So I have been tasked with the repair & salvage of this Hoppecke 8kWh Lithium battery. I thought I would post this entire project as it has unfolded. The battery unfortunately has a nasty fault & the BMS is not very programmable unless you are the agents. So began the project of battery cell capacity testing & BMS retrofit to get some power restored & this battery cycling again. 

This is a German made Lithium battery but unfortunately the BMS is not very user friendly & cannot be reset & the agents will charge a small fortune to get this battery back producing power again. 

So I capacity tested all 32 cells & they all tested at good capacity levels. They are 75ah cells stacked in parallel of 2p16s. The battery design is very robust & extremely strong. The BMS reports in German & a quick Google translate gets us to the cause of the problem. 

Now there may have been an event that spiked the BMS to protect but imagine, how do you reset it. According to the limited knowledge out there there is no way to reset without taking her in for diagnostics. 

So began the hack...

The trusty JBD 300A Contactor BMS was my preferred BMS of choice & for a number of reasons. Mainly it's got a contractor & love the idea of a contactor Vs just MOSFETs. Also it can deliver 300A continuously without failing. It's peak is double that figure so I'd say we have an appropriate power delivery system. 

The Seplos BMS & a few others like the JK BMS have major limitations on Current. Both generally top out at 150A & 200A respectively. Hence my decision & also because I have experience with the Contactor based BMS & it's really a treat to work with. The largest cells available on the market at the moment are the 300ah cells & that would future proof this BMS & makes it capable to pair with any inverter on the market because 300A (15kW) is a heap load of energy & that was my main reason. 

This taken from the Hoppecke manual that corresponds to the fault code displayed on the BMS display. 

@Steve87

By any chance have you tried disconnecting the BMS for a day and checking if it resets a long shot though.

Hi @Raj35tried & failed. Looks like the BMS keeps memory. Another major reason as you are accustomed to the JBD BMS & it's very user friendly Bluetooth control via a Phone application.  If the BMS did reset it's also to prevent this show stopping experience from re-occuring in the future. 

I did try to to disconnect but the BMS had other ideas 🤣

Further also on a nother note, since I now have more exposure to the Sunsynk & Deye inverters we will build that communication support for these machines. The last 12 months & exposure has helped a lot & with more of the DIY packs being built this is a natural progression to build the Comms support. 

On the Voltronics/ Kodak's this support is already in place just to get the Sunsynk sorted. 

Edited January 5, 20233 yr by Steve87

She is Alive. In between doing installations by day, I have had to dedicate some time to the Hoppecke. 

Finally today she is producing her first power again since rebuild. It was challenging especially because the batteries configuration is 2p16s. So I had to take special attention to how I was going to wire her. Actually I just reused the OEM wiring harnesses & then investigated the Voltage & cell number with a Multimeter & diagram. 

Got to admit it was time consuming & I messed up the wiring on the first attempt then only to have to tackle the harness again & correct the mistake. I will add some critical advice to any DIY builders. Check the voltage on the wiring harness in steps of 3.3V & they should increase in cell count by +-3.3V. If I did not do so on the first attempt I would have fried the 300A JBD BMS. 

I tried to fit the JBD into the old BMS enclosure but she was a bit too snug for my liking so I placed her on the top & will insulate her with rubber mat. Luckily there is mount holes I could use to secure her. 

I have used Insulation tape as a temporary measure but will add heat shrink now that the build is complete. 

I am currently testing her on my OG7.2 with great results so far. Looks like the German Lithium Battery has more life in her yet!! Pulling 4.6kW with ease. 

The old BMS depicted here with the massive heat sink. Marking the original harness so that I can track the wiring later. 

Must admit the battery is extremely well built & very robust. Makes working on the cells very easy. 

Retrofit of the new BMS to the old harness. Wish I had the same pin connectors would cut out a lot of work. I have had to adapt to using a crimper & automotive connectors. Works a charm & my crimper has done many of these crimps & they are perfect & continuity is guaranteed with the Kleintools Crimper. 

The 300A JBD BMS is in my opinion the benchmark for BMSs. With its 1A Active balancing & 300A continuous discharge current & 600A peak: this represents the entire range of energy requirement across any inverter brand. This covers all the way from Sunsynk 5kW to the 12kW & 16kW range. 

I know there are more better looking BMSs like the Seplos & the JK BMS but they cannot match the 300A Output of this BMS. 

22 hours ago, Steve87 said:

I have had to adapt to using a crimper & automotive connectors.

@Steve87. Suggestion - solder and heatshrink would make better and neater (although nobody will see it when the unit is closed up...) connections. 

Edited January 30, 20233 yr by GreenMan

Hi @GreenManI'm not a big fan of soldering especially when it comes down to wire connections. I prefer mechanical connections like a connector with mechanical locking pin etc. The connections made using the automotive connectors are actually very robust & strong. 

BIt I guess it's just preferences. Maybe my soldering just sux 😂

Very well done

To think that batteries might end up getting tossed away for stupid reasons like this

Great thing about lithium batteries is how recyclable they are

 

In the future you may want to try consult a electronic repair shop

You said that allowing the battery to drain did not clear the unit memory, electronic repair shop may be able to wipe the storage without affecting the operation (normally stored separately on a ROM chip).

My main core business is solar installations. I just have a particular interest in Lithium Battery tech. So hence i have the equipment to be able to make good judgements on cell health etc. But yep this battery bank would have been tossed in the bin. I am glad I could save this very valuable bank of batteries. 

It's waiting for the owner to collect & we will carry out an installation using the same batteries. Hence I am starting to realise that buying unknown batteries that are cheaper or even Batteries like this with zero history can be assessed & saved. 

In fact all I need is 16 LFP cells delivered to my workshop & we can create something useful in a matter of a few nights over a beer. I still get so much joy when building these. It's extremely rewarding. 

This rebuild has been a major success. After about 10 cycles I am happy to report that the Hoppecke has been fully restored to produce & store energy again. 

The function of top or bottom balancing cannot be stressed enough.