Frequently Asked Question

CLASSIC - LITHIUM - How do I set the Classic to charge Lithium batteries (archived)?
Last Updated about a month ago

The Classic has no native support for charging Lithium battery packs.  All you can do is use some of the Lead-Acid settings.

The Classic can charge Lithium battery packs that have a BMS (Battery Management System) installed. We don't recommend nor support charging of Lithium battery packs without a BMS. "Balancers" are not considered a BMS.

The ABSORB setting will be the voltage the BMS wants/needs to charge the battery. The ABSORB TIME will be set to however many minutes are required. Sometimes this is set low as when this voltage is reached some lithium batteries want the charge to stop. The Classic has a low limit of 3 minutes. The EQ setting is generally not used.

NOTE: It is actually the BMS that is charging the battery. The Classic can not be setup to insure EACH Cell gets a proper charge. Over-charging a Lithium Cell can have disastrous results as well as financial consequences.

Most Lithium batteries don't need nor like to have a FLOAT voltage so you need to set that to a low value so the BMS sees it as not enough to try and charge. Refer to the Lithium BMS manual for more information. It is common for the Classic to report BATT OVER V and this is nothing to be concerned about, this just means the battery voltage is above the FLOAT setting and charging is now disabled.

The Classic now has a few new features that can be of use for Lithium Battery Systems.
Lithium batteries generally do not require temperature compensation like Lead-acid batteries do. Setting the mV/degC/cell to the lowest value without flipping the setting to DISABLE is about all we can do right now. This allows the BTS (Battery Temp Sensor) to function and this allows us to set an emergency HIGH BATTERY SHUTDOWN temperature in the LIMITS MENU under the CHARGE Menu in the Classic. When this temperature is sensed the Classic will stop charging to avoid a catastrophe.

The other feature of use for Lithium and its BMS is the AUX-2 INPUT to force the Classic to STOP CHARGING. It is detailed in the manual as LOGIC INPUT LO and LOGIC INPUT HI. Look at the attached PDF.

Many Lithium systems want charging to stop @ a voltage and start back @ a voltage. This would be accomplished by setting the ABSORB TIME to 4 minutes (3 minutes is the lowest setting) and using the REBULK Voltage to trigger the Classic to go back charging. REBULK is setup under the BATTERY MENU/ADVANCED. ABSORB TIME is set under CHGTIME.

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