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After a cloudy week at the cabin, the battery bank sits low and the charger shows no current flowing, and why won’t my lithium battery charge usually comes down to the charger, the connections or the battery’s own protection. A lithium battery stops charging when the charger profile does not match, when a connection is loose or corroded, when a fuse has blown, or when the battery’s protection has cut the battery off. The steps below work through those causes in order.
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Why won’t my lithium battery charge: the quick answer
Check the charger, the connections and the battery, in that order. A charger made for lead-acid batteries will not charge a lithium battery correctly, and a lithium battery whose protection has cut it off needs a charger that can wake it. Loose or corroded terminals, a blown fuse and a charger set to the wrong battery type all stop charging, and each cause has a simple check. A Victron Blue Smart IP22 charger lists 12V and 30A output for lithium and deep cycle batteries, with a bulk, absorption and float algorithm for Li-ion batteries.
Step 1: Match the charger to the battery
A lithium battery needs a charger with a lithium profile. A charger made for lead-acid batteries charges to the wrong voltages and may never finish, or never start, a lithium charge. Check the charger for a lithium or Li-ion setting before anything else. A Victron Blue Smart IP22 charger lists 12V and 30A output for lithium and deep cycle batteries, and it charges Li-ion batteries with a bulk, absorption and float algorithm. The same charger carries IP22 protection and certification to UL1236. If the charger has no lithium setting, it is the wrong charger for the battery, and a charger with a lithium profile is the fix. See the lithium vs lead acid charger guide and the best way to charge a lithium ion battery guide.
Small cells take a different charger from a 12V battery. An EBL 8-slot charger (on Amazon) lists 8 independent slots for 1.5V lithium and 1.2V Ni-MH cells, with LED indicators: solid green means fully charged, solid red means charging in progress, and flashing red means the charger has found a non-rechargeable or damaged battery. A 12V lithium battery never goes in a slot charger made for small cells.
Step 2: Check the connections and the fuse
Loose or corroded terminals stop a charge as surely as a dead charger. Take the terminals off, clean them, and fit them back tight. Check the fuse in the charging line and replace it if it has blown, with the same type the manual names. Look over the cables for breaks, melted spots and loose crimps, and check that the charger plugs firmly into its outlet.
A meter tells the charger from the battery apart. Measure across the charger output with the battery disconnected: a charger that puts out voltage is working, and the fault sits in the wiring or the battery. Measure across the battery terminals too: a battery that shows no voltage at all has cut itself off or failed, and a battery that shows voltage but will not take a charge points back to the charger or the connections.
Step 3: Wake a battery the protection cut off
A lithium battery that ran flat can cut itself off, and a charger then sees no battery to charge. The charger shows no current flowing, and the battery looks dead, but the cells may only need a wake-up charge. A charger with adaptive battery management and a lithium profile can wake such a battery: the Victron Blue Smart IP22 lists microprocessor-controlled adaptive battery management that optimizes charging based on battery usage. If the battery will not wake after a charge attempt, the battery itself may have failed, and the maker or a battery specialist should check it. See the battery management system guide for what the protection does inside a lithium battery.
Step 4: Rule out temperature and a worn-out battery
A battery left in the cold may refuse a charge until it warms up, and a battery left in strong heat may stop charging to protect itself. Move the battery to a mild spot and try again. A battery stored flat for a long time may cut itself off as well, so check a stored battery through the off season and recharge it before it runs flat. A battery that has served for many seasons and now holds little charge may simply be worn out; if it will not hold a charge after the other checks, it has reached the end of its service life.
Ways to keep a lithium battery charging
- Use a charger with a lithium profile matched to the battery.
- Keep the terminals clean and tight, and check the fuse in the charging line.
- Do not let the battery run flat; recharge it before it cuts itself off.
- Store the battery where it stays mild, and check it through long storage.
FAQ: power away from the grid
Can I charge a lithium battery with a lead-acid charger?
Not reliably. A lead-acid charger charges to the wrong voltages for lithium, so the battery may never finish charging. Use a charger with a lithium profile, such as a Victron Blue Smart IP22 charger that lists 12V and 30A output for lithium batteries.
Why does my charger show no current flowing?
The battery’s protection may have cut it off after it ran flat, or a connection may be loose and a fuse may have blown. Check the terminals and the fuse, then try a charger with a lithium profile that can wake the battery.
How do I know if my lithium battery is dead?
If the battery will not wake after a charge attempt with a lithium-profile charger, and the connections and fuse check out, the battery may have failed. The maker or a battery specialist should check it before you replace it.
Can cold weather stop a lithium battery from charging?
Yes. A battery left in the cold may refuse a charge until it warms up. Move the battery to a mild spot and try again, and keep the battery where it stays mild through storage.
What does a flashing red light on my charger mean?
On an EBL 8-slot charger, a flashing red light means the charger has found a non-rechargeable or damaged battery. Take that battery out and try another slot; if the light still flashes, the battery is damaged and should go out of service.
Related solar guides
See the lithium ion battery problems guide, the can you overcharge a lithium battery guide, the how to recharge a lithium battery guide and the battery charger problems guide.
