Charging With Bench Power Supply

[Engineer DIY]

Hello All,

I am in a dilemma here to understand, do I need a special Lithium charger or Can I use my Switching Power Supply Gophert CPS 1660 ( 16 V 60 Amps max) it does have CC and CV modes, to charge my LifePO4, My build will be 48V 280 Ah, However after top-balancing and capacity testing I will have to charge it back up and top balance again. So I was thinking to speed up the process perhaps I can charge it with Bench power supply in 4S configurations with 12V 4S BMS? Another option is to add Hobbyking Turnigy Reaktor QuadKore 1200W 80A (4 X 300W 20A) Balance Charger to my Gophert Power supply.
I wanted to get progressive dynamics charger but they only do 110V AC version but in my country is 220VAC.
Link for Turnigy Charger: https://hobbyking.com/en_us/turbo-c...468&indexName=hbk_live_magento_en_us_products

 

[GSXR1000]

3.65v on CV in parallel and wait 5 days x 24 hours....

 

[Steve_S]

Bench Power Supplies are a common staple for us.
LFP only requires CC/CV which makes it simple.

AMPS:
ESS (Energy Storage System) Grade LFP cells can typically discharge @ 1C and charge up to 0.5C. EX: 100AH cell @ 1C=100A, @ 0.5C=50A
! refer to cell datasheet ! never exceed specifications.
Start with High Amps and the power-supply should flip from CC to CV as it progresses. Never exceed 3.650V. In fact it is better to "target" 3.600.
As charge progresses amps taken will reduce. Most cell types are considered fully saturated by the time they reach 0.05C @ Target Voltage.
You can do One Cell or multiple IN PARALLEL, the more cells in parallel the longer it will take. With large cells like the 280's, it can take quite a while.

Voltage:
Charging over 3.65 causes damage. Over Voltage is the quickest & most common way that LFP cells can be damaged.
ALL LFP will settle from Full Charge. They will typically rest at 3.450-3.500 within 4 hours of 100% Full @ 3.600-3.650.

TIP:
Bench Power-supplies can be tricky. When connected to the cells they will start at usually 1.0-1.5V above the cell actual cell voltage, so you want to monitor the voltage @ the cell terminals / Busbars if in sets and compare to the output voltage at the PS terminals. There will be a bit of voltage differential there. Be certain to Right Size the wire from PS to Cells as it will warm up. NOTE that "Gator Clips" are NASTY ! It is best to use Ring Terminals and actually screw the terminals onto the cells.

See this for more info which will be helpful to you
https://diysolarforum.com/resources/luyuan-tech-basic-lifepo4-guide.151/download

Hope it helps, Good Luck.

 

[Engineer DIY]

Thanks a lot Steve for such a detailed overview. It certainly helps a lot, I am actually waiting for Chinese New year to finish so that Amy can send me the cells, meanwhile I am trying to prepare for the build hence your response and the guide does help a lot in gathering all the basics before the D-Day. Thanks once again.

 

[Steve_S]

Your Welcome, Links 2,3,4,5 in my signature will likely be the most help for you.

Always nice to help folks who still have social graces and say thanks, becoming rarer all the time.

 

[Engineer DIY]

That's awesome will definitely be great assistance. We should always be courteous enough to appreciate if someone is helping. And once again thanks.

 

[Steve_S]

We should always be courteous enough to appreciate if someone is helping

Agree Wholeheartedly. Too many feel they are "Entitled" and have no social grace at all. Also it seems that some get the odd notion we are paid or something, everyone here is a volunteer, including mods & admins and those of us who would never do that job again for ANY reason. The old BTDT and won't do it again, gang. LOL.

 

[Engineer DIY]

Completely agree with you, infact I also wanted to appreciate your gesture of helping Amy in developing the documents. I have noticed some of the people here were also using a commanding tone with her rather than requesting and this all considering that she is always going above and beyond to resolve customer queries. In my opinion she is the best example of great customer service.

 

[Engineer DIY]

@Steve_S I need your assistance on charging again, apologies for asking too much its just that I am in preparation mode for my cells to arrive.
Basically I already have a 5KW solar setup at home with a Chinese All in One Hybrid Inverter, couple of years back when I got it the seller said its compatible with Lithium Batteries but since I had been using it with Flooded batteries I never checked settings about Lithium. Upon requesting information about the Lithium compatibility I was given the response ( The settings allows to Select "User Defined" as a type and further gives a selection of CCV(48V-58.4V) and FCV(48V-58.4V) hence it is compatible with Lithium battery. Please see attached extract from the user manual and let me know if it is compatible and secondly what settings should I use ? I do have another question but that is related to BMS so will be raising a new thread for that.
Thanking you in advance

 

[Steve_S]

From what I can see, it seems that unit can be configured for the correct voltages and you can set amperage rates as well. My Advice is to start "Conservative" say Mid-Ground settings. Bulk Voltage settings for 48V = 56.0 - 58.4, I'd start with say 57.0V which is 3.56V per cell.

 

[Engineer DIY]

Thanks a lot Steve, so just to confirm CCV 57.0V and FCV 54V? Also there is one RS422 Com port on the Inverter but no information available about it. I recently purchased several types of BMSs (Heltec, JBD, ANT & Seplos) for testing and finalising one of them and Seplos bms has RS485(RJ45 connector) along with a CAN port(RJ45 connector) and I was thinking perhaps I can use one of these ports on BMS and somehow connect to the RS422 port. Is there anyway to identify the scope of the RS422 port on this hybrid inverter to understand what information can be extracted and what information can be given to the inverter via this port?

 

[Steve_S]

I can't speak to how anyone has implemented their communications & protocol stacks. That info you will have to get from the various manufacturers as to what/how they implemented things. More than likely you will need an intermediary in the mix, something like a Raspberry Pi running Python, Node-Red and whatever other software to interact with everything. I tinker with my own software stuff but there are others here who do so as well and have shared a variety of software, scripts & flows etc relative to what they are using. Below is one such thread with lot's of valuable info.

Off-grid Solar / Battery monitoring and control freeware

Im building a freeware realtime software/hardware monitoring solution that provides intimate details and decision making information about a solar system. I intend to be fully off grid in the near future and want to be self sufficient for power. My goal is complete control over every aspect of...

diysolarforum.com

 

[Engineer DIY]

Perfect, Thanks a lot Steve, will go through this.

 

[Javalord1]

Bench Power Supplies are a common staple for us.
LFP only requires CC/CV which makes it simple.

AMPS:
ESS (Energy Storage System) Grade LFP cells can typically discharge @ 1C and charge up to 0.5C. EX: 100AH cell @ 1C=100A, @ 0.5C=50A
! refer to cell datasheet ! never exceed specifications.
Start with High Amps and the power-supply should flip from CC to CV as it progresses. Never exceed 3.650V. In fact it is better to "target" 3.600.
As charge progresses amps taken will reduce. Most cell types are considered fully saturated by the time they reach 0.05C @ Target Voltage.
You can do One Cell or multiple IN PARALLEL, the more cells in parallel the longer it will take. With large cells like the 280's, it can take quite a while.

Voltage:
Charging over 3.65 causes damage. Over Voltage is the quickest & most common way that LFP cells can be damaged.
ALL LFP will settle from Full Charge. They will typically rest at 3.450-3.500 within 4 hours of 100% Full @ 3.600-3.650.

TIP:
Bench Power-supplies can be tricky. When connected to the cells they will start at usually 1.0-1.5V above the cell actual cell voltage, so you want to monitor the voltage @ the cell terminals / Busbars if in sets and compare to the output voltage at the PS terminals. There will be a bit of voltage differential there. Be certain to Right Size the wire from PS to Cells as it will warm up. NOTE that "Gator Clips" are NASTY ! It is best to use Ring Terminals and actually screw the terminals onto the cells.

See this for more info which will be helpful to you
https://diysolarforum.com/resources/luyuan-tech-basic-lifepo4-guide.151/download

Hope it helps, Good Luck.

@Steve Swenson