Boat battery

[duckman18]

I think it’s about time to change the deep cycle out in my sled. I’ve just been running a 27 series deep cycle from Costco. It Powers a 55 pound thrust Minnkota electric motor. I use it for side drifting Rivers and duckhunting. What is the best set up out there for batteries? Is it worth stepping up to a lithium? I’m usually always running it on speed 3,4,5  so I tend to only get 4-six hours out of a charge on a new battery.

[CP]

Yeah, lithium is worth it.  LiFePO4 batteries have made lead acid obsolete.  Try one and you will never go back.

[hunthard]

What's the cost of these? I have the Les Schwab optima battery and they seem to last 8 years or so. The last one I bought was $250 I think.

[CP]

Looks like about $170 for a 50Ah.  A 50Ah should outperform any group 27 lead acid.

https://www.amazon.com/dp/B0BHHQTQRT/?coliid=I3KTIQXFWGBOHQ&colid=383QQYN24QZ61&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it

[Skillet]

I agree with CP.  If you're fully discharging a trolling motor battery, LiFeP04 is going to be a major upgrade over lead-acid. 

There are still a few scenarios where lead-acid makes sense, but  they are getting rarer and rarer.

[Stein]

Only reason I would not go lithium is for high draw situations like starting engines and sometime pot pullers depending on the current draw.

[HUNTNORTHWEST]

Tagging

[Skillet]

Only reason I would not go lithium is for high draw situations like starting engines and sometime pot pullers depending on the current draw.

I wasn't aware this was a limitation of Li batt's.  If a high amperage draw is needed, does a Li batt get damaged or is it just unable to do the work compared to a lead-acid or AGM?

[CP]

Only reason I would not go lithium is for high draw situations like starting engines and sometime pot pullers depending on the current draw.

I wasn't aware this was a limitation of Li batt's.  If a high amperage draw is needed, does a Li batt get damaged or is it just unable to do the work compared to a lead-acid or AGM?

LiFePO4 batteries have a BMS (Battery management system) that is programmed to shutoff if at some high current.  If it is a good BMS, the battery isn’t damaged and can be restarted but that is their major limitation. 

A lead acid battery is a very good choice when you need a lot of amps for a short period of time and then you immediately recharge the battery (e.g., starting an engine).  But for deep cycling, they can’t complete with LiFePO4.

[Skillet]

Good to know, thanks for the explanation.

Are the BMS' hackable, or open source?

[CP]

Good to know, thanks for the explanation.

Are the BMS' hackable, or open source?

Not open source.  They may be hackable, but well beyond my skills to do so.  Programmed in firmware, so who knows what all is in there?

[Skillet]

Good to know, thanks for the explanation.

Are the BMS' hackable, or open source?

Not open source.  They may be hackable, but well beyond my skills to do so.  Programmed in firmware, so who knows what all is in there?

Probably a good fire starter if you didn't have the coding chops to figure it out 

[Woodchuck]

My BIL recently added this to his boat and is thrilled with results. Best price he found was from Hodge Marine in FL.
https://minnkota.johnsonoutdoors.com/us/shop/battery-chargers/board-alternator?v=101926#learn-more-anchor

[RockChuck]

Wow the price has really come down on lithium! Just make sure you have a charger capable of charging lithium.

[GWP]

It not only depends on the BMS, but also the amp output capability of the individual Lithium cell.
I have 18650 cells (cells that most battery packs are made from) that range from a max 4 amp output to max 20 amp output. That is the individual cell (like a single C cell battery for comparison), and that means the battery pack made from the 4 amp will not be able to put out as much amperage and will not have as much capacity.
Each battery can only put out the max amperage it is rated for. If you push the capacity of the build, the BMS will eventually cut it off for heat or overdraw to protect itself. It WILL turn itself back on once the conditions are back to normal.
There are individual Lithium cells rated for 200 amp output that are pretty scary power wise. 6 of those will easily start or jump start a car.
I built a 24V 75 amp LiPo4 120 cell pack for my trolling motor to replace a pair of 31 Lead Acids. Half the weight, power all day. Probably closer to 100 amp capability compared to a Lead Acid.
The best thing about the Lithiums is it is full power until it is dead. No power dropping off and turning the power up to maintain the same speed like a Lead Acid.

[HUNTNORTHWEST]

Alright my main questions are the following.


Will these work in negative temperatures for a trolling setup.?

Also I’m seeing mixed results for a main motor cranking lithium application.?
Do they work for the main?

[BuckDuck77]

I replace my 48v golf cart with a lithium and man what a difference.  The bad part is now I want to do the same for my trolling motor batteries. You won’t be disappointed.

[GWP]

https://techwithtech.com/safe-temperatures-for-lithium-ion-batteries-ranges/

[goldenhtr]

My BIL recently added this to his boat and is thrilled with results. Best price he found was from Hodge Marine in FL.
https://minnkota.johnsonoutdoors.com/us/shop/battery-chargers/board-alternator?v=101926#learn-more-anchor

Only charges,
Battery Type   12v AGM, 12v Flooded Lead Acid

[storyteller]

As an added note, when you go to dispose of the  lithium battery, cheapest place I found  was  interstate battery, $5.00 a pound  for disposal, my Torqeedo lithium was 55 lbs, so $225.00 to get rid of it.

[HUNTNORTHWEST]

https://techwithtech.com/safe-temperatures-for-lithium-ion-batteries-ranges/

I appreciate the link. I googled it as well. Just looking for some real world experience.

I fish in eastern wa all winter not sure these will work. Also mixed results on using these as a cranking battery.

[CP]

There are different types of lithium batteries (6 or 7 anyway).  LiFePO4 (Lithium Iron Phosphate) is not what you have in your cell phone or your Tesla, or your ebike.  LiFePO4 is stable, doesn’t burst into flames, makes for a very good deep cycle battery. 

No battery likes the cold, but you can discharge LiFePO4 batteries when they are frozen.  But if you try to charge one while frozen, it will be damaged.   Some of them have thermal protection, some even have heaters in them.  I don’t fish in freezing weather so I don’t worry about it.

Also, I would not choose a LiFePO4 battery for a starting battery.   As I posted earlier, they can shutdown if you pull too many amps and they have been known to damage alternators because of the BMS switching.  A cheap lead acid makes a better starting bat. 

I have a small AGM battery in my boat for starting and only for starting.  Everything else runs on LiFePO4.   In a pinch a LiFePO4 could start my main, it’s only 60hp, but I would not leave it connected.

[CP]

As an added note, when you go to dispose of the  lithium battery, cheapest place I found  was  interstate battery, $5.00 a pound  for disposal, my Torqeedo lithium was 55 lbs, so $225.00 to get rid of it.

Snohomish County Transfer stations will take them for free.

[Bunny Thumper]

Tag

[spin05]

https://techwithtech.com/safe-temperatures-for-lithium-ion-batteries-ranges/

I appreciate the link. I googled it as well. Just looking for some real world experience.

I fish in eastern wa all winter not sure these will work. Also mixed results on using these as a cranking battery.

Your better off with one of these. i put one in my Wooldridge. Its a dual purpose battery and i run everything off 1.  Good down to -40 deg.

https://www.odysseybattery.com/products/odx-agm31m-battery-31m-pc2150st/

[CP]

Cold weather trollers:

https://www.amazon.com/Lithium-Battery-LiFePO4-Parallel-Road-Trip/dp/B0BGS16NF7/ref=asc_df_B09Z3N356Q?tag=bingshoppinga-20&linkCode=df0&hvadid=80401920009136&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584001437306672&th=1

$359.99 for 100Ah - That's the cheapest auto-heated LiFePO4 that I've ever seen.