Thanks for this explanation - it is very helpful. I donât know anything about Dryness, but I donât have any intention on getting Pylontech - @Gman warned me in the other forum about getting those.
So, Freedom Won Lite Home 5/4 LiFePO4 that I listed in my original post is 1C and would be a good option? Understanding that I may need two of them if I plan to take the inverter to full load. Do I understand this correctly?
Which BSL battery would be a good alternative to this? And @Stanley, could you please comment on whether my inverter would be able to communicate with BSL batteries.
That is correct, BSL has a new 8kw model that you would only need one of, but itâs not in you budget, they also have a 6.14 and a 5.1kw unit⌠The only one that fits into your budget is the 5.1kw.
The inverter got itâs own build in Shunt, close to something the one victron is selling. In the inverter you can adjust what size ah battery bank you running and you can adjust the Peukert factor to. This what i did with mine.
My diy lifepo4 banks didnât communicated with inverter but every bank got itâs own screen that shows SOC. Over time charging and discharging and charging the SOC on the inverter and on the lifepo4 got closure.
Oh I am in absolute agreement with you and I am sorry if I wasnât obvious. I didnât intend to say that the C-rating is somehow a measure of excellence or performance (though it can be, depending on your application).
Besides, as @Village_Idiot also said, it tends to be a marketing gimick anyway. The battery has a recommended discharge rate, and where that discharge rate is low compared to the capacity of the battery, you make up for it by adding more battery. See for example the Acquion salt-water battery (I know they went bankrupt, and someone else picked up the tech, no idea where they are now). That is a battery with a really low discharge rate, but in theory (because it is cheap, and if you have the space), you make up for it by having a massive battery instead⌠which also gives you significantly more capacity and is therefore, in many ways, significantly better despite the low C-rating.
The only practical advantage would be if you had a constrained budget, and an inverter thatâs a little too large for the battery capacity you can afford. Then a 1C battery would allow you do âoverdoâ it a bit until you can expand the bank. Not sure if thatâs as selling point, but there it isâŚ
Those old G2 powerstar inverters have a battery type setting (if the firmware version is new enough) that allows you to select between Lead-Acid and Lithium. At the time, Freedom Won batteries had some analog outputs for SOC and CCL (charge current limit). When the lithium battery type option is chosen, the inverter uses 2 analog inputs to read the SOC and CCL from the battery. The CCL allowed the BMS to tell the inverter to reduce the charging current or stop charging completely. If the battery doesnât have those analog outputs then you must not choose the lithium battery type, but rather select lead-acid and just set the bulk and float voltages correctly according to the battery manufacturerâs recommendations.
The compatibility document is rather old, but it was assumed that you would want to be able to use the inverter at full load without causing the battery to trip. I recommended the Freedom Won 5/4 to the OP because I know you can actually use them at more than 1C (for a short time at least) without causing them to trip, but they are slightly outside of his budget so I then said the eTower has the same cells and can be used at 1C but are quite prone to tripping if the 100A current limit is exceeded so he would need to be careful with his load.
Those old powerstarâs donât have any battery comms but if the BSL can be used without comms then I donât see why not. (Iâm not familiar with the BSL batteries)
I just spotted a guy on 4x4 Community wanting to sell 3x Pylontech US3000âs less than 2 years old, he is also in the Cape.
Just thinking out loud, this might also be a option for you and you might very well be able to fit it in to your R30k budget ending up with 10 kWh usable capacity.
I would really vouch for the BSLâŚ
Using two 6.4kwhâs, or 6.14s⌠at my house and very happy. They are not strained at all, connected to a 5kva mulit II victronâŚ
Installed a single 6.4kwh in the karoo on easter weekend also connected to a 5kva muliti II victron with 5.4kw PV (1.8 E, N and W), now that one is working, and doing so flawlessly!!
And then going to install another 5kwh on another 5kva multi II, new system in Malgas now in the coming weeksâŚ
Speak to jaco, push the budget and get yourself a 6.14kwhâŚ
If needed Iâm sure you can down tune the powerstar a little bit to suit the battery⌠run on voltage parameters⌠and maybe use the dry contact for low bat and protection feedback to the powerstar if it can use itâŚ
The victron 5kva mutli II can pull 9kw peak, and both Victron and BSL is happy with the 5kva multi II -6.14kwh BSL combo⌠So Iâm sure youâll be fineâŚ
Thanks for all of the replies and the advice. And big thanks to @JN.V for giving me the heads-up about the 3 x Pylontech US3000 batteries that were listed on the 4x4 community forum. I got a fantastic deal on them and now am the proud owner of these three batteries, including the cabinet ⌠and within my budget
And a big thank-you also to @JacoDeJongh for coming with me to test the batteries for me. I really appreciate you taking time out from your work to help me.
To be honest, @BruceHill is a bit too modest here, he did not get these batteries at a good deal, he got it at an absolute stealâŚ
We tested this almost 18 month old batteries only to find the cells nearly perfectly balanced and with only 10 cycles on each battery. He payed less than halve of my cost price as installer.
Apologies for bringing this old thread back to life. I have a 7 year old hybrid solar system with a 7 year old 48v bank of Trojan batteries using an MLT 6kVa PowerStar II inverter. The batteries are near the end of their life. I am in the process of changing the Microcare MPPT to a Victron 250/100 VE Can and plan on changing the Pb batteries to a Freedom Won Lite 10/8 lithium. I really dont want to have to change the MLT as it works perfectly and thought using the can comms from the MPPT connected to the Freedom and carefully setting the inverter voltages I should be ok but donât want to ruin an expensive battery. Advice please.
Speak to @Gman - heâs got 2 x MLTs, big lithium banks, and can see his inverter wattages (Carlo Gavazzi), and the battery values (BMV) all on the Victron portal. He also went from Micorcare MPPTs to Victron 250/100âs.
I donât know anything about Dryness, but I donât have any intention on getting Pylontech - @Gman warned me in the other forum about getting those.
