Question about undercharging

[klubber]

Does the standard controller in a clubcar DS IQ shut down at a level that would prevent a lithium battery from being over discharged?

[bronsonj]

I thought the standard controllers worked until they were in the 24 or 25v range.

If you put a lithium pack in a cart and are relying on the stock controller to stop your over-discharge you will be sorely mistaken. You can put in an aftermarket controller and set the low voltage cutoff, but then that is the entire pack voltage and not individual cells.

If you are going to install an aftermarket controller, bottom balance your pack and then make sure your pack stays balanced this can be a workable strategy, but you really need to know your lithium cells well before attempting this. The safer option is to install a BMS and have the BMS control your solenoid (or other LV cutoff mechanism).

[klubber]

Originally Posted by bronsonj

I thought the standard controllers worked until they were in the 24 or 25v range.

If you put a lithium pack in a cart and are relying on the stock controller to stop your over-discharge you will be sorely mistaken. You can put in an aftermarket controller and set the low voltage cutoff, but then that is the entire pack voltage and not individual cells.

If you are going to install an aftermarket controller, bottom balance your pack and then make sure your pack stays balanced this can be a workable strategy, but you really need to know your lithium cells well before attempting this. The safer option is to install a BMS and have the BMS control your solenoid (or other LV cutoff mechanism).

Thank you. i thought that was the case, but was told that it was possibly different. What you say makes more sense to me.

[Volt_Ampere]

No way would I run with Lithium and no BMS. Undervoltage protection on a per cell basis is necessary to protect the pack from damage. Mine is a loud alarm - no actual cutoff.

[klubber]

Originally Posted by Volt_Ampere

No way would I run with Lithium and no BMS. Undervoltage protection on a per cell basis is necessary to protect the pack from damage. Mine is a loud alarm - no actual cutoff.

It wasn't a consideration to run with no BMS, but as I was given to understand the BMS does not protect on its own from over discharging.

[Volt_Ampere]

Originally Posted by klubber

It wasn't a consideration to run with no BMS, but as I was given to understand the BMS does not protect on its own from over discharging.

Some do. My home built one does. Look up LVC (Low Voltage Cutoff)