GoldenMotor.com Forum
General Category => General Discussions => Topic started by: erdurbin on July 16, 2007, 08:59:36 PM
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Has anyone heard of using the dewalt 36v li-ion batteries? I think they are rated for 2.3ah. I saw a setup somewhere online where a guy had 3 of these on a 3-way switch = 6.9ah. Whenever a battery would get low, he would flip the switch to the next. They advertise 1500-3000 life cycles, with an average of 2000. If I used and recharged these everyday, I am looking at an average of 5 years for the batteries (and I don't ride everyday). They are about $110 for one, with a charger around $35. They only weigh 2.4 lbs. a piece equaling 7.2 total lbs. of batteries.
Rough estimate of cost
3 batteries = $330
2 - 1 hour chargers (home and work) = $70
Total = $400
average 2000 miles a year.
batteries last 5 years = 10000 miles on one battery pack potentially
=$.04 a mile for batteries alone
SLA cost
200-500 recharge cycles (one year of use)
my cost was $85 for 3 12ah x 5 years = $425
10,000 miles
charger included with kit
= $.0425 a mile
This is a rough estimate and I may be way off since I have not been riding my e-bike setup for more than a month. I am going from other forums and what people say about the longevity of the batteries.
I am just looking for an alternative to my heavy SLA's and when they die, I probably will be looking into these dewalt batteries very seriously.
Plus, only 7.2 lbs of battery and one-hour recharge per battery is nice. If I got 3 chargers, I could be ready to go in 1-hour.
I am not sure what the range would be, but I read somewhere that one battery could be good for about 6 miles.
Any thoughts?
If these go down in price next year when I replace my SLA's, I will be even better off.
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I've been watching the dewalt batteries myself as a possible battery option when I buy a goldenmotor kit; see my post regarding cutoff voltage for the controller. The controller cutoff voltage seems to be one of the few obstacles to using the dewalts as a power source; you could potentially miss out on a lot of the pack's stored capacity. myelectricbike is reporting a cutoff voltage programmed into the controller at around 31.5 volts. The dewalts are really only 33V to start with, and have a recommended low-voltage cutoff down near 22V. Depending on the current draw you might get shorted a significant amount of capacity unless you can reprogram or trick the controller to allow voltages down to near 22V.
Folks with 4 dewalt packs are reporting in the neighborhood of 20 miles pedal-assist range. I have also seen a motor only range reported on the order of 6 miles for a 2-pack. It might be higher for your use, because he was using them in series to power a 72V motor and it sounds like he was running at a higher top speed (~25mph?).
Durability on these batteries is reportedly amazing. One guy ran a continuous charge - discharge test on a cell at a 30A draw (13C) and the cell still had 80% of its rated capacity at the end of 1050 cycles. Lower discharge rates should allow for more cycles.
You can actually wire your batteries together to work with one charger if you get ambitious. It doubles the recharge time, but they still get charged rather quickly. Search for "aerorider" and "dewalt" on Google. David wired 5 packs together for his. He bulk ordered some connectors and still has some to sell to other users who are interested in paralleling their packs together for charging. There are threads on visforvoltage.net and rcgroups.com discussing the dewalt batteries for non-tool usage.
Let us know when you take the plunge and set your bike up for operation on them. I'd love to see what your actual range per pack ends up being and how well it cooperates with the controller.
-Mike
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Do you have a picture of the Dewalts?
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http://www.dewalt.com/36v/
Skip the intro, click on battery/charger. There is a picture there.
This guy on VisforVoltage has a bike built around 4 dewalt packs and a "Golden Island" 400W hub motor... wonder if there is any similarity to the goldenmotor 500W made by Golden Island Machinery?
http://visforvoltage.net/member-vehicle/25-36-volts/769-electric-hybrid-bicycle-using-four-dewat-36-volt-nano-phostphate-lith
Might be worth contacting him to find out more specifics on range, terrain, and where he got his motor and controller.
I'm assuming the original poster has already seen http://gristmill.grist.org/story/2007/6/1/1287/76804, but I'll link to it from here for anyone else to take a look. The guy has several other posts on the same forum, and one of them is where the reported 6-mile range is given by a user (he initially quotes 6-km for a 2-pack, but later corrects to 6 miles)
-Mike
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What does the warranty look like?
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Good question.
If you buy the batteries as part of a tool pack, it might be covered under a 3yr warranty/1yr service contract/90day money back guarantee the tool comes with. You can get 2 batteries and charger as a kit for ~$275 or so (with hammerdrill and carrying case included at no extra charge ;D) on ebay. I don't know if the warranty is tied to an authorized retailer. If warranty is a major concern you can check on the battery coverage by chatting with the folks at 1-800-4-DEWALT (1-800-433-9258). It is hard to say whether use in an e-bike will automatically void the warranty on a tool battery, but you might want to throw some sawdust at the drill before trying to get the battery replaced under warranty ;)
The folks at the RC forums don't seem to care much about warranty -- they rip the packs apart and use the individual cells wired up in various series/parallel combinations to meet their flight needs. They are much more interested in how they perform in use. They've been burned by extremely short cycle life of LiIon and Li-Polymer cells in the past. There is at least a core of enthusiasts who have been won over by these batteries.
-Mike
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If the DeWalt batteries are indeed 2.3 Ah, it would take over 6 packs to equal 15 Ah! ( 15 Ah / 2.3 Ah = 6.5 Packs) Each pack is going for approx. $100 dollars on Ebay including shipping. Unless someone used these batteries for their trade such as contractor, it would make little since to go this route since a golden Battery pack of the same size(36v 15Ah @ $472)would cost potentially less and give more performance than the Dewalt system. :o
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Agreed. For the 15Ah capacity pack sold by goldenmotor you will come out with a significantly better price.
Depending on the user, one may not need the range provided by 15Ah. If sized to the desired range, the DeWalt system could be cheaper in total, albeit with less capacity. Considering the typical SLA pack seems to be about 12Ah (since carrying much more weight seems to be out of the question) and SLA is usually only run to ~80% depth of discharge, this is similar to about 4 packs. Some folks have survived with 7Ah SLA packs (the "standard" range pack for some motor kits), which would be equivalent to about 2 1/2 packs, so either 2 or 3 depending on how far you need to go.
Another consideration is the longevity of the battery pack. Depending on the formulation and the way it is manufactured, a LiFePO4 battery may or may not have an extremely long life. The claims by the DeWalt cell manufacturers have been backed up by user punishment tests. I hope the same is true of the pack sold by Goldenmotor, but I don't know. Does anyone have some 3rd party data on the cells used for the Goldenmotor pack?
If one were to buy enough DeWalt packs to cobble together a 15Ah system (the 6 packs you mention) it would be able to put out the same performance as the goldenmotor pack. The A123 cells in the DeWalt packs are rated at 20C and have been put through user punishment tests at 13C with good results. The disadvantage is the do-it-yourself assembly and the $600 price tag for those 6 packs.
In summary, I am agreeing with you. I hope the goldenmotor packs grow the same reputation these DeWalt cells seem to have picked up. If they do, the only decision factor between the two becomes whether one needs 15Ah at a discount, or a smaller capacity at a higher incremental cost (with the DIY hassle thrown in the mix just to keep life interesting.
-Mike
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Mike, I agree with your post, but it never fails that you think that you have enough batt power to get to your destination only to end up pedaling the rest of the way! :'( The Dewalt packs contain a123 batteries(a123racing.com or a123.com) The RCers break apart these dewalt pack because it is cheaper than buying the batteries individually. I totally agree that the a123 batteries have been proven to perform. The only person on this forum that possibily could shed more light on this subject is myelectricbike. He eluded that he has a 36v 15Ah pack and knows what the actual run time and approx. recharge time. When I try to cobble together a project like this one, It seems never to work out to my advantage. :'( Anyone else want to add their experiences ??
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Nope, sorry, I don't have a LiFePo4 pack yet - only the authorization to sell them and I have not yet sold any. I have asked for a sample Golden pack in order to give you guys a report but please understand that I'm in a learning mode myself as to the cost and technological benefit and I'm learning a lot of this stuff by monitoring and interacting with you. My own personal interest, however, is centered around fuel cells rather than battery technology although for an ebike application they are not yet stand alone but remain interdependent.
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I'll continue to agree with you MustangMan. It is certainly an equation of leg power, battery power and how far you need to go. How far you can realistically go on a DeWalt battery pack is going to be a significant concern. How much is that reduced to when there is a headwind is another concern. How much extra pedalling will you be forced to do if you make a detour to a store on the way home is yet another concern.
Maybe when the price of an e-bike suitable fuel cell system is in the right ballpark...
Ah, wishfull thinking for future days.
-Mike
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Ballard currently has a fuel cell that produces 1200 watts of power, but the price at the present time is very prohibitive. PLEV's (plug-in Light Electric Vehicles) such as electric bikes will benefit the most with the advances in fuel cell technology. The time frame for fuel cells to become economically viiable is anywhere from 2 to 5 years, maybe sooner if oil prices continue to rise. It always takes time for the market to gear up for new tech. (remember the price for the first computers, $3000-5000 per unit what know cost $500-1500) ::)
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As for comparing computers how much would you pay for one of those $3,000 machines now? Except as an antique they are worthless. If you include the difference in computing capacity in your evaluation then today's computers would be worth $3,000 but cost
$10 -$3,000.
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Along the same lines as other PLEV concepts it will probably be most efficient to pair the right fuel cell witht the right battery system. Size the fuel cell to provide enough power to maintain 20mph "on the flat" (I'm just guessing here, maybe 200W continuous?) Pair that up with the right battery system for those 30A bursts during startup, acceleration and hills. That should give you a nice combination of range and performance.
A pair of Jadoo's N-gen (100W 12V) at $1K each, a few extra capacity canisters at $850 a pop, and a fueling station at $600, we'll throw the DC/DC boost converter in for free... Hmm, that's 20 lbs of power plant (sans battery) $4,300 and we're only up to the equivalent of 36V/20Ah. A bit short of infinite range, but we're working on it ;D
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I sent um an email. Maybe they have something in the 25 to 85 watt range to extend the range of post office home delivery vehicles that could be adapted to an ebike.
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How much would you pay for a used dead battery pack? A computer or battery has a limited lifespan. I was just trying to point out that fuel cells are not economically sound at this time. With electronics (such as computers, cell phones) the the time frame for a new product to come to market can accurately be determined by Moore's Law( the co-founder of INTEL). I wish we could accurately predict when fuel cells will become cheap enough so we could afford to make the transition from PLEV to fuelcell LEV. I hope I did not offend anyone in my previous posts, my intention was to inform of the possibilities. I personally will start with a SLA system then upgrade to LiFePo4 as the battery price gets even more attractive. I can hardly wait for the affordable fuel cell eBike !!! :) (if you build it, will they buy it? At what Price??)
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I don't think anyone has taken offense. We're all tossing around the plethora of permutations one could have for electric bicycle commuting. I'd say your contributions to the conversation have been right on target. Mine too ;D
I wish batteries followed Moore's law. I think they are improving at a rate closer to doubling
(capacity/energy density/total delivered power) every 1/2 century. Some of the most promising technologies of the last few decades have really come with some significant gotcha's.
Another thing favorable to the LiFePO4 battery chemistry is it is not supposed to self-oxidize and lose capacity over time regardless of use. I hope that claim bears out. I hate that my two laptop batteries are DEAD DEAD DEAD after having very limited unplugged use. Much of the LiIon chemistries eat themselves up regardless of charge state, or use, and lose much of their capacity within a few years. Of course many users will replace their laptop within the 3-year life span of the battery, but I'm currently typing on a 2001 vintage model that still browses just fine. It would be nice to be able to unplug and surf wirelessly, but I'm not about to spend $100+ to replace a battery on a laptop that is currently worth say $30 (although I doubt I would even have any takers at that price point)
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My tendency is to overreact... I'm not offended but possibly put off by being asked if I have found a good use for the TRS-80 Model I when I'm sitting at the Model II and the Model III is sitting next to me when what I really need is Internet distributed processing. :D
LiFePO4 is certainly a great improvement over lead acid in many ways if you are willing to make the financial commitment but if you are going to do an improvement quest then you should focus on state of the art and look for ways to make it affordable like maybe a 10 watt fuel cell that you could make yourself and then another and another and another while just keeping an eye on LiFePo4 instead of doing it the other way around.
Not offended but maybe put off. ;)
Update on the Golden LiFePo4 battery pack... Philip Yao reports shipping is on hold due to an issue with one of the packs so for the time being the Dewalt batteries appear to be the only way to go.
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I am glad we seem to be on the same page. :) I hate tossing out a perfectly good computer just because something "new" has come along. PALCAN is developing a fuel cell aimed directly for our segment of LEV's because the most air pollution is caused by short trips and the cost per Ah in this category. Palcan has developed a 500 watt all the way to 5000 watt fuel cell. Please take a look at their website as well as Ballards. Most fuel cell manufactures rate their output on 12 volts not 36 volts. :)
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I have some new information directly from dewalt regarding their 36 volt battery packs:
Subject
DeWalt Battery control module for DC9360 battery paks
Discussion Thread
Response (Jeff) 07/17/2007 03:40 PM
Hello mustangman, and thanks for using DEWALT's on-line support.
The control module for this battery pack is not available separately.
The amp hours of this battery is 2.4 amp hours or 2400 mAH. We do not have an estimated run time as this varies depending upon application.
Thank you for allowing us the opportunity to serve you. If your question remains unresolved or if you require additional information please update this incident.
Sincerely,
Jeff
Product Level 1: Cordless
Product Level 2: Batteries
Product Level 3: 36 Volt
Category Level 1: DEWALT
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If it has a control module then most likely there is a limit set on rate of charge and discharge. Maybe this is why there is so much interest in testing charge and discharge rates in the RC community.
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The battery pack does have a control module, and the R/C community has done some reverse engineering to figure out what exactly it does. That is still a work in progress. In addition to the pins that run through the control module, there are two spade connection slots that bypass the control module and are wired to the positive and negative end of the series of cells. The negative end connection is fused at 15A so anyone who tries this for a 500W motor may want to use at least 2 parallel packs to give a fused 30A available current. A number of e-bikers have bypassed the 15A fuse in the pack to allow for higher draws on individual packs.
The R/C community mostly tears these things apart and are only interested in the cells inside. The R/C aircraft hobby is very interested in the available draw because they run these cells at 30A or more in their stunt planes while doing rolls, vertical climbs, and other "3D" aerobatics. One of their attractions to the A123 cells is they can provide that kind of draw without killing the cells. Some of the other lithium chemistries and even the NiMH and NiCad have very short cycle lives at high draws, so they have to provide more parallell packs. These cells they can get away with only 1 or 2 sets of parallel cells (anywhere from 3S1P to 7S2P depending on the size of the model airplane)
For the e-bike community you can keep the packs intact because the pack weight isn't as critical as it is in aircraft hobbies. The tool battery form factor is fairly convenient to an e-bike. Keeping the packs intact you can still utilize the standard DeWalt charger.
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If you troll around the R/C forums you can probably pick up a control module from the inside of a pack for ~$10 by paypal. They tear the packs apart and throw away anything that isn't a cell anyway.
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One of the folks on the R/C forums is a EE professor at some university. He had his undergrads pull apart a hammerdrill and a battery pack to draw schematics. I think he assigned them a lab exercise to build a new tool that could utilize the existing pack. The control scheme and electronics in the drill were quite simple; most of the brains are already on the battery's control module. Fortunately, you can bypass all of it to use as a simple e-bike power source.
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I ran across this post before, but didn't remember the author's comment in a later reply...
From: http://gristmill.grist.org/story/2006/9/8/82015/17778
One battery is adequate for about 6 or 7 miles. I chose not to put them in parallel because the batteries in each pack are matched (within a few percentage of each other in charge) but it is unlikely that the batteries in each pack would match other packs and could back-charge. Using them one at a time is the same as using them in parallel since the current draw never seems to exceed a single pack's capacity. Turning a switch to connect a new battery when one goes dead is trivial and has the advantage of letting you know how much charge you have left, as I mentioned before.
I'm pretty sure the 6 or 7 mile range per pack is not motor-only, and the speed is left unstated, but this is from a user who rides on the hilly roads around Seattle. Quite promising. I wouldn't worry too much about paralleling packs. The manufacturer's technical folks actually recommend putting cells in parallel, as it allows the stronger cells to protect the weaker ones and also spreads the current draw.
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http://endless-sphere.com/forums/viewtopic.php?t=1427
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Well, according to tha article, I should get to know my local dewalt repair facility, and maybe, just maybe I could get my hands on some "defective" 36 volt battery packs and rebuild them myself!!! It would cut down on the cost of making a large enough batt pack to travel more than 5-7 miles at full power economically feasible. (buy a few and repair a few)
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I was thinking the same thing. From the 3 packs he got on his first visit there were still 19 good cells, only 1 shy of two full packs. I'm going to visit my local DeWalt dealer to see if I can help them out by unburdening them of any bad packs they had to accept on warranty.
I think the packs use a TORX security bit (the star shaped ones with a hole at the bit's center).
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You might have to pay a small amount of money since we are competing against the RCers who might also have the same idea of reclaiming some battery packs for their own uses. If I found a good source of packs, I would try to keep it silent since information like this travels fast through the grapevine. ;D
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Just noticed this one at the first post on the page
How much would you pay for a used dead battery pack?
Too funny to pass up.
Hey, if you find a good source (and I don't) I'd be willing to pay shipping and handling for any dead packs you don't wind up breaking into. I'm willing to reciprocate if the situation is reversed.
And before anyone asks...I don't think dead packs come with a warranty :P
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Ha HA, Now I am going to eat my hat!! :D I should have said How much would you pay for a slightly damaged used, but salvagable battery pack that contains cells that are $10-15 dollars a piece. Oh by the way, can you please pass the ketchup, my hat is a little dry! ;D
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Cheer up! Maybe somewhere there is an article on how to build your own LiFePo4 cells like the article on How to build your own Methanol fuel cell (http://www.makezine.com/blog/archive/2006/06/how_to_build_your_own_band_aid.html). ;D
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Well, in the spirit of that article here is another how-to: Build your own LiFePO4 battery pack:
1. Get some cheap wire and solder - think Home Depot or Lowes or another hardware store
2. Get a volt meter.
3. Buy cells (they are really expensive)
4. Put it all together.
5. Charge them. Doing this right might help your battery last longer, but don't worry about it too much. (A buddy with an actual charger can help)
6. Use them.
:P
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That's a great idea but I was thinking more in line with... putting together the Fe in say a nail with the Po4 from say some laundry detergent and say maybe a couple of Li pills from your neighbor's wife's medicine chest... Just go over to borrow a shovel and then ask if you can borrow an aspirin from the bathroom, mistake the Lithium pill for the aspirin and drop a dollar on the floor. (That way you are covered if the dollar is not returned.) (Boy, they should never have put me in the can for running over that dog!) ;D
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Fair enough. Did you see the guy's how-to on using aluminum cans as a source of energy? It's another homebrew version of a proposed post-oil energy replacement. I think it was an aluminum -> aluminum oxide reaction that was supposed to produce the energy The "waste" product is the same product aluminum producers use to create the metal, so it is essentially a reversible reaction. Someone took the idea and tried applying it with aluminum cans. As with the bandaid fuel cell I think it was only putting out <100mW of power. Unfortunately only about 1/1000th of where it needs to be to become practical to our application.
If someone can get their hands on defective DeWalt packs and harvest the good cells from them it becomes an economical "homebrew" solution to provide a decent energy/power density and enough range for everyday e-bike commuting. Until fuel cells mature a bit further, come out of the lab and become commercialized these could be touted as a good interim solution.
Now to make some phone calls ;)
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Aluminum-air battery technology exists and the phone company is one of the primary users but Zinc-air is said to be so viable that its use has been discussed in terms of establishing the Zinc economy!
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Give the fuel cells a little more time(and a few billion in investment capital) plus a $10,00/gallon gasoline, then we will see some progress in mass produced fuel cells. Another item I ran across was the Prius now has NiMh batts, I wonder if we could scavage some cells from totaled hybrid cars to run our ebikes????
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Have you checked with the parts department as to the specs and cost of the replacement batteries? That's the place to start.
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According to my local wrecking yard, prices vary depending on condition of the batt pack(avg. price $1,300 US). Since we are not using the entire pack,(which is over 300v) we can use "defective" or damaged packs and scavenge cells to make our 36v or 48v packs. The blogs I have looked at, it seems cell #13 is the most likely to be defective.
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Back to the DeWalt's...
I came across a pair of these at my local Lowe's on Saturday. They were on sale for $99 (a local markdown, in pen), which is the going eBay rate. I had to remind myself I don't actually have a motor yet to convince me not to buy one. If they drop another 25% I'll be forced to buy it anyway.
I just called my local Fastenal dealer to see if they sell these things (and service the warranties...), but they don't carry them in-stock ("I can bring it in from Haward if you want"), so I doubt the local contractor's user base is very big yet. You need lots of users to get warranty calls... darn! That set at Lowes is calling to me.
Anyone else found a source of "dead" packs?
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No but you just gave me an idea... Ever see one of those booths at the mall where they sell watch batteries and keep the old battery that they remove? Humm... let see that's $460 per week booth rental, another... naw forget it. Maybe I can set up one on the street... you know like "Bannanas! Bannanas! Get your bananas's here! We also replace power tool batteries! Get your banana's here!" What do you think?
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HaHa!! lol, myelectricbike you got me there. Seriously, we are just looking for an alternative source for batt pack for the DIY that are economically feasible and practical using materials that are widely available.
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Maybe you should think more like taqueria van or snap-on tools van. Drive around to the worksites and give on the spot "warranty" service.
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...as in "Hey Joe here comes the guy in the snap-on van again. Quick, hide all the batteries!"
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Hide the dounuts too!!! lol ;D
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I know there may only be limited interest on this forum about using DeWalt 36V battery packs as a power source (especially since we have been unable to recreate Doctorbass' success in claiming defective warranty packs from a service center) but there has been some additional information on using the packs for e-biking over on the Endless Sphere forums. The folks at Neodymics did some reverse-engineering on the BMS to be able to pull power from an unmodified pack and allow the pack to provide low voltage cutoff and other features. The folks on Endless Sphere took that information and played with it until they were able to pull 19A from the packs. The BMS provides a low voltage cutoff at 26V, and also provides overcurrent protection. Once again, this is from packs with no modifications, and they are being used under the same specifications the power tools are using them, so you can reasonably expect any warranty on the battery to still be valid after using them for your e-bike.
Place two packs in parallel, and you get 38A of available current, which should be more than enough to keep your controller happy. Of course, at 30A on only two packs you will completely drain them within 10 minutes, so the earlier discussion about needing enough packs for your desired range and riding conditions still applies.
The testing and experimentation popped up in a thread about modifying the charger, so I'll link to a later post where the battery-related fun begins...
http://endless-sphere.com/forums/viewtopic.php?t=2050&start=17
You will still need to modify the resistors on the Goldenmotor controller so controller's cutoff voltage is less than the battery pack's cutoff voltage, otherwise the controller will shut off well before you have drawn all the available power out of the pack. See the cutoff voltage thread on this forum for those details.
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I liked the battery chemistry , but the price and the lack of solid information and customer service has caused me to postpone any purchases until these items can be solved.
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I agree. I think most of the issues have been ironed out at this point, but price is still a huge deterrent. If I were able to get defective packs from a warranty service center and rebuild them I would be all over this. Of course, long-term the batteries should prove less expensive than lead-acid batteries, as they tend to get used up after abusing them for a few hundred cycles. The DeWalts weigh in at 2,000+ cycles. (in its literature A123 systems is now claiming up to 7,000 cycles to 80% of initial capacity)
We have enough technical and user info to be able to use the packs without much problem, and they have been user tested in a way that generally confirms the outstanding claims that the manufacturer is making about them. This wiring setup allows a user to use the packs untouched without risking blowing a fuse or otherwise damaging them. We are not putting the batteries through anything different than they would experience in a power tool (the hammerdrill is rated at 750W!) so you can use the warranty service that comes with the tools and batteries with a clear conscience.
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Thank you OneEye. I Agree
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Ditto for me too!! ;D
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Hey guys I would agree, but my doctor just confirmed that I need tokeep my lead acid batteries and start using my regen controller to keep them charged, instead of relying on the grid. :(
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OK, I will acknowlege most of us should/could shed a few extra pounds., but witout a good regen controller, this feat is more difficult.
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According to my doctor what I need is an unpowered bike with a trailer full of lead acid bricks. :-[ :( :'(
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Ok, build a trailer, hang around the local home depot on the weekend and offer to take customers loads home for tips. Make sure the trailer can handle 300-500 lbs. That will trim offf a few pounds fast!!!
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erdurbin...I purchased the 36V LiFePO battery below from campsolution.com and paid about $450.00 incl. charger/bag/rack.
Hu setup an Item number: 280149246440 on eBay for me to make the purchase. I am not affiliated, but we are both on the west coast.
The battery uses LG cells which appear to be some of the best on the market. I have tried SLA, Ni-MH, and now LiFePO which seem to be state of the art. I checked into the Dewalt solution, but was not excited about dealing with the Goldemmotor controller cutoff voltage was a problem.
I am looking forward to scourcing a higher Ah LiFePO battery as soon as they are available at better prices.
Please keep me posted if you find a better deal. I have several E-bikes and only one LiFePO battery.
The fully charged battery below starts out at 42V just like the SLA batteries that the controller is designed for.
Below are the specs. on the battery from campsolution.com
About Li-Ion battery Module: 36V 10.4 Ah ( 374 Wh) with PCB ready (40 x 18650 10S4P):
* 36V Li-Ion Battery pack is made of 40 pcs LG 2600mAh Li-Ion 18650 Cell
* One Special 10 cells(4 cells parallel to 1) PCB is installed in battery pack to protect battery from over charger, overdischarger and over drian
* Voltage : peak - 42V, working - 36V
* Capacity: 10.4Ah
* Energy: 374 Wh
* Cut-off voltafe: 26V
* Max. discharging current: 18amp
* Two terminals from the pack:
* One cable with two hole connector ( black ) for chargers
* One terminal is for discharging: - 8" long 16 AWG pre-wire Tamiya connector for connecting to your device
* Please choose 1A 36V Smart Li-ion battery charger to charge this 36V 10.4Ah battery module. The charging time is about 12 hours
* Dimension: 7.3" L x 2.6" W x 3.7" H
* Weight: 4.6 LBs
* Applications:
o RC Robot: to drive DC motor < 600 W
o Small size e-bike ( < 26" wheel )
o It can be used an internal pack to drive 36V DC motor to achieve faster speed and power for RC toy
Net Weight: 4.60 lbs
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Correct me if I'm wrong but it appears that you got rooked, which is a recent complaint about Li-Ion/Li-Po (poly) batteries being sold as Lithium-Iron Phosphate (Lithiated Metal Phosphate and not Ion, Lithium Metal Oxide) batteries, on the excuse that the seller was not aware of the difference. Hope I'm wrong.
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With greed as a motive and not wanting to get stuck with outdated/LiPo technology, we will see many scams before the real deal is really here. The basic problem is confusion on the battery chemisties and the cheap sales pitch for the inferior batteries.
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Gentlemen...My mistake...I am no expert by far. The cells are LG Li-Ion 18650 CR18650 3.6V 2600mAh ICR18650 B2. I was looking for the best bang for the buck. The vendor didn't misrepresent the product. Who is making the best Li battery for the best price?...thanks in advance?
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LiFePo4 technology from companies like LionEV is hot right now and instead of $100/KWh you are looking at $1,000/Kwh, excluding battery management controls, although LionEV on September 1, 2007 published a price of $373.00 per KWh. Anything less and you might want to check with the police.
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The problem with the LiPo's as mention in earlier posts is that they are tempermental little things. They can not take an overcharge and they can not be overdischarged before getting overheated and possibly exploding or causing damage therefore shortening their lifespan drastically.
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If cared for correctly, the Li-Ion packs you purchased should serve well. 2,000 cycles would be too much to expecte out of Li-Ion however. Remember not to store them for long periods of time at full charge or near full discharge, the chemistry tends to eat itself under these conditions. Li-Ion has the greatest longevity if keept between 30% - 70% state of charge.
LiFePO4 is the new kid on the block, with a lot of hype to go with it. The LiFePO4 is overpriced like the iPhone when it was released. Hopefully over the next year or so the price will slide by about 25%.
Or maybe the DeWalt service center in Fresno will start delivering damaged packs to mustangman by the truckload instead of paying to ship and recycle them. Then we could get packs from him for say $15 each. If 2 out of 3 cells are good that comes to less than $25 per pack ;D
One can always hope.
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esource,
You may want to tinker with the low voltage cutoff on your controller anyway. According to the specs you posted your pack cutoff is 26V. Unmodified, the goldenmotor controller will cut out at 31.5V. pdonahue posted the equation and resistor locations for adjusting your cutoff voltage in the "cutoff voltage" thread. It shouldn't be too dificult to set up.
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Sorry no luck yet, probably because there is not too many out in the field yet! Patience grasshopper, we will soon be rewarded for our efforts!! ;D