EV Batteries
Dewalt Cordless Batteries and Chargers FAQs
Submitted by Gman on Mon, 06/04/2007 - 07:23Dewalt Cordless Batteries and Chargers FAQs
1. Is it better for DEWALT
batteries to be completely discharged before charging?
No. Just the opposite, you should stop using a
battery as soon as you feel a substantial decrease in power from the tool.
Completely running down a battery may damage the battery.
Do not tape trigger to run down the battery.
2. How is the Voltage of a Battery Pack Determined?
A battery pack is made up of a series of individual battery cells
connected together. Each cell has 1.2 volts. With the addition of each
cell the battery pack voltage increases by 1.2 volts. For example, a 12
volt battery has 10 cells X 1.2 volts.
3. What is Memory, and do DEWALT batteries have
it?
Memory is one of many conditions which causes a loss of runtime. Memory is
created from repetitive light use in the exact same application (i.e.
Cordless Phones, Video Cameras, Electric Shavers, etc.) Our products
rarely see light use or the exact same loads, due to variability from the
user, the bit size, as well as the material. The same variability which
causes different runtimes, prevents our cells from developing memory.
Power tools are considered high-drain applications. Memory typically
develops in lower-drain rate applications, such as cordless phones,
laptops, etc…, because the rate in which the battery is draining is
continuously the same. Power tools draw higher currents and have sporadic
drain rates minimizing the opportunity for the battery to develop a
memory.
Definition of Runtime - the number of holes drilled, screws run,
or cuts which can be made on a charged battery.
4. Does it hurt DEWALT
batteries to leave them in the charger?
No. The DEWALT
chargers have a maintenance mode which allows batteries to remain in the
charger, maintaining a fully charged pack until the user is ready to work.
If the batteries are stored outside of the charger, they will discharge
naturally, 15-20% the first 24 hours, 7-10% the next day, and about 1%
every day there after. NiCd batteries lose the bulk of the capacity when
outside of the charger in the first 3 days. In fact, it is better for the
battery to leave it in the charger to be sure it goes through Equalization
and Maintenance Modes.
5. My battery does not hold a charge anymore, Why?
The potential reasons for this condition are as follows:
1. A connection between the individual cells has broken.
2. A single cell or multiple cells have been overheated and have
failed.
3. The battery has reached the limit of its useable life.
4. Poor charging practices
If the battery still runs, but with limited runtime, the cells may be
unbalanced, requiring charging through equalization mode to bring each
cell back to its maximum charge.
6. What can I do to improve the runtime of my battery?
If no permanent damage has been done to your battery, you may be
able to improve its runtime. The correct procedure for charging your
batteries is as follows:
1. Discharge the battery under
normal use. Remove the battery, once you feel a lose of power from the
tool. Do not tape trigger on, this will make it worse.
2. Let the battery sit out of the charger for a least 2 hours until the
battery is at room temperature.
3. Place battery in the charger overnight to allow for a full charge on
each individual cell. (A minimum of 8 hours at room temperature.)
If there is no difference in runtime, there is either permanent damage
or the battery has reached the end of its usable life. In either case, the
battery should be replaced.
7. Does the outside temperature affect batteries? How?
Yes. If the batteries are too hot (1050F or higher) or
too cold (below 400F), the batteries will not take a full
charge. Attempting to charge batteries outside the 400F-1050F
range can result in a permanent loss of runtime. When batteries are being
charged and discharged a chemical reaction is taking place, and if it is
too hot or cold the chemical reaction is disturbed causing a loss of
runtime.
8. Can an Automotive Charger charge batteries over 12V?
Yes. The new Automotive Charger, DW9109, will
charge all Battery Packs, 7.2V to 18V, in about one hour.
9. Does a DEWALT 15 Minute Charger give as much
charge as a 1 Hour Charger?
Yes. The 15 Minute Charger has the same 3 stage charging process
as the 1 Hour charger, which balances and fills each cell to its fullest
capacity. The fast charge mode takes only 15 minutes versus the 50 minutes
required by the one hour charger.
10. Does our 15 Minute Charger reduce battery life?
No. Our 15 Minute Charger does not hurt the battery due to the
Patented Charge Termination System. Many of our competitors’ 15 Minute
Chargers overcharge their batteries, reducing battery life.
11. Can the DEWALT charger be used with a
generator?
Yes. All of DEWALT chargers, excluding the
DW9106, have been designed to handle the variations in voltage and current
delivered by generators.
12. Why can’t I use a 9.6V battery in a 12V Drill?
The tools are designed to run at the specific voltage provided by the
battery pack. Too much voltage, as well as too little voltage, can cause
poor performance and life from the tool. The tool may run for short
periods of time with the wrong battery pack, but it shortens the overall
life of the product. This is the same reason corded products designed for
220V cannot be used in the U.S. where we have 120V outlets.
13. Why is the battery warm when you take it out of the charger?
As a battery approaches a full charge, some of the energy being loaded
into the battery generates heat. It is OK for the battery to get warm, but
it should not get so hot that it is difficult to hold in your hand.
14. Can the XR pack be used in a product which comes with Compact
Batteries, or vice versa? (i.e. XR Pack in a DW952)
Yes. XR, XR2, XR+, and compact Batteries can all be used
interchangeably. The only difference is the Extended Runtime Batteries
will allow the tool to run longer on a charge. The only rule to
interchanging batteries is to match the battery voltage with the voltage
of the product.
15. What should be done with batteries once they have gone bad?
RECYCLE. The material in these batteries (nickel-cadmium)
is toxic, and must be disposed of properly. A Federal Law was
approved in May of 1996, under the Mercury-Containing and Rechargeable
Battery Management Act, mandating the proper disposal of these batteries.
If continued efforts to recycle nickel-cadmium batteries fail, the states
will outlaw their use. Without these batteries, cordless power tools will
not be available as they are today. DEWALT
is an active participant with RBRC (Rechargeable Battery Recycling
Corporation), the organization which is the international leader in the
collection, transportation, and recycling the NiCd cells so they can
remain a viable battery option in the U.S. and the rest of the world. Old
batteries should be disposed of at Black & Decker Service Centers. For
more information call 1-(800) 8-BATTERY or 1-(800) 8-228-8379.
Gelled Electrolyte and Absorbed Glass Mats Batteries
Submitted by Stleride on Sun, 06/03/2007 - 17:37
Gelled Electrolyte and Absorbed Glass Mats
Submitted by Gman on Sun, 06/03/2007 - 17:30This is the first time I've heard of them. I learn something new everyday, I'll have to a Gelled Electrolyte and Absorbed Glass Mats Hand Book.
Gelled electrolyte
Gelled batteries, or "Gel Cells" contain acid that has been "gelled" by the addition of Silica Gel, turning the acid into a solid mass that looks like gooey Jell-O. The advantage of these batteries is that it is impossible to spill acid even if they are broken. However, there are several disadvantages. One is that they must be charged at a slower rate (C/20) to prevent excess gas from damaging the cells. They cannot be fast charged on a conventional automotive charger or they may be permanently damaged. This is not usually a problem with solar electric systems, but if an auxiliary generator or and bulk charger is used, current must be limited to the manufacturers specifications. Most better inverters commonly used in solar electric systems can be set to limit charging current to the batteries.
Some other disadvantages of gel cells is that they must be charged at a lower voltage (2/10th's less) than flooded or AGM batteries. If overcharged, voids can develop in the gel which will never heal, causing a loss in battery capacity. In hot climates, water loss can be enough over 2-4 years to cause premature battery death. It is for this and other reasons that we no longer sell any of the gelled cells except for replacement use. The newer AGM (absorbed glass mat) batteries have all the advantages (and then some) of gelled, with none of the disadvantages.
AGM, or Gelled electrolyte
A newer type of sealed battery uses "Absorbed Glass Mats", or AGM between the plates. This is a very fine fiber Boron-Silicate glass mat. These type of batteries have all the advantages of gelled, but can take much more abuse. We sell the Concorde (and Lifeline, made by Concorde) AGM batteries. These are also called "starved electrolyte", as the mat is about 95% saturated rather than fully soaked. That also means that they will not leak acid even if broken.
AGM batteries have several advantages over both gelled and flooded, at about the same cost as gelled:
Since all the electrolyte (acid) is contained in the glass mats, they cannot spill, even if broken. This also means that since they are non-hazardous, the shipping costs are lower. In addition, since there is no liquid to freeze and expand, they are practically immune from freezing damage.
Nearly all AGM batteries are "recombinant" - what that means is that the Oxygen and Hydrogen recombine INSIDE the battery. These use gas phase transfer of oxygen to the negative plates to recombine them back into water while charging and prevent the loss of water through electrolysis. The recombining is typically 99+% efficient, so almost no water is lost.
The charging voltages are the same as for any standard battery - no need for any special adjustments or problems with incompatible chargers or charge controls. And, since the internal resistance is extremely low, there is almost no heating of the battery even under heavy charge and discharge currents. The Concorde (and most AGM) batteries have no charge or discharge current limits.
AGM's have a very low self-discharge - from 1% to 3% per month is usual. This means that they can sit in storage for much longer periods without charging than standard batteries. The Concorde batteries can be almost fully recharged (95% or better) even after 30 days of being totally discharged.
AGM's do not have any liquid to spill, and even under severe overcharge conditions hydrogen emission is far below the 4% max specified for aircraft and enclosed spaces. The plates in AGM's are tightly packed and rigidly mounted, and will withstand shock and vibration better than any standard battery.
Even with all the advantages listed above, there is still a place for the standard flooded deep cycle battery. AGM's will cost 2 to 3 times as much as flooded batteries of the same capacity. In many installations, where the batteries are set in an area where you don't have to worry about fumes or leakage, a standard or industrial deep cycle is a better economic choice. AGM batteries main advantages are no maintenance, completely sealed against fumes, Hydrogen, or leakage, non-spilling even if they are broken, and can survive most freezes. Not everyone needs these features.
12 Volt 9 Amp Hr. UB1290 AGM SLA
Submitted by MB-1-E on Sun, 06/03/2007 - 16:03I did quite a lot of research to find as many Amp Hours as I could fit into a limited space.
I'm sure these are not nearly as common as using a couple or even three 12V-12Ah AGMs but I wanted range and I didn't want to have to use more than about half capacity for my trips. As we all know, the less you deplete SLAs, the more cycles they are likely to give you.
I have two battery banks in my array.
Each bank has 4 batteries in parallel. (8 batteries total)
My system is 24V so I placed one bank in series with the other ... A series/ parallel system.
I only have a 12V charger, so I needed a means of switching them all to parallel for charging.
Thanks to some astute, electrical types on this board, I was able to accomplish this with one DPDT (Double Pole, Double Throw) switch.
Time will tell if my Universal UB1290's hold up, but so far, they take a charge well and sure had no problem delivering lots of amps on demand.
2.56" Deep
5.94" Long
3.74" High
3.98" Total Height
The only thing that I really don't like about these is the small terminal size. These only have .1875" wide spade connectors. There may be the same battery available with .25" wide connectors.
I drilled a hole through each in order to place a #4 machine screw through each terminal. I used internal star washers to get a good bite on the screw head and drilled a hole through each of my homemade lugs. I placed a #4 nut directly on to the screw to clamp the lug tightly to the terminal. Some of the screws I left longer so I could connect another lug on top of the first, as needed.
The battery size worked well for me, although I changed my configuration several times before finding the most stable array that would keep the center of gravity low on the bike.
I keep a good charge on them using an Iota 3 stage charger made especially for AGM or Gel type batteries.
From my research, I have found that you want to top these batteries off as soon as possible after use and deplete them as little as possible during use to give them a longer life.
This is the main reason that I wanted the 36Ah at 24V, so I could have a good reserve that I wouldn't need to tap into too deep.
The payoff, of course is the added weight.
I haven't made it easy to do at this point, but I can always use a smaller number of batteries in each bank.
I'm sure after time, I'll find the best balance of weight to Ah in terms of range and battery life.
May all your Amp Hours be happy ones!
Dave (aka MB-1-E)
