Battery swaps. EV battery trailer

[jago25_98]

Idea:

- remove all batteries from the EV
- connect up a trailer
- rewire batteries into the trailer

You can now make a new trailer and store this at a relatives home and double your range.

Battery swaps on an e-bike conversion kit would also be useful.

But I never see much written about this idea.

[a8ksh4]

Nah, batteries are too expensive to leave in trailers at relatives houses...

[Ryland]

The electric bike kit I bought nearly 20 years ago had a battery you could swap and nearly every kit I've seen along with half the ready to ride electric bikes come with batteries you can swap, it's not a new idea at all.

As for putting all of your batteries in a trailer on a car... you'd end up with a very light car and a very heavy trailer so handling becomes an issue, you also have to drive around with a trailer all of the time so you limit where you can park and most of the time the average person only uses half the full range of an EV.
I have thought about a battery trailer for longer trips to extend my range but either borrowing a gas vehicle or using my current 50mpg gas vehicle seems to work just fine for those longer trips.
In tests that I've read about, putting an identical battery pack in a trailer will increase range by 80%.
I'm kind of hoping that at some point someone makes a pusher trailer out of the front end of a Prius and plugs it in to the EV's battery pack.

[a8ksh4]

If one had a motor & charge controller that supported it, I could see throwing a generator into a trailer and toting it along for extended range. Generators are supposed to be pretty efficient... 10-20HP in the trailer could probably keep a car going all day long with a battery pack to buffer the power.

[Ryland]

Originally Posted by a8ksh4

If one had a motor & charge controller that supported it, I could see throwing a generator into a trailer and toting it along for extended range. Generators are supposed to be pretty efficient... 10-20HP in the trailer could probably keep a car going all day long with a battery pack to buffer the power.

If you are just using the battery as the buffer you shouldn't need a charge controller or anything other then a high voltage cut off that will only act as a safety.

A mechanical drive to the road is going to give you better economy then a generator if you are driving down the highway (long distance) and a generator is going to be easier to drive with for stop and go driving.

A power assisted battery trailer is something I've thought about building because you could use it for non EV's as well for hauling more then the vehicle could normally tow if you had a telescoping hitch that worked as the throttle, if tuned right you could even tow such a trailer with a bicycle.

[oil pan 4]

Originally Posted by Ryland

If you are just using the battery as the buffer you shouldn't need a charge controller or anything other then a high voltage cut off that will only act as a safety.

A varrac and rectifier array would be the cheapest most efficient way to go.

The problem with a bunch of batteries sitting on a trailer is after 5 to 10 years they will be worth less for extending range, no matter if you used them a lot or not.
A generator on the other hand as long as you keep the rain off it, store it with fresh oil in the sump and no gas in the gas tank or if a diesel with bio free diesel in its fuel tank it will still run good as new after 10 years.

[oil pan 4]

Originally Posted by a8ksh4

If one had a motor & charge controller that supported it, I could see throwing a generator into a trailer and toting it along for extended range. Generators are supposed to be pretty efficient... 10-20HP in the trailer could probably keep a car going all day long with a battery pack to buffer the power.

4 pole 1800rpm generators are fairly efficient.
Cheap 2 pole 3600rpm units are loud, shake them selves apart and suck fuel as if they have a hole in the fuel tank.

Edit: if any one needs a small gen or batt trailer I am the resident trailer builder.