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Bitmain Antminer S21+ Hydro (319-395 TH/s)
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Bitmain
Bitmain Antminer S21+ Hydro - 319-395 TH/s Bitcoin Miner BTC Mining
Bitmain Antminer S21+ Hydro - detail view 1 - Bitcoin miner
Bitmain Antminer S21+ Hydro - detail view 2 - Bitcoin miner
Bitmain Antminer S21+ Hydro - detail view 3 - Bitcoin miner
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Bitmain Antminer S21+ Hydro (319-395 TH/s)

2049
excl. taxes / incl. shipping
In stock, ready to ship
Available at short notice
No longer available
Only used available
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Minimum order quantity:
1
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Leasing from €10,000 (only in Germany)
  • Lots of hashrate for little money

Variants & Prices

Delivery: In stock.

Quantity
Variant (power consumption)Cryptohall24
warranty		Manufacturer’s
warranty		Availability
Antminer S21+ Hydro 395 TH/s (5,925 W)SKU BTM-S21PHYD-395TH€3,029€2,739In stock, ready to ship
Antminer S21+ Hydro 319 TH/s (4,785 W)SKU BTM-S21PHYD-319TH€2,049€1,759In stock, ready to ship
Antminer S21+ Hydro 338 TH/s (5,070 W)SKU BTM-S21PHYD-338TH€2,599€2,309In stock, ready to ship
Antminer S21+ Hydro 358 TH/s (5,370 W)SKU BTM-S21PHYD-358TH€2,739€2,449In stock, ready to ship

What the Cryptohall24 warranty covers: 12 months from purchase - if a device fails, you simply send it to us. We handle the entire process: initial diagnosis, shipping to the manufacturer, ticket management, final testing and return shipping to you. You deal with a German contracting party and a dedicated contact in your own time zone. With the manufacturer’s warranty only, you arrange air freight, import and export handling and the manufacturer’s ticketing yourself - the effort and the downtime risk stay with you.

Technical data

ManufacturerBitmain
ModelAntminer S21+ Hydro
AlgorithmSHA-256
CoinsBitcoin, Bitcoin Cash
Hashrate319-395 TH/s
Power consumptionapprox. 4,785-5,925 W
Efficiency15.0 J/TH
CoolingWater cooling
Dimensions (W x D x H)339 x 173 x 207 mm
Weight14.5 kg
Noise level50 dB

Description

Bitmain showed the Antminer S21+ Hydro on 9 October 2024 at Bitcoin Amsterdam together with the air-cooled S21+, and the first units reached customers in spring 2025. The water-cooled Bitcoin miner is built for the SHA-256 algorithm and can be used to mine Bitcoin or Bitcoin Cash. Bitmain released it in four levels from 319 to 395 TH/s, and every one of them works at 15.0 joules per terahash. It has no fans, weighs 14.5 kilograms and is fed three-phase at 380 to 415 volts.

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Performance levels of the Antminer S21+ Hydro

  1. S21+ Hydro 319 TH/s at 4,785 watts (BTM-S21PHYD-319TH)
  2. S21+ Hydro 338 TH/s at 5,070 watts (BTM-S21PHYD-338TH)
  3. S21+ Hydro 358 TH/s at 5,370 watts (BTM-S21PHYD-358TH)
  4. S21+ Hydro 395 TH/s at 5,925 watts (BTM-S21PHYD-395TH)

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Across all four levels the efficiency stays the same; hashrate and power draw grow in the same proportion with the level. Bitmain measures these figures at 35 degrees Celsius coolant temperature at the inlet, and in operation an individual unit sits slightly above or below them.

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Design, power connection and cooling of the S21+ Hydro

The housing measures 339 × 173 × 207 mm; the shipping carton brings it to 570 × 316 × 430 mm at 16.4 kilograms, and noise is around 50 dB. As with nearly every hydro miner there is no pump inside the S21+ Hydro; pushing the water through the unit is the job of the external cooler, so the miner only works as part of such a loop.

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Bitmain allows a coolant temperature of 20 to 50 degrees at the inlet, at 8 to 10 litres per minute and no more than 3.5 bar, connected via pipe fittings of 10 millimetres outer diameter. Approved coolants are an antifreeze mix at pH 7.0 to 9.0, pure water at pH 6.5 to 7.5 and deionised water at pH 8.5 to 9.5. If temperatures drop below freezing where the miner is operated, antifreeze must go into the loop, no exceptions.

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Power arrives three-phase from 380 to 415 volts at 50 to 60 hertz, with Bitmain specifying a maximum input current of 12 amps. Network connectivity is Ethernet via RJ45 at 10/100 Mbit.

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Braiins OS and Vnish offer custom firmware for the S21+ Hydro. It sets the power level per hashboard, lower to save electricity or higher for extra hashrate at the cost of some efficiency. We can flash it before dispatch on request at 29.90 euros net per unit; that offer covers miners you run yourself and excludes units in our hosting. Flashing ends the warranty, at Bitmain as with us.

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For operation at home or in a small commercial space the Lian Li cooling unit fits this machine as a ready-made cooler.

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As standard, Bitmain gives a 365-day factory warranty on the machine, counted from the shipping date; our standard price always includes our own warranty.

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Comparison with the previous and next generation of the S21+ Hydro

The predecessor is the Antminer S21 Hydro from the same series. The successor is the Antminer S21 XP Hydro, the next generation the Antminer S23 Hydro. Ordered by efficiency:

  • Antminer S21 Hydro: 16.0 J/TH (319 to 335 TH/s at 5,104 to 5,360 W)
  • Antminer S21+ Hydro: 15.0 J/TH (319 to 395 TH/s at 4,785 to 5,925 W)
  • Antminer S21 XP Hydro: 12.0 J/TH (473 TH/s at 5,676 W)
  • Antminer S23 Hydro: 9.5 J/TH (563 TH/s at 5,349 W)

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The step from the S21 Hydro to the S21+ Hydro is small, one joule per terahash, but the ladder of levels on the Plus reaches up to 395 TH/s. To the S21 XP Hydro it becomes a fifth fewer joules per terahash, and the S23 Hydro goes below 10 joules. The S21+ Hydro's place in daily yield, measured against everything else we offer, is recorded in the miner comparison.

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Verdict: Bitcoin mining with the Antminer S21+ Hydro

With the S21+ Hydro we see the same picture as with the S21 Hydro: a solid unit that shows practically no failures when operated sensibly and runs through without interruption. We know of no problems with it.

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It is cheap to buy and delivers a lot of computing power for the money. For operators with cheap electricity who want units that run stably around the clock, the S21+ Hydro is highly recommendable.

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The Bitcoin mining calculator runs the S21+ Hydro through with your electricity price and the chosen level. Its two inputs, the Bitcoin network hashrate and the price, come from the cockpit, which alongside them keeps the Bitcoin mining pools with share and fees.

How the Purchase Process works

1
Request & Quote
You send us your inquiry, we come back with a binding quote and advise you on the right performance level. Once you confirm, we reserve the units.
2
Shipping & Import
Freight from Hong Kong, customs clearance and import VAT are handled by us. Before forwarding, we test every unit - you receive the machine cleared, taxed and tested.
3
Delivery or Hosting
We deliver to you, fully insured - or the machine goes straight to one of our hosting sites and is operated there under ideal conditions.
4
Commissioning
Pool, firmware, network: we set everything up together with you until the miner runs. We remain your point of contact - including in any warranty case.

Warranty provided by our German Company

When you buy mining hardware via Cryptohall24, you get a guarantee of 12 months In contrast to manufacturer warranties, our warranty only begins when the hardware is sold to our customers and not as soon as it leaves the factory. Since there can often be several months between production and sale in the mining market, our customers often have a longer effective protection than with the pure manufacturer's warranty.
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Optionally, the hardware can be added to insured for up to 36 months become.

Cryptohall24 employee providing technical support on an ASIC miner - Cryptohall24

Why Customers buy Miners from Cryptohall24

⌀ 4.8 / 5 stars
based on 135 Google reviews
Legally secure corporate structure according to German law
German contact person with personal support
Transparent prices with no hidden fees - with 12 months of warranty
Professional advice about mining hardware, hosting and profitability
Support with structural, tax and legal matters
Service Excellence through long-term partnership
FAQ
Do you have any questions?

How does buying a miner work?

The process is clear and done in a few steps: you enquire about the device you want, you receive a written quote with the final price from us, and as soon as you accept it, we issue the invoice. After full payment is received, we trigger the order and the hardware is on its way to you.

That way you know where you stand at every point - from quote to delivery, a continuously supported process with a personal contact.

How can I pay?

You can pay conveniently by bank transfer in euros, in crypto (Bitcoin or USDC) or in cash against a receipt.

As throughout our business, payment is in advance: we trigger the order as soon as payment has been received in full. That keeps the process clean and predictable for both sides.

Are there discounts for larger quantities?

Yes, discounts are possible for larger quantities. How large they are depends on several factors - the device, the quantity, the delivery location and the respective procurement conditions.

That's why we state the right price best directly in an individual quote. Just tell us the model and the quantity you want and we'll work it out for you.

What is included in the delivery?

On modern ASIC miners the power supply is built firmly into the machine and is therefore always included - it does not have to be bought separately. An external power supply only existed with very old first-generation models.

So you receive a ready-to-run device. Whatever else specifically belongs to the respective product is stated in the product description; in case of doubt we clarify it in the quote.

Is the miner in stock and how quickly is it delivered?

You can see availability directly on the product; in case of doubt we confirm it in the quote. The majority of our hardware is located in our main warehouse in Hong Kong and is shipped from there directly to your destination.

Individual devices are in stock in Germany (Hamm) - those reach you particularly quickly. We state the concrete delivery date bindingly in the quote, as soon as device and destination are clear.

How is it delivered - internationally and with customs clearance too?

We deliver worldwide. We handle the shipping and the complete import processing including customs clearance for you - you don't have to deal with it yourself. We state the shipping costs transparently in the quote.

That way the miner arrives ready to use at your place or the desired site. On request we deliver directly to our hosting, then the device goes into operation without a detour.

What requirements do I need for operation?

To operate at home or in your own business you mainly need three things: a suitable power connection (ASIC miners draw several kilowatts continuously, large devices often three-phase power), enough space with ventilation, and a stable internet connection via LAN.

On top of that come noise and waste heat: air-cooled devices are very loud and heat the room noticeably. Anyone who doesn't meet these requirements usually has the miner hosted - then we take care of power, cooling and operation.

How do I set up the miner and can I get help?

Commissioning is straightforward: connect the device, plug it into the network and configure it to your mining pool and wallet. After that the miner runs around the clock.

We don't leave you alone with it - we support you with setting up pool and wallet and the first steps, even without prior experience. Your personal contact is available for questions.

What warranty do I have on the device?

As a German company we offer you 12 months' warranty on your hardware as standard.

Alternatively, you can exclude the warranty in the purchase contract and handle it via the manufacturer's warranty - then the device becomes cheaper. We offer both routes; which one makes sense for you we clarify in the quote.

Can I have this miner hosted directly instead of running it myself?

Yes. You can buy the device from us and have it hosted in the same step - then it runs at a site with low-cost electricity, without noise and heat at your home.

For many this is the most economical way. You can read how hosting works on our hosting page.

As a business customer, can I cancel or return?

We sell our devices to businesses (B2B). A statutory consumer right of withdrawal therefore does not apply in B2B business; in addition, we procure and import the hardware specifically for your order.

So you buy in a targeted and binding way. That's exactly why we calmly clarify the right device for your project before the quote - so you make the right choice from the start. If you have questions before buying, we are always reachable.

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