TheOldJarHead power station + external battery "hack" thread.

[Æon]

I wanted to make a dedicated thread about this, because I'm really curious to see if any of you are willing to try this.
The Old Jarhead made a few videos about connecting an external, 3rd party battery to a power station (Oupes Mega 1) in this case, and got it to work as though it was a regular expansion battery.

I'm very tempted to do this, but I already have 2 B2 expansion batteries for my Oupes Mega3. Not 100% daisy chaining an additional 5KwH, 51.2V server rack battery would work without issues... but I still want to try!

 

[emcvay]

Hey, thanks for posting!

I must admit, I'm working with them (not naming names but you can figure it out) on a new project where they use that port for a similar purpose Without saying more than that for now, it appears the port has a circuit breaker or electronic switch of some kind (I'm no electrical engineer) that the power station energizes when on but de-energizes when off. Otherwise it appears a direct connection to the internal battery.

However, the internal battery does drain a little faster than the external when doing this. I've surmised that this is because the internal battery is connected pretty much directly to the inverter etc vs the external battery via the cable and maybe the difference would be less if I used all four conductors vs just two (I need to test that theory). Maybe someone with more electrical knowledge could answer that. Perhaps it's slightly different chemistry? Or perhaps because the 'parallel' connection isn't the same as you would do in a battery bank where the inverter is cabled to draw of the bank and not a single battery in the bank?

I know some of my viewers are doing this now (one with two 5kwh GCB's attached) and have reported excellent results.

My next project is a Pecron and maybe a Dabbsson (shhh don't tell them! ha!).

The Old Jarhead.

 

[Æon]

Looking forward to hearing the update, sir.

 

[StuzaCtj78]

I forgot this thread was here. I posted some info over here as well

Thread 'Adding a 48V external battery to a power station - and also charging from solar'

Apr 26, 2025

OK I'm sorry if this is beating a dead horse, here, but I just need to know definitively how this works. The general consensus has been that it's a pain and not really worth it and that one should just use the overpriced proprietary expansion batteries etc. But please just humor me. \

If I want to use my power station on a regular basis to power my home (as I have been doing), and expand it using say, a 48V golf cart style battery hooked up to its solar charging port, and be able to charge that battery from solar panels at the same time... is that possible? And what exactly does that look...

• Æon
• Replies: 7
• Forum: DIY Solar General Discussion

I'm running a parallel setup of those golf cart batteries with a Mega 2. The M1 since spring and added in the second one a month back.

 

[StuzaCtj78]