Dear forum

I am up and running from Saturday and decided to test my batteries for the first time.

i have two Narada 48v 100ah LiPo connected in parallel. They trickled for the past 3 days. I swith the inverters (two 4kw infini V’s in parallel) to battery mode and observed the discharge. Only the one battery discharged while the other one remained full. The two batteries are stacked on top of each other, connected with two short cables + to + and - to -. Then the top battery connected to the + in parallel to inverters and the bottom - in parallel to inverters. Please refer to pic. You will note bottom battery on 50% and top battery still full.

Thanks guys

 

I think you'll find that these are LFP (LiFePO₄), not LiPo (Lithium Polymer). LiPo is the sort of cells used in model planes: higher density, lower safety.

It's weird that they don't share the current, you seem to have connected them properly. Perhaps check the short negative cable between modules; perhaps there is a bad crimp or loose terminal. The other thing is that they could be at different states of charge; perhaps carefully disconnect the positive wire between the two modules to discharge the top one until it's at the same number of LEDs as the bottom one, then reconnect. Even then, it may just take a few weeks for the modules to balance with each other.

Do you not have to connect any data cables between these modules? I don't expect that to affect balancing, however.

1 hour ago, Coulomb said:

I think you'll find that these are LFP (LiFePO₄)

Jip correct😊

 

1 hour ago, Coulomb said:

Do you not have to connect any data cables between these modules?

I will follow up with supplier today.

Another strange thing, if I switch off the top battery, there is no impact on the system. If I switch off the bottom one (top one on) the system shuts down. But they do charge together. That indicates wiring is ok. Lastly the bottom battery’s discharge light is on while the top battery’s status is steady. Its probable a slave/master issue I have to resolve with cables.

Just some feedback... for future. Apparently these batteries have an antitheft setting which we believe has been activated on the top battery. Will let you know if issue has been resolved...

I have seen this behavior twice before on sites. Both sites however were running comms cables as well, and the solution was to swop Master/Slave, and then all was well from that point forward.

My initial thought on these two were that there is no way in hell, as they are paralleled by some serious cable, both should share very close to 50% of the load.

I think the BMS has some control over these, beyond what we know maybe.

But once the Master/Slave settings and cable was in place, both systems gave no more issues.

Confirmed guys, anti theft was activated. Thanks!!

On 2019/06/01 at 8:25 AM, 31shkom said:

anti theft was activated.

Any idea how to deactivate anti theft?

I received a call from a customer a few days ago about this very same problem. 

7 hours ago, Solaris said:

Any idea how to deactivate anti theft?

I received a call from a customer a few days ago about this very same problem. 

Yiu have to get the importers out . They are very strict on software

14 hours ago, 31shkom said:

They are very strict on software

Noted. 

I think I am going to decline this job. I question why the anti theft was activated in the first place. Likely due to theft...🤔

19 hours ago, Solaris said:

decline this job

I was thinking the same thing. If there was a simple way to get around it, you know like maybe sacrificing a goat, then drawing a pentagram around the battery with its blood and holding the reset button for sixty seconds while singing John Lennon's Imagine... then wouldn't that sort of defeat the purpose of anti-theft measures? 🙂

I am somewhat reminded of similar measures in cars. Swapping one ECU might activate a protection feature in another, eg the body computer might refuse to talk to the engine computer when a new one shows up. But in order to not leave you completely stranded, it's usually implemented as an irritation rather than a complete lock: After a certain timeout you can start the car. The idea is that you're not completely stranded... but you are gently encouraged to get it sorted out!

Edited June 12, 20197 yr by plonkster

29 minutes ago, plonkster said:

sacrificing a goat, then drawing a pentagram around the battery with its blood and holding the reset button for sixty seconds while singing John Lennon's Imagine... 

Bloody hell! 😂😂😂 How do you come up with these funny quotes? 🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣 I have been laughing for a long time about this one! You clearly have a vivid sense of humor. 

 

Anyway I told the client that I cannot help him and that he should rather contact his supplier (who likely has something to hide) to get the battery sorted while still under guarantee.  

 

7 minutes ago, Solaris said:

You clearly have a vivid sense of humor. 

The goats don't think so.

@31shkom from who did you buy them from if i may ask. I see there is a place in cape town side around the corner of my work that selling them with a 5 year guarantee. 

On 2019/06/12 at 1:25 PM, Gerlach said:

@31shkom from who did you buy them from if i may ask. I see there is a place in cape town side around the corner of my work that selling them with a 5 year guarantee. 

Fullcircle solar in Wadevill