Post by Shampoo on Sept 19, 2011 19:29:46 GMT -5
Hey all,
As some of you may know, I'm a process engineer for Exide technologies. They are a manufacturer of industrial batteries. Therefore, I'd like to impart some knowledge upon you guys about how important it is to maintain your batteries properly. Some of this may get boring, and/or confusing, so if you need clarification, just ask!
I'll stick to generalities for the sake of argument and time.
The most important thing, and what sparked my interest in relegating knowledge was a little issue called Thermal Runaway. These figures are based upon Lead Acid, but they are pretty close to Ni-Cd.
Thermal Runaway is when you have a battery that not only generates it's own heat, but does not have sufficient means to acquire a steady-state temperature. This may not seem like much of an issue to you, but it is, and here's why;
Many of us are implementing PEQ boxes, which are for the most part, completely encased. This does not allow for proper convective heat transfer from the battery. Additionally, we tend to oversize batteries to get a bit more ROF out of it (at least I do)... Furthermore, we attempt to put more strain on the electric motor from higher spring constants, which means that there is an amount of voltage feedback to the battery, especially if the anti-reversal gear is a 2,3, or 4 point. For these gearsets, if you don't hit a full cycle, there's voltage feedback to your battery. Even if not, the battery must try to pull more energy from the battery and may exceed your batteries' rated discharge rate. This causes many issues, and one of them is a problem in Thermal Runaway. We play in the summer, with our heat-generating batteries in non-heat transferring PEQ boxes, and draw a LOT of current from them.
Well, great info, Greg, but how is this useful? If you are careful about using your battery, it won't be. You lose 5% of your battery for every 10 degrees F above 77F that you run in. A lot, huh? So, if you do some simple modifications to your PEQ box, or your battery-storing habits, you'll be able to bring that to the minimum 5%. Additionally, if you leave your batteries in direct sunlight, the positive posts or plates in your batteries corrode faster... alarmingly so for every 10F above 77F you have it in.
So, don't leave it lying about. Additionally, everyone knows that black absorbs heat. Where do you think that the heat from your black PEQ box goes to? Your battery. So, Doc, get excited, everyone, SPRAYPAINT YOUR PEQ's!!! heat dissipation will increase, and then your battery will stay cooler.
Don't get it too cold though... everyone knows that their batteries suffer in winter games. Simple solution that some of us have already implemented; hand warmers. Do your best to conserve the heat of your battery in the winter time.... Run a long wire and strap it to your balls if you need, but cold weather combined with a standard charger can lead to premature battery half-life and super poor performance.
Additionally, for those of you who discharge your batteries to almost 100%, stop that. a proper full discharge should include a "float charge" that is dependent on your battery type and voltage. If you fully discharge your battery and DONT leave a float charge, your battery will begin to corrode faster and faster with each successive charge/discharge cycle. Smart Chargers have this built-in... running it out on a race-car does not.
This conclues installment 1 of Battery information. STAY TUNED!
As some of you may know, I'm a process engineer for Exide technologies. They are a manufacturer of industrial batteries. Therefore, I'd like to impart some knowledge upon you guys about how important it is to maintain your batteries properly. Some of this may get boring, and/or confusing, so if you need clarification, just ask!
I'll stick to generalities for the sake of argument and time.
The most important thing, and what sparked my interest in relegating knowledge was a little issue called Thermal Runaway. These figures are based upon Lead Acid, but they are pretty close to Ni-Cd.
Thermal Runaway is when you have a battery that not only generates it's own heat, but does not have sufficient means to acquire a steady-state temperature. This may not seem like much of an issue to you, but it is, and here's why;
Many of us are implementing PEQ boxes, which are for the most part, completely encased. This does not allow for proper convective heat transfer from the battery. Additionally, we tend to oversize batteries to get a bit more ROF out of it (at least I do)... Furthermore, we attempt to put more strain on the electric motor from higher spring constants, which means that there is an amount of voltage feedback to the battery, especially if the anti-reversal gear is a 2,3, or 4 point. For these gearsets, if you don't hit a full cycle, there's voltage feedback to your battery. Even if not, the battery must try to pull more energy from the battery and may exceed your batteries' rated discharge rate. This causes many issues, and one of them is a problem in Thermal Runaway. We play in the summer, with our heat-generating batteries in non-heat transferring PEQ boxes, and draw a LOT of current from them.
Well, great info, Greg, but how is this useful? If you are careful about using your battery, it won't be. You lose 5% of your battery for every 10 degrees F above 77F that you run in. A lot, huh? So, if you do some simple modifications to your PEQ box, or your battery-storing habits, you'll be able to bring that to the minimum 5%. Additionally, if you leave your batteries in direct sunlight, the positive posts or plates in your batteries corrode faster... alarmingly so for every 10F above 77F you have it in.
So, don't leave it lying about. Additionally, everyone knows that black absorbs heat. Where do you think that the heat from your black PEQ box goes to? Your battery. So, Doc, get excited, everyone, SPRAYPAINT YOUR PEQ's!!! heat dissipation will increase, and then your battery will stay cooler.
Don't get it too cold though... everyone knows that their batteries suffer in winter games. Simple solution that some of us have already implemented; hand warmers. Do your best to conserve the heat of your battery in the winter time.... Run a long wire and strap it to your balls if you need, but cold weather combined with a standard charger can lead to premature battery half-life and super poor performance.
Additionally, for those of you who discharge your batteries to almost 100%, stop that. a proper full discharge should include a "float charge" that is dependent on your battery type and voltage. If you fully discharge your battery and DONT leave a float charge, your battery will begin to corrode faster and faster with each successive charge/discharge cycle. Smart Chargers have this built-in... running it out on a race-car does not.
This conclues installment 1 of Battery information. STAY TUNED!