• Howdy! we're looking for donations to finish custom knowledgebase software for this forum. Please see our Funding drive thread

Yet another Yellow Ninja 250 Conversion!

For the tach meter, I would want to monitor Voltage mostly. Kinda like a fuel gauge and overall battery condition. After 500 miles now, I can tell the state of my batts charge by watching the voltage sag under accelertion. Maybe remove the display and replace with an expanded 50 - 90 volt display?
 
Yeah, I guess you could take it out.... but Tach's go up over 10krpm, so you could have 0-10 be state of discharge... 0-100%

I like the stock look I guess, and you don't have to fabricate a way to mount something. Plus, you've already got the meter, the electronics to drive a signal is cheap, its designed to be easily seen, and they're backlit already. Hell, it could be SOC, Volts, Amps, Watts, throttle percent, motor temperature, just about any analog/digital signal.

Whats your absolute longest range on the bike so far?
 
My longest range to date is 23 miles before hitting the Kellys LVC under accel. Once it hits, I can still maintain 40 + MPH but must keep the amps below 100 on accel. This is with in town driving. My ride to and from work is 14 miles round trip, this is 90% 45-50 mph mostly flat, the LVC will kick in at about 18 miles. I am now charging at work so as to preserve the batts. If my mission was to get 25 miles I bet I could, but it would require conservative accel and reduced high speed runs. I started out with a 12 tooth drive, then 13 and now 14. I picked up about 3.5 mph per tooth and give up range. Funny, once you get the higher speed you don't want to go back! Going to PSI's will give me more range and performance (as the packs voltage will sag less).The Agni at 84 volts would give me the speed, range increase and allow a 6:1 ratio.

I just ordered 2 Analog Devices AD537 V/F sample's. Looks to be an excellent chip for the tach interface.
 
Thanks for posting this. I'd like to start working on a conversion this spring (have to get my wife a vehicle of her own first she said), and I have a similar commute - 14mi round trip. I was thinking of going with bigger SLA's, but seeing that you have plenty of range, I think I will be fine with some smaller ones for the time being, as I'd like to get the bike together for fairly cheap so my wife doesn't kill me. So far it looks like it'll cost me around $2300 not including the cost of the bike..

Hope you don't mind, I'll be using your build as a good reference for mine, whenever I start that is :)

I think the most difficult part is going to be finding a bike for cheap.

Mind if I ask how much that Agni motor cost? Is there still room on the Ninja for another battery that can still be hidden behind the fairing?
 
If you go with sla's, get the B&B 35AH. You could fit 44AH cells if you stacked then 3 high by 2 wide by 2 deep up front, but you would have to widen the lower fairing. The Agni was $1,250, price varies based on the exchange rate. The Mars is a good motor too and less then half the price. Buy a clean late model bike, the motors sell well on Ebay. I think my bike was $1,000 and I sold the motor for $700. It barey had 1000 miles on it. The new 08 / 09 Ninja 250's look hot.
 
Is there any particular reason you would recommend the B&B's over the Powerstars you currently have?
 
Well, I've never tried the B&B's as the Powerstars are my first pack and they have worked out well. However, many, many others have stated they get more out of them. I get about 22 AH's outa mine in the summer and I've always wondered if I could have done better with a premium battery. Now that I've built my bike and see how much I enjoy it....If I was to buy AGM's again, it would be ethier B&B's or Greensavers. The B&B's would cost about 50% more. I'm also going to upgrade my chargers from 3 amp to 5 amp so I can get 2 full charge rides a day.
 
Any update on Agni vs Mars?
 
Yes, first off, the Agni's a keeper. Comparison based on following. Keep in mind the Mars was geared 5.5:1 (50 rpm per volt) and the Agni is geared 7.2:1 (71 rpm/volt). I geared both for a top speed of 50 Mph based on their respective rpm/volt. A better comparison would be made with the Mars (or Etek) 08 motor which is 70 rpm per volt also...but I (or Mars) wouldn't reccomend running it at above 50 volt as the rpm would be too high... the Agni armature is reinforced. I have my Kelly controller set for a max of 200 amps which it would easily peg with either motor on acceleration.

1). Under inital aceleration the Agni is considerabily stronger....the Mars has a softer feel (better eff over 100 amps?).
2). Feels very smooth. Better balanced ?? Even though it is spining ~ 2000 rpm higher then the Mars.
3). Acceleration from 30-50, much better (motor or gear ratio? or both?).
4). The Agni runs cooler.
5). Weight, the Mars 09 weighs 36lbs, Agni 24.
6). The Agni can handle 84 volts and 6K rpm....wide rpm range is nice when you have a single speed transmission.

I would guess that the Mars motor would compare favorabily to the Agni when current is kept below 150 amps and voltage under 50 (for the Mars 70 rpm/volt). Once you surpass these numbers the Agni quickly widens the performance gap.
 
Thanks for the great comparison.

Do you have some amp draw numbers at speed to see the difference in efficiency.

Are you planning on trying a higher gear ratio to get a higher top speed, or is 50 enough for you?
 
It uses about 52 amps at 50 mph just like the Mars did. Which is what I'd expect, at higher currents is where the Agni would start to out due the Mars. I have it geared for 50mph to allow decent range with the 35 AH AGM batteries I'm currently using. I have an 11 & 12 tooth drive gears that I'll try when the weather breaks. The 12 should get me close to 60 MPH, at the expense of another 30 amps. I could also goto 84v which would get me to 58 with my present gearing. What I'd really like is 96 of the new 14AH PSI cells!
 
thomas said:
Have you got any prices on the 14ah cells?
Click to expand...

I don't, but Andyh has hinted they may be 20% more cost for 40% more capacity.... he should know when they will be available but I don't think they are shipping yet. Jozzer has said he is getting them for the IOM race...sounds like he may be sponsored by Lifebatt???
 
I switched my yellow Ninja 250 over to B&B batteries and I'm not getting nearly the range that you are. I'm running six 35 ah deep cycle batteries, a kelly controller, and a Perm 132 motor. I set the LVC to 70 volts. It's geared to hit 48 mph when the batteries are fresh (11/60 teeth). After only six or so miles, the controller drops out and blinks a 1-3 sequence, which indicates low voltage. If I coast for 5 seconds or so, it will kick back in, but as soon as I get near 40 mph, it will kick out again. For some reason, the Kelly never seems to go into low power mode, it just cuts out abruptly.

Anybody have any ideas?

- Brad
 
Brad, that doesn't sound right at all. With my Mars motor geared for 48 I averaged about 16-20 miles depending on how I pushed it. When I was geared for 42 (12/72) I could get over 20 no problem. The Mars 09 is a 50 rpm/volt motor and I was 14/72 I think. With the Angi 95 (70rpm/volt) and geared for 52 I average 15-18 miles. My 35AH Powerstars have 1000 miles on them now. B&B's are claimed to be the best SLA's. I bought PS's because they were only $52 each and I expected them to only last 1 season, but they are still going strong....probably come from the same factory in China?? I use 3 on board 24v 5ah smart chargers and they are always on float.

DATA...

Do you have a current / AH meter? The CA HO is good. At 50 on flat I pull about 65 amps (V is about 72). I average about 18-20 AH out of my pack in ABOVE 65 temps before the KELLY kicks in. When my Kelly kicks in (under ~50 volts) it immediately shuts down, if I back off I can resume but I have to accellerate slower. I can still use full throttle and drive home several miles, just my top speed is reduced by about 7-8 mph and I have to keep accell current under 100 amps or the LVC will kick in.
 
What do you have your LVC set at on the Kelly? In a previous post, you had it set to 70V. If that's the case, how do you get under 50V?
 
I never changed the level from stock....assumed it calculated this? Just from observation its 50volts under heavy load (>150 amps). If you set yours at 70 then thats your problem.....mine dips under 65 v under acc all the time. I never use below a resting / no load voltage of 70 volts.
 
OK, then that's my problem. I put a volt meter on it and the controller is doing what it's told to do. When it gets to about 69 volts under load, it trips out. Resting voltage is still 73 volts. I'll have to program it for a lower voltage. Thanks for the help.
 
I took a ride this morning with my 8 year old, combined weight of 240 lbs. Rest voltage 83. Under inital full accelleration I dip down to 64 volts, current is about 210 amps for a couple seconds. If you can go 6 miles before you go below 70 v, it sounds pretty impressive for the B&B's. I did about 12 miles this morning, no cut off, used 14.5 AH. Resting voltage was 74 volts.

Brad, let me know your range and the AH's you get out of the B&B's, really interested to compare to mine batts.

Phil
 
Are you still using proportional regen with the agms? From what I've read, they don't like too much charge current (unlike the LIFEPO4's). I use 20% max. Possibly something to consider...you don't want to boil them with 80 amps while braking!

Post a pic of you batt mounting if you get a chance.
 
Phil,

I lowered my LVC to 55V. Right off the charger, I can go about 48 mph. After 14 miles (back and forth between full speed and 30mph), I could still do 45 mph. I stopped at 15.5 miles, ending with a long climb up my driveway. When I turned it off, the voltage was 69 volts, but crept back up to 71 volts in about 60 seconds. This is about what I was expecting.

I had read in your thread that you didn't let the voltage go below 70 volts. I mistakenly thought that was where you had your LVC set. Now that you've educated me, it make sense. With the LVC set to 70 volts, I was hitting the "slow down" mode on the controller. I didn't feel like "slow down" mode. It just felt like the batteries were drained. With the LVC set to 55 volts, I still get reasonable acceleration after 15 miles.

Thanks again for the info. I was starting to get really depressed over how these batteries were acting.

The bike is much heavier than it was with the Headway cells and the range isn't quite as good, but it looks like the AGM's will give me more trouble free trips to work and back this summer (11.2 miles).

I'll take a photo of my setup before I put the plastic back on.

- Brad
 
You must log in or register to reply here.
Back
Top