Spare battery kit was very handy. My wife and I both bought River Trikes which came with one extra battery between the two of them. I purchased another spare battery so we each have 2 batteries now. We have been riding on average twice a day. So we always have a charged battery ready to go when the one we are using needs charged.
To top it all off, we bought an 6 X 10 aluminum cargo trailer and attached ratchet strap anchors strategically located to secure our two river trikes. So now we are ready to transporr them to distant trails.