16 all the way! You can easily turn it down for the young one if you need to. My son was only 3 and a half when he moved up to the 16 after riding the 12.5 for a year.
My alarms are coming from HobbyKing - Voltage-Alarm/18588 Hobbyking 2-8S Cell Checker with Low Voltage Alarm = $3.46
I bought 2 as they are so cheap and I'll put one on a battery in each bank. That said with the amount of power I have stored, I hope that I have bought enough time that low voltage isn't an issue.
gwhy - I don't want to stick anything extra electrical on the bars - it will get crunched.
Re the rear shock, I got a new 6.5" Air RockShox for US$100(older model) www.pinkbike.com. Raised the top mount with a bracket from the old mount up under the seat to get the same ride height as the 5" OSET shock.
Setting up the pressure - get a pump with the shock (seller gave me one free). We are at the lower end of the pressures for both compression and rebound.
I would be really keen to see a pic of the bracket you made to make the shock fit, this is something I have wanted to do for a while. Have you looked into replacing the fork with something better? Sorry to hijack this thread.
As for the Lipo's I really dont think you need an alarm on your lipo's I just carry a little hobbyking monitor with me and check them every now and then, you get a feel for how far you will get out of them pretty quickly. I have two of the latest 16's both running 10s lipo setups and I also have a 12.5 running a 7s setup, i've never had a problem with running them to low.
I havent seen any aftermarket suppliers per se - mostly skunk works of dedicated dads like yourself. The 12.5 doesnt seem to get much other than electric upgrades. Here's one of the trickest 16's ive seen with all new suspension parts added in a very professional manner.
(you may have to sign up for the site to see the thread - its a small trials fourum on advrider)
Hi New Here 12.5 Or 16 For The Little Ones
in OSET Electric Trials Bikes
Posted
16 all the way! You can easily turn it down for the young one if you need to. My son was only 3 and a half when he moved up to the 16 after riding the 12.5 for a year.