I have a Multiplus 48/8000/110-100 connected to a Fogstar 32kW LiFEPO4 for ESS. Nominally everything appears OK; charging and inverting as expected from excess PV and overnight grid if necessary. However on digging into the VRM stats, I am not seeing a full 110A charge rate overnight. I have checked all the usual suspects: DVCC: enabled, charge current limited to 115A, max charge current of 115A in ESS, weak-ac (off). Max charge and discharge in the Fogstar BMS is 280A so it’s not that. The charge ceiling seems to top-out at almost exactly 100A, only backing off in the short time as it tapers to cut-off voltage. There are some AC-out connected loads that come on and off during this charge window, but the battery charge current stays exactly where it is, which makes me conclude this isn’t a symptom of a max overall power limit.
I can’t remember now, but I did wonder why I configured a max charge current, when I’d be limited by whatever the Multiplus can physcially provide anyway, which is well below the max rating of the battery itself. Worth a try disabling this? Any thoughts?
While the discharge limit of your BMS might be 300A it still can ask the victron system to limit the charging current to a lower number. My 10Kwh system only likes 40A while it can output 200A.The slower you charge you Lifepo4’s the longer they will usually live. Also the cell-balancer can be a limiting factor.
I can see the charge and discharge limits right there on what the BMS reports to the Victron and they are both constant 280A, which is well above what I want or need, so that shouldn’t be a limiting factor. I just don’t understand why the Multiplus is not going flat out at 110A; this is after disabling any other possible charge limit restrictions locally in ESS as I described previously. Last night for example, I asked for a charge up to 65%, it was almost exactly 97A the whole time
I might be off-track but can your energy supplier provide all that current consistently? In theory, mine limits to 100A but in reality, it’s more like 80A. Some even limit to 50A.
Well that has just confirmed a choice for me. Like you I have a 32Kwh Fogstar running with an MP2 48/5000, It does the job well. However we are getting rid of our LPG boiler for a Heat Pump so am looking to increase our charging ability with either an 8 or 10 Kva MP2, so during the winter we can use our battery to its full potential. We have a 5 Hr window to charge at cheap rate so need more than our 48/5000 can do. Looks like the !0Kva unit it is then Thanks..
In a warm climate we upsize. It is never realistic to expect data sheet performance, continuously, when it is based on laboratory conditions that we can rarely reproduce.
Always pays to upsize. It avoids regrets.
I had pretty much decided on the 10Kva as I would always prefer to run under full potential but reading this and the other thread has decided for me.
I have 3 x 2.5Kw LFP golf buggy batteries that are used for seven months but sit idle over the winter so shall set those up with my 48/5000 as a second independent ESS, just to give a little extra storage.
