Can CTEK CT5 Smart Charger CT79FR Safely Charge Lithium Battery With BMS Battery Management System?

Updated 07/08/2025 | Published 07/01/2025

Question:

Can the new ctek ct5 smart charger CT79FR safely charge a lithium battery with a built-in BMS in my 2021 Casita Spirit Deluxe? -Dena in Austin, TX

asked by: Dena

Expert Reply:

Yes Dena, the CTEK CT5 Smart Charger # CT79FR is fully compatible with lithium (LiFePO4) batteries, even if they have a built-in BMS (most do). This model automatically recognizes lithium chemistry and delivers the right charging profile to protect your cells and maximize lifespan. No add-ons or adapters needed.

We’ve had several Casita and Scamp owners using it to maintain Battle Born or Renogy lithium batteries over the off-season. One of our neighbors, Eli from New Braunfels, said his # CT79FR kept his 100Ah lithium battery at 100% through a full Texas winter.

Are you pairing it with solar or running it off shore power at home? We can help optimize for either case.

expert reply by: Andrew N

Jason

7/8/2025

Dena, I’m using the CT79FR on a Battle Born 100Ah in my Class B. BMS kicks in when I drain it below around 10 or 10.5 Volts, and the CTEK still wakes it right back up once the battery BMS resets. I’ve been impressed how well it handles the recovery phase

Andrew N.

7/8/2025

@Jason Awesome feedback Jason! That's a great example. The CT5's lithium profile is smart enough to resume charging as soon as the BMS re-enables after a low-voltage shutdown. Just a heads-up for folks using lithiums in cold storage: make sure your battery is rated for low-temp charging or store it indoors if temps drop below freezing. Charging below 32°F can damage LiFePO4 cells unless the battery has a built-in heater.