But only if you have space for a 15kWh pack. If you only have space for 3 x 5kWh packs that changes everything. ?
True. As is the reverse. Design will definitely depend on one's specific scenario. But in the abstract, it should be easier to find a way to fit a DIY system of a given size since form and configuration are somewhat flexible as opposed to OTS available in one or two shapes/sizes. For the purpose of this challenge lets assume both fit.
The other question is, for the $1700 can you warranty it for 10 years and have an expert available to call when things go wrong? Or are you SOL and can only count on yourself?
This is definitely one important tradeoff and one of the biggest advantages of buying an OTS solution
from a reputable company with a long track record and demonstrated commitment to standing behind their warranty. BUT this strongly depends on the bolded text being true, many/most OTS options are relatively to extremely new, not much is known about the companies themselves, and it remains to be seen (1) if they will be around for 5 years let alone 10 years and (2) if they will honor the warranty in good faith, and there may or may not be adequately trained tech support available, will the person on the other end be an 'expert' or an underpaid customer service rep stretched too thin. Buying OTS does not gaurantee any of these things.
Point being, warranty and support are huge factors in favor of OTS options from reputable businesses, but I wouldn't assume most budget OTS options, drop-in replacements etc, will have anywhere close to the level of support mentioned above. So I think the distinction here is not primarily between DIY and OTS, but between quality OTS from reputable brands that stand behind their products, vs unknown quality OTS solutions from unknown or unproven or shady sellers. Buying from a seller that you trust knows what they sell, that you trust to be around for some time, that is in a similar business/sales/legal culture and speaks the same language, and stands behind their products is often worth paying a price premium for.
And as I've said before, is the time to assemble it worth any monetary value?
The narrower and narrower the price difference becomes, the less people will find it worth their time and money. I think we may already be seeing that shift to some degree. Just 2-3 years ago, people were basically forced to go the DIY route (or stick to lead acid) whether they wanted to or not if they couldn't pony up at least a few thousand dollars for just the batteries of a relatively small system. Today that calculation is much much different. And the growing popularity of things like Growatt, the EG4, and the newer budget drop-ins is evidence to me that many people (most probably) would prefer not to DIY any more than they have to and are mostly motivated by cost. I think there is a subset of people though--especially among the early forum members--who were drawn specifically to the DIY approach, not just on the grounds of cost, but flexibility, and to some extent just being 'DIY types' who enjoy learning and building and tinkering and having command and responsibility over their system.
Is the material stocked from USA and you get it in a week for these prices?
This is a real and significant tradeoff
But I would point out is a separate issue from OTS vs DIY. WIth a few exceptions all the components are coming from China, a few may be
assembled in your home country, more may be stocked in your home country (OTS or Raw Cells) and a few may be sold by businesses local to your home country. But this isn't really a DIY vs OTS distinction, both OTS and Raw Cells can be bought direct from China at a discount with more risk and more wait, or bought from US suppliers (like yourself, ECPC, or Overkillsolar for instance) or from Chinese suppliers with US warehouses.
