NiMH installation

Well, they are in and running-sortof.
An unbelievable amount of work. All the battery boxes I spent a summer fabricating and installing had to be removed and the support they provided had to be replaced. Additionally, the rust worm had been at work so some more body work was called for.

Here you can see what the installation looks like. The battery pack is now in 2 battery boxes, one under the hood and one in the bed. Unfortunately, there was not enough room between the frame rails to put the new rear battery box under the floor. I hated to lose the space in the bed! Anyway, the boxes are of plywood painted with aluminum paint.

Behind the front battery box to the left you can see a blue Zerex bottle that is the coolant reservoir. The pump pickup line is a U of copper tubing, and there are 4 return lines from the packs. I wanted to be certain that water was flowing through all the circuits.

I ordered parts to build a control to turn off my DC/DC when the pack voltage was high (like when charging) from a company called Master Distributors. Pieces are dribbling in. Worst run supplier I have run into. I have hopes that the last two relays will show up soon. They already told me that they "couldn't find" the listed as in stock fan I ordered. They seem to have mastered getting to the top of Google listing, but they are still working on fulfillment. Not recommended!!











Here is the view inside the rear battery box. I decided that the headers I was supplied could be replaced. I set it up so that there are just 2 flows in this bank. There are water jackets on each side of the battery. The sides to the front of the car are fed with one flow, those to the rear with a second. The batteries at the beginning of the flow are at the end of the other. I figured the temperature would be more uniform this way. The green hose with the copper tee is the feed line. Smaller clear plastic lines go to the water jackets which are plumbed in series.

I may have to replace the clear plastic with a reinforced variety. It gets pretty soft when heated.


This is the inside of the front box. It has 6 12v modules while the back one has 7. You can see the plumbing more clearly here.

The red fuse holders are lines from each battery to the test panel which allows me to check the voltage and possibly charge each battery from a central point.

I bought a circulator pump from Harbor Freight. It worked, but was way too noisy so I am awaiting another pump from an Ebay vendor.

These batteries put out a lot of heat toward the end of charge. Discharge doesn't seem to produce as much. I planned to modify an indoor/outdoor thermometer to handle 2 remote sensors, but I seem to have destroyed it. I got a unit with a wireless connection which works well for monitoring one box. Serendipitously, I can monitor the temperature from inside the house while she charges in the garage.

An electronic thermostat was recommended to control the pump, but I was not happy with its operation. I pulled a bimetallic thermostat from an old space heater and mounted it on a piece of sheet metal. It is designed to turn off 110v, and I want it to turn on 12v. I wired it up to a 12v automotive relay. Connecting the pump to the normally closed contact on the relay keeps the amperage through the thermostat so low that the 12v arcing is insignificant and when the thermostat is closed the pump is off. When the thermostat gets hot it opens and the pump is turned on.

I have driven it on several trips, one over 15 miles, and it is working well. I keep a wary eye on the thermometers, but they have stayed under 90. Charging is another matter. My charger is programmed for lead acid. It doesn't want to turn off! I am hoping that when the cooling system is operational all will be well. Until then, I have to watch the heat buildup very carefully. I pull the plug on the charger until they cool down.