This site is now in read-only archive mode. Please move all discussion, and create a new account at the new Victron Community site.
Is the minimum 400Ah 24v pack recommended in the manual for the Phoenix 24/5000 inverter based on lead acid battery chemistry?
Would I be correct in assuming that as LiFePo4 chemistry has more than double the usable energy of lead, that a 200Ah 24v LiFePo4 would suffice (with a BMS of 1C continuous / 3C for 1s burst) ?
Yes the manuals usually refer to the lead acid based systems. And lithium can do much more than lead acid.
If your bms can give the full fault current to allow the inverter to shutdown without catching on fire then it is ok for use.
So in your case 5000÷ 24v = 208A bms ability for continuous running. Usually a bms will allow the overload fault current if you match the nominal continuous. Then make sure the cells you have chosen will also be ok with the current as well.
Hi @Alexandra,
Thank you for the reply. Yes it appears I've made a mistake in my calculations as I was looking at W instead of VA. It appears I need to add some batteries in parallel.
Just wondering if you know how long the 10Kw peak power on the Phoenix lasts for as the BMS on these batteries does 3C for 1s?
For this 10Kw burst I think I'll also need breakers rather than 100A Mega fuses on the batteries as the fault curve says the fuses blow at about 0.8s at 3C.
Understanding overloads there is a video here. Its a long one. But is dependent on a number of factors like battery bank voltage sag and heat derating. The video explains best.
But really if you have sized your loads under the peak draw at the max 5000VA of the inverter you dont need to stress.
The fuses blowing Victrons ones are a bit special I have found. There is a guy who demos them here vs others.
We usually size them for the nominal max load. Not had one blow yet. I am not a fan of breakers on batteries, basically too much protection can also cause issues. But that is up to regulations or your preference. Maybe take a look at wiring unlimited linked at the end of the article so you can analyse your design idea.
Thank you for the info @Alexandra.
The video of the fuse tests rather concerns me as a few hours later I received 15 of the Victron Mega fuses in the post. I hope that was just a bad batch. Victron does not have any fuse blow graphs for these fuses on their product page like BlueSeas does. It seems a bit odd as everything else Victron is nothing but the highest standard from what I've seen so far.
The video by Johannes is also excellent.
