Rotax battery information

Keith Smith · Joined: 11 Jul 2002 Posts: 24 Location: Chico, Ca

I've done some testing on my Stock Rotax battery, that has 22 races over a 1 year period. I thought it was going bad, so I took voltage readings at different times. Battery was charged till green light came on. I charged in between heats also. I usually charge for atleast a one full day before raceday.

Volts-
Full Charge- 13.2v
durring cranking-12.1v
running- 12.6v
after heat race- 12.1v

One week sitting Idle-12.5v

My conclusion is the batteries, work or they don't. A volt meter should be in your tool box. Let me know what #'s the rest of you come up with.

Nick Weil · Posted: Thu Sep 26, 2002 12:28 pm Post subject: Rotax battery information

Keith,

Per the Rotax Owner's Manual those voltages you show are perfect. The manual states that voltegas at or near 11V are insufficient to produce enough ignition spark.

Keep in mind too fellow Rotaxians, when trying to check your battery...
Removing the plug from the cylinder and grounding it out while checking the spark is not a good test. First off, if you mistakingly don't get the plug grounded to something you can damage the coil. Secondly, the battery will produce a LOT more spark when not having to fight the compression of the plug being inside the cylinder...

Nick Weil
SpeedQuest WebSite

Chuck Groat · Joined: 04 Apr 2002 Posts: 60 Location: Salt Lake City, UT

Nick, I concur with Keith's assessment regarding the batteries work or they don't and disagree with your statement that the batteries will turn the motor over when the voltage is greater than 11V. I had not one, but two batteries that would not start the kart more than one time after being charged for approx 5 hours after the green light and both batteries remained over the volatge numbers provided above and by the manual. I had the battery tested by another individual that makes posts to this site and he advised the battery was junk even though voltage was greater than 11. The battery would not hold a charge but showed normal volatge. I've sense gotten a third battery which I have had no problems following the same procedure as the previous two.

Nick Weil · Posted: Thu Sep 26, 2002 5:09 pm Post subject: Rotax battery information

Chuck,

You must have misread/misunderstood my statement. I made no mention of turning the motor over (starting). Nor did I imply that ANY battery in the world would start ANY motor. The only thing I pointed out is that to produce sufficient spark for the system to operate there must be a minimum of somewhere near 11V.

I do not doubt that with the use and abuse that we put these batteries through that there are some which have cracked cells internally, or pinhole leaks in their cases. And I also don't think that the battery manufacturer does not probably have some DUDS leave the factory. These batteries come over on pallets all the way from Europe. I am sure that everyone that handles them along the way is very loving and caring to them and that they are not subjected to sudden drops, jarring movements and the occasional bouncing...

Nick Weil
SpeedQuest Website