Gell cell batteries
Gell cell batteries
This is a question for Jim. How does one know that their gell cell battery is nearing death. I've used the length of time to do a recharge as an indication of pending death but got tricked by a battery at the runoffs. It was fully charged but failed to start the car later.
The above post is for reference only and your results may vary. This post is not intended to reflect the views or opinions of SCCA and should not be considered an analysis or opinion of the rules written in the GCR.
Re: Gell cell batteries
I'm no Jim Schings, but here goes...... 
Battery testers and Battery conditioners can give you the % capacity info on a battery. I am not positive it works on a gel cell, but I believe so.
You can also put a meter on it, crank the motor and check the voltage after you stop cranking. Anything less than 12 and something is wrong. Never looked at it while it is cranking.
A note to newbies (Brian knows this as he watched it happen to me) a shorted out cell in the battery will cause you to only have about 9 volts. The car won't rev over about 5000 RPM.
Battery testers and Battery conditioners can give you the % capacity info on a battery. I am not positive it works on a gel cell, but I believe so.
You can also put a meter on it, crank the motor and check the voltage after you stop cranking. Anything less than 12 and something is wrong. Never looked at it while it is cranking.
A note to newbies (Brian knows this as he watched it happen to me) a shorted out cell in the battery will cause you to only have about 9 volts. The car won't rev over about 5000 RPM.
Stephen Saslow
FV 09 NWR
FV 09 NWR
Re: Gell cell batteries
Not real easy. There are typically 3 failure modes. One is just a shorted cell bank. That is easy. Your voltage will be way down under any load at all. (Similar to what Stevan pointed out.) Another is deteriated matts or structure. Normally caused by an excessive charge or discharge rate. I like to keep our charging rates below 5 amps.brian wrote:This is a question for Jim. How does one know that their gell cell battery is nearing death.
The last is just sulfation. Without going into the technical details, the net is the battery that was once a 17 or 18ah battery becomes less, until it won't last a session. All batteries sulfate, but the longer they spend their life at full charge the less sulfation occurs. A battery that is held at or near full charge all the time will last 5+ or even more years. Ours are discharged to probably a 70% level every session. The longer it sits like that the more sulfation that takes place. So a top off after every session is a good idea.
A lead acid gell cell will read ~12.7 volts when fully charged. At 12.2 is is about dead and needs recharging. You need a good digital meter to read these voltages. (Right after a charge it may read as high as 13 V, but will drop almost immediately to 12.68 with any load.)
About the only way to determine how much life is in the battery before an actual failure is with one of the smart chargers now available that have a setting for gel cell or AGM batteries and a percent of charge indication. If the charge rate is very slow or very fast compared to when it was new you know something is going. The charger in our trailer that we use for all 3 rentals indicates the percentage of charge at any point in time. We know that it takes about 10-12 minutes to go from ~70% to 100% after a session. If that varies much, we figure a battery is suspect. Actually we have only had one battery failure in 4 cars over the last 3 years. That one was about 2 races ago and it showed up as charging very quickly but was always down to 40 or 50% after even only one restart.
Re: Gell cell batteries
Thanks a lot Jim. I have the % charger and will follow times more closely.
The above post is for reference only and your results may vary. This post is not intended to reflect the views or opinions of SCCA and should not be considered an analysis or opinion of the rules written in the GCR.
Re: Gel cell batteries
Gel -AGM batteries need a special charger for extended life. The charge at a much higher voltage than a wet cell battery. Most are of a 3 stage type charging to 80% at one voltage then going higher to bring the battery to about 95% them another voltage to top it off in what is called a float mode. Google it for more specifics.
Dave
Dave
Re: Gell cell batteries
I have one of these chargers, price is right and it has options for normal or gel batteries and it will display percentage charged and battery voltage.
Product Description
Easy to use, this Fully Automatic Battery Charger/Maintainer, 80 Amp Engine Start, Battery and Alternator Tester with Reverse Hook-Up Protection for 6 and 12 volt batteries is ideal for Automotive, AGM, Gel Cell and Deep Cycle batteries. 30 Amp Rapid and 12 Amp Fast charges for Car, Truck, Marine, RV and Farm Equipment keeps you moving! The 2 Amp Slow/Maintenance is ideal for Motorcycle, ATV, Snowmobile, Lawn Tractor size batteries by providing power at all times and to keep batteries warm too. Includes:125 amp battery clamps for top and side-mount battery posts. UL listed.
$79.99 Diehard at Sears.
http://www.sears.com/shc/s/p_10153_1260 ... ry+charger
[ external image ]
Product Description
Easy to use, this Fully Automatic Battery Charger/Maintainer, 80 Amp Engine Start, Battery and Alternator Tester with Reverse Hook-Up Protection for 6 and 12 volt batteries is ideal for Automotive, AGM, Gel Cell and Deep Cycle batteries. 30 Amp Rapid and 12 Amp Fast charges for Car, Truck, Marine, RV and Farm Equipment keeps you moving! The 2 Amp Slow/Maintenance is ideal for Motorcycle, ATV, Snowmobile, Lawn Tractor size batteries by providing power at all times and to keep batteries warm too. Includes:125 amp battery clamps for top and side-mount battery posts. UL listed.
$79.99 Diehard at Sears.
http://www.sears.com/shc/s/p_10153_1260 ... ry+charger
[ external image ]