Power Jack charging mode

[Rafaelmedina23]

I have a PJ 8k, I would like to connect the charging mode, but I don't dare because once I had a 15k one, I connected the charging mode and it burned, this has some instructions where it says that you have to turn it off completely, I would like to put it on work but still I dare not.  I have asked several people and they recommend that I do not do it in this type of PJ investors.  what dou you recommend?

[Sid Genetry Solar]

Let me just sum it up this way: it's a wonder the PJ firmware works at all.  I definitely cannot recommend the PJ charge function--but for some people it works very well.

[Paul]

Lol that's a good summary. My experience of PJ charging function has been variable;

v3 (2013) PJ '8k' 230V <> 24V - switches between charge to inverter mode quite happily even under load. Done it hundreds of times without issue. However it _must_ have the cooling fan running shortly before and all the time before and during charge mode. If not, then something goes very bad with the FET timings and a loud 50Hz rattling noise comes from the trannies, a lot of power is being consumed on the AC side with very little charging output. I guess when some component is warm the timings get messed up. Amazingly though it's never blown any FETs.

v10.3c (2020) 'Upower' 8k 230V <> 24V - switches quite happily (with it's undersized ASL3 tranny - not tried it yet with my big home-wound tranny), no issues switching between modes. Not tried switching with any significant AC loads connected though. Only done this a few times.

Other people on this and other forums have reported PJ boards blowing FETs every time they switch from charge to inverter mode though. Maybe I have just been lucky, or the single-voltage units we use in the UK/EU are simpler and less prone to issues than the 'split phase' ones you have in the US.

[Sid Genetry Solar]

I think the biggest part of the problem is the haphazard firmware doesn't check to see if the AC output has fallen to zero before restarting the FETs.  If the relay sticks / doesn't turn off (or wasn't turned off!), it'll try to drive the FETs in inverter mode against the AC mains.  (This is a battle that most FETs lose.)  If the mains voltage is significantly higher than the inverter regulation voltage, it'll run just a low "inverter throttle", and wreck quite the mess with the AC input and battery (because it won't be synced).  Yes, this'll sound horrid, and isn't good for it...

3 hours ago, Paul said:

Other people on this and other forums have reported PJ boards blowing FETs every time they switch from charge to inverter mode though. Maybe I have just been lucky, or the single-voltage units we use in the UK/EU are simpler and less prone to issues than the 'split phase' ones you have in the US.

PJ really doesn't make much of a change for "split phase"--they use a center-tapped transformer, and (usually) regulate the inverter from just one of the phases (120v).  That's pretty much it.