Oset Batteries Lithium (LiPo) Conversion Directions

[ninefives]

Heymak,

Re chargers - mikedufty makes a good point as you are running at 6S voltage, all the batts are in parallel, so 1 charger that does 6S could do - just would take 2x as long to charge 2 batts. For my 36v I have to use 2 banks of 5S (2x18v so 36v) so I have to charge them separately. My guess would be that with the Accucell charger I use would charge 2x5000 in about 2-3 hours from 30% left, but a bigger power supply and charger or 2 chargers = faster time. For me I charge at home at the end of the day so it doesn't matter, but you could charge over lunch with the right setup.

His comment on small stages is right on - the only downside is shipping costs, there is a minimum shipping charge - when you are in the ordering page at HK it shows the weight remaining for the shipping cost shown - you keep buying little bits to fill up the shipment weight!

I made up a spade to XT60 lead so the original connectors are still on the bike, as per comment above, I can swap in the SLAs if I need to (probably when I sell the bike!)

See Froggers photo for the low voltage alarms setup - these are made for RC model kits so the alarms are designed to sound from inside the helicopter 100ft up. I couldn't find a handlebar mounted voltage display/alarm that would survive a trials environment. I think that the alarm should be loud enough even covered in the battery box that we get the message. Get ones you can set the voltage, that way you could build in a "reserve" by setting the voltage to say 22v to have enough to get back to the van - trial and error on that I'm afraid!!

[gwhy]

See Froggers photo for the low voltage alarms setup - these are made for RC model kits so the alarms are designed to sound from inside the helicopter 100ft up. I couldn't find a handlebar mounted voltage display/alarm that would survive a trials environment. I think that the alarm should be loud enough even covered in the battery box that we get the message. Get ones you can set the voltage, that way you could build in a "reserve" by setting the voltage to say 22v to have enough to get back to the van - trial and error on that I'm afraid!!

I am trying to think of a way of adapting my handlebar voltage display for the osets, it is robust enough for a trial environment but the problem I have is that so many people are using different voltages so they would need to be adjustable to take into account for this whereas at the moment my monitor is setup for 12s ( 48v ).

[ninefives]

One thing on the reserve idea I didn't think about! The buzzer can't be turned off without disconnecting from the balance lead which would be a PintheA out at a trial - Guess just make them muffled enough and get the charger on quick - still work in progress here or set them at the vary lowest voltage as purely a last minute reminder. As mentioned in previous posts - I do have a voltage and ma used display that sits on top of the batts so have a fair idea of how much left already, my alarms will be set as a last ditch reminder when they arrive.

[frogger]

The battery monitors I use have a few different indicators to show where you are at in terms of voltage but to be honest I am just relying on the alarms. Here is the user manual that come with them.

[ninefives]

Thanks Frogger - still waiting for my alarms.

Trawling the web I have come up with this:

Also these comments:

"A healthy lithium pack bounces back up after a LVC (Nine5s - assume that is Low Voltage Cutoff) under load is reached.

Most "experts" are saying to set the LVC to 3.3 volts per cell and it should bounce up to 3.7 volts after resting a few minutes. They say this will help the packs last longer. "

This is in the RC world where the batts are hit with heavy continuous load (think helicopter) Our use profile could be different. Blasting solidly around the field is the same, but typical trials stop start rest allows the batts to recover so the voltage showing may be the resting voltage - Frogger - what say you?

I would hate for folks to think that they could go down to lower voltages and trash the LiPos

Other comments from the RC forums -

"There is a large initial voltage drop off which then evens off. Closing the throttle and decreasing the load on the battery allows it recover somewhat."

And if I could find a way of cutting and pasting there are LiPo discharge graphs out there. What I see is a cliff your battery falls off in terms of residual power once you go below 3.7v resting.

"The LVC is the last chance for your lipo,,,think of it as the net on a aircraft carrier,,if you always run your lipos to LVC your cutting the life of the lipo in half"

Edited March 10, 2012 by NineFives

[gwhy]

if you leave 20% capacity in your discharged battery this can add a extra 50% to the life span and the same with charging them, if you only charge them upto 95% of there full charge this can also add a additional 20% to the life span. I dont nessasary agree with the chart that was last posted, its ok as a guide but the values very much depend on the make and age of the cells, all my packs ( I have 2 of 3 different makes of 6s batterys and are at 50% capacity when the voltage is 23.2v )

[betarambo]

_{Wow. I started this topic just as a way to document all the cool tips Rick Keffer gave me when I started out to make Hannah's bike work better. I tis now 7 pages! Thanks everyone for all of your awesome tips.}

_{These days I have 6 batteries in the 6S1P 5 AH configuration plus two 3s1P that I put in series to run her 24V bike at 36V. I normally run two fo the 24V 5 AH batteries in parallel at a time. Three might make more sense, but I like keeping the wieght down. She has ridden Beginner (the lowest adult class) three times now and the bike has worked grat. We change the batteries out after each loop since we run three loops and we have three pairs of batteries. We don't run the 36V setup for competition as traction becomes challening. I charge them one at a time at 10A (2C) and laways balance charge them. At the event I run them off the 12V system in my camper and at home I run it off a 25A Radio Shack power supply I "borrowed" from work. I also use a Hobby King current meter combo thingee for like $25 that lets me monitor pretty much everything I could want.}

_{We are on the waiting list for the new 20" Oset. I am really anxious to find out what the electrical configuration of it is. I heard a very vague and unreliable rumor that it is 48V. I also suspect (with no real information) that maybe they made the leap to lipo.}

_{I am curious about the low voltage warning you guys are all talking about. I get that it makes sense in the RC world. For the Oset world I think it doesn't make sense. I was told when I started on the lipo path that an Oset will not even move when the voltage gets that low. I later confirmed this. In fact, my daughter is so performance oriented now that she askes me for new batteries after she uses 4 AH of the 10 AH setup she runs (40%). I think she is so into it that she can detect the first small drop off in voltage.}

_{Anyway, I am wondering if anyone is using a low votlage alarm because they actually burned a battery on an Oset or if people are using them because their experience int he RC world makes them want one.}

_{Also, I feel obligated to poitn out that when people ask for a shoppign list, it is on the first page of this post. That is why I made it!}

_{Lovign the Oset lipo world!}

[gwhy]

_{I am curious about the low voltage warning you guys are all talking about. I get that it makes sense in the RC world. For the Oset world I think it doesn't make sense. I was told when I started on the lipo path that an Oset will not even move when the voltage gets that low. I later confirmed this. In fact, my daughter is so performance oriented now that she askes me for new batteries after she uses 4 AH of the 10 AH setup she runs (40%). I think she is so into it that she can detect the first small drop off in voltage.}

_{Anyway, I am wondering if anyone is using a low votlage alarm because they actually burned a battery on an Oset or if people are using them because their experience int he RC world makes them want one.}

_{Lovign the Oset lipo world!}

I am aware of 5 battery fires thoughout the e-bike community that Im in touch with in the last 3 years and one of these was a lifepo4 not lipo ( this is a very small percentage of fires) , 2 of the fires were whilst riding and the other 3 were whilst charging. I have no real information as to what happened or how sound the wiring was on these bikes but I do know the 3 fires from charging were all being bulked charged at high rates i.e 10A + and all 3 had a BMS fitted ( this is why I would never have a BMS on my battery's ), one of the 2 fires whilst riding also had a bms fitted and the other was using secondhand lipos ( he didnt know the history of the batterys ). nobody was hurt and no buildings were damaged but all 5 bikes were writeoff's as the batterys were being charged on the bikes. Some way of monitoring the lvc of lipo's is a must as a cell that is discharged beyond its safe limit is a major factor of becoming a fire risk when charging.

Edit:

This is not osets e-bikes by the way....!!!

Edited March 11, 2012 by gwhy

[ninefives]

Did a field test on Sunday, kids ran the batteries pretty much constant high load - (loads of riding around followed by 50+ laps of the field) down to a point where my son made a comment that the bike wasn't quite as sharp but still OK (not the crawl along that you can get to with the SLAs). Voltage check was 33.68 (ie 3.368v per cell). We stopped at that point. Batt bounced back to 3.68v by the time I got them on the charger (3 hours later), balance charged them as its been about 5 cycles of straight charge since last balanced. I'm gonna set the LVC at 3.4v or 3.5v as my youngest will just twist the throttle til it stops, at least this way the buzzer might stop the battery carnage!

[betarambo]

So if I understand you correctly, the fires probably happened from charging a battery with a bad cell that was below the low voltage limit. In that case I would think that balance charging them one at a time every time would catch it as most of the chargers check for that sort of thing when you start a balance charge. For that matter just throwing one of those little meters on the balance port before charging to check for a bad cell would catch it. I guess I am not really sold on needing the low vaoltage alarm. This is particularly true since my daughter has gotten so into it that she claims she can feel the performance hit at 40% of capacity and wants new batteries!

So a couple of wrecks in the sand and the bike quit running on us this weekend. Having replaced a throttle once before I figured it was this. Trying to remember what Oset tech support had told me back then, I tried shorting some of the hall effect wires in different combinations. Nothing made the wheel spin so I figured I had a bigger problem.

Once I got home I did some more troubleshooting. Finding nothing I went back to the hall wires. I found that shorting the two outside pins would spin the wheel at full power for a second. So I decided it must be the throttle. I ordered one up, but this week is spring break and she is anxious to ride. I went over to a buddy's house and borrowed a throttle off his for sale Oset. Both ae 24V although mine is 16" and his is 12.5". I had to swap the connector as his bike was the 5 pin connector and mine is the two connector setup with one 3 pin and one 2 pin for the indicator lights.

Hooked it up and I got nothing. So I pulled the pins back out and tried every combination of the 3 wires with no result. I went back to the shorting trick and got it to spin. The throttle worked on his bike at his house. So I am stuck now. Any thoughts?

My bike and his are both several years old, maybe like 2008 or so but his throttle is about a year old.

I may end up waiting for the new throttle from Oset and hope that that does it. Maybe the wiring guide it ships with will help. I sure hate to have her miss riding on spring break!

While searching the web for ideas, I tripped across this cool sounding product. It is a box you put between the throttle and the motor controller. They have one specifically for the Oset. It claims to change the control algorithm from RPM control to torque control which would in theory make throttle response more similar to a gas bike. I am not sure about how well it might work given that it only connects to the hall sensor wires. I would think that you would need some feedback from the controller like RPM, but I must be missing something. I also has some dip switches to set different characteristics. For the price ($180 US, 130 EU) it is probably better to try the Kelly controller that Ian wrote about a few years back.

http://www.automotive.picoamps.de/en/products_more_en.htm#dmm

Any thoughts from anyone who has tried this (or not) would be appreciated.

Waiting for her new 20"...

[gwhy]

So if I understand you correctly, the fires probably happened from charging a battery with a bad cell that was below the low voltage limit. In that case I would think that balance charging them one at a time every time would catch it as most of the chargers check for that sort of thing when you start a balance charge. For that matter just throwing one of those little meters on the balance port before charging to check for a bad cell would catch it. I guess I am not really sold on needing the low vaoltage alarm. This is particularly true since my daughter has gotten so into it that she claims she can feel the performance hit at 40% of capacity and wants new batteries!

So a couple of wrecks in the sand and the bike quit running on us this weekend. Having replaced a throttle once before I figured it was this. Trying to remember what Oset tech support had told me back then, I tried shorting some of the hall effect wires in different combinations. Nothing made the wheel spin so I figured I had a bigger problem.

Once I got home I did some more troubleshooting. Finding nothing I went back to the hall wires. I found that shorting the two outside pins would spin the wheel at full power for a second. So I decided it must be the throttle. I ordered one up, but this week is spring break and she is anxious to ride. I went over to a buddy's house and borrowed a throttle off his for sale Oset. Both ae 24V although mine is 16" and his is 12.5". I had to swap the connector as his bike was the 5 pin connector and mine is the two connector setup with one 3 pin and one 2 pin for the indicator lights.

Hooked it up and I got nothing. So I pulled the pins back out and tried every combination of the 3 wires with no result. I went back to the shorting trick and got it to spin. The throttle worked on his bike at his house. So I am stuck now. Any thoughts?

My bike and his are both several years old, maybe like 2008 or so but his throttle is about a year old.

I may end up waiting for the new throttle from Oset and hope that that does it. Maybe the wiring guide it ships with will help. I sure hate to have her miss riding on spring break!

While searching the web for ideas, I tripped across this cool sounding product. It is a box you put between the throttle and the motor controller. They have one specifically for the Oset. It claims to change the control algorithm from RPM control to torque control which would in theory make throttle response more similar to a gas bike. I am not sure about how well it might work given that it only connects to the hall sensor wires. I would think that you would need some feedback from the controller like RPM, but I must be missing something. I also has some dip switches to set different characteristics. For the price ($180 US, 130 EU) it is probably better to try the Kelly controller that Ian wrote about a few years back.

http://www.automotiv...more_en.htm#dmm

Any thoughts from anyone who has tried this (or not) would be appreciated.

Waiting for her new 20"...

The main problem within the e-bike community nearly all e-bikes are run on 48v upto 110v and there is no off the shelf fast charging equipment for lipo at these voltages so people improvise chargers to allow fast charging of there packs so the risk of something going wrong is much greater than if using a charger designed for lipo. Most Lipo chargers will count the total cell voltages and compare it to what the charger is set to and if they dont match the charger will warn you, and this in it self is a very good safety net. I always check my batterys with a battery medic before I connect the battery to any of my bikes or my charger, this will give a readout of each cell voltage of the pack and this give me a very good indication of the condition of the battery and weather the pack needs balancing. A short in the wiring on the bike can cause a fire ( but this can be with any type battery , not just lipo ) or if a cell gets punchered or damaged . If a cell is much lower in voltage than the rest of the pack (cells ) when in use this will generate heat from the low voltage cell and can also become a problem ( maybe not so much of a problem on the oset's as they are only drawing around 40A max ) my bikes can draw around 100A+ .

if you were able to get the wheel to spin at max by shorting ( +5v to the throttle input of the controller ) then this would indicate that it is the throttle at fault. What are the colors of the wires from the throttle and the colors of the wires going into the controller ?. 95% of all the throttles I have played with are red,black, and green but this do not always match up with the color of the wires going into the controller. If there is red and black then these will always be +5v and 0v the green wire is the signal wire.

This box for throttle response was talked about in this thread http://www.trialscen...hrottle-on-36v/

( I may have come up with a really easy fix for this but I need to get out and test it ).

Edited March 13, 2012 by gwhy

[betarambo]

Thanks for the tips. I found the problem. I called Oset for tech support and it took 5 minutes. The trick is that sometimes in troubleshooting you need a second set of eyes to check your assumptions.

The original problem was indeed the throttle. While I was troubleshooting it on the trail I was in a rush. As I was digging through the wiring I found a disconnected set of connectors. Without thinking much about it I reconnceted them to see if it helped. It turns out that what I did was reconnect my bad pot that I had unhooked a couple of years back. So when I got the new throttle even though it was all happy, the bad pot was screwing me up. So I disconnected it and everything was happy. The bottom line is that I was being an idiot!

Kudos to Oset:

1. I ordered the throttle online Sunday night. I took the only shipping option available which was ground. On Monday they revised my invoice, dropping the shipping charge down a few bucks. Tuesday afternoon the throttle was at my house from Fed-Ex in a UPS box.

2. I called their phone number on the invoice and they were happy to help and got me going in 5 minutes.

While I was on the phone I got some rumours about the 20". He didn't tell me it was secret so I hope I don't make anyone mad by posting it.

1. It will probably be 48V with sealed lead acid batteries. This gives me the greenlight to order up more 6S1P Lipo packs since I can run those in a 2S2P configuration to get 48V and 10AH.

2. It will probqably hit the US in late summer or early fall. This is a bummer, but he said they are trying to make sure everything is just right on it so I guess it is what it is.

[betarambo]

Wow, I am even dumber than I thought. After further digging I found that the root problem was actually a bad solder joint on the watt meter I was using. I had bought a $25 watt meter from HobbyKing so that I could monitor how many AHs she had used. I got to using it so often that I cable tied it to the frame. Since the meter had no mounting provisions I just tied the cable ties around the wires. One of my batteries has a shorter cable than the others and last weekend I kind of tugged on the wires to make it work.

Apparently when she wrecked it put just enough force to finally disconnect this wire. When I got the meter opened it barely had any solder on it at all so I fixed it and hit all the other joints to avoid this in the future. If I had just routed around the meter in the first place I would have nailed it. I then would have avoided mistakenly reconnecting the pot and probably didn't need a throttle.

Then again, the throttle was pretty beat and full of plastic dust so it probably didn't hurt to replace it.

Anyway, I just had to share my goof in case it helps someone else in the future.

Since the new 20" wont be here for a while I ordered up some more toys for the existing one tonight. It makes me wonder. Who are these bikes really for anyway? We like to say they are for the kids and my daughter certianly loves her bike. But then again, I get to spend money on tweeks and upgrades and tools and claim it is for my kid. I may be having more fun than she is, but I get points from the wife for my time in the garage "trying to make sure the kiddo will have fun next weekend". I think maybe these little bikes might be my favorite hobby. Don't let the wife know or she might make me use my own money!

[ridgeracer]

Ok I got my 3 Zippy 3/s 8000 all packed up and connected. Now I need to charge them, I have an Onex 230 charger that can charge up to a 6 cell.

My question is do I charge all the packs at the same time? Or do I have to disconnect and charge them separately.

I'd like to think that I can set the charger to a 3/s charge rate and charge them all at once.

Or do I keep them connected and charge with the balance plug.

1) Leave connected and charge at the same time as a 3/s pack? (or is it now a 9/s pack?)

2) Leave connected and charges with the balance plug?

3) Take apart each time and charge separately?

4) Get a 9/s charger? Or can I use this one?

Any help would be great

Ridgeracer

[gwhy]

I assuming you have these battery's in series so this means that when they all connected this will be equivalent of a 9 cell pack so you will have to disconnect them to charge them as a 3 cell battery you could parallel them all together for charging then you would charge all 3 packs at the same time as 1x 3 cell pack , I not aware of a 9cell charger that is designed for lipo. Yes you could charge them through the balance taps but this will take for ever as you would have to keep the charge current down to no more than 1A due to the thickness of the balance wires. I would recomend buying a additional 2 HK 6cell chargers ( I think they are around $18 each) then at least this will make the whole charging process much faster.