Pulling 12v off a 24v battery.

[IHaveThePower]

Is it safe to pull 12v to a dc distribution box off a 24v battery system (2x 12v 200ah)
Or must I buy a dc/dc converter and draw directly from the full string?
I'm wondering how drawing off one side of the string will affect the 24v balance and the shunt readout.

 

[rmaddy]

Please download "Wiring Unlimited" and read chapter 3.

Wiring Unlimited

Wiring Unlimited is a great resource that covers many many common topics and questions relevant to DIYers. It is a free E-book from Victron Written by Margreet Leeftink. Check it out! Download

diysolarforum.com

In section 3.5 you will find:

It is not allowed to connect loads to the midpoint of a battery bank in order to be able to run loads that require a lower voltage. Doing so will create a large imbalance in a battery bank. This imbalance is much bigger than a battery balancer can potentially rectify (larger than 0.7 A) and the battery that is used to provide the lower voltage will fail prematurely.​

In short, never pull partial voltage from batteries in series. You will need the 24V-12V DC-DC converter.

 

[IHaveThePower]

Please download "Wiring Unlimited" and read chapter 3.

Wiring Unlimited

Wiring Unlimited is a great resource that covers many many common topics and questions relevant to DIYers. It is a free E-book from Victron Written by Margreet Leeftink. Check it out! Download

diysolarforum.com

In section 3.5 you will find:

It is not allowed to connect loads to the midpoint of a battery bank in order to be able to run loads that require a lower voltage. Doing so will create a large imbalance in a battery bank. This imbalance is much bigger than a battery balancer can potentially rectify (larger than 0.7 A) and the battery that is used to provide the lower voltage will fail prematurely.​

In short, never pull partial voltage from batteries in series. You will need the 24V-12V DC-DC converter.

Thank you
I figured balance would be thrown out of whack, wasn't sure if the batteries would notice or self balance such small dc loads.
I appreciate the info.