BlitzWolf – A 5 port USB charger review and teardown
BlitzWolf is by far a better charger than most. Still it is hardly perfect…
The charger is Surprisingly compact, it's only 9cm long (3.54") and 6cm wide (2.36") it's thickness is 2.4cm (1.2"). The charger weighs 158gr (5.6oz)
The build quality is great, it is very solid and robust. certainly not a "toy"
Let's dive right in to the tests, first the open circuit voltage
The voltage is actually 5.09V (allow for 0.03V measuring error). The voltage must be between 4.75V and 5.25V to conform to the specifications of USB ports. Of course the closer to 5.00V is better.
We now take one step forward with the test and load the charger with two 1A loads:
We can see that the charger has no trouble at all and holds the voltage on 4.97V-4.98V
We now step it up to two 2A loads:
The charger is beginning to strain, the voltage drops to aprox. 4.85V, still well within the acceptable boundaries. The loads require 4A and receive 3.63A total.
We now connect two 1A and two 2A loads to the charger for a total of 6A:
The charger remains within the specification with approx 4.81V.
We now continue to the maximum load test of 8A:
As you can see, the charger is connected to four 2A loads. The total actual current is 7.24A and that is not bad at all!! very nice.
Safety is a major concern with wall chargers, especially with cheap Chinese charger. So I will do my best to canalize the safety of the BlitzWolf charger.
Opening the plastic case of the charger was very difficult! I had to cut it open with heavy tools.. it is a strong point in it's favor that the case is so strong. Of course it adds to the safety of the device!
The build quality of the circuit is very good, the soldering is good, the distance between the lines on the printed circuit seem good and there is a lot of insulation (RTV) between susceptible components.
The first component after the mains is a fuse that already provides certain amount of protection.
I was happy to see a transient filter circuit that protects from voltage surges, alas, it is a simple one, there is only on X capacitor and worse than that, the MOV is missing:
In the first image you can see the RTV insulation, but after scrapping it, you can see that the second image reveals the missing MOV (Metal Oxide Varistor) which is a kind of voltage regulated ressistor that supposed to short voltage surges to the ground. This component is not mandatory and in fact, cheap chargers never have MOV but it is an important part of a 'good' power supply and it's a shame to see that they chose to omit it.
A few components identified in this charger
- AS358_A – Operational amplifier
- D4UB100 – Rectifying dide bridge
- FTP10N60 – N channel MOSFET
- k1010 – OptoCoupler
I'm no expert on power supplies but I think that the existence of only one electrolytic capacitor instead of two implies a circuit with PFC and not a voltage doubler which is good.
The BlitzWolf is a high grade charger but far from perfect. It's good to see a transient filter protection but unfortunately without MOV. In performance terms, it easily delivers the goods, it will handle 5 phones simultaneous charging without a hitch. It certainly worth the money. We hope to find an even better charger in the future but this one is already a few grades above your usual Chinese charger.
Thanks to Banggood for providing me with the BlitzWolf for this review.