Buy Your Friends Batteries
A proposal to “buy your friends batteries” — pooling birthday gifts so each household can afford a 5 kWh plug‑in home battery — is prompting scrutiny of both the social and financial logic behind the idea. Commenters question whether most people can spare €50–100 per friend, highlight that the 11–13 year payback often matches or exceeds battery lifetimes, and note that opportunity costs, grid fees, and degradation further weaken the arbitrage case unless paired with solar or highly unreliable grids. The conversation also surfaces practical concerns around legality, installation, fire safety, and equity for renters, while comparing the scheme to informal rotating savings clubs that can entangle friendships in complex financing arrangements.
Concept of a “battery birthday club” / rotating finance
- Many see it as a rotating savings / informal loan club (tanda, susu, building society analogue) where people effectively pre‑finance each other’s home batteries.
- Critics say it’s more like peer‑to‑peer installment financing than a real “gift,” with fairness issues for people with later birthdays.
- Several note that this assumes:
- 15–30 close friends.
- Most are homeowners.
- Everyone can comfortably front ~€1,600 over a year without risking friendships.
- Some argue this reflects a fairly privileged slice of the population; others respond that it’s targeted at that slice, not “everyone.”
Economics and payback of home batteries
- Typical claim: ~11–13 year payback via price arbitrage between cheap and expensive grid power.
- Multiple commenters question the math:
- Degradation over ~10–15 years lengthens payback.
- Grid fees/taxes often aren’t considered correctly; they can erase much of the arbitrage unless you’re storing your own solar/wind.
- Spread between cheap and expensive hours may shrink as more storage is added.
- Comparisons are made to:
- Investing the same money in index funds or bonds.
- Spending on insulation instead.
- Consensus in thread: for arbitrage alone, standalone batteries are marginal financially; coupling them with on‑site generation helps.
Practicalities: installation, legality, and use cases
- Plug‑in batteries/“plug‑in solar” that sync with grid phase are discussed; legal in some places, restricted or illegal in others.
- Whole‑house backup generally requires invasive, permitted electrical work; many suggest a middle ground of extension cords to a portable battery.
- 3 kW output is seen as enough for essentials (fridge, lights, router), but not for large loads (HVAC, electric range, water heater).
- Renters face more constraints, though small “balcony” solar and plug‑in solutions exist in some countries.
Reliability, resilience, and alternatives
- Outage experience varies widely: some report near‑perfect reliability; others have frequent multi‑hour or multi‑day outages, or war‑related damage.
- For many, resilience value (keeping food cold, staying online, preventing winter damage) is the primary motivation, not savings.
- Debate exists over whether cheap batteries vs generators are better:
- Batteries: quiet, low‑maintenance, good for modest loads.
- Generators: cheaper per kWh, noisy, need fuel and maintenance, but can run larger loads.
- Some warn against “preparedness theater”; others argue society should expect households to manage a few days without services.
Safety, quality, and system‑level impacts
- Concerns about fire risk and code compliance, especially with very cheap imports; preference by some for local, certified products.
- Note that if many households add storage:
- Price spreads may compress.
- Grid fixed costs could shift onto remaining users, risking “energy islands” and higher tariffs for those who stay connected.