I own a 72 volt 2007 Zenn electric vehicle (EV) with six 12 volt Discover (AGM) batteries. This EV has 2 batteries located in the front of the vehicle and 4 located in the rear.
As you know, lead acid batteries loose much of their power when exposed to cold winter weather - causing the range of the EV to be drastically reduced.
So how can I maintain adequate range during the winter months? The answer is to somehow keep the batteries warm. Some EV owners have purchased 110 volt electric battery warmers that wrap around each battery. These warmers just plug into any 110 volt household outlet.
Specific details are most welcome. Here is the information I am looking for:
What is the best battery warmer brand? I have seen the Kat 80 watt warmer (model 22200) advertised. It is 36 inches long by 6 inches high and sells for about $32 at NAPA.
What is the best orientation of the battery warmers around the batteries?
How Many battery warmers are required? My guess, for the Zenn, is 2 in front and 4 in the back.
Should insulation also be used (in addition to the battery warmers)? What kind of insulation? Where (under the batteries. for example)?
Should all of the battery warmers be hard wired into the 110 volt Zenn recharging connector located on the right rear fender? This would allow the batteries to be kept warm at the same time they are being re-charged. Maybe this is a bad idea, because then the batteries would be warmed even during summer months.
I cheated and purchased an EV outright rather than building one. I’m in the steep learning curve zone now.
I too will be looking at battery blankets for the winter months. Obviously the better you wrap the batteries the better the heat stays in. Warm air is going to rise, so you’ll want to cover the top. Be careful not to insulate too much if you are using batts that give of hydrogen gas - you don’t want pockets of that. AGM batts are sealed and can be enclosed well.
I don’t see a problem wiring the blankets in with the charger plug unless you are pulling too many amps through the wires.
[QUOTE=grose;2437]Hey everyone, first post here!
I don’t see a problem wiring the blankets in with the charger plug unless you are pulling too many amps through the wires.[/QUOTE]
What I was concerned about is whether or not it is a good idea to warm the batteries during summer weather. Could that be damaging to the batteries? If the warmers are wired that way, there is no way to prevent warming the batteries during the heat of the summer unless some switch is wired in to disconnect the battery warmers.
[QUOTE=voltsrus;2440]What I was concerned about is whether or not it is a good idea to warm the batteries during summer weather. Could that be damaging to the batteries? If the warmers are wired that way, there is no way to prevent warming the batteries during the heat of the summer unless some switch is wired in to disconnect the battery warmers.[/QUOTE]
batteries actually perform better slightly heated. Now, it speeds up the chemical process, but you should still get the same life out of them in watt-hours.
[QUOTE=voltsrus;2440]What I was concerned about is whether or not it is a good idea to warm the batteries during summer weather. Could that be damaging to the batteries? If the warmers are wired that way, there is no way to prevent warming the batteries during the heat of the summer unless some switch is wired in to disconnect the battery warmers.[/QUOTE]
As you can see from the title, [I]Battery warmer for extending the range of an electrically powered vehicle[/I], it’s certainly relevant to this topic. In the patent description, the vehicle in question is a golf course greens mower. The batteries have an insulated compartment with a resistive heater under them. Another interesting feature they use is a duct carrying waste heat from the electric motors to the batteries.
Since this vehicle is a mower, the Textron Corp must feel that it is beneficial to warm up the batteries beyond just the winter months (when grass is dormant). In fact, they state that the system thermostat turns on at 70F and shuts off at 85F.
They state that the warmer system is appropriate for lead-acid, NIMH, NICd, NiZn, Zinc-air and Zinc-bromine batteries.
