“Can I put two converters together to get more power?” It depends entirely on how you mean. Feeding one converter from another is a legitimate technique with predictable trade-offs. Connecting two outputs in parallel to the same load is a different thing altogether, and without documented support it is a good way to destroy both units.

The one-line answer

Cascading (one converter feeding another) works, but efficiency multiplies and so do the failure points. Paralleling (two converters sharing one load) needs documented current sharing — none of the converters in this shop documents parallel operation, so for more current, choose a single larger model instead.

Cascading: feeding one converter from another

You cascade when one unit cannot bridge the gap on its own. Typical reasons:

  • You have a 48 V pack and need both a 24 V rail and a 12 V rail, so you step 48 V down to 24 V and then 24 V down to 12 V.
  • You need a voltage above your supply and the available step-up converter cannot supply enough current on its own — so you step up to an intermediate rail and convert again.
  • You want to isolate a sensitive load behind its own regulator, so that a disturbance on the main rail does not reach it.

Efficiency multiplies, not adds

This is the most misunderstood part. If the first converter is 96% efficient and the second is 96%, the pair is not 96% — it is 0.96 × 0.96, or about 92%. The losses compound, and so does the heat, in two separate places.

Combined efficiency of two cascaded stages
Stage 1 Stage 2 Combined
96% 96% 92.2%
98% 96% 94.1%
95% 92% 87.4%

At 500 W of output, that last row means around 63 W of waste heat spread across two cases instead of one — and 63 W is not a small amount to get out of an enclosed space.

The checks that catch most mistakes

  1. Input range of the second stage. The first converter’s output must sit comfortably inside the second one’s documented input range, including at no load and at full load, where the output may sag slightly.
  2. Startup and inrush. The second converter draws a surge when it powers up. If the first one treats that as a fault it may shut down, restart, and oscillate. Powering the stages up in the right order usually solves it.
  3. Current budget. The first stage must supply the second stage’s input current, which is higher than its output current by the efficiency factor. Feeding a 12 V, 20 A load from a 24 V rail means the first stage supplies roughly 10 A plus losses, not 20 A.
  4. Grounding. These are non-isolated converters, so the negative input and negative output are effectively the same node. That is normally fine, but on long cable runs it can create a ground loop. Keep the negative return path short and single.
  5. Two ways to fail. A single converter that fails takes the load down. Two cascaded converters each add that risk, and the second one depends on the first.

Paralleling: two converters into one load

This is where people get into trouble. Connecting two regulated outputs directly together does not make them share the load evenly. In practice:

  • The unit with the marginally higher output voltage supplies almost all the current until it current-limits or heats up.
  • When it folds back, the second unit takes over, and they can oscillate between the two states.
  • If one is switched off or fails, the other may try to push current backwards into it.

Converters that are designed for this document it explicitly: current sharing, droop characteristics, or an N+1 configuration. None of the models in this shop documents parallel operation, so do not assume it. If you need 150 A, buy a unit rated for 150 A.

Also unsafe without documentation

Do not connect outputs in series to add voltages either. These converters are not documented as having floating or isolated outputs, so putting two in series can place the enclosure of one at a potential well above earth.

When one correctly sized converter is the better answer

For most systems the right move is a single converter with a documented input range wide enough to cover your supply and a current rating above your worst-case load. The catalogue includes high-current models documented as naturally cooled, which removes both the fan and the cascaded losses:

Single units for high-current loads

These cover a wide span on their own — for example a 10–60 V input range with an adjustable 12–48 V output, or 30–60 V in and 24 V out at up to 85 A. One unit, one heat source, one failure point.

Cascading done well: a worked example

Suppose you have a 48 V lithium pack (which may sit anywhere from roughly 40 V to 58 V) and you need a stable 12 V rail at up to 40 A.

  1. Option A — one converter. Choose a model whose documented input range covers the whole 40–58 V span and whose output includes 12 V at 40 A or more. This is the simplest and most efficient answer.
  2. Option B — cascade. Step 48 V down to a regulated 24 V rail, then 24 V down to 12 V. This only makes sense if you also need a 24 V rail for something else, because you pay for it twice in losses.

If you do cascade, feed the second stage from the first stage with short cable, power them up in order, and check the second stage’s input range against the first stage’s measured output at no load — not against its nominal figure.

Frequently asked questions

Can I get more current by using two identical converters?+

Only if the manufacturer documents current sharing or parallel operation. Two ordinary regulated outputs connected together do not share current evenly and can fight each other. None of the converters here documents that capability.

Does cascading double the input voltage range?+

No. Each stage has its own documented range, and the first stage’s output must fall inside the second stage’s input range. Cascading is about producing a different rail, not about extending a range.

Is cascading ever more efficient than one converter?+

Essentially never on its own merits — the efficiencies multiply. It is justified when it provides something you cannot otherwise get: two rails, isolation, or a voltage no single unit produces.

What happens if the second converter’s inrush trips the first?+

The symptom is a click, a restart, or a squealing oscillation at power-up under load. Power the first stage up first, let it stabilise, then apply the second stage’s load. If it persists, the first stage is too small or its current limiting is too aggressive for that load.

Do I need a fuse between stages?+

Yes. Fuse at the source end of every cable that could otherwise carry a fault current. The intermediate link carries real current and is just as capable of starting a fire as the main feed.

Efficiency, current and cooling figures quoted above are supplier-stated for the exact models and are not independently tested by PVShop. No converter in this catalogue documents parallel or series operation; do not assume it.