The batteries used on our Mini z cars are AAA size batteries, their are many choices os batteries that can be used, but There seems to be a pattern or certain batteries that are being used.
They are Orion batteries whis come in 750,900 and 1100, Kyosho have now brought there own battery out in 2020, this being the Kyosho speed house battery, that come s in 800 size.
anothe rcouple of battery types that some are using are eneloop battery and a Lipo AAA battery, like chassis's its a drivers preference at the end of the day ,, but this is my experience of these batteries.
ORION 900
These were one of the first batteries that I started to use and still one of my main batteries still, I get a very good time with these and have a great top end, and drop of near the end of the charge
ORION 1100
This was the second Battery that I used and I find this still my favorite some say th e)rion 800 is a fast battery I have not found that so I find the 1100 is abou tth esame but has a longer running time that suites me so I can get more 3 minute races in before changing the over for a nealy charge set.
SPEED HOUSE 800
These batteries Kyohso has now branded to replace the Orion batteries, they have loads of power but people are finding that there original chargers are no good in charging these batteries, Kyosho has brought there own 4 cell charger to charge them, also Isdt have chargers that charge them well.
It seemed like the small chargers were getting to warm when charging them.
I am getting to like these batteries more and more.
ENELOOP
These I do not like very much the shops bought these for a replacement of the Orion batteries for some reason, yes they hold there charge for a long time but they do not have the top end of power all the others have they seem to have a 80% all the war till they run out., so for beginners they could be very good has they don't need the top end.
AAA LIPO
Now these are ballistic you only need two of them and a pair of dummies which are to plastic battery shells and you put some tin copper wire from one end to the other so th epower circuit stays the same, you can use 4 lipo batteries but you need to alter the wiring on the power system.
The dummies come from China or Ebay as do the Lipo batteries.