Lithium Battery Question

[Scott_Julie]

I am thinking about converting my 2020 lance to Lithium batteries. I want to do it as inexpensively as possible. (Battle Born ain't gonna happen) Can anyone tell me what specifications I should look for on Ali express. I have found some LIFEPO4 that seem correct for under $400 but don't know enough to confidently pull the trigger.

A couple of possibilities

https://www.aliexpress.com/item/4000617901237.html?spm=a2g0o.productlist.0.0.fdebad25XMz3hT&algo_pvid=9cfc3aa3-f3aa-4d78-8a9d-e8f5b3be5269&algo_expid=9cfc3aa3-f3aa-4d78-8a9d-e8f5b3be5269-8&btsid=0ab6f83a15881757234012506e3f57&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

https://www.aliexpress.com/item/4000015994891.html?spm=a2g0o.productlist.0.0.fdebad25XMz3hT&algo_pvid=9cfc3aa3-f3aa-4d78-8a9d-e8f5b3be5269&algo_expid=9cfc3aa3-f3aa-4d78-8a9d-e8f5b3be5269-3&btsid=0ab6f83a15881757234012506e3f57&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

Thanks in advance

Scott.

[3_tons]

Curious about this issue, I just checked out the Victron’s manual.

In section 4.2.1. one can note that the meter’s charging voltage is programmable - I’m not sure, but this parameter may contain the answer...

After a re-check of the Linklite set-up manual, it turns out that both float voltage and float current programmable and are part of the meters ‘auto-sync’ parameters - this is good news!

[3_tons]

pianotuna wrote:
3tons,

I know that the smartgauge will not work with LI chemistries and it checks voltage many times per second (1500 iirc).

Well, as I previously stated, I have no ‘first hand’ knowledge with Victron’s SOC Meter...However, my neighbor has a Victron meter on his LiFePO4, and I questioned him about this very issue just this afternoon, in which he stated that his meter seems to not need these routine re-synchronizations since it typically restores itself to 100% SOC upon each recharge!!... My guess is this may just point to a difference in the way the Victron arrives at SOC...I do plan to follow up on this...

https://www.victronenergy.com/battery-monitors/bmv-712-smart

3 tons (in the High Desert)

[pianotuna]

3tons,

I know that the smartgauge will not work with LI chemistries and it checks voltage many times per second (1500 iirc).

[pianotuna]

grizzzman wrote:

pianotuna wrote:
A great price!

https://www.ebay.com/itm/Lithium-12v-100Ah-Rechargeable-Deep-Cycle-Battery-with-Home-Charger-BMS-Sol...

$530 usd

thats a fire ready to start. Stick with lifepo4

That's why there is a battery management system. "Lithium 12v 100Ah Rechargeable Deep Cycle Battery with Home Charger BMS"

[3_tons]

BFL13 wrote:
I wonder if the poor oppressed OP has his answer yet. 🙂

Agreed, “Nothing more to see here, Please move along”!!

[BFL13]

I wonder if the poor oppressed OP has his answer yet. 🙂

[3_tons]

Due to the flat voltage/discharge characteristics of LiFePO4, I seriously doubt that any of today’s ‘over-the-counter’ sourced SOC meters (Diet Coke vs Diet Pepsi comes to mind!) will be able to provide as accurate of readout as it would with an FLA (though not sure about Victron...). But due to the extremely wide operating breadth of Li (post ‘Real World’ eval, where occasional top-ended re-synchronizations and approximation proves adequate...), the value of a ‘dead on’ SOC readout appears to be of a relative minor concern, thus the salvation of having a ’dead on’ SOC display being far more beneficial (if not sometimes critical) to the various FLA types... JMHO...

3 tons

[BFL13]

Trimetric lets you kill AH auto-reset for when you have solar, or else it resets every time it gets dark. Didn't see that with LinkLite, so over to you on that.

There was something there about four minutes at full? How does that work with BMS holding time? ( I got confused again.)

[Itinerant1]

3 tons wrote:

BFL13 wrote:
http://www.xantrex.com/documents/Accessories/LinkLite-Battery-Monitor/LinkLITE_Operation(975-0428-01...

Don't see a program for charging efficiency.

Do see the one for Peukert--change that to 1.05 (I saw somewhere)

Need to kill auto-sync but can't see where.

Don't like that idea the battery is full just because the charger dropped to float voltage. That is just nutty IMO. Maybe I don't understand that part. ( I don't like the way Trimetric does it either)

It said to make sure the wires on the shunt are twisted or else your amps reading will be off. (The Trimetric wire comes with them twisted, don't know about LinkLite's.)

LinkLite wires are twisted (by ME - lol). With Li, the only feasible way I can see to determine ‘batt full’ is when battery current (zero) and voltage (maximum) have been holding steady for awhile, though (based on historical energy consumption) I don’t run the Li down to the lower range of DOD, the displayed SOC is an adequate approximate...I’ve yet to try the Coulomb counting method...Having said that (nuances aside), with solar I believe there’s little need to try and keep the batt full except for an occasional balancing of cells - the nice thing about Li is the uber expansive operating range where as a practical matter voltage drop becomes mostly irrelevant...JMO

X2, sometimes close is good enough. 😉

[3_tons]

BFL13 wrote:
http://www.xantrex.com/documents/Accessories/LinkLite-Battery-Monitor/LinkLITE_Operation(975-0428-01...

Don't see a program for charging efficiency.

Do see the one for Peukert--change that to 1.05 (I saw somewhere)

Need to kill auto-sync but can't see where.

Don't like that idea the battery is full just because the charger dropped to float voltage. That is just nutty IMO. Maybe I don't understand that part. ( I don't like the way Trimetric does it either)

It said to make sure the wires on the shunt are twisted or else your amps reading will be off. (The Trimetric wire comes with them twisted, don't know about LinkLite's.)

LinkLite wires are twisted (by ME - lol). With Li, the only feasible way I can see to determine ‘batt full’ is when battery current (zero) and voltage (maximum) have been holding steady for awhile, though (based on historical energy consumption) I don’t run the Li down to the lower range of DOD, the displayed SOC is an adequate approximate...I’ve yet to try the Coulomb counting method...Having said that (nuances aside), with solar I believe there’s little need to try and keep the batt full except for an occasional balancing of cells - the nice thing about Li is the uber expansive operating range where as a practical matter voltage drop becomes mostly irrelevant...JMO

[BFL13]

http://www.xantrex.com/documents/Accessories/LinkLite-Battery-Monitor/LinkLITE_Operation(975-0428-01...

Don't see a program for charging efficiency.

Do see the one for Peukert--change that to 1.05 (I saw somewhere)

Need to kill auto-sync but can't see where.

Don't like that idea the battery is full just because the charger dropped to float voltage. That is just nutty IMO. Maybe I don't understand that part. ( I don't like the way Trimetric does it either)

It said to make sure the wires on the shunt are twisted or else your amps reading will be off. (The Trimetric wire comes with them twisted, don't know about LinkLite's.)

[3_tons]

Sorry, double post...

3 tons

[3_tons]

Itinerate1 said:

“ What you're describing it sounds like the cells aren't going through the full balancing period but without being able to see the individual cells or mini packs inside it's just a guess. ”

I believe that at least a primary rational for the battery needing to be held for a period of time (??) at voltage ‘x’ is to allow sufficient time for individual cell balancing. My guess is that depending on cell voltage differentials (possibly related to the previous DOD?), this process might vary from say only a few minutes to maybe an hour. Determining which cell is the laggard?? - advantage Prism...

3 tons

[BFL13]

The bouncing voltage should be confirmed with a DVM at the battery. Maybe the monitor is acting funny. Eg, the Trimetric ISTR has a sort of smoothing filter so it reads steadier. Not the same thing, but whatever, cross-check with a different meter IMO.