Power queen 100AH grp 31 heated

Think of selling 2/3 of my Power queen grp 31 100ah 12v lithium batteries at the end of season. They have been great and I have no complaints only reason for selling 2/3 is I would like to get the Bluetooth models as I do use them a fair amount more than most people and would like to monitor them closer. Going to keep one to run as a designated electronics battery, or such is my plan. Just looking to see if there is any interest in them here, wouldn’t be available until November. Again, zero issues or complaints.

https://www.amazon.ca/LiFePO4-Batte...+queen+12v+100ah+heated&qid=1759242392&sr=8-6
These are what I have…

thinking around the $500 mark, might be flexible on that who knows…

 

FYI, you can get an add on Bluetooth battery monitor such as the one at https://www.amazon.ca/dp/B0BZ8D71NY?th=1. I have 2 and they work great!

 

yeah I know and I thought about it, just more for me to wire into the boat etc, to be honest I’m trying to eliminate as many redundant or excessive things to kinda simplify the current rigging I have… I can go 4 days easy in fairly heavy use with zero issues, and can display the amps being used on the screen of the HDS, this is more for me to know “hey better plug in tonight” without having to do more wiring other than swapping batteries… like I said I’ve been happy and had zero issues, and a built in solution will work better for me that something else to wire up… with a few unexpected gremlins in my new to me boat this spring I had to do things a little more on the budget friendly side of things lol…

 

Those units measure voltage.........they can't measure the flat discharge curve of LFP's properly, they are no better than a typical voltage gauge.......they can not display an accurate SOC for LFP batteries....nothing that monitors voltage will.

The only way to accurately monitor and display SOC of an LFP battery is to use something that incorporates a shunt and monitors/measures performance using amps and not volts! Amp capacity, amps out and amps in....is the only way!

And, yes I know the description reads can be used with Lithium batteries.........well it can (they aren't wrong), it just won't be any different than a typical voltage gauge and be useless determining SOC of an LFP battery. They are able to fool a lot of people I guess......if anyone is contemplating adding these to an LFP battery, save your money!

That being said, there are many tables/charts that will convert volts into SOC for LFP batteries....if one wants to go that direction, seem somewhat accurate.

The best method of monitoring performance of an LFP battery is one that has onboard monitoring and is Bluetooth enabled.

I have used and supply Victron Energy smart shunts on LFP batteries that are not Bluetooth enabled, they work great..

https://www.victronenergy.com/battery-monitors/smart-battery-shunt

 

Patty, it's an easy add-on. Nothing more in the boat to wire. The Victron Energy one I linked in my other post is very simple to install. The shunt attaches to the - terminal of the battery, your load and charger lead attaches to the other terminal on the shunt, these is a smaller gauge wire that runs to the + terminal of a battery just to power the shunt.

Certainly more economical than replacing batteries to get onboard monitoring.

 

No, they are not useless for displaying the SOC for a lithium battery. Although, they are not as accurate as a shunt style (yes, I tried one and it didn't last long) they still give a fairly good indication of the SOC, even for the much flatter lithium battery curve, which is all that really matters.

 

Those will tell you no more or be anymore accurate than a typical voltage gauge/meter, any thing that uses volts to monitor LFP battery performance can't calculate/display remaining capacity in an LFP battery. I have one of those on my AGM starter battery, the unit itself works well in a lead acid install.

Seemingly it works for you though, carry-on!

 

FYI, lithium batteries have a much flatter discharge curve. That doesn't mean that it can't be monitored fairly accurately. You said it yourself "That being said, there are many tables/charts that will convert volts into SOC for LFP batteries....if one wants to go that direction, seem somewhat accurate". I have used the one that I provided a link to on several lithium batteries. You have not! It is also cheaper and easier to install with just positive and negative terminals. It works quite well and was a good indicator of SOC. It was a bit out on the Power Queen lithium's, but I manually adjusted it's pre-set voltage curve. The shunt system that I used, worked properly for a while but then it wouldn't properly recognize the SOC when charging.

 

Seemingly it works for you, carry-on!

So as not to hijack this thread anymore than it is already, I won't be posting any further responses. Patty, once you decide what direction you are going......If you need info feel free to reach out, be glad to help.