Who reviews BATTERIES ? !
Well, me for one, as they’re expensive items and there are things to watch out for, depending on what they’re used to power, that i’d like to point out…
Hawk-Woods manufacture their own range, in the UK, of various Pro and pro-sumer ‘standard’ battery types used on cameras, lights and audio equipment.
I bought 2 of their DV-980 batteries, together with the DV-MC2 dual-charger and DV-XLRR battery adaptor. These are sometimes called ‘DV camcorder’ type, hence Hawk-Woods designations, but the Sony-made equivalents are called NP-F-950, 960, 970, and these are also referred to ( e.g. by Sound Devices ) as ‘L’ type Li-ion batteries. Nominal working voltage quoted is 7.2V but straight off the charger they will reach around 8.4V
(obviously 1 battery under charge here on the left, middle LED power on, left LED – charging, and as-yet-unlit green LED comes on when charge is complete )
This latter item i mentioned ( right pic ) is a step-up adaptor, i.e. it contains a DC-DC converter, and is fitted with a 4-pin XLR that ouputs 12V. Other variants of this are fitted with Hirose 4-pin or other connectors but all output 12V, so i assume that they all use the same dc-dc converter unit. Well, 1 of them is is a step-down unit, again to 12V, but that’s because it’s a physically larger unit that uses 2 batteries simultaneously in series as the input. I considered getting that adaptor for 2 particular reasons but … well, maybe another time.
The batteries i got are the highest capacity Hawk Woods do in this type, 7200maH, i.e. 7.2AH. Some makers now quote Watt-Hours, which can be the more useful figure to compare battery capacities between ranges with, as it takes the battery (nominal) voltage into account.
In any case, working out the WH figure for the DV-980 ( 52) i estimated that one of these should run my Nagra for around 4 hours via the external DC ( 4-pin XLR, hence why i bought this model of adaptor ), because the smaller Nagra battery, at a nominal 10.8V and quoted as 4.8AH capacity, neatly works out as also being 52WH, and it runs the recorder for just over 4 hours with all 8 tracks recording.
The DV-980 did indeed run the Nagra for 4 hours 20 minutes before dying.
Measuring literally 0V at the battery terminals at this point I was then quite worried that because i was using the DV battery via the external DC-DC adaptor to feed a constant 12V into the Nagra – which therefore couldn’t know ‘when to stop’ drawing current from the external battery ( with its own battery attached it automatically cuts off or switches to external power before the Li-ion volts drop too low ) – then i’d somehow ‘killed’ the DV-980, since you aren’t supposed to completely discharge Lithium Ion batteries.
However, a helpful chap at Hawk Woods told me what i’d hoped was the case; that although the DC-DC converter itself will only work down to about 5V on its input, thereby making it impossible to fully discharge the battery, the circuit inside the battery itself will cut off the output at around 6V, and when i say cut off i mean it actually disconnects the output terminals, thereby showing 0V, so it can’t be discharged more. Only when it’s put on a charger and the voltage ‘outside’ is higher than that inside, causing current flow in, will that circuit then ‘reset’. The battery in question then charged back up fine.
Phew, that was a relief, possibly also a relief for you to get to the end of that long-winded explanation, but i thought this might be useful for any potential users who might have thought the same thing would happen when using a step-up battery adaptor. Maybe i was over-thinking this ( as an electronics guy ) but i prefer to know the full facts rather than just ‘trust’ that all such equipment will work together without mishap. I describe all of this really because the little leaflets supplied with the batteries don’t exlain this.
Anyway, to return to a bit of basic fact. The DV-980s recharge after 5-6 hours, irrespective of whether the charger has 1 or 2 batteries on it. The DV-MC2 charger itself does get warmer than i’d like on its underside, despite the multiple vent-slots.
I suspect this is partly down to the fact that it’s been made so compact and light overall ( no big internal heatsink ?) but of course in a travelling situation this is what you want ancillary stuff like chargers to be. It can run on 100-240V input naturally, and i can’t think of anything more to say about it than that now.
One thing that surprised me about the step-up battery adaptor was i expected the 12V out lead to the XLR to be a thicker cable, although given that it’s unlikely to be supplying more than a couple of Amps the cable it has fitted should be fine.
One reason i opted to buy this type of battery as my ‘reserve’ supply for the Nagra, rather than the ‘old standard’ NP1s that i was considering, is that it’s also the type used on plenty of other gear now. Most Sound Devices recorders use them, the AETA 4Minx recorder that was top of my shortlist not so long ago uses them, various LED lighting panels take this type, and also on-set portable monitors, to name a few, not forgetting various Sony cameras of course !