Can the batteries be cooled by forced air during riding?
Please forgive this question if the answer is obvious. I have only seen pictures of the batteries and battery box and I know little about the cooling path of air over the batteries. If they can remove the heat from a 1000+ cc motorcycle through air flow at normal road speeds why can't the same be done for V's relatively small heat load in the battery. I would think it would be easy to keep the batteries at ambient, or slightly higher, given access to a 35mph wind at cruising.
I know there are ducted inlets at the front fork that lead through tubes to what appears to be the bottom of the battery tray. Are these the primary cooling for the batteries or something alltogether different?
Again forgive my ignorance of the layout of the batteries. Reading material and info is welcome.
Todd
The amount how heat that can be dissipated from air cooling is a function of both air flow and temperature difference.
on a petrol bike, the temp difference is around 60 deg C, and easy to get the wind to it through the radiator.
on the Vectrix the temperature difference is around 5 deg C, and the whole battery needs relatively even cooling.
a small temperature difference over a large volume is actually very hard to work with.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Hi Todd,
theese two inlets are the airintakes for the battery tray. The tubes are attached to the bottom of the battery tray (between the
middle and the forward 1/3 of the battery tray). There is some kind of small "chamber" below the two battery boxes from where the
air flows upwards between the cells. With this configration rain and small waterdrops should stay in this chamber, water can leave
through two small holes in the rear section of the tray.
For my feeling the two intakes are rather small to keep an suficient airflow through the batteries during ridng wthout the fans
running. installing two "funnels" on the intakes might increase the amount of air during riding. Or you modify Mik´s ABC-cooling
by installing a 12V battery in the trunk to start the two fans manual if wanted.
Greetings Mike
Thanks!
I live in Houston so the temps reach and stay above 80F/26C during most of the summer, day and night. Battery temp is often 30C when idle and I see 40C+ riding and charging. Heat has been a problem and I am looking at various ways to deal with it.
Matt-
I understand the temp differential, and the smaller the differential the more air it takes to make less of a difference. I have seen my batteries at 10C+ above ambient. I keep thinking with the volume of air available at road speeds you should be able to dissipate even the heat buildup generated during charging once on the road.
Mike -
I had a feeling that was the case. I don't recall where but I saw photos of the V during assembly a while back. I agree with your assessment about the size of the intakes - they are small and screened. If I recall the tubes were about 2" diameter and about 24" long with bends. This sounds rather restrictive given the shear area the battery occupies. While it may work in cooler regions I think it could be improved for warmer climates.
I was thinking the funneled intake you mentioned combined with larger tubes should allow a significant increase of air flow to the batteries.
Any thoughts on how to address the intake/funnel?
Todd
Hi Todd,
Forced air cooling. Definitely a good move. But the easy way, despite the occasional adverse comments, is to run the fans whenever the Vectrix is being used.
If you check the specifications on the 'altered Charger Software' you will find that this is the first change I implemented.
It is, basically, a 'fiddle'. The original software has a battery temperature limit, beyond which the fans are supposed to run when the bike is being used. That temperature WAS in the region of 40 degrees plus. What I have done is to change that temperature level to 5 degrees C. Which means that, unless you ride in temperatures below 5 degrees C, the fans will run at all times.
No doubt someone will complain about the use/waste of battery current. Well the power supply which provides the twelve volts output for the fans, lights etc is about 80% efficient so it draws around 0.5 amps from the Vectrix battery whilst running the plenum fans/impellers. In 1 hours riding this will 'cost' you about half to one mile off your expected range. By keeping the battery cooler, you may well get some of that back due to lower battery losses due, in turn, to better temperature control of the battery. There may also be a long term benefit of a longer lasting battery, but that is speculation on my part, of course.
Best Wishes, keep smiling:-)
The Laird.
Hi, don´t know how it would look like,but that is the space
where I would place the intake. The spoted lines could be left
if there is not enought space because of the frontfender.
Greetings Mike