Lithium batteries and new solar charger

[Slownsy]

I am replacing my 4 6V batteries I think 2 lithium, have never been impressed by the 30A PWM charger for my 600W solar, probably my fault for using 8 avg wire on a 9m run. Thinking if I get a Victron 100/75 MPPT controller I can go parallel and series for 24V and have less voltage drop and hopefully better charging, and also maybe adding 2 more panels. What say you.
Frank.

[Itinerant1]

Slownsy wrote:
About 2/5 of that and Inclosed on top except for the 2 terminals.
Frank

Covered with the GBS covers that come with batteries they work well.

[Slownsy]

I will never have to heat it , as newer se that cold temps, the BMS has inbuid temp cencor for outside temperature .
Frank.

[afidel]

The way to heat it is 12V pads in parallel with the battery, if the BMS has the battery shut off from charging all the power will flow into the pads and allow them to heat quickly, once the batteries are warm enough to accept charge the resistance of the pads will be so much higher than the battery that most of the current will flow into the battery.

[StirCrazy]

Almot wrote:

StirCrazy wrote:

which brand did you buy? evey raw cell I have looked at say it can handle 1C all day long and maintain the 3000 to 4500 cycles its rated at, the optimal 0.2C and such will get you around 7000 cycles.

Steve
Steve

Lynaclithium.com. Essentially a Chinese battery by Canadian importer. They claim 6000 cycles at 0.2C. I "doubt" that I will live that long, but chemical deterioration due to aging will likely kill it sooner.

ok so not raw cells, but a built package from a company who can put anything on there and most will be geared to protect them and there warenty.

But, ya thats about inline with the rest, 3-4000 cycles at 1C and 6-8000 at a reduced rate.. age wont kill it realy, but it will take away some of the capacity over time so your 100ah battery will be come a 88-85AH battery after the initial cycle life, but from what I have played with the remaining seem to fuction normaly just a reduced capacity.

the thing is when we are taking 1C charging the issue you need to watch for is internal battery heat. if you dont heat that battery up internaly you can charge at that rate for the life of the battery. this is why electric cars have built in battery cooling/heating. for us as RVers we should never encounter this issue because of the way we tend to set up and charge batteries. we build large banks, 200 to 500 AH and the average charger in a rv is 45 to 55 amps. so on a 200ah battery that gives you a 0.25C (aproximatly) and even lower by far on a 500AH system. so that leave the tempature of the batteries when charging the only concern, and because of the low charge rates we wont have to worry about that creating heat, but the actual utside tempatures influence on the batteries. ie, is it -30 out and your battery has been sitting. how are you going to warm it up so you can charg it etc...

Steve

[Almot]

StirCrazy wrote:

which brand did you buy? evey raw cell I have looked at say it can handle 1C all day long and maintain the 3000 to 4500 cycles its rated at, the optimal 0.2C and such will get you around 7000 cycles.

Steve
Steve

Lynaclithium.com. Essentially a Chinese battery by Canadian importer. They claim 6000 cycles at 0.2C. I "doubt" that I will live that long, but chemical deterioration due to aging will likely kill it sooner.

[Slownsy]

About 2/5 of that and Inclosed on top except for the 2 terminals.
Frank

[Itinerant1]

Slownsy wrote:
The cels are GBS Life po4 3.2V. 4 cels joined together by manufacturer in to a 100A battery with some kind of balancing attached to each cell that then connects to a outside BMS that can be adjusted to different settings for smaller or larger battery packs, op to 3 per BMS. I have not purchased them yet. It is a local west Australian company that builds there own batteries and BMS systems. And have been around for several years, and many recommendations.
Frank.

Something like this.

Been using for 5 years now.

[Slownsy]

The cels are GBS Life po4 3.2V. 4 cels joined together by manufacturer in to a 100A battery with some kind of balancing attached to each cell that then connects to a outside BMS that can be adjusted to different settings for smaller or larger battery packs, op to 3 per BMS. I have not purchased them yet. It is a local west Australian company that builds there own batteries and BMS systems. And have been around for several years, and many recommendations.
Frank.

[time2roll]

StirCrazy wrote:
which brand did you buy? evey raw cell I have looked at say it can handle 1C all day long and maintain the 3000 to 4500 cycles its rated at, the optimal 0.2C and such will get you around 7000 cycles.

Steve
Steve

Individual prismatic cells shaping from CN

Note here constant current is listed twice. Specs do not always translate well.


ange of application
Product name: lithium iron phosphate cell
Shell Material: Aluminum
Nominal capacity: 310Ah
Minimum capacity: 310Ah
Internal impedance: 0.1 ~ 0.3m?
Nominal voltage: 3.2V
Discharge end voltage: 2.5 v
Recommend constant current: 310a (1c)
Recommend constant current: 155a (0.5c)
Charging voltage: 3.65 v
Maximum continuous discharge current: 310a (1c)
Life cycle (80% dod): 4000 cycles
Charging temperature: -5 60 60 ° c
Discharge temperature: -30 60 60 ° c
Dimensions (l*w*h): 211*170*70mm

[StirCrazy]

BFL13 wrote:


(They don't want you to adjust for temp when doing the actual charging to get the batts up in SOC though. Stay at 14.6 or less whatever they say for Vabs, since colder temp comp would make that higher in voltage--14.6 is 15.2 or whatever near freezing, and that temp comp would put you over the max of 14.6 right there.

So no temp comp when using 14.x. Temp comp should be ok with 13.x ? Don't know, but to play it safe IMO stick to about 13.5v no matter what and you should be good.

thats right, the only temp comp you should use is a cutoff and if you want to get fancy a amp limiter, but it has to remain constant voltage.

that way you could set a max charge rate at colder temps and charge all the way down to -20. it would be painfully slow and dont know if it would be worth it, but you could do it.

Steve

[StirCrazy]

Almot wrote:

Slownsy wrote:
Ok the speech from manufacturer is charge to 14.4-14.6 then float at 13.3-13.8V.
The BMS is set to cut out at 11.6V and above 15.0V the 11.6 threshold equates to about 2-5% remaining battery capacity.
The manufacturer recommended to connect loads and charging with 00 cable but my 3000W Magnum hybrid inverter charger specs is for 0000 which is what I currently have but may not be able to fit to batteries and BMS. I have never used over 200A as per my display running microwave fridge etc not HW or air conditioner and according to cable chards 00 can handle 200A for quite some distance.

I would not float at 13.8V. This is what 100% full LFP would have after you've finished charging it at 14.6V, it doesn't need any more current at this point, unless you begin discharging it right then. There is a "knee" at the beginning of discharge, at 5% DOD it drops quickly to 13.1V, then the curve becomes almost flat for a while. You might want to set Float to 13.2-13.3V.

I am also skeptical about 1C charging current (i.e. 200A in your case). My LFP suggests 0.2C as "optimal" charging/discharging, 1C max continuous current <=5 minutes, and max instant current 2.5C <= 5 sec (the latter is for discharge only). It might handle currents higher than 1C for longer but at the expense of the lifespan.

which brand did you buy? evey raw cell I have looked at say it can handle 1C all day long and maintain the 3000 to 4500 cycles its rated at, the optimal 0.2C and such will get you around 7000 cycles.

Steve
Steve

[BFL13]

100a charging on the 200AH LFPs is their recommended charging rate of 50% so you are good. You can use higher, but will lose some battery "lifetime" doing that very often. Using 50% charging rate, the graph for that shows tapering starts around 90-95% SOC, so you get longer constant amps in Bulk, which means less generator run time to get the recharge done.

Battle Born FAQ says to Float at 13.6v or lower. But their very own spec with their 100AH batt says float is 13.4 to 13.8v. Those voltages are supposed to be at 25C/77F and would be lower if hotter out and higher if colder out.

(They don't want you to adjust for temp when doing the actual charging to get the batts up in SOC though. Stay at 14.6 or less whatever they say for Vabs, since colder temp comp would make that higher in voltage--14.6 is 15.2 or whatever near freezing, and that temp comp would put you over the max of 14.6 right there.

So no temp comp when using 14.x. Temp comp should be ok with 13.x ? Don't know, but to play it safe IMO stick to about 13.5v no matter what and you should be good.

[Slownsy]

Thanks Almot tha discharge spec for each battery is 300A continuous, I intend using 2 and can’t se where I would ever use more than about 200A when microwave on for whatever amount of minutes.
Charging for each recommendations is 50A normally or 100A occasionally, again with 2 batteries 100A should be fine?. I don’t know how long the Magnum charger will stay at 100A with the lithium,but with the flooded it tapered down pretty quickly. And this is only for in emergency when solar don’t do it’s job. I am not sure about the float charge but as I always run a inverter fridge 24/7 when using FW always a drain of 3-7A. If not using FW will turn all charging off.
Frank.

[Almot]

Slownsy wrote:
Ok the speech from manufacturer is charge to 14.4-14.6 then float at 13.3-13.8V.
The BMS is set to cut out at 11.6V and above 15.0V the 11.6 threshold equates to about 2-5% remaining battery capacity.
The manufacturer recommended to connect loads and charging with 00 cable but my 3000W Magnum hybrid inverter charger specs is for 0000 which is what I currently have but may not be able to fit to batteries and BMS. I have never used over 200A as per my display running microwave fridge etc not HW or air conditioner and according to cable chards 00 can handle 200A for quite some distance.

I would not float at 13.8V. This is what 100% full LFP would have after you've finished charging it at 14.6V, it doesn't need any more current at this point, unless you begin discharging it right then. There is a "knee" at the beginning of discharge, at 5% DOD it drops quickly to 13.1V, then the curve becomes almost flat for a while. You might want to set Float to 13.2-13.3V.

I am also skeptical about 1C charging current (i.e. 200A in your case). My LFP suggests 0.2C as "optimal" charging/discharging, 1C max continuous current <=5 minutes, and max instant current 2.5C <= 5 sec (the latter is for discharge only). It might handle currents higher than 1C for longer but at the expense of the lifespan.