Also be careful when tightening the battery hold down. The bolt does not need to be bottomed out, I have seen more than one distorted battery case from over tightening. Can lead to premature failure.When replacing a battery on a G4 if you use a brand other than Yuasa make sure the top of the battery design is identical to the Yuasa or the bracket that holds the battery will not fit properly. Been there!
That's the first time I hear of this brand. There isn't many manufacturers of Powersport batteries. Like many other brands it could even be made by Yuasa. It doesn't really matter at 15F, but it can become a real problem at -15F if the battery isn't in good health or not strong enough to pull its weight in cold weather.
First thing imo is to make sure the sled has a pull start.
These are things that I consider for a new battery:
1. If shipped factory activated, it should show 13.0+ Vdc.
2. If shipped without acid, follow the instructions to fill and wait before charging, then use an adequate smart charger.
3. Re-charge every 3 months at the longest. More frequent is better.
4. If it doesn't hold near 13 Vdc for at least a couple of weeks after a fresh charge, consider it a bargain battery.
5. 12.8 Vdc is good, but not great. It is still ok for a new battery, and if so consider it a bargain.
6. Older batteries may only hold 12.7 if not 12.6
7. If lower, then consider desulfasion by discharging to ~11.0 Vdc under high load with a battery load tester (those with a 100A heating element), then recharge using a smart charger. Repeat until it reasonably stops rising in cranking amps. And yes I have done so. It's nothing magical either. If the battery has burnt cells for whatever reason like having been frozen while deeply discharged, there isn't anything that is going to save it, no even the fancy tricks. But if it is only sulfated from extended discharge like from March to November with no recharge, then yes it can be rejuvenated to an acceptable level. A brand new battery that has been left to discharge to 12.3 Vdc will take much less effort than an older/worn battery that will never reach par.
Best bang for the buck performance in Electric Start is the least voltage drop across the Starter Solenoid and Grounds.
The performance of batteries is much like the performance from power upgrades. You can buy all the fancy power upgrades for an two stroke, but if the engine is not even outputting 80% from lack of compression due to excessive blowby, those upgrades mean nothing. The same with the battery. You can get the best battery and even a higher CCA, but if 10-30% of its voltage is lost through those two connections, than a 5-10% gain from a stronger battery won't count for nearly as much.
The SDI has a weakness for its Voltage Rectifier Regulator. Avoid boosting the battery. Sure it can work, but it is known to cause trouble like some of the earliest Fuel Injected cars. I used to have the links to show the earliest problems with Fuel Injected cars before I lost them in a laptop crash. Doing a search in 2020 is nowhere near what it was in 2012. It has become increasingly difficult to find the older problems since the later models have been made more resistant. If you want to look it up, search SAAB and BMW. If you know your history of FI, it won't be too difficult to find. Consider the SDI as an old problematic FI car with those early problems. I've been there, hence why I needed to look it up.
I look for a minimum of 14.2 Vdc when the sled idles after using the electric starter (for both SDI and E-TEC). Hopefully it will reach 14.5 at idle, but definitely nowhere in the 13s. After a good ride I want to see 14.7 to 14.8 Vdc at the battery which is without shutting the engine. It is summer and you can't ride, but it can be cheated with LEDs or removing the head light fuse. The battery still needs to sustain 14.7 to 14.8 to show this high voltage.
If it still won't reach high enough voltage, you can add an adequate capacitor to the circuit. If it is a manual start then it should already be wired with one. This is about all I have, so hopefully it helps some.
It has become difficult to sort through YouTube videos, so below is the one that I have used for many years. Do yourself a favor and read through the comments, especially those from the Original Poster knurlgnar24.
At 3m9s he speaks of pulse charging. My smart charger once did this on a worn-out Yuasa battery. The voltage shot sky high to around 22 Vdc and the battery temperature rose to a scary level. All it did was kill the battery even more, so I'm not trusting that feature. That battery was so far discharged and dead that it wasn't worth it, but I mention it to be mindful of your smart charger and keep an eye on what it is doing.
Also note that he discharges the battery with about 40A. I mentioned 100A because that is what I have on hand with a battery load tester. I could not tell you the pros and cons of 40A vs 100A.