps as before in reverse.

Connection Steps:

1. If you have been running the Battery Management System as a power supply, switch this off and unplug it. 
2. Connect your positive terminals. If you have multiple batteries, connect all of them at this time. 
3. Connect the Battery Negative terminals. if there are more than one, connect them all. If you have a BC300, check our article "How do I add a BC300 to my system?"
4. Connect the Negative Output 1 terminal if present.
5. Connect the Bat+ cable at the charger, followed by the Bat-
6. Insert your fuse. Note that if you are upgrading to large capacity systems or lithium, it may be best to upgrade this fuse to a 40amp one, the maximum allowed. Check with us if you're unsure. 
7. If you have a display which shows battery levels, and you have changed the total capacity of the system or type of battery, you will need to update the display to suit. See our article "How do I change the battery capacity of my system?"
8. Turn on mains to finish the installation.

If adding a second battery, wherever possible, try to balance the draw from the batteries by connecting them as below. Ensure the cable size is equal to or greater than the minimum requirements for the system.

If you have added Lithium batteries, refer to the article "How do I set my system to lithium batteries?".

Failure to do so can lead to damage to the batteries and the power management system.