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Author Topic: Lithium 100 ah battery  (Read 5932 times)

taxid

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fishinator

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Re: Lithium 100 ah battery
« Reply #1 on: Dec 13, 2020, 06:29 AM »
That does seem excessive at first glance. But if they really do last 4 times as long as SLA batteries (2000 cycles vs 500) then I would say its worth it. I pay about $200 each for interstate group 31.
  Those are way lighter and have more capacity. And that deal includes a charger. Big initial investment but over the long haul its really about the same.

taxid

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Re: Lithium 100 ah battery
« Reply #2 on: Dec 13, 2020, 07:39 AM »
That does seem excessive at first glance. But if they really do last 4 times as long as SLA batteries (2000 cycles vs 500) then I would say its worth it. I pay about $200 each for interstate group 31.
  Those are way lighter and have more capacity. And that deal includes a charger. Big initial investment but over the long haul its really about the same.

I guess I didn't do the math. Didn't see the charger included either.
“The trouble with quotes on the Internet is you never know if they are genuine.” —Abraham Lincoln

Mac Attack

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Re: Lithium 100 ah battery
« Reply #3 on: Dec 13, 2020, 10:53 AM »
Jeff and I are currently negotiating on a 200aH liFePo unit from this place.

https://www.lithium-battery-factory.com/product/36v-200ah-lithium-rv-batteries/#body_sele


A bit less money for it than Dakota.
I have done a ton of research on these, and the companies involved.

I want 150ah minimum, but strongly want the 200ah.
Unlike lead acid deep storage batteries, if you charge a LiFePo battery sooner, when it is still at a higher percentage charged, you will get more charge cycles out of it.
BTW, you want a LiFePo battery as these do not have the fire/explosion issues related to the earlier lithium batteries that we have heard about.

A deep cycle only has X amount of charges.  That's it.  Which is one of the reasons you are instructed to take them down low before charging them.  They are built to handle this, hence the "deep cycle" designation.
Unlike car and boat starting batteries that are buiilt for super high current draws for short bursts, and require steady charging.
Also, after each charge you get a reduced ah available from the battery.  They age and you realize this.
So each cycle lead acid batteries give you less time out on the water.
LiFePo batteries do not act this way.

500 charge cycles is a tad low if a guy were to seriously take super good care of his lead acid deep cycle batteries.
So let's say 600 charges.
And I know that if you buy larger 200ah LiFePo batteries, and only use say 150ah of them, that 2000 charge cycles now goes up  to like 2666 charge cycles.  (2000/.75=2666)
But if I inly use 1/2 (100ah), it now goes up to 4000 charge cycles.
So let's use the 3000 vs 600 and I now get 5X the life.
I was looking at $180 Duracells from Sams Club.
I needed 3 to get the 36 vdc I need, and they would only be 100ah.
(If I want 200ah I would need 6 batteries wired in series parallel)
So three (3) batteries cost me almost $600 with the sales tax (not including the core charge they hit me with either)
Six is $1200.

The 36vdc 200ah LiFePo unit is $2500 (I'm working on getting that down).
This $2500 includes the charger, overseas shipping, the BMS, and the optional bluetooth feature so I can monitor the battery from our smartphone.

So, for 5X the life, I am paying 3.125X the cost of the 3 lesser ah batteries.
And an even better deal if I can get him down to $2000.
Not to mention the savings if I went with 6 lead acid batteries.

Yup, major investment to say the least.
But huge payback.

Also, my plan is to pull that battery and take to Florida for my other boat down there during the winter.
The seriously lighter weight is a major factor here for this.

Next, let's assume I only use my boat 3X a week.
That's like every other day.
I might do this at first when retired, but doubtful it would continue.
Still, lets assume this.
That's roughly 150 charges a year.
If I get 2600 charges out of the battery it works out to more than 17 yrs.
In reality, this battery will most likely outlive me and Jeff will contune using it.

Again, yup -  major outlay in cash.
But if you do the math it really pays for itself.

I have the 36VDC Minn Kota.
Now I need a battery.
We will order this thing in the next couple weeks.
It takes about 24 days to build and they say about 35 days to ship.
So we are looking at 2 months before we get it without any delays.
I want the battery in late March so this works for us.

filetandrelease

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Re: Lithium 100 ah battery
« Reply #4 on: Dec 13, 2020, 11:49 AM »

 Mac are you putting in an lithium on board charger, and a lithium crank battery

Mac Attack

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Re: Lithium 100 ah battery
« Reply #5 on: Dec 13, 2020, 01:30 PM »
Mac are you putting in an lithium on board charger, and a lithium crank battery

The single 36vdc 200ah battery we are buying for the Minn Kota will come with its own charger from the manufacturer.

This means I’ll be selling my 3 bank on board charger in the Spring if anyone is interested.  BTW, it can charge lithium batteries too.

We are going to replace both of the crank batteries with standard lead acid series 24’s.  Might go dual purpose here but not sure yet.  I already have the 2 bank on board charger installed for these.  I mounted it in the cuddy and ran heavy gage wires rear to the batteries in the bilge area last summer.

filetandrelease

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Re: Lithium 100 ah battery
« Reply #6 on: Dec 13, 2020, 02:05 PM »
 
 Nice

Mac Attack

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Re: Lithium 100 ah battery
« Reply #7 on: Dec 13, 2020, 02:25 PM »
I hope so anyway.
I’ll keep everyone posted on the good and the bad.

filetandrelease

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Re: Lithium 100 ah battery
« Reply #8 on: Dec 13, 2020, 03:13 PM »

 Thanks

zwiggles

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Re: Lithium 100 ah battery
« Reply #9 on: Dec 13, 2020, 09:07 PM »

mcully

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Re: Lithium 100 ah battery
« Reply #10 on: Dec 14, 2020, 08:08 AM »
Did they give you a weight estimate on the unit you want?
Is the single battery footprint much smaller than three lead acids?
Always looking for less weight and more space.

Mac Attack

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Re: Lithium 100 ah battery
« Reply #11 on: Dec 14, 2020, 08:26 AM »
Did they give you a weight estimate on the unit you want?
Is the single battery footprint much smaller than three lead acids?
Always looking for less weight and more space.


yes and yes.
Weight is about 122# for the single 36 VDC unit.
The size can be custom done but that costs more.
I don't have the size of mine yet and I'm still working on the price with the guy.
I thought about puting it inside this side area on the port side down in the cuddy.
That will require a long narrow battery, but it gets it out of the way.
If I put it all the way up front in the bow it provides a little ballast up front and I can let them decide on the physical size and save a few bucks.

Jethro

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Re: Lithium 100 ah battery
« Reply #12 on: Dec 14, 2020, 08:49 AM »
I pulled all the batteries out of my boat yesterday, brought them inside and boy I sure wish I had lighter batteries. Those 3 group 31's are heavy.

Lithium would be great, but I am happy with the money I paid for the Interstates. $179 ea for group 31 batteries. Yes, way less charge cycles and like you said Mac, it gets weaker each cycle, but for the money and with a good charger I should still have these for many years to come. If you take care of them the decreasing performance becomes nominal. Would lithium be better- oh you betcha. But I'm not spending $2500 on a battery!

One thing I worry about Mac, the lithium batteries which I am very familiar with since I've been using a bunch from Amped Outdoors last year, they use that battery management system (BMS). They are regulated batteries which means they push the same, exact amount of power for a given time until it shuts off completely. Not like lead acid where it's only full power the first few moments of using it, then it's a very gradual but continuous drop off until the battery is dead. There have been a lot of times with my Ulterra that I have pushed the wet cell batteries HARD, so much I am worried it won't auto stow but it always does. The lithium with the BMS, if you push past a certain point, you won't get any voltage to the motor at all. The lead acid at least I have enough to stow the motor. That's my only worry with the lithium. I'd rather have it pushing a weak 36v of power than having a BMS that cuts all power once it dips below a certain capacity. Or at least I think I would.

The bonus is I'd be able to have a very accurate battery gauge, not like the gauge I have now for lead acid. With lithium and the BMS you'd be able to know exactly how many hours/minutes or even seconds of battery you have left. That would be really nice. A lead acid gauge is kinda like a mystery. You know how many resting volts you have, but not how many amps it's pushing.

What Duracells were you looking at that were 100ah? They must not be group 31's. I have 210ah batteries.


Mac Attack

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Re: Lithium 100 ah battery
« Reply #13 on: Dec 14, 2020, 10:39 AM »
I pulled all the batteries out of my boat yesterday, brought them inside and boy I sure wish I had lighter batteries. Those 3 group 31's are heavy.

Lithium would be great, but I am happy with the money I paid for the Interstates. $179 ea for group 31 batteries. Yes, way less charge cycles and like you said Mac, it gets weaker each cycle, but for the money and with a good charger I should still have these for many years to come. If you take care of them the decreasing performance becomes nominal. Would lithium be better- oh you betcha. But I'm not spending $2500 on a battery!

One thing I worry about Mac, the lithium batteries which I am very familiar with since I've been using a bunch from Amped Outdoors last year, they use that battery management system (BMS). They are regulated batteries which means they push the same, exact amount of power for a given time until it shuts off completely. Not like lead acid where it's only full power the first few moments of using it, then it's a very gradual but continuous drop off until the battery is dead. There have been a lot of times with my Ulterra that I have pushed the wet cell batteries HARD, so much I am worried it won't auto stow but it always does. The lithium with the BMS, if you push past a certain point, you won't get any voltage to the motor at all. The lead acid at least I have enough to stow the motor. That's my only worry with the lithium. I'd rather have it pushing a weak 36v of power than having a BMS that cuts all power once it dips below a certain capacity. Or at least I think I would.

The bonus is I'd be able to have a very accurate battery gauge, not like the gauge I have now for lead acid. With lithium and the BMS you'd be able to know exactly how many hours/minutes or even seconds of battery you have left. That would be really nice. A lead acid gauge is kinda like a mystery. You know how many resting volts you have, but not how many amps it's pushing.

What Duracells were you looking at that were 100ah? They must not be group 31's. I have 210ah batteries.


Geoff - Interstate 31's are not 210ah.  (sorry buddy)
That 210ah is RC (Reserve Capacity) Min @ 25 Amp draw.
It's a good indicator but not true ah for the battery.
Here's a good link -

https://www.autobatteries.com/en-us/how-to-choose-your-car-battery-replacement/reserve-capacity-c20-amp-hour-ah


The 112 Ulterra's we bought will draw 50 amps at full throttle per Minn Kota.
So using 25 amps for comparative purposes isn't really a bad thing.

The Duracel's I was looking at are the 31's that are AGM.

https://www.samsclub.com/p/duracell-agm-deep-cycle-marine-and-rv-battery-group-size-31dtmagm/prod3590232?xid=plp_product_4

RC is almost as yours at 200
But look closer at  that link and look at "Minutes at 25 amps:210"
That is only 3.5 hrs

I have spoken to guys that actually use the trolling motor to "troll" and this is what they are getting, depending on how high or low the setting is they are using.
Yea, I know.......YMMV.
Anyway, as you know, I went thru all of this on my Lund with the 80# Terrova years back and ended up with two 24's in parallel with two 31's in order to get enough time out on the water.
I estimated I had a total of about 140-150 ah, when they were new.
It worked and gave me 6+ hrs of trolling as I was looking for.
Now I have a much larger boat and will need more thrust - hence the 112# vs the 80# I had on the Lund.
And I'm figuring I will need the same ah, or 150, to get the job done.
So my decision to go with the 200ah unit whould work pretty good.

The thing is that there are no real numbers published by these battery companies that I really trust.
And there is probably no way to trully compare the lead acid batteries to the LiFePo batteries.
So it's a crap shoot, kinda.

I will run the Ulterra up front for steering and 20-30% of the thrust required to troll for walleye and salmon at 1.6-4 mph.
The Honda 15hp 4-stroke on the transom will handle 70-80% of the thrust.
Walleyes we typically are at 1.6 - 2.5, being mostly in the 1.8-2.2 area.
So walleye trolling I should get longer days than salmon trolling at say 2.5-3.5 mph.
But I don't salmon troll that often and when we do I don't go all day.

The stowing with a dead battery can certainly be a problem.
We are getting the BMS with a gage on it that shows battery life remaining, etc. as you mentioned.
I am also electing to get the bluetooth option so I can also monitor this info on my smartphone.
But I have a phillips screwdriver and other tools on board if I goof up and somehow need to manually stow the motor.
I watched the video on Youtube and it isn't hard, however doing it in 3-4's up there on the bow might prove dicey - lol
Here is a link to a few of the videos if you haven't seen any yet -

https://www.youtube.com/results?search_query=ulterra+manual+stow

This was one of the reasons I tossed back and forth between the Ulterra and the Terrova so much.
But I now have the Ulterra and need to live with it - and make sure I'm prepared as well as I can be.


Jethro

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Re: Lithium 100 ah battery
« Reply #14 on: Dec 14, 2020, 12:28 PM »
Oh, interesting, that makes sense.

The lithium will definitely be an accurate battery gauge which would be nice. I'm hoping some day that technology comes down in price, but until then I am happy with the lead acids other than moving the d**n things. I've salmon trolled for 16 hours in harmony with the gas kicker no problem, so I am happy with my capacity for now. Hopefully I don't notice too much drop in performance as they age, but I might because I use them hard. Drain them every time pretty much.

They tell you to do the auto stow procedure but to reset it is supposed to be done by Minn Kota, so I want to avoid that. But to be honest the auto trim motor has a clip to disconnect it... you can just use that and a bunch of straps to hold the heavy motor up while the shaft stays in the upright position. I don't know why the emergency stow procedure includes removing the lift piston.. I would drive with it in the upright position before I disconnected the lift piston, but what do I know.


 



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