mikedufty

Just sort them from most expensive to least and you will find this one near the top. https://hobbyking.com/en_us/turnigy-reaktor-30a-1000w-balance-charger.html

I've got the cycle analyst on my push bike. A bit expensive but a great device, very good for tracking your power use and battery condition. As standard the low voltage cut off just shuts it down. Generally you can limp along a bit as the voltage will rise again once it shuts down, but you wouldn't want it to cut out somewhere difficult. There is quite a bit of scope for customisation with the throttle control etc, but I don't recall seeing anything that allows it to change automatically. You can set up an external switch to change modes, which I guess could be hooked up to some kind of voltage sensor. As above, if you contact the manufacturer and ask they can probably give a better answer, also search endless sphere forum.

Gwhy's diagram http://www.trialscentral.com/forums/topic/34845-oset-batteries-lithium-lipo-conversion-directions/page-22#entry403998 Looks good for the 5s setup. Bowser's diagrams are showing 3 5s in series which will be too high a voltage I think. Gwhy's diagram is the setup I use daily on an e-bike charging twice a day for commuting. It is not that difficult, I leave the parallel charge wiring attached to the charger and the series wiring attached to the bike. Just detach the 2 batteries and move between them. Only hassle is the balance lead, which I only bother with every 2nd charger. The wiring is pre wired XT60 parallel or series connectors bought from hobbyking to avoid soldering, I posted links to the bits previously. I've done over 3500km on this setup - 250 charges without wear and tear being a problem. I did have an issue early on when I connected the parallel balance leads while the batteries were still connected in series and set fire to the balance leads - that is avoided if you make sure the series lead stays attached to the bike. If you want a longer duration battery and need to run 4 batteries, that complicates things a little, but maybe start slowly with 2 batteries, see how that goes, it is as easy to add another pair later as to do it in the first place.

The S is the number of cells in series within the pack, so a 12v pack is always 3S and 6S packs are always 24v. I've only bought the zippy packs, because they are very cheap and seem well liked. The biggest 3S hobbyking have is 8000mAh http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=40081 This would probably give similar range to the standard lead acid, but much lighter. If you wanted more capacity you could get another set of 3 and either run it in parallel, or have it ready to swap over when needed. I've combined the approaches, use one set for running around the paddock, put both in for a trail ride. If going with 2 sets of 3 you could consider the hard case packs http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=40081 Only 5000mAh, but comes with a hard plastic case instead of shrinkwrap, so needs less protection. Hobbyking sell little fire resistant bags about the size of the batteries, which also makes an easy option for toughening them up a bit. http://www.hobbyking.com/hobbyking/store/__1114__85__Batteries_Accessories-Lipo_Safe_Bags.html

The hobbyking chargers can all be used for either battery type (you need to select the battery type when you use it). I think I listed most of the parts above. I've been running a 24v(6S) plus a 12V(3S) lipo in series, but mainly because I had it all running on 24V first so already had the 6S. If you were building it as 36v from scratch it would probably be better to run 3x12v (3S) batteries because you could charge them all at once in parallel. I have to charge the 6s then the 3s which is a bit of a nuisance.

These are neat for doing series connections. http://www.hobbyking.com/hobbyking/store/__10264__XT60_Harness_for_2_Packs_in_Series_1pc_.html or these for parallel http://www.hobbyking.com/hobbyking/store/__23132__XT60_Harness_for_2_Packs_in_Parallel_1pc_.html But will only work if you first convert the battery connectors to XT60 They have an XT to 4mm bullet converter for the LiPo batteries, but for the 5.5mm on the LiFePO4 you would probably need to solder some of these on http://www.hobbyking.com/hobbyking/store/__9572__Nylon_XT60_Connectors_Male_Female_5_pairs_GENUINE.html A bit of a pain, but nice to have connectors that are hard to accidentally short or get reversed, and most of the chargers have an xt60 output. I thought one of the best parts of the LiPo conversion was being able to use the hobbyking chargers which have a screen that tells you exactly what they are doing and have done (voltages, Ah in etc.) they have a huge range. I've bought this accucell 6 which has been good. http://www.hobbyking.com/hobbyking/store/__7028__Turnigy_Accucel_6_50W_6A_Balancer_Charger_w_Accessories.html Also this hobbyking branded one, which has a noisy fan but otherwise works OK And just recently this X120 which has a really nice colour touchscreen interface that shows all the stats at once, but seems to charge one cell 0.1V more than the others which may be a problem. http://www.hobbyking.com/hobbyking/store/__74035__X120_120W_Touch_Screen_Smart_6S_Balance_Charger_AU_Warehouse_.html If you disconnect the batteries for charging you can run them in series and charge them in parallel. Use a parallel balancing lead pack to do balance charging in parallel http://www.hobbyking.com/hobbyking/store/__27075__JST_XH_Parallel_Balance_Lead_6S_250mm_6xJST_XH_.html Actually if you are getting the 12v lipos you probably need the 3s leads http://www.hobbyking.com/hobbyking/store/__32031__JST_XH_Parallel_Balance_Lead_3S_250mm_6xJST_XH_.html?strSearch=balance%20lead%203s I forgot to mention the chargers above all need a 12v power supply. If you don't have one hobbyking sell them, but I've had no problem finding old laptop chargers for free that work great.

If you don't change the voltage the standard controller will work with lipo. On mine (2007 model I think) it will still work with 36v (9 cells in series LiPo). I haven't touched anything on the bike other than unplugging the old batteries and plugging in new ones. I think I read that on some of the later 24v models, particularly the 12.5s the controller may not work at 36v, which would necessitate changing it.

The installation for me was just attaching an xt60 connector to blade connectors to match where the oset batteries connect. A part to connect the lipos in parallel (24v) or series (36V) can be bought from hobbyking. I originally changed the lipo battery connectors to XT60, but more recently have just been buying adapters for that from hobbyking too. Then all you need to do is make sure you have plus and minus the right way around and don't short circuit anything. The XT60s make it pretty hard to get anything wrong once it is put together the first time. There is also the physical mounting of the batteries. I just stuck them in the silicone sleeves from hobbyking and strapped them down with the original velcro. Other people have stuck them in a fireproof bag or even built a metal box for extra safety, really just mechanical. I can look up the part numbers of the adapters etc if you are interested.

I'm running a 24v oset 16 on 36 volts, and it goes very well. No modifications, just swapped the battery (and charger). This thread has pretty much everything you need to know about a lipo conversion if you read back through it, and it is also pretty easy. The lipos can be dangerous if not treated correctly though, so its probably wise to steer clear of them if you don't think you understand them. I haven't tried the LiFEPO4, but from what I've read on electric car forums they offer much better performance than lead acid, but not as good as lipo, but are also more forgiving/less likely to burst into flames, so may be good for you.

The battery alarms I am using are this one. https://www.hobbyking.com/hobbyking/store/__18588__HobbyKing_8482_Cell_Checker_with_Low_Voltage_Alarm_2S_8S_.html Mine is an older model that is shrink wrapped rather than the plastic case. They are OK, but a bit of a fiddle as they go on the balance plug, so have to be manually plugged and unplugged (they aren't disconnected when you switch the bike off). They also make a loud test alarm when first plugged in. On the plus side they monitor each cell individually, and give you an accurate voltage display and they are cheap. I guess ideally you would want one for each battery but I just use one and assume they are all discharging fairly equally. I use extension cables for the balance plug which makes plugging and unplugging and mounting them somewhere visible a lot easier. https://www.hobbyking.com/hobbyking/store/__9739__JST_XH_Wire_Extension_6S_20cm_10pcs_bag_.html I have a cycle analyst on my bicycle and have to say they are really good if you have the money and can find a good spot to mount it (fairly big).

I'm not sure I would trust the built in voltage cut out even with the standard batteries. I had a hobbyking low voltage alarm which would go off before the bike cut out when I was running 6s lipos. Now using a 6S and 3S in series on the 24V oset 16 and it goes much better. Could be too much on the 12.5 though.

If you want to start small, my set up with 2x5000mAH batteries and a single charger works well. I usually charge the batteries at once in parallel, you can do them separately for a balance charge every so often, but they seem to stay balanced pretty well for me. I've kept the standard connectors so I could swap the Lead acid batteries back in for extra run time if needed, but have never needed to so far. I did get a bit of range anxiety on some trails recently and have now ordered a third battery and some battery monitors. It is easy to do in small stages and add extra batteries/chargers etc if needed later. The main downside would be possibly extra shipping costs from Hobby King, though they now have a few local warehouses. I got my latest extra battery with cheap shipping from their Australian warehouse. The battery monitors generally plug into the balance connector on the battery pack. I ordered extension cables for these balance connectors to allow more convenient placement of my monitors when they arrive. The cable on the battery is quite short.

Depends a bit on what you want from it. I've posted some stuff above about my minimal conversion on a 24V Oset 16. I used two 5000mAh 6s batteries in parallel. While this is nominally a little less than the standard batteries, in practice it goes much further on a charge. The lead acid batteries shouldn't be fully flattened either, I suspect you don't get anywhere near the rated capacity. There is certainly room for plenty more batteries.

I converted a 24V using 2x5000mAH zippy flightmax, so nominally about the same capacity as the original lead batteries. I haven't measured hours, but have a speedo showing distance. On the Pb batteries it was getting very slow after about 6km. With LiPo the furthest I've had it go is 12.5km, that took 6700mAh to recharge had 3.7 volts per cell, so 0.5 v to spare and possibly close to a third capacity left, was still going much stronger than the lead batteries after 6km. Seems like a very significant improvement to me. There is room to get double the batteries in too if I needed to, as they are so much smaller than the Pb batteries. May vary depending on how you use the bike and the condition of your lead acid batteries. Talking to electric car builders a big advantage of lithiums is they age much better than lead acid, cost more up front but save money in the long run.

Thanks for that. Mine would have been about 33% left, so getting close. I guess I need to get a power meter if I'm to manage it properly. If it starts to get close more often I'll probably buy some more batteries though.

Starting to get a better idea of how the lipos perform. Longest ride on them yet, my kids took turns and totalled 12.5km bike was still going OK but not as spin happy as fully charged. Charger reported 6700mAh in (nominally 10000Ah capacity) Min voltage was 22.5, so averaging 3.75v per cell, so could possibly have got a fair bit more out of it. The originally batteries were pretty feeble after 6 or 7km, so this is a good improvement. (this was pretty easy riding, 2km to a park and back, plus heaps of laps of a pretty flat park with a couple of ramps, mainly paved).

My kids started on the strider type bikes from 18 months, but still prefered them to a pedal bike up to about 4 years old. The 12" pedal bikes don't really go any faster than the push bike due to the low gearing, but weigh about 4 times as much. I wouldn't be in too much of a hurry to get him a pedal bike. On the other hand the JD bug trainer bikes we had, had proper pneumatic tyres which I think is a big advantage over the foam ones. The ability to get both feet on the ground makes a big difference to balance and confidence on obstacles though. Mine were really keen on all the obstacles at a local park on the trainer bikes, but on pedal bikes still go around most of them years later. They both also had a strong tendency to want to use their feet to stop at first on the oset. I don't know if the 12.5 is better, but my youngest couldn't really use the brakes on the 16" oset until about 5 years old, even though he was proficient at skids on the trainer bike which had a similar rear band brake, but a different lever.

I suspect charging a 36v from a car battery will run the risk of flattening or damaging the car battery. I did initially charge my 24V setup from an old car battery, with a cheap car battery charger connected to it to stop it going flat. It worked, but I'm not sure if it was a good idea (the car battery charger is too high an output for my charger, but I figured the battery in the system would level it out). I'm much happier with my current setup, which is much neater and also free, I just found an old laptop power supply brick with the right output voltage and current. I imagine there are plenty of suitable ones being thrown away regularly everywhere, not quite sure how to get your hands on them though if you don't have your own lying around.

Does the 36v come with disk rear as standard, or did you convert the band brake. I'm finding the band brake very noisy on the 24v, (also doesn't work well in reverse) and it would be nice to change to a disk, but looks like it would need mountings fabricated.

6S is the size you want for 24V Are you wanting it for a 36v? zippy are the cheap ones. Seems to be a 10s for $82 but it looks a bit long, might be hard to fit. Probably do better with a 6s and 3S in series. http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=235&LiPoConfig=10

I don't think you'd find them at a bicycle shop, more of an industrial machinery chain, does look similar to a motorcycle cam chain. Do you know OSET sell them through their web page? http://www.osetbikes.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=O&Category_Code=prts16

Something else you can do with 20Ah of hobbyking batteries

Some Pictures of my conversion. Very quick and easy apart from soldering the XT60 connectors with my dodgy soldering iron and skills. Album http://imgur.com/a/wBwL4 Batteries wiring and a bit of foam to stop things moving around. Same thing from further back and with the original cover holding it in.

That's right, they were still going OK. I'm guessing based on the recharge that I used somewhere between half and all the useful capacity, won't know where until I actually run them until performanc starts dropping. The indicator lights on the throttle actually seemed slightly more usefull with the LiPo than the standard battery, it slowly dropped from 3 down to one. With the pb it tends to show full almost till it stops going. I got the cheap zippy batteries listed above.

The grown up bike sounds interesting, have you posted details anywhere? I got my oset wired up with the LiPo batteries today. Seems to go well, defintitely lighter. Did 6km around the house and took 5000mAh charge after, so theoretically half the stated capacity. Seemed to be still pulling well, whereas it would be very sluggish after that distance on the lead acid batteries. Best bit is there is plenty of space to double the batteries. Is there anyone here who has actually tried the 36V? Very tempting although my kids really have more problems with wheelspin than lack of power at the moment - need to learn some technique.