Wow!
Progress is really flying along now! In just a few short days I've created and
installed the control box and controller and pre-wired them all ready to go.Step Fourteen - Installing the Batteries
Wow!
Progress is really flying along now! In just a few short days I've created and
installed the control box and controller and pre-wired them all ready to go.
Now comes the last major purchase and task - the batteries!
The battery pack in the car will consist of twelve 12V Deep Cycle batteries connected in series to create 144 volts. Considering these are small batteries weighing less than 230Kg (506 pounds) in total, and that these batteries have over 840 cranking amps available on a warm day, the performance of the car is expected to be the same if not better than when it was running off the original 1.6 litre noisy old "carbonator".
Once the batteries arrive, I'll go about installing and securing them into the car. While the front ones I can take care of myself, the six rear batteries will require specialist attention to make sure they're seriously secure as the boot (trunk) of the car is considered inside the Passenger Compartment.
Hooray! The batteries have arrived!
I collected them this morning from my company's office and brought them home safe & sound. As it turns out, they have plenty of room to move while sitting in the racks. So much so that I'm going to put in some wood strips surrounding the batteries. Coupled with the rubber matting underneath each battery, the vibration of a typical drive will be reduced a fair amount.
It's interesting to see the Tredia sitting down closer to the ground again. I got used to resting my knees against the front bumper while leaning in there and now the bumper sits just below my kneecap. You can see in the first picture at the bottom of the page, the difference in the Tredia's height before and after the batteries were added.
Now that they're comfortable in their new home, it was time to secure them... securely. :)
The rear rack will need to have a top-half welded and bolted in so I saw my welding guy and asked him to come over with his welding gear as soon as possible. It gave me time to secure the front batteries.
I also created the bottom half of the rear battery box. It was fairly straightforward, I just bought some board from the hardware shop and build it up around the batteries, leaving room for the super-clamp that will hold those six little batteries in snugly.
Firstly though I had to install the front batteries. While I was painting the rear battery box, Rob came over and put rubber stripping around the base of each front battery rack. He then measured up a sheet of board and cut out a base for the front batteries to sit on, then Rob built up a surround to stop the batteries moving about. Then we both tackled the job of securing each front battery with an individual stainless steel strap and clear flexible tubing (to prevent damaging the batteries.
Check out this photo on the left to see an example of the strapping we used to secure the front batteries.
We put each strap through some clear & flexible PVC piping to reduce stress on the corners of each battery and to insulate the strap that rubs so close to each terminal.
The base and surrounds will stop lateral movement (and reduce vibration), while the strapping will prevent the batteries flying about in an accident. Not only is this method immensely strong, but it's slim, minimalist and (my favourite) cheap!
Now that the front batteries are in and not moving in a hurry, it was time to install the rear ones.
I measured, cut up and created the bottom half of the box. It fitted well so I took it out and covered it in water proof, oil proof, flame-resistant super paint called POR-15. This stuff is so amazing I'm sure NASA and the Федеральное космическое агентство России (Russian Space Agency) use it on the space station!
Once the paint was dry I put it into the rear battery rack in the boot and installed the batteries with a spacer board in-between to help insulate the batteries and ensure there's no movement. Now all that's left is to secure the rear batteries to the floor. I was going to get my welder to come over and create a removable frame to bolt all the batteries in place, but I've decided to use the stainless steel strapping instead! It's cheaper and ultra strong and easier to work around when completing the top half of the battery box.
Far out! Yet again, I spend just a couple of evenings in the garage and I end up finishing a whole section! I installed and secured the rear batteries with steel strapping and clear PVC pipe and built & installed the top section of the battery box as well. All that in two evenings!
As you can see in the video at the bottom of the page, I installed an adhesive lined foam strip around the lip of the battery box base. This means when the top half of the battery box is placed on top and clasped in, there is no way for the gas to leak into the car's boot while charging.
To prevent gas buildup, I installed a couple of fans into the top half of the box. One of the fans blows air into the box, the other extracts air out. They're both brushless DC fans operating at (collectively) 0.2 amps and are connected to the turbo timer and a switching relay. This allows the fans to switch on when the charging plug is installed, and when the plug is removed, the turbo timer under the back shelf forces the fans to stay running for 3 minutes. Not only is it a good idea, it's one of the NZ rules for converting a car to electricity. I'm yet to install some flexible hosing to and from the extraction fans. I'll try to do it this weekend.
The fans also start when you turn the ignition. The rear box fans start up, and once you've finished driving and turn off the ignition, they remain on for 3 minutes before switching off.
It sounds really complex but it wasn't. I just ran the fans through the turbo timer and then through a switching relay so that the power from the charger doesn't interfere with the power from the ignition. I hope that makes sense! It was all a bit of trial and error to get it working but it was well worth it.
I ended up with a well built, water & oil proof and flame retardant battery box housing 6 strongly secured batteries. I'm now just waiting for my main cables to arrive and I can start wiring up the car ready for that first fantastic trial run!
And as always, you can view the video of the whole exciting story right here:
Here are some photos of the progress too:
