BUILD
BATTERIES Each group 24 lithium battery comprises of 36
cells. 6 cells tall, 6 cells long. That's 72 cells total. This shows
ONE of the two batteries, as well as all the connections. for the balance
connectors and bigger power connectors. This gives a 108 Ah battery.
Considering that only about 50 to 60 percent of the RATED Ah of a lead
acid/gel/AGM battery is actually available and useable, this means a HUGE range
increase is possible. E.G. a 70Ah group 24 powerchair battery has only 35 to
45 Ah actually usable. Where the lithium battery has almost all of its rated
108Ah usable. So DOUBLE the range is easy.
The same thing with the smaller
(lower) battery below:
These batteries will be exactly 174mm
wide x 240mm long and 240mm high for the 108Ah one, and 40mm lower in height for
the smaller 84Ah one. But you have to realise that ALL of this capacity is actually usable. With lead
batteries only around half the rated Ah is accessible due to resistance, Peukert
voltage drops under load and depth of discharge issues.
The
SECOND image shows the same thing for the 40mm lower height group 34 battery,
(200mm tall), is made from 28 cells. Or 56 cells total.
That's 5 cells tall and still 6 cells long, but with some missing from the
top row.
The batteries here are
arranged in parallel groups, and these groups are then also connected end to end
in series. Look at the diagrams.
So the group 24 EQUIVALENT battery above for E.G. has groups of 9 cells
connected in parallel. Each group of 9x 12Ah cells is connected with all the
negative terminals, and all the positive terminals linked together. So it gives
a 108Ah 3.2v "big" single cell.
These parallel groups of 9, are then connected in series. That
is positive to negative. There are four of these groups per battery, and EIGHT
groups of these "big cells" in total (both batteries) so we get 8x 3.2v = 25.6v
in total.
Each battery separately is a 9p 4s pack. The total battery
(both together) is then called a 9p 8s pack. Because its 9 in parallel, and now
8 in series, to give us the required 108Ah at 25.6v.
Each one of the above batteries, behaves exactly like an old 12v
lead based battery. That is they are fitted in the same battery space, and only
need a sheet of plastic or some other insulator to stop the cell ends touching
metal, or each other. But at twice the usable Ah, and at half the weight. And 5
times the service life.
PROVIDED you do not run them down below their safe voltage limit,
(2.5v per cell) OR charge any cell beyond its safe 3.65v limit. This is easy
enough, as the voltage stays pretty much constant in use. Then drops off a cliff
at the point where the cells are depleted. As SOON AS YOU NOTICE THIS STOP! Go
no further. And you will not damage the batteries. Or monitor the battery cells
with a hobby battery tester.
The HYPERION charger monitors all cell parallel groups during
charge and will not allow OVER VOLTAGE to happen. This is why we need the 9
thinner wires, that go to the Hyperion balance ports. See the Hyperion
instructions. They tell the charger to slow down, and then each cell is balanced
individually. After charge each cell will be within 3/1000ths of a volt the
same!
The BATTERY METER on your mobility device will be totally useless
with a lithium battery. The best measure is to see EXACTLY how many Ah is
returned during recharge which is measured by the Hyperion charger. If its
under 90 percent of the battery capacity you are safe! It will be because range
will be huge.
