This pack is your standard configuration 11.1V lithium pack with three
cells in series. The pack is rated as a 10C-12C pack giving a theoretical
maximum safe amp draw of 26.64 amps. More than adequate for all but the
most power hungry motors that could be fitted to the Trex.
The Tanic lipo is fitted with three of what is referred to as 'Tanic Taps',
these are little power connectors that allow you to plug in a special lead
and charge the lipo cells individually. This allows the pack to be balanced
properly so that all cells are charging and discharging equally in terms
of voltage. This is a nice idea as it allows easy maintenance of the pack
and should result in a longer life / increaed number of charge / discharge
cycles.
The pack comes sealed in a plastic bag with the 'Tanic Taps' charge lead.
The lipo has it's terminals covered in heat shrink tubing to avoid any
shorting out. Connectors of your choice need to be soldered before the
pack can be used.
The pack is very similar in size to the Thunder Power 2100 3S 11.1V pack
and in the third part of this review I will be making direct comparisons
between this Tanic pack and the Thunder Power pack.
The pack has a manufacturer stated weight of 145g, on my scales it came
out at 148g, which is probably the weight of the wires attached to the
pack.
In terms of dimensions the Tanic pack has a 105mm length with width and height of 35mm and 21mm respectively. Rather disappointingly this makes the pack only just too large to fit between the Trex side frames (as is popular with this style of pack) see addendum below. However, I have never been keen on the lipo being against or close to the motor anyway, firstly because of heat and secondly because a front impact will put a nice 'motor can' sized dent into the lipo.
This would mean a configuration change to the Trex Tuning test machine
to allow for an 'under slung' lipo position, with the pack sitting along
the bottom of the machine side frames between the under cart skids.
Again this has some advantage in that the pack is centered in the machine
rather than making it nose heavy.
The first task is to solder the connectors for the pack. Given that the
first test of the pack will be with the Align 400S motor a set of standard
20A 2mm gold connectors were selected and soldered in place. The pack was
now ready for connection to the charger to be run through a standard set
of charge / discharge cycles to get the pack ready for higher amp draws
in flight.
The packs will be each cycled 3 times before being put to proper use in
the Trex, this is essential breaking in procedure for any lipo.
Initial connection to the charger showed an 11.462V charge in the first
pack, a nice healthy level and no cause for concern.
The charger will be set for a 2.2A charge on the Pro-Peak Prodigy charger
with a 50ma discharge down to approx 10V to follow.
Below left can be seen the 'Tanic Taps' for balancing the packs and the
charge lead inserted in the picture to the right.
Procedure for balancing the packs can take one of two forms
1. Each cell is charged individually through the 'Tanic Tap' connector.
A time consuming process as well as one for caution as the Taps only connect
to a single cell and therefore the charger should be set to single cell
lipo charging mode.
2. Delta-Peak charge the pack until the amp draw drops off significantly,
then top up each cell individually through the 'tap'.
Either will elongate the life of the pack.by keeping all the cells in synch.
The initial charge of the pack (from factory supplied) resulted in 1226mah
being given to the pack, meaning that the packs had been precharged with
approx 1000mah before shipping.
Below left can be seen the gold connectors after fitting and heat shrink
tubing.
Below right is a reasonable shot of the 'Tanic Taps' charge lead. Warning - when soldering the connectors for the pack do not allow the two bare wire
ends of the lipo to touch. The resulting electrical current delivered could
be enough to sever a finger. I would recommend deans ultra or 4mm gold
connectors for this application.
Addendum After a lot more fiddling and inserting at an angle I did finally get
the pack between the side frames, having got it in I was also able to put
the canopy on. The pack is a very snug fit, going right to the end of the
canopy and almost touching the motor can at the other end. It seems other
Tanic 2220 pack owners are also able to get this pack to fit in the canopy,
so it would appear that my pack is perhaps a little unusual in being such
a tight fit width wise.
Further to this I have found that Tanic have now put a slightly smaller
gauge wire on the pack. I'm told it now fits snugly but not quite as snug
as the review packs featured.
Over the past few weeks I have flight tested the Tanic on various different
motors. Rarely have I know this pack get over 60 degrees centigrade and
it has handled evrey motor I have thrown at it. Performance is far better
than my baseline pack (the JetPower 2200).
The Lab test has unfortunately been inconclusive, the pack submitted to
the lab has been deemed faulty after consultation with R/C Toys and they
have offered to replace the pack under warranty. This is due to thermal
problems when discharging the pack at high amps. The new pack when it arrives
will be submitted to the lab for testing.
In the meantime the test on the faulty pack is available for download but
the figures contained within may well be inaccurate when compared to a
properly functioning pack.
Update 18/04/2004
After testing the newly supplied pack the thermal properies of the Tanic
are not significantly changed, which leads to the conclusion that the original
pack was not faulty OR both of them are faulty. Either way the implications
are not good as either the pack isn't as capable as stated or they are
prone to being faulty. The full lab test should be available shortly but
it would appear that although the Tanic can handle actual use within a
T-Rex quite well it's specification may well be a bit over stated, which
is becoming a theme in the testing of lithium packs. Whilst this might
be seen as just marketing ploys to sell packs I'm not sure I agree with
this continual over exaggeration of a packs capability, particularly as
it leads the consumer to think that they can safely discharge the pack
at currents equal to that specification, which as we are finding may not
be the case at all and could lead to one of these packs (not just Tanic)
going into thermal runaway. The implications of which are not pleasant.
