2000XR A123 battery question

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johnnullstream
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2000XR A123 battery question

I'm looking to upgrade my 2000X (nimh) motorboard with A123 lithium batteries from a Dewalt pack. Does anyone know if the stock 2000XR battery pack uses a BMS? Will I be able to use a stock 2000XR charger with an A123 Batt kit I build myself?

chas_stevenson
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Re: 2000XR A123 battery question

Since your 2000X uses NiMh batteries it does not matter if it has a BMS because the voltage of NiMh cells is 1.2-volts and the A123 Lithium Ion cells are 3.3 volts. This is like mixing apples and green beans.

Switching to Lithium Ion is a good plan but they will require a BMS designed for this type of Cell.

Grandpa Chas S.

johnnullstream
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Re: 2000XR A123 battery question

Thanks for the reply but I don't think I was being clear enough. Let me rephrase my question. I have a NiMh 2000x motorboard and would like to upgrade it to A123 Lithiums (LiFePO4). I'm too cheap to by a battery from the manufacturer since they want 300.00 for the same number of cells as a single Dewalt 36V pack. I might be willing to buy their Lithium battery charger however unless someone knows of a better charging solution for A123 cells (5 cells x 2). My question is does anyone know if Roth's Lithium battery pack has an included BMS or not? Will I be able to charge my homemade A123 pack from their Lithium charger without a BMS?

chas_stevenson
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Re: 2000XR A123 battery question

First the BMS is NOT in the charger it is in the battery pack and the DeWalt battery packs come with a BMS although many of us have had problems using it with an e-bike. You must open the pack a connect a plug directly to the battery output. The plug is then used to power the e-bike or scooter. As long as you change nothing else you can still use the DeWalt charger to charge the pack.

Grandpa Chas S.

methods
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Re: 2000XR A123 battery question

I converted my 1500 over to 6S Lipo. At 22V it is a little testy. . . wants to pop into safety mode. If I start off real easy and can get it rolling there is no problem. Goes -way- faster than I care to go on those bumpy little wheels. Oddly there is not that much torque even though I bumped the voltage up from 16V to 22V with a much stiffer pack. Must be the computer getting in the way. . . It is over-engineered if you ask me.

Started off with (3) 6S TP2200mah Extreme packs (25C) in parallel
Just picked up (4) 6S 4100mah 20C Zippy R packs from Hobby City. That will give me 16 amp hours and I can source about a giga-amp.

I have two boards (officially I got the second for my wife. . . Painted it pink).
I taped over every other slot in the break-beam wheel to try to increase the top speed.
On that unit I just ended up increasing the minimum speed (lol). . . Going to try it with the bigger packs.
On the 22V scooter I hit some kind of cutt-off though I dont know if it was speed, current, heat, load, or what. . .

Currently fantasizing about a more serious project. I am thinking about stripping down a golf cart to a couple of hundred lbs. . . bike tires and everything, then running brushless and lipo.

-Patrick

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Re: 2000XR A123 battery question

That's odd that you haven't managed to get more torque. I'm about to update my batteries this weekend to a 2 parallel nimh packs that can source 80A continuous 160 peak. I'm really hoping for more torque as the 2000x is currently very wimpy on hills - at least with my weight. I'm not interested in additional speed. I wonder if the drive system is just slipping in your case? I'm curious what the safety mode conditions are. I don't know about the 1500, but on the 2000x control board all they could be watching is voltage and speed (certainly not current). With your batteries you are not hitting any under-voltage, so all I can assume is they are watching acceleration and detecting slip.

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Re: 2000XR A123 battery question

Definitely not slip. I have run up against that already. Secret (as you probably know) is to just swap the front and rear wheels. Slip plays a telltale note that you can hear.

I agree that there is not a current sensor in there but there could be an RTD or PRT (probably not though). They very well could be monitoring acceleration with the number of teeth they are using. . . Monitoring load or speed alone would not be enough… If they were governing acceleration my “tape wheel mod” would spoof that system by a factor of 2. Maybe I should try putting the big packs in the spoofed scooter.

I never measured more than 36A while running mine at 22V btw. My new packs are good for 240A cont. and easy bursts to 360A. Too bad it would take soda can size wires to conduct that much efficiently =)

I should also say. . . I have high expectations so it is not to say that there was –no- increase in torque, just not as much as I expected. In stock form I could pull up and ride a wheelie so I expected this mod to throw me off the board. I weigh 190ish but have a very high center of gravity (6’5).

I suspect that the efficiency of the system sucks. Those are beefy brushed motors but brushed none the less. I love brusheless. . .

Let us know how your mod turns out.

-Patrick

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Re: 2000XR A123 battery question

I'll let you know how it goes.

Much more important than the whole power and range issue, for me, is trying to get the friction drive system to be tolerant of a little water. I'm not talking about riding in a heavy rain, I just need to be able to get around with a little moisture on the ground. I live in the Seattle area and unless I find a solution there I'll probably only be riding this thing 7 weeks out of the year. I'm curious if anyone has had any success in that department. I'm thinking about things like pressing a knurl pattern on to the motor spindles and maybe put some wiper blades on the sides of the wheels to squeegee the water off. I've already tried gluing waterproof sandpaper onto the spindles. That worked very well when wet (ok I had no brakes at all) but I kept getting error trips up hills when dry. I suspect the additional thickness of the sandpaper, the bumpiness of the overlap (to keep it from coming apart) and extra friction just put too much load on the batteries. I didn't run it long enough that way to see what it did to my range let alone to see what it would do to the wheel long term. I wish I knew what the actual error trip means.

I actually just picked up a second 2000x off ebay with a dead battery. It should be here next week. That will give me a backup (or spare parts) in case I decide to try more extreme mod experiments.

-John

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Re: 2000XR A123 battery question

6S Lipo update:
(4400mah 25C)

Top Speed Mod: Taped over every other slot on the wheel. It is confirmed, the governor is defeated and I was able to obtain much higher speeds. I need to hook up my air speed monitor but for now we will call it "faster than I can kick speed".

Drawback: Now to get it started I have to hold down the throttle to 20% and kick the board up into the air. If I can get the wheel turning then I can jump on it and ride. I cant seem to kick it fast enough to start the motors. When you "jump start" if WOT is on with 6S Lipo it goes into safety mode.

24Vish safety cutoff: I could not get it to start with fresh 24.8V pack. I ran them down to around 24V then it started. Dont know if that is a high voltage cutoff or just flaky electronics. The stock charger is supposed to charge them to 19.8V so I could see a safety upper limit.

Peak Amps at 22V - 24V: With governor on, 36A. With governor off, 40A

858 Watts Peak

Motors are starting to slip a little under load.
I would say this setup would last only a few days.

On to a bigger board. . .

-methods

johnnullstream
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Re: 2000XR A123 battery question

I got my packs built over the weekend and I had a chance to try them out. 2x 12S 4500mah NiMH 10-20C. I definitely have more torque and hill climbing power. It doesn't throw me off the scooter, but I can get up hills now that I had to kick on before. That was my goal. I get a bit more slip also, however, if I don't keep the side walls clean. Now I'm breaking in the batteries so I can see what they will do for range. Technically I should have about the same Ah with my new packs at 9Ah vs. the stock 8Ah. But since these batteries can source more current without capacity degradation I'm hoping for a bit more range as well. Oh and they are almost 1lb lighter than the stock pack.

Speaking of range I got a look at the low voltage detection finally and I think that the 2000x is cutting it off too high. The low battery indicator is kicking in between 14V - 13.9. That is close to 1.16V per cell. I'm not sure yet where it actually cuts out but I suspect it is still a bit above 1.1V per cell. My batteries claim they can be discharged to 1V at some fraction of 1C and lower @ .9V or so at 1-10C. I wonder if it is worth trying to tweak the board to let the batteries discharge a bit further to extract a bit more range. Of course, only if this doesn't degrade the battery life.

methods
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Re: 2000XR A123 battery question

I let the magic smoke out of mine.
Not sure where yet but the Gate to Source of the mosfets is rated at 20V max and I was giving it 25V. Should not have done it but something did.
There are two mosfets in there: One for "go" and one for "stop". My brake mosfet was shorted. I de-soldered it only to smell more magic smoke.

Next step is to replace the factory electronics with a DC speed control from an airplane / car. Then I dont have to worry about error codes or my Lipo's.

Let us know about the Voltage Cutoff.

-Patrick

johnnullstream
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Re: 2000XR A123 battery question

Man that sucks. I'm not sure if the new control boards on Roth's site are compatible with the 1500 or not, but it might be worth a try. They don't have regen, but instead have one mosfet per motor. The boards are tuned for the A123 batteries at 18V.

Flaz
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Re: 2000XR A123 battery question

I upgraded my 2000x battery to a 5 cell 5000mAh LiPo battery and I love it! I purchased the battery from http://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_index.asp for $120 (it's their Zippy brand) and it is rated for 20C. The improved torque is nice and lets me actually hit the max speed. I've been running the board daily now for a week (riding 2 miles each day) and the battery is using about 2300mAh so I'd have about a 4 mile range. Also, with this battery my motor board is 2.5lbs lighter.

methods
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Re: 2000XR A123 battery question

Good call on the 5 cell.
I have not had much time to look at mine but it appears that the LTC1625CS cant handle 6S.
I have moved my Hobby City 6S packs over to my future electric bike to make an 88V pack.
I will repair my 1500 board and just run 5S.

-Patrick

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Re: 2000XR A123 battery question

I pulled 2 rookie moves in a row:

First, while removing the LTC1625CS I lifted a pad (slaps head).
While beating myself up for lifting a pad I neglected to note the orientation of the chip (slaps head a second time).

Reverse engineering the orientation was simple enough. Deciding if the lifted pad was critical was a little more complicated. The original engineers were not the type to leave things floating. Every other pin was tied to something. This one single pad appeared to be floating. If it were floating, that would also explain why it was so easy to lift the pad.

Went through the datasheet a few times, concluded that the pin did in fact have a function for "open" and I am going to solder in the new chip and hope it works. I tried to confirm beyond doubt that it was intended to be open but ran out of patience. I can solder it in 45 seconds and just test.

Will report.
Will not use 6S again =)
5S is the ticket for this board.

-methods

jackluu
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Re: 2000XR A123 battery question

Inspired by what you guys are doing, I've gave it a try but failed. I have a Motorboard 2000x. Here's what I did, can anyone give me some insight as to what went wrong?

1. I bought a bunch of new laptop Lithium Ion packs and disassembled them. They each contained 12 cells, 3P 4S. The tag states 14.4V 3900mAh. Each cell outputs 1300mAh???

2. I assembled 45 cells; 9P and 5S. This measures 20.2V and I ASSUME its outputting 11700mAh(9*1300mAh). I added a PCM to limit it to 10A. I bought this one http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3387

3. I connected it to my Motorboard and nothing. The power light is green, then it just dies. The battery is reduced to 4V then I wait 2min and it's back to 20V.

Any help would be greatly appreciated. I'm looking to get the speed up a little and the double the current distance. I'm currently getting 4.2 miles at 11mph. I'm 155lbs.

doralevich
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Re: 2000XR A123 battery question

Hey All, I'm hoping someone here can help me out, I'm completely new to this, but found the group by doing a Google Search. I just purchased a Go Motorboard 2000X from Craig's List - mint condition, some wear on the tires and 2 batteries. It came with the original battery (which the guy said could still work) and what was supposed to be a brand new battery (never used). When I got home, I charged the "new" one about 8 hours + and got about 30 seconds worth of juice on it until I went from full battery to nothing. I am pretty sure that I charged it correctly. Just plug the battery in and connect the charger (I made sure that the scooter was off), right? I did this a few times throughout the past 2 days with both batteries, but get the same result on both.

Any suggestions? Ideas?

The guy who I bought it from seemed like a good guy and promised me that it worked. Is it possible that the "new battery" having never been used, never took to a charge and will never work? Is there a special way I have to charge these battery's, a sequence, or something that I'm missing.

What is my best bet in fixing this. Your suggestions above are something that I just am not capable of understanding, it all sounds a bit foreign to me (kudos to you guys). I read about upgrades to batteries (more power, longer life etc). Am i just too nice of a guy and took someone's word on it working.

I have had a hard time getting people who know about this stuff and or reaching Roth themselves.

Any help would be appreciated and helpful.

Thank you!
David

(Sorry if you are receiving this more than once).

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