I do not care about battery price, money already spent, device must work.
Also, I have only about 150 battery cycles within a year. With 8000 cycle expected battery life it is >50 years, what does not make sense.
Thatâs not how it works (the cycle cost is there for a very good reason) but up to you.
I canât force you to be right.
- âŹ3400 for a 30kWh battery is extremely cheap
Is that the actual total cost of your battery?
The cost of my 30kWh BYD stack was over âŹ10000 - The battery cycle life is a point of discussion.
Some use the amount of cycles that the battery is expected to reach over its total lifespan but in my opinion thatâs not the right amount.
Also because battery capacity will be severely deteriorated when it reaches that amount of cycles.
What I use is the amount of cycles to be expected within amortization and warranty period.
For my BYD stack that is 10 years and 3000 cycles (counted as the total amount of energy charged & discharged from the battery during the warranty period).
The battery needs to pay for itself within a reasonable time.
Any energy I still get out of it after warranty and amortization is virtually free.
Lifespan of a battery is expressed in years and amount of cycles, whichever is reached first.
Even if you only cycle 10 times per year, your battery is unlikely to last 20 or 50 years and still be in acceptable condition.
In my case that ends up in a battery cycle cost of ~âŹ0.11/kWh.
Since Iâm not cycling the battery all too heavy, Iâve set a cycle cost of âŹ0.09/kWh.
This amount is important because it determines as from which grid price itâs actually cheaper to use energy from the grid instead of the battery.
And thatâs if you can charge the battery for free (typically using solar or negative grid prices).
If youâre running in Trade Mode itâs double important because then the injection (from battery) price needs to be at least as high as the cost to charge from the grid + the battery cycle cost.
There are many people running in trade mode who have set their cycle cost to virtually zero, so they can charge from the grid at (for example) âŹ0.13/kWh and sell back at âŹ0.15/kWh, thinking they are making money.
If their actual cycle cost is (for example) âŹ0.10/kWh or even âŹ0.05/kWh, instead of making money they are losing money at those rates.
With my current contract, the highest injection price is very rarely higher than the lowest consumption price (including grid costs and taxes, since I have to pay those for every kWh I pull from the grid) and virtually never higher than consumption cost + battery cycle cost.
So at least for me, running Trade Mode will never be profitable.
YMMV but for me it seems that the battery purchase cost youâre using is extremely low and the cycle life extremely high, resulting in an (according to me) artificially and unrealistic low battery cycle cost.
I bought 2 pcs last year. They were 100 euro more expensive at that time. This year adding another one.
BYD, Pylon, Huawei, etc - they are selling at extremely high prices. Why people are buying from them, it is another rhetorical question.
Your TV does not need to pay for itself, why battery shoud? Battery is a household appliance.
But anyway, according to report in gbb optimizer, this monthâs profit is about 200 euro. Same amount was in sunny months last year. So battery will âpay for itselfâ in 2-3 years.
That is indeed a very low price.
You still need to account for shipping, assembly and installation costs but even then the price is low.
Very easy question: warranty & accountability.
I have customers complaining about the high cost of the BYD batteries I use, since they can buy batteries so much cheaper from China and other often shady outlets.
My first reply is to wish them very good luck if/when they ever need to call in warranty for whatever defect that occurs between today and 10 years from now.
Then I point them to posts like this one, where such a battery (almost) caught fire, possibly burning their house down.
The first thing your insurance company will ask for is the manufacturerâs safety, warranty, conformity and approval certificates.
For those cheap China batteries, there are none.
At best youâll get a few years of warranty on parts, but very little to no certification at all.
The insurance company is then very likely to refuse your claim because you brought it upon yourself by using non-certified material.
And that will hurt.
Most people end up buying the professional (expensive) battery, only a minority will go âYOLOâ and go for the cheap one.
A TV is a luxury appliance, I donât know anybody who buys a TV with the intention to save money with it.
Battery is totally different use case.
Impressive amount. Even without battery or solar I donât even consume that much from the grid so my possible savings are limited as well.
And with prices in my neck of the woods very difficult to earn that with trade mode.
I also donât have enough solar to charge my battery cheap enough, but working on that.
3X price does not justify it.
Batteries do not âcatch fireâ by itself, cause is almost always in installers or (ab)users.
YOLO is array of MB31 cells on a wooden shelf, with exposed wiring, etc. Or bringing electric vehicle cell arrays inside the house. This is dangerous. DIY kit, which is assembled according to instruction manual, is fine.
1 Like
If you really know what youâre doing you can go for a DIY set like the one you posted.
It looks exactly the same as the one in my previous post that nearly caught fire (and many more examples like that one) so Iâm taking their safety with a grain of salt.
Most people however have no clue whatsoever on how to assemble or handle such a battery.
They come to me for a battery that is safe, approved etc and will hold me accountable for anything that goes wrong with said battery.
Since I need to cover my ass for such claims, I canât take the risk inherently present with such batteries.
If the customer explicitly wants the ultracheap non-certified battery they can buy and install it themselves since I wonât sell it to them.
And theyâll need to sign me a waiver stating that I, as an installer, can never be held accountable for anything that happens if they purchase and install a non-certified battery and they take full accountability.
The sector is littered with stories of customers who refused to pay for professional material, went for DIY themselves and then start complaining at the installer when their cheap sh!t blew up in their face, sometimes even literally.
If you pay for quality, you only pay once.
If you want it cheap, donât come complaining afterwards.
It seems the issue with the battery in your post was caused by a loose bolt that overheated.
This DIY kit is reasonably priced, especially when considering the market value of its components. A metal enclosure, a BMS, and 16 cells simply do not amount to âŹ5,000 by any stretch. Thereâs nothing particularly high-tech inside a Pylon or BYD battery, they use essentially the same components, with slightly different BMS.
Additionally, since this DIY kit is sold within the EU, it is certified and CE-marked. And no, itâs not from Aliexpress.
Thereâs a big difference between having a CE sticker on it (Iâm not even seeing one anywhere) and being conform safety requirements 
On all the images I can find of these batteries there isnât even a manufacturer sticker or serial number to be found.
At best you get some paperwork for the internal JK-BMS but I havenât seen a single Lithium cell inside them that has so much as an identifier on it.
The argument âYou can buy it (in the EU) so it is certified and safeâ is moot and invalid.
Thereâs so much you can buy that has all sorts of stickers and approvals but still is a conformity nightmare.
Many of the Chinese PV inverters are âcertifiedâ, perfectly legal to install yet donât even come close to the required EMI standards. Itâs a nightmare.
As a professional installer having to adhere to all sorts of standards and accountability, such stuff is simply not an option for me.
Other installers have less scrutiny but theyâll drop you the moment something funky happens or the EMI inspectors (that have judicial police status over here and can just confiscate your device if it misbehaves) knock on your door because your cheap and crappy device is causing problems with some other system.
Iâve had to fix many such installs, often at the cost of the customer because the original installer or manufacturer goes AWOL.
But hey, it was cheap when they bought itâŚ
You sure ?
Almost âŹ600 cheaper than your source.
Every cell has QR code. Cells and battery box are nicely packed, there is no sharp metal edges on the enclosure. Wiring and soldering is good. All internal screws well tightened (I checked this). Can give a good mark for this manufacturer, nothing to complain about (except BMS algorithm, which is not fully compatible with Victron specification).
You are right to some extent. But since device is being sold in EU, one may assume it is tested and certified according to EU import laws. If not, why shall one trust that BYD/Huawei is certified? Because the price is high?
And there is another big âbutâ - 10K euro / 30kWh battery simply is not worth buying at all, it is a waste of money (IMHO). No chance it will ever âpay for itselfâ.
Look closer. It is only for the box on Aliexpress.
By writing âit is not from Aliexpressâ I meant I bought it in EU.
The QR code on each cell is not one I have much confidence in.
Tried scanning one on the top, got no result.
The one on the side isnât from the original cell manufacturer.
A âCEâ label is, unfortunately, pretty much worthless for day to day electronics, since its usually the manufacturer doing a self-certification.
Basically it boils down to the manufacturer making a âDeclaration of Conformityâ but without guarantees that it actually is conform.
External conformity verification is rarely required and is very expensive, so most manufacturers skip it if not really required.
As long as not too many complaints or accidents happen they can usually get away with devices that in reality are not conform at all.
If Iâm not mistaken, Victron has a more than decent EMI testing lab, which is why there are so very few complaints about their devices.
Itâs also the reason why theyâre so expensive, same for the premium battery brands.
A DIY battery can never be guaranteed conform to any standards, simply because there is no way to verify that the person assembling it did so according to the requirements.
The manufacturer claim in this case is âevery individual component is conform the standards, so the assembled result of all components is automagically conform as wellâ.
Well yeah⌠No.
That argument wonât stand 5 minutes in court if your house burns down because a bad cell or busbar connection in your DIY battery caught fire.
Your big âbutâ argument is very valid by the way: unless you have very specific reasons for putting in a battery, the Return On Investment result is often that theyâre not worth it.
Cheap DIY batteries are the lucrative approach but again: the magic only lasts as long as nothing goes wrong.
You can be lucky and save big.
If your house burns down because one of them catches fire, itâs âtough luckâ and youâre on your own.
You stated yourself that their BMS algorithm isnât fully compatible with Victron spec so in case something goes very wrong, Victron will rightfully decline support or warranty.
If you buy the premium, tested and officially supported brands youâre mainly paying for assurance.
If thatâs worth the high price is something everybody needs to decide for themselves.
The price for the box on AliExpress is batteries included by the way.
The catch there is that it excludes possible customs costs.
BasenGreen has depots in EU so you can perfectly buy them here in EU.
As long as CE certificate is available, insurance company will have no point to dispute.
And your whole BYD system is also DIY, yes? Vendors sell parts, large or small, you assemble them according to installation manual and your experience/certifications. Same applies for any electrical system.
Hahaha. You funny.
I just said that the CE sticker/certificate from the manufacturer has no guarantees of conformity yet you immediately assign it a binding legal value.
It has no such thing.
Only a conformity certificate from an approved independent certification authority holds any actual value.
Insurance companies hate to pay out so they will always search for some non-approved component to put the blame on.
And since you are not an approved or certified battery assembler, theyâll void your claim if they can prove your battery started the fire.
This is the exact same reason why any electrical installation needs to be approved & signed off for by an independent inspection authority (at least it does over here).
Anybody can install an electrical system and claim it to be safe and conform but you need an independent external auditor to make that legally valid.
In the approval report the manufacturer, model type, ratings, serial numbers and approval documents of PV inverter, battery inverter, batteries etc need to be present.
Your DIY battery doesnât have those documents so the install wonât get approved or certified.
Without that approval document you can 't even get a grid connection over here.
What many people do of course is get their basic system checked & approved and then start tinkering and adding DIY stuff, actually voiding the initial approval.
Legally the install should be re-certified after any change.
After a major incident (house burning down due to electrics shorting out for instance), first thing the insurance company will do is request the latest approval report and then check that with the actual installation.
If the installation has been changed since the approval, theyâre going to have a field day in searching for a reason to bail out from paying.
A burned DIY battery is their wet dream and golden ticket out.
No, not at all, where did you pull that idea from?
I buy my BYD batteries completely preassembled, sealed, validated and signed off for.
All I do is connect the external cables and do the programming.
After that, the external auditor comes, checks that I connected everything according to specs and requirements, that documentation (schematics, serial numbers etc) are up to date and then gives my install an approval mark.
You may ask yourself how you can screw up an install if all you have to do is connect the cables, but youâd be surprised how badly some people manage to do that.