I purchased a 100 AH Lithium battery from a local kayak dealer here in NH about 2 years ago. I have never used it or hooked it up to anything. Is there anything I can hook up to it to see if it's functional? I have put the battery on a it's charger, but it reads that the battery is at 100% full. I would presume some sort of discharge would happen, but I could be wrong. I purchased this battery at 1/2 off as the manufacturer went out of business. Enduro is the brand name. 

     Another red flag for this battery is that the app isn't reading the battery. Then again, seeing as how the battery is new and has never done any work, maybe the Wi-Fi function of the battery isn't enabled yet. What I'm looking for here is something that is easily attached to the battery just to do a functions check. 

Have you checked it with a voltage meter?  Have you synced the app with the battery before?

 

My guess is the battery is fine and the app is not synced to the battery.

 

Anything that requires 12 volts could be used to test it.  If you don't have anything, you can buy something like this.  This tester is $4 at Harbor Freight.

 

 

I’ve had lithium batteries in storage before for up to 9 months and they were almost 100%. But then, they were full charge when I put them in storage. I think if they are low when put away, they can drain faster. 

No one wants to spend money on something they rarely use, but you can get a meter from Amazon on sale for next to nothing, and it will work for your TM batteries, car batteries, household receptacles, even going through those "are these AA batteries still good?" box in the closet.  It can even help you find a short in your boat trailer lights.  A tester light is great for "any" amount of charge, but you want to know if you have 12.1 or 12.6 before you hit the water.  That's a make or break your day difference.  I use my meter frequently so I have a name brand, but this one from Amazon gets good reviews:

https://www.amazon.com/AstroAI-Multimeter-Voltmeter-Resistance-Continuity/dp/B0CLV8R7QF/ref=sr_1_6?crid=102BA61KDTKMD&dib=eyJ2IjoiMSJ9.BFQ75Xh-9VsMNCgA75NChJ4EvBn03HSeasFjjzBAbBIzhgk78K5bFg24Cvnlt3mtUfKrd-91bOcklO5P_E21uJihtdmg-O0I4tDWfvIbKF4Dcd4OrS_YIP47OWngrUy81pANJ_gb-9X_5hmOb4ylfLD8WP_NYbFqfrYB7D2wBnK71Mk5sjH40EURHc5HG4istGCkpVvRa_s3QRBq2uDZkAMQte_otN3s9FOvpiLj6TQorVWjJyFj6Aw3oFqFKQL3g0yLGxy4aZaiJpPApRldTRaXNThGzO-eWpd6jLjYya0.XCMhRfLyNYQB_Q2qyvmFSrojTdd-FAzx1L0Q3mUzWVY&dib_tag=se&keywords=voltage%2Bmeter&qid=1764513845&sprefix=voltage%2Bmeter%2Caps%2C161&sr=8-6&th=1

 

 

 

I agree, a multimeter is a good tool to have.

multi meter for sure.  that is my first move for anything electric.

 

my Dakota Lithium can sit for months and not even fart down a blip of juice.  

Just placed an order for a Multi Meter. Thanks to all for the replies.

 

     I have also heard that the battery may be "Sleeping". To wake it up, I should hook it up to a NON LITHIUM Battery charger for 10 seconds or so. Can anyone else here verify this?

NEVER - EVER -EVER hook a Lithium battery to a charger not rated for it....not unless you want to buy a new battery.

3 hours ago, RLinNH said:

 I have also heard that the battery may be "Sleeping". To wake it up, I should hook it up to a NON LITHIUM Battery charger for 10 seconds or so. Can anyone else here verify this?

This almost certainly will not work.  Most chargers will not apply a charge if they don't detect a battery connected.  Lithium chargers will apply a charge for a short time even if no battery is detected to restart them.  If you don't have a lithium charger you can use another battery to jump start the battery.  Many LIFEPO4 makers say you must use a lithium charger with their batteries.  I would never tell someone not to follow manufacturers recommendations but my guess is they just don't want to deal with people submitting warranty claims because their battery won't take a charge when it's just asleep.  The manufacturer of my battery (Battleborn) says you can use a traditional charger on the AGM setting.  On my charger the AGM and LifePo4 charge profiles are identical.  The only difference is the LifePO4 setting will restart a sleeping battery.  

 

A basic charger that doesn’t detect anything from the battery (by design) hooked up to a lifepo battery will wake it up. As will jumping it to another 12v battery. It just needs to feel 12v for a minute to wake up. 

So that's a hard no to hooking it up to a Battery Tender. I'm thankful I asked. 

     I do have a lithium charger. I'll hook my lithium battery up to that prior to me installing it in my boat6 after I install the trolling motor onto my Sum Dolphin Pro 120. Thank you for the education folks...👍