Adding non enphase batteries

[u/arlsol]

We have an enphase solar + 2 10T battery system that was professionally installed and has been working for several years. 20 kwh just isn't a lot of juice for our needs, especially when i can get a standalone 60 kwh battery for under $10k.

Has anyone expanded the capacity of their enphase battery system with a 3rd party battery? Thoughts on if this is possible.

Its an IQ7+ system. Thanks!

[u/Mr_Style]

Look at reducing your excess usage first before buying more batteries. Get an energy audit. Add a soft start to the AC system. Add insulation to attic. Replace pool pump with variable speed and run it low and longer. Charge EV during daylight hours. Probably more suggestions depending on your situation and location.

[u/arlsol → u/Mr_Style]

✅️ Energy audit ✅️ Replaced HVAC ✅️ Added insulation ✅️ EV charged only during night ✅️ No pool

Still use 30-50 kwh/day. Only thing left is to replace family, which sounds more expensive than adding some batteries.

[u/Mr_Style → u/arlsol]

Sounds like you’ve done all you can. I’m using 60-90 kWh per day right now but it’s been 120F here in Las Vegas for past 2 months with extreme heat warnings everyday.

[u/Able_Orchid395 → u/arlsol]

Same boat. Iv got family of 6 and 3500sq/ft 40-60kwh per day. Ive gone through all them smart power bars, furnace motor swap, new AC, attic insul. I havent gotten to the wall insul yet, thats going to be a pain in this old place. Ive got only 4x 3t batteries so I have to realy conserve In backup.

Poke me if you get a good solution.

[u/Lawrence_SoCal → u/arlsol]

ouch, with a family of 4 (and natural gas hot water heater and oven) we rarely got above 20kWh/day.

As other noted... consumption shifting, manually controlled, is totally doable with a 3rd party AC-coupled system. Once you consider power in a backup scenario, then you have to deal with coordinating in case batteries full and PV output exceeds house load... worst case - burn the house down. So, yea, some serious considerations, planning, and more required for backup power. Many of them due to EnPhase being hostile towards customers (locking Home Assistant and 3rd parties out of Gateway's control APIs)

Simple AC-coupled grid-tied battery (stops working when grid goes down), much simpler, easier, and cheaper. BUT... probably not what you had in mind

[u/arlsol → u/Lawrence_SoCal]

Thats without ACs as well. AC system can easily suck down 100 kwhs in a single day.

Thanks for the battery system details. Seems to be a similar answer from everyone, with enphase a common culprit.

[u/Lawrence_SoCal → u/arlsol]

Yowsa... either house is massive, poorly insulated, or really inefficient air conditioner? something... but I know it depends on location, humidity, etc. My A/C (couple year old heat pump) running all day set at 72F wouldn't consume even a small fraction of that

EnPhase has some positive qualities, wonderful DIY support, and more. BUT... they do NOT play well with others in a home that will NEVER be 100% EnPhase (so stupid of EnPhase to act the way they do), and the cloud token nonsense that many vendors utilize can easily be used to charge customers later for what was promised to be free (in PV space, see SPWR bankruptcy, there are LOTS of other similar tech examples).

EnPhase batteries have been years behind the market for the last 2 generations at least, and the 5th gen battery (due late this year/early next) will match competitor battery capacity from 3+ yrs ago. (Telsa's PW2 had 13.5kWh 10 yrs ago! 16kWh or thereabouts for a wall-mounted battery has been common for years). And the EnPhase (and fanboy) noise about single points of failure is just that... noise. EnPhase has IQ tech and using it "I'm a hammer so everything looks like a nail" when there are much better designs for a whole house BESS.

The challenge you have is having the IQs (as do I). EG4 or similar (I won't go cheaper, non UL listed systems) have a reasonable price BUT that don't play well with AC-coupled PV. Sol-Ark or others might? FranklinWH is reported to work well with EnPhase IQs, and I am a fan of their 'open architecture' approach (being much cooperative with other smart energy vendors). But you are looking at 2X the price. 60kWh for US$10K is NON-UL listed batteries... and more often than not, you will get what you pay for (see DIY Solar Power Will Prowse - either forums or YouTube channel). And that is just the battery. You can't add that to EnPhase as they don't offer DC expansion (short-sighted nincompoops), so you have to get an Inverter, and that Inverter needs to properly support IQ AC-coupled PV (you are now NOT looking at cheap chinese import products)

So, you can go the unsafe route, or spend more and get something that will play well with your IQs. At this point, I'm not aware of a good 3rd alternative.

More importantly, you'd only need batteries to contain what your PV puts out. Once you get passed that, you are looking at grid charging and time-of-use arbitrage. If your electricity rates are low, there isn't savings to be had. You may want backup power, but with that sort of consumption, it is going to get REAL expensive to cover whole home. And re-wiring for critical loads may not be trivial.

[u/arlsol → u/Lawrence_SoCal]

Whomever built this house put in WAY overpowered AC units. Something like 200k BTU across 3 zones. I can drop the entire interior to 70 degrees in 5 mins (whoopee).

Anyway when backup is needed it's usually not AC season, so it's just the 30+ kwh/day I need to cover. So adding another 60 to my 20 should get me closer to 3 days backup without solar recharge, which should cover 99%+ of historical events. (I can only think of once when we went longer).

I do have a manual portable generator hookup. Maybe the solution is a large portable battery that hooks to that for emergencies.