Wednesday, July 13, 2011

The cargo trike is now in its eighth year of operation. One thing I had to decide upon over the winter was the battery pack for its electric assist, as the most recent one had started to die late last year and I barely squeaked through November with it (though through proper charging and management I did get two years out of that pack, which was darn good).

I'd been using sealed lead acid batteries (SLA) since the assist was installed, but that is not the best technology for the high power drain of such a set-up. Over the years I was advised to look into a lithium pack, but they were darned pricey (SLA was $200, lithium $800 at the time). But the prices have come down, and my friend BlackBurnPete told me of Ping Battery in China. This Ping fellow was getting excellent reviews of his products on e-assist forums, as he apparently has done his homework to make sure the batteries and their technology are reliable.

My previous pack was 12AH (amp hours) but being an SLA pack something called the Peukert Effect comes into play so the it only delivered perhaps 8AH. The above lithium pack is 15AH and does not suffer the same effect, so I'd be getting almost twice the range! 

One can feel a sense of trepidation sending money to an overseas seller and hoping everything will be OK. And this transaction was problem free. He notified me as soon as the payment was received and that he would let me know when it was being shipped and provide a tracking number. It arrived as advertised, and as the leads are supplied bare I asked my friend Charles R., who had done electrical work on the trike in the past, to add Anderson connectors.

Since this pack is smaller I simply cut down the battery box (easy to do when made out of coroplast and duct tape) and added some foam padding underneath, since instead of four solid SLA batteries I now had an assembled bunch of smaller lithium ones, and vibration might cause connections to fail. Perhaps this thing is rugged enough as it is, but it is little effort to add this protection. One addition is the piece of recycled plexiglass added to the top so I can see the LEDs for the battery management system.

This uses the same Anderson connectors as before going to the controller, but the charger uses 3-pin XLR (yes, same as a microphone, which could be confusing for a drummer like me).

The battery management system, the proper design of which is the key to having a healthy battery pack, It makes sure all the cells are properly balanced when charging.

The biggest advantage to this new pack is that one does not have to constantly recharge a lithium pack. SLAs can get damaged due to sulfation if left in any state of discharge, so if the trike is going to be parked for more than an hour or so the pack has to come out and get recharged. So for almost any gig I did I had to take the charger with me, unplug the pack, and take it all into the gig and make sure it was hooked up. And then reverse at the end. It was not the end of the world, but just one more thing to deal with when getting to the job. But just like your laptop, a lithium battery can be drained will not suffer any damage. So unless I have a rather lengthy ride (more than 20km return) I can wait to recharge when I get back home.

Now that part is fabulous. And the more I use this new set-up the more I like this aspect. But in the previous incarnation the pack just sat in a bracket in the cargo box of the trike, since it was almost always being removed. Now it can stay with the trike, but just lying out in the open is not a good idea. Time for a sort-of hiding place...

Cut through the floor, bolt in a cradle made from aluminum strapping recycled from my first trailer (that got damaged in an accident), then line that with coroplast and add the ubiquitous duct tape.

Drop the pack in (notice even more foam, since the trike has no suspension beyond its fat tires), hook it up and off we go!

So far everything has worked out very well. Charles updated the wiring, and later cleaned out a troublesome Anderson connector that had temporarily rendered the assist inoperable. I've very much enjoyed NOT having to always take the battery pack with me into gigs (try taking a duct tape-covered black box with wires sticking out of it into a Federal Government building), and while I've not yet had to test the full range of this new pack I've been happy not to worry about how far it can go for the trips done so far. So it looks like a big thumbs-up for this new set-up!


Farmer George said...

Mark, a friend gave me a link to your page. I've built a few trikes and planing another. I was curious about the steering on your trike. How difficult is it to steer and does it stay stable at higher speeds. Thanks in advance for your comments.

Mark said...

It steers just fie, though due to the design the trike has a huge turning radius, which most of the time is not a concern. But if I'm in a tight spot I can just stand up, lift the front end, and walk it around. The design did cause me to add bungee innertubes to keep the front end centred, as road camber makes it want to lean to the curb. The positive result of the design is that it rides rock solid down hills.