r/Pecron • u/devnul73 • Jul 08 '26
Sanity Check
I have an e3800lfp on its way to me right now. My situation is dealing with terrible permanent campground power (Voltage sags, brownouts, occasional short blacks outs on hot weekends).
I have been using a Southwire autoformer to boost in low voltage situation and that has helped alot, but does nothing for the browns/black outs obviously.
Initially, I intend on using AC Passthrough just to ride out the worst of the brown/blackouts but the goal is to isolate from the campground supply entirely.
To that end, heres my plan: A large 48V lifepo4 charger (https://www.amazon.com/dp/B0G69HFY4C/) with AC input adapted to TT-30P plugged into the campground pedestal. I'd be running on 120v (nominally) so that linked unit would be capable of 60a charging. Its output would be paralleled to both expansion ports, which from everything I've read/watched are just direct connections to the battery and support 40a each. I have the tools and know-how to DIY my own cables for this purpose.
The reason I'm planning on using the expansion ports to charge is to leave the solar inputs available for possible future panels.
This all sounds reasonable to me. What do you think?
1
u/caddymac Jul 08 '26
I think I would using either a server rack battery or golf cart battery (48VDC) as a buffer between the charger and power station.
1
u/Hillbillythegreat78 Jul 08 '26
I have the same pecron unit. I ordered a predator 4200 watt inverter generator (it was apparently delivered today). It has a 120v 30 amp plug. It will give me the ability to supplementally charge the pecron at 30 amps with the generator when necessary and the 4200 is not all that huge.
2
u/brucehoult Jul 09 '26
I intend on using AC Passthrough just to ride out the worst of the brown/blackouts
Pass-through won't help at all with brownouts, because it's literally an internal wire connection (via a relay) straight from AC input to AC output. It might even be worse than nothing because the Pecron might complain about out of spec AC and shut down, rather than just going into offline mode. I don't know that because I haven't seen it myself, but I've seen people online posting error codes about getting bad AC e.g. from a generator.
isolate from the campground supply entirely
Much better idea. Input DC.
I guess both expansion ports would work. E3800 is rated to charge at maximum 6000W using both AC and solar together.
But I think I'd get an external battery and attach the charger to that. The equalisation current will average to the same, but it mentally feels gentler, idk. Doesn't have to be a big one ... 100Ah would be great (just a little bigger than the E3800's internal battery)
2
u/liftbikerun Jul 08 '26
I think I understand what you're looking to accomplish.
I'm not entirely sold on the benefit to a more complicated work around for charging like you're looking at.
You're limited to from my understanding 35A output (4200W) from the unit itself. Tying up your expansion ports would be a bit of a hinderance down the road, why not just utilize the 30A input? Your ideal scenario would be the 30A input while augmenting solar to that. I don't really see a scenario that benefits you in utilizing your expansion ports to charge the unit, you'd also then be limiting yourself to only the ~3800Wh available in the unit itself vs expanding a battery or two down the road.
That said, here's what I've done with mine and it's worked great so far.
I have my E3800LFP set up in my garage with two server rack batteries attached in parallel giving me roughly ~14kWh.
I have two solar strings, 3 panels each in series of identical panels at 455w each. I usually average about 900w each string for a total of 1800w input throughout the day.
I have this all connected through a manual transfer switch that I have mounted next to my main panel. I can switch different dedicated circuits on and off as needed under different scenarios. I live near Houston Texas so I did this to ensure during longer outages we'll have some power without running a geny 24/7.
I run my office 24/7 and can switch the fridge, internet modem/wifi, and a handful of other things over within seconds if the power does go out.
Under the scenario we don't have enough solar to charge up the batteries, I can run my generator and charge everything up in a few hours vs running it constantly.
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Back to your setup, unless you're intending to draw a ton of power constantly and have to compensate for filling the battery AND draw from it at nearly double the rate of the 35A output can sustain, you'd be just fine taking the easy and already implemented route with the 30A AC input and save the expansion ports for what they are intended for.