Lithium Battery in 36V system

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LookoutRanch
Posts: 86
Joined: Sun Feb 24, 2019 3:01 pm

Lithium Battery in 36V system

Post by LookoutRanch »

Recently bought a boat with 3 K2, 27 Series batteries running the Ultrex up front. When I bought the boat I did some checking and was told the MinnKota charging system would charge the batteries without an issue, but to get 100% of the energy to use the dedicated lithium charger do to the charging at lower Amps and Higher volts. Fast forward 3 months of use under the same charging practices as the original owner and I had 1 of my batteries shut off while out fishing rendering us with no power to the trolling motor. Since then I’ve got the run around from K2 following there steps of buying their special charger and advice with no changes. When I hook up the battery to a volt meter it shows 13.3 volts and 12.6 when loaded.
Now here’s the part I need advice.....I’ve heard you can jump these batteries to wake them up to start accepting charges again, but there’s not a lot of info I can find and I’ve only heard good things about Lithium batteries. Just looking for the ugly and if anyone else has had these issues. K2 is hard on the 12 month warranty even though they boast a 9-10 year life and over 5000 discharge life. Any advice, suggestions, I’ll take them
2017 Ranger Z520C
ETec 250 HO

Let’s Go Brandon
Bassfishman
Posts: 99
Joined: Sat Jan 23, 2016 9:50 am

Re: Lithium Battery in 36V system

Post by Bassfishman »

Not sure which Minn Kota battery charger you have but on their website the MK Precision charger says the following:

Battery Type Selection: Each charging bank can be selected to your specific battery type (AGM, gel or flooded lead acid) to guarantee a safe, protected charge.

So it doesnt say its compatible with a Lithium Battery System.

Since one of your batteries went dead on the water I would say the MK charger is not fully charging your batteries because it doesnt have enough voltage output to fully charge the lithium batteries.

I'd say you really should put a battery charger in that is designed to charge Lithium Batteries and their unique voltage and full charge characteristics. I would think K2 would love to sell you one. It might be pricey though. Hopefully your lithium batteries arent damaged, they just are not getting charged. You may or may not know it but a traditional lead-acid battery has 6 cells in series that operate at about 2.1 volts each and the lithium battery has 4 cells in series operating at about 3.6 volts each. The MK charger is putting out about 12.6 volts where as the lithium battery needs about 14.4 volts to get fully charged.

As for "jumping" the batteries - I'm not sure what that means, but I wouldnt attempt it. I'd invest in a lithium battery charger first.

It chemistry. The lithium is great for the application but its not lead acid and it needs different supporting equipment and the battery charger is the most important piece.
LookoutRanch
Posts: 86
Joined: Sun Feb 24, 2019 3:01 pm

Re: Lithium Battery in 36V system

Post by LookoutRanch »

Thanks for the reply. I checked the MK460 charger and pod 2 charged another battery no problem. I did get the specialized charger and the battery continues to shut down.
I called Minnkota and they state the charger will charge Lith. Batteries but to only 85% due to the lower voltage that the Minnkota puts out which is about .8 volts less than the Lith factory spec required to get 100% charge.
Again today got the run around from K2. I’m sure you hit the nail on the head about wanting to sell another battery to me. I’m pretty much to the point, I will go buy 3 X2’s Group 31’s and put a bow on it. I just want to go fishing again.
Anybody want to buy 2 K2 Group 27’s?? I’ll make you a good deal or take rods/reels in trade.
2017 Ranger Z520C
ETec 250 HO

Let’s Go Brandon
Paul Matthews
Posts: 81
Joined: Wed Nov 23, 2005 6:54 pm

Re: Lithium Battery in 36V system

Post by Paul Matthews »

You can wake that battery up. Disconnect it from the system and jump it with your truck running. This is what lithium pro advices. Not familiar with K2 but if you set on using lithiums, Lithium Pro will not give you the run around, Ben running them for 3 years. Had 1 issue and they where all over it. You get what you pay for BTW how much is a 12v k2?
LookoutRanch
Posts: 86
Joined: Sun Feb 24, 2019 3:01 pm

Re: Lithium Battery in 36V system

Post by LookoutRanch »

I’ll try jumping it again. I attempted to do this but the internal breaker keeps shutting the battery down and won’t allow it to charge or discharge.
I was on customer service yesterday giving them all the readings and load testing it with my equipment and the battery shows charged and good but after 5-15 minutes of use the internal breaker pops and shuts the battery off.
K2 customer service response was”that’s never happened before, it must be a bad battery or circuit board inside, our batteries are meant to be used for over 5000 cycles or 8-9 years”.
But since mine are 16 months old they won’t warranty it and we’re prepared to sell me another $1100 battery. Ah no thanks.
I think at this point I’m going to switch back to old reliable Group 31, X2 AGM’s that I’ve had on my other boat and they exceeded life span to 5-6 years.
Sucks one of the perks and increased price point of the boat was the batteries on board. If I upgrade again I think LP’s are way to go.
2017 Ranger Z520C
ETec 250 HO

Let’s Go Brandon
Paul Matthews
Posts: 81
Joined: Wed Nov 23, 2005 6:54 pm

Re: Lithium Battery in 36V system

Post by Paul Matthews »

1100 bucks for 1 12 volt. You can buy a 36 volt Lithium Pro for around 2k. It weighs 29 lbs. They are pricey but well worth the money if you fish a lot.
Paul Matthews
Posts: 81
Joined: Wed Nov 23, 2005 6:54 pm

Re: Lithium Battery in 36V system

Post by Paul Matthews »

BTW Lithium Pros are a 4 year warrantee.
Bassfishman
Posts: 99
Joined: Sat Jan 23, 2016 9:50 am

Re: Lithium Battery in 36V system

Post by Bassfishman »

Whether its $1100 or $2000 for Lithium batteries, either way, you can buy a lot of Lead Acid batteries for that. Yes the Lithium batteries are lighter and its cool technology, but does it really matter in your boat? Ok you get on plane a half of a second faster ... big deal.

BTW, I worked on developing lithium batteries in the '70's and for communication satellites in the early 2000's. For some applications, like a Tesla car or a cell phone or a communication satellite its perfect. But for a bass boat, the advantages are not that many relative to the cost.
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