You obviously understand the pitfalls of such an arrangement very well. Really very well done.I have a soft case battery made by Jimmy. I have wrapped it in an extra layer of high density foam plastic and it sits in the bottom of one of my panniers.
I am careful to monitor it's physical condition, including the connection leads. I always measure both it's voltage and the rack battery voltage before connecting them together. Both important for health and well being of the battery and yourself/household.
It is extra weight but it's relatively low down and I'm not really aware of it. That said my riding is all tarmac, no acrobatics !
In combination it gives me a ridonculous nominal 28Ah, much needed in hilly W.Wales to aleviate range anxiety.
Also, using both at the same time, halves the current draw from each battery so stressing them less and, hopefully, extending their life.
The pannier is suffering weight stress, but it's been about 4 years now doing this and it is still going strong if damaged. (Axiom panniers).
Good post.Yes - the warnings about fire caused by connecting un-alike batteries in parallel need to be clear to people. Even when some users made electronic provision to isolate the second battery to stop a flat one being surge charged by a good one, there have been failures. There was a video on here made by some New Yorker who had connected a new high capacity battery to his ebike in parallel with his old battery and the video showed a spectacular fire outside his apartment. This guy was blaming the 'Chinese' ' Cr@p' battery he had bought, but I think his battery isolation technique had let him down and that there was a massive flow of current from one battery to the other.
Carrying a spare battery and swapping them out is completely safe. That is what I would do if I needed extra range.
I think its true to say that we all learn as we go along, methods change and get improved on, though such a Tarp is unlikely to strike a chord with most of the e-bike community I feel......speaking for myself of course, but I rarely "fiddle" with the insides of batteries, and know enough not to connect two together.....In one of Guy's programmes they deliberately set an e car on fire by remotely shorting the batteries, fire brigade tested a large fireproof type tarp to cover the whole car. And is more practical then hoisting a car in to a tan of water. As they demonstrated the flames extinguished due to no oxygen but the process of allowing the heat to cool was needed to prevent self ignition again.
Brilliant thank you, exactly what I was looking for, I take it it just velro's to the rear rack? is it sturdy?I've got this rack bag
It has a special compartment in it that unzips and you can slide in a spare Hailong-1 battery, with room for other stuff in the top half and the side pockets
A reasonably sorted quality high wattage resistor could allow the two batteries to achieve identical voltages, but restrict the current to a reasonably low value.For belt and braces connections use a schottky diode inline to prevent reverse current flow. XT connectors for me one simply can't connect up incorrectly once soldered right.
Contrary to what many believe, AC is far more dangerous than DC. But only the really good books actually state that.I remember when I was attending evening class on electronics at the local tech college, the teacher told us keep one hand in your pocket when working with dc to avaoid the risk of a small current across the heart.
Carrying a second battery. on my old Ezee Sprint, I made a bracket to fit on the seat down tube to hold the battery. When the first ran out of power, it took only seconds to remove both batteries and swap them around.