The only problem is the rattling
Ive have 2 batteries built in these bottles, they're easy to set up and very convenient to remove. My problem with these lies in the rattling and generally loose fitting. They do not fit very snugly into the base, and rattle and jostle around on a ride. Hilariously, it makes more noise than my motor! I could deal with this except it is bad enough that the rattling causes the connectors to short/spark and overheat, which has ended up melting the plastic around the connectors. I'm going to try and find a way to get them to fit more snugly, or I will have to rebuild my battery solution entirely. Also, you will have to charge these batteries with a barrel connector, which I would argue is inferior to something like an xt60. Other than these things, the battery is top notch! I'd suggest going with a shark or dolphin pack over this, simply for the better case design.