Easun SPS 3000W charge cutoff

[avdept]

Hi everybody. Due to ongoing issues with electricity in Ukraine I decided to build small power wall for my condo. I bought 2 Porsche taycan battery modules (24v, 6s2p) 2.7kwt each and Easun SPS 3000W inverter(don't ask why this, because there's nothing else available on local market atm). While it has low DC cut off, how do I set high DC cut off, so that I would not overcharge batteries and thus prevent battery damage or even fire? The reason I can't install BMS because modules itself are packed into aluminium case which only can be disassembled with some heavy tools.

Inverter has firmware 04.23 so I was wondering if there's newer firmwares which has high cut off?

 

[yabert]

Hi. You will have to change the battery type (program 5) to USE (user setting).
After you will have to change program 26-27 and 31 (and other charging voltage limit if there is) to a maximum voltage around 24.5V(6 cells x 4.08V). Don't charge up to 4.2V per cells because there is very little energy available between 4.1V and 4.2V and you increase the risk of overcharging a cell.

Also, I strongly suggest you to don't rely only on the cheap inverter to prevent an overcharge and potentially a disastrous fire.
Please try to find a high voltage relay. Something like the relay switch controller A30-U3 will give you a safe redundancy when correctly programed.

 

[avdept]

Hi. You will have to change the battery type (program 5) to USE (user setting).
After you will have to change program 26-27 and 31 (and other charging voltage limit if there is) to a maximum voltage around 24.5V(6 cells x 4.08V). Don't charge up to 4.2V per cells because there is very little energy available between 4.1V and 4.2V and you increase the risk of overcharging a cell.

Also, I strongly suggest you to don't rely only on the cheap inverter to prevent an overcharge and potentially a disastrous fire.
Please try to find a high voltage relay. Something like the relay switch controller A30-U3 will give you a safe redundancy when correctly programed.

Thanks for your reply. I already did that, set 26, 27, 29 to Low DC cut off 21v and charging voltage to 25.0. I had watt meter connected before inverter and when battery reached 25v wattmeter was reporting usage of 1w(which I assume was used to power the inverter itself).

Im wondering if there's some sort of BMS what would connect to external battery terminals and could report SoC and also could cut off charging at say 90%

 

[Mattb4]

Without cell level protection that a BMS provides I would suggest that the battery be mounted in a non flammable location away from living spaces. It should be fused and have a solid disconnect switch.

 

[LRoman]

Hi. You will have to change the battery type (program 5) to USE (user setting).
After you will have to change program 26-27 and 31 (and other charging voltage limit if there is) to a maximum voltage around 24.5V(6 cells x 4.08V). Don't charge up to 4.2V per cells because there is very little energy available between 4.1V and 4.2V and you increase the risk of overcharging a cell.

Also, I strongly suggest you to don't rely only on the cheap inverter to prevent an overcharge and potentially a disastrous fire.
Please try to find a high voltage relay. Something like the relay switch controller A30-U3 will give you a safe redundancy when correctly programed.

Hi. I have the same battery. Could you help me with the floating charging voltage? I set up the charging voltage to 24.6V so what floating charging voltage I should set up for this battery? I read that Li-ion batteries do not need floating charging, but the investor doesn't have the ability to turn it off. Thanks

 

[yabert]

I read that Li-ion batteries do not need floating charging

Exact and it's ok to set bulk charging, floating charging and equalization charging at the same voltage. 4.1V per cell is ideal (so 24.6V for your 6 cells in series).

 

[avdept]

Ok, so 2 months after using this setup. I set my charging voltage to 25, the battery was about 24.9 when the charge would be finished. Inverter never reported about full charge simply because it doesn’t know anything about battery soc. Lately I’ve installed BMS to my modules but that only added a bit of safety because the system runs in my apartments

 

[LRoman]

Exact and it's ok to set bulk charging, floating charging and equalization charging at the same voltage. 4.1V per cell is ideal (so 24.6V for your 6 cells in series).

Thanks for your reply. Is it not too much 24.6v for floating charging? I read that li-ion batteries don't like float at all. Now I set the floating voltage to 24v, but when the charge is completed (24.6v on batteries), the inverter cuts off charging and works from the mains, and the voltage on the battery drops to 24v for 20 hours without any load. Is it ok?

 

[yabert]

I read that li-ion batteries don't like float at all.

As answered, they don't need float at all.

Is it not too much 24.6v for floating charging?

Short answer: no.
Long answer: yes, if you look to have 10 000 discharge cycles out of your battery, you should charge it at lower voltage and there is many other parameter to consider. But, generally, charge at 4.1V/cell (24.6V) will longer the battery life compare to fully charge it at 4.2V/cell. Keep it at temperature around 10-30°C is also a must to extend life.

 

[Нерозуміючий]

Спасибі за Вашу відповідь. Чи не забагато 24,6 В для плаваючої зарядки? Я читав, що літій-іонні акумулятори взагалі не люблять плавати. Зараз виставляю плаваючу напругу 24в, але коли закінчується заряд (24,6в на акумуляторах), інвертор відключає зарядку і працює від мережі, а напруга на акумуляторі падає до 24в протягом 20 годин без навантаження. це добре?

Вам вдалось налаштувати свій інвертор , ви використовуєте акумулятор з BMS платою?

 

[LRoman]

Вам вдалось налаштувати свій інвертор , ви використовуєте акумулятор з BMS платою?

Yes, 1 month while waiting for BMS used without. Now I already use it with BMS. On the inverter, I set the charge voltage and floating voltage to 24.6V, and the discharge voltage to 20V. Charge current 25a.

 

[LRoman]

As answered, they don't need float at all.

Short answer: no.
Long answer: yes, if you look to have 10 000 discharge cycles out of your battery, you should charge it at lower voltage and there is many other parameter to consider. But, generally, charge at 4.1V/cell (24.6V) will longer the battery life compare to fully charge it at 4.2V/cell. Keep it at temperature around 10-30°C is also a must to extend life.

Thanks