I have a new 12v 100AH lithium battery. It has been sitting on a shelf for over 18 months unused. I hooked it up to my Sun Dolphin Pro 120 today and my worries were validated. It's in "Sleep" mode. I contacted the shop I purchased the battery from and their answer was to purchase a "Smart" Lithium battery charger, from them of course, and over charge the battery to wake it up. When I asked them if they would do that for me they declined. They stated that this doesn't always work. So. Anyone here know how to get a lithium battery out of sleep mode? I really don't want to have to purchase another battery. Especially when this one has never been used.

Jump it with another battery. A smart battery charger might not do it because it sees ‘sleep’ on the other end and stops trying to charge. If the charger has a wake up mode then do that. Or, a ‘dumb’ charger connected to the battery will probably do it. It just needs a jump of voltage. You can jump it to another battery (same terminals connect) and that will do it too.

This always works for me.

20 hours ago, casts_by_fly said:

Jump it with another battery. A smart battery charger might not do it because it sees ‘sleep’ on the other end and stops trying to charge. If the charger has a wake up mode then do that. Or, a ‘dumb’ charger connected to the battery will probably do it. It just needs a jump of voltage. You can jump it to another battery (same terminals connect) and that will do it too.

20 hours ago, casts_by_fly said:

Does the other Battery need to also be a lithium battery? Or can I use the 12v Lead/Acid Battery from y camper with jumper cables?

lead acid is fine. The BMS just needs to see a voltage applied to it for 10-20 seconds or so.

1 hour ago, casts_by_fly said:

lead acid is fine. The BMS just needs to see a voltage applied to it for 10-20 seconds or so.

After I "jump" the battery, then hook it up to the lithium charger and let it charge. Correct?

Yep.

Dissolve some No-Doz in water and pour it on the terminals. 😁

Nothing to date has worked. Battery is still in sleep mode. I have tried to jump start the battery from another battery. It hasn't worked. I believe that the company that manufactured this battery went out of business for a reason. I'll probably wind up purchasing an old school deep cycle lead acid battery after this fiasco. $800.00 battery 19 months ago, and now it's ****. unreal...

What brand is it?

It is possible that it died from sitting if it was put away empty and then sat for 2 years. 19 months at 1-3% per month is 20-60% of the capacity it could have self discharged. That’s extreme but not out of the realm. I wouldn’t give up yet. I would bet that the cells are depleted and the BMS is in sleep mode. It will need a wake up and a charge, it’s just how do you trigger it to do that. If all else fails, put the lead acid battery and the lithium in parallel to get the bms jump and then connect the charger at the same time. The lead acid will have enough voltage to wake up the bms and then the charger can push current. You might have to leave it sit this way for a little bit but once it comes out of sleep mode you’ll be okay.

3 minutes ago, casts_by_fly said:

What brand is it?

It is possible that it died from sitting if it was put away empty and then sat for 2 years. 19 months at 1-3% per month is 20-60% of the capacity it could have self discharged. That’s extreme but not out of the realm. I wouldn’t give up yet. I would bet that the cells are depleted and the BMS is in sleep mode. It will need a wake up and a charge, it’s just how do you trigger it to do that. If all else fails, put the lead acid battery and the lithium in parallel to get the bms jump and then connect the charger at the same time. The lead acid will have enough voltage to wake up the bms and then the charger can push current. You might have to leave it sit this way for a little bit but once it comes out of sleep mode you’ll be okay.

The brand is Enduro

Every BMS and charger can be different so don't give up yet. The BMS has disconnected the battery cells from the terminals because the cell voltages are below a set threshold. Your battery charger doesn't detect a voltage so it doesn't charge. The BMS will allow a charge but may not show voltage until the voltage on every cell rises above the minimum threshold. Just connecting another battery to your battery may not do anything. You have to fool your charger into suppling a charge long enough to bring the cell voltages up above the cut off threshold. Leaving another battery connected in parallel for a few minutes while charging may do the trick.

5 hours ago, Tennessee Boy said:

Every BMS and charger can be different so don't give up yet. The BMS has disconnected the battery cells from the terminals because the cell voltages are below a set threshold. Your battery charger doesn't detect a voltage so it doesn't charge. The BMS will allow a charge but may not show voltage until the voltage on every cell rises above the minimum threshold. Just connecting another battery to your battery may not do anything. You have to fool your charger into suppling a charge long enough to bring the cell voltages up above the cut off threshold. Leaving another battery connected in parallel for a few minutes while charging may do the trick.

I left another battery connected in parallel for over an hour while charging.. Nothing. Thanks to all for the recommendations. Much appreciated!!!

7 hours ago, RLinNH said:

$800.00 battery 19 months

I assume it's still under warranty. Contact the seller you bought it from.

19 minutes ago, gim said:

I assume it's still under warranty. Contact the seller you bought it from.

I just looked it up. Seems like they went out of business about a year ago. This might explain why.

Dang…$800 for a 100ah lifepo4? This is why I bought cheap $150 no brand name ones on Amazon. I have no confidence in the brand name warranties. I’ll just buy another cheapo lithium if needed.

@RLinNH If you were my next door neighbor I would fix the battery for you. I'd be willing to bet it wouldn't be very hard. Worst case I would return the battery to you working but with the case duct taped together. 🤭

16 hours ago, Tennessee Boy said:

@RLinNH If you were my next door neighbor I would fix the battery for you. I'd be willing to bet it wouldn't be very hard. Worst case I would return the battery to you working but with the case duct taped together. 🤭

TB, I'm cracking the lid open on this battery to have a look see. Other than the obvious non connected wires and what not, what else should I be looking for while doing the exploratory surgery? Also, while it's open, is there anything I can do while the lid is off to take it out of Sleep?

What charger are you using on the Enduro battery? Hopefully, it's a Noco Genius 10 smart charger. If so, To wake up a sleeping lithium battery with a NOCO Genius 10, use Force Mode. Connect the charger to the battery, press and hold the mode button for 5–7 seconds until the modes flash, then select the lithium mode. This forces 12-13V into the battery, bypassing the low-voltage protection.

While not the same as your problem, I followed these steps to bring back an X2 agm battery which showed only 3.2 volts. Charger shut down a couple times but repeated the steps for the third time and it completely recharged the battery overnight.

3 minutes ago, Capt Ed said:

What charger are you using on the Enduro battery? Hopefully, it's a Noco Genius 10 smart charger. If so, To wake up a sleeping lithium battery with a NOCO Genius 10, use Force Mode. Connect the charger to the battery, press and hold the mode button for 5–7 seconds until the modes flash, then select the lithium mode. This forces 12-13V into the battery, bypassing the low-voltage protection.

Ed, I'm using the Enduro charger I purchased with the battery. It isn't a smart charger. But, I just pulled the trigger on the smart charger you mentioned. Should be delivered by end of business tomorrow. I'll let you know how it goes. 🤞

I just took my new voltage meter out of the box and gave myself a brief education into the utilization of it. My camper deep cell battery is reading 13 volts. The Enduro Lithium battery is reading 2.03 volts. ☹️ Crossing my fingers that the smart charger will wake her up. If not, it's all good. I can use the new smart charger on whichever battery I choose to replace the Enduro.

What brand smart charger? Some brands like NoCo have a repair mode which you have to manually activate.