Hi all

Currently running 2x Dyness 2.4kwh batteries on Growatt 5000spf hybrid. What are my options if I want to increase this? 

1) must I again use Dyness or can I use any Lithiumion? Pylontech? DIY? 

2) must it be 2.4 or can it be the 3.6kwh or even 4.8kwh batteries? 

From what I have read, best is to make new batteries the Master and the older ones slaves. 

I'm guessing I will have to stick to Dyness or other brand with the same bulk charging voltages. 

Thanks 

 

 

@Tsado you have the specs of these Dyness batteries? Are they 15s LiFePO4?

Yes, they are LiFePO4 batteries. I'm not 100% sure on the amount of cells, but do recall 15 being mentioned.

They are very similar to the Pylontech's, and apparently a sister company.

If you can do it, go the DIY way, get yourself some cheap cells from BLS on Ali and a BMS , connect it to your existing system and you have lots of extra power. If you have question about that just ask.

Thanks, thats ideal yes, the question is just how would that setup physically work?

So now you have Inverter talking to battery pack (Dyness or Pylontech) BMS with specific paramaters for charging, cut off etc. 

Now do you just parallel your new battery pack (be it DIY or another Dyness\Pylon) and who says the parameters that are configured are compatable with the DIY cells?

 

On 2020/03/04 at 12:42 PM, Tsa said:

Now do you just parallel your new battery pack

Yes. Build another 15 LiFePO4 bank with its own BMS, simply connect + and - with your existing pack and there you go.

 

On 2020/03/04 at 12:42 PM, Tsa said:

who says the parameters that are configured are compatable with the DIY cells?

I do

17 hours ago, RikH said:

Yes. Build another 15 LiFePO4 bank with its own BMS, simply connect + and - with your existing pack and there you go.

 

I do

I intend to do exactly this but @weber suggests that paralleling old Lifepo4 batteries with a new one will kill the batteries.

 Have you done this before and what was your experience?

On 2020/03/08 at 12:21 AM, ojeysky said:

but @weber suggests that paralleling old Lifepo4 batteries with a new one will kill the batteries

I thought I was a bit more nuanced than that. 🤣 I did give at least one suggestion for making it work.

https://powerforum.co.za/topic/4614-axpert-settings-for-lifepo4/page/2/?tab=comments#comment-70618

 

Edited March 9, 20205 yr by weber

1 hour ago, weber said:

I thought I was a bit more nuanced than that. 🤣 I did give at least one suggestion for making it work.

https://powerforum.co.za/topic/4614-axpert-settings-for-lifepo4/page/2/?tab=comments#comment-70618

 

Lol..... Yes resistors/wire guage 😀

On 2020/03/07 at 3:21 PM, ojeysky said:

 Have you done this before and what was your experience?

Paralleling is what these DIY powerwall guys do all the time with batteries that test very different. I've made a 12p14s battery once with Li-ion 26650's and that thing does it very well. But these are no big fat LiFePO4 prismatic cells off course. But I wouldn't know why not to parallel these big cells even when they are not the same capacity. You only have to look after well matched sets of parallel cells. So let's say you have 15 cells that where originally 100 Ah and now maybe 80 connect each old cell to a new 100 Ah and you have 180 Ah again. What @weber said is more for lead acids I'm afraid.