betarambo Posted February 16, 2011 Report Share Posted February 16, 2011 One of the best upgrades you can make to your Oset is to replaces the sealed lead-acid batteries with LiPos. A LiPo (lithium-ion polymer battery) is an evolution of lithium-ion batteries where the electrolyte is basically held in plastic rather than a solvent. LiPos allow you to shave a lot of weight and to reduce charge time dramatically. While the benefits are impressive, they do not come free. Lipos have significant risks and require a higher level of technical competence and attention than the stock batteries do. If you are not somewhat technical, willing to learn, and willing to put some extra attention into the care and maintenance of the bike then stop here and enjoy a really cool bike as it is. Safety disclaimer: I am attempting to relate how I modified my daughter Quote Link to comment Share on other sites More sharing options...
lineaway Posted February 16, 2011 Report Share Posted February 16, 2011 As always very nice Gimpy, maybe some pictures of the other upgrades would show the daddy`s the real potential of these bikes. Quote Link to comment Share on other sites More sharing options...
brewtus Posted February 16, 2011 Report Share Posted February 16, 2011 Nicely written up, MooMoo. Quote Link to comment Share on other sites More sharing options...
ridenm Posted February 17, 2011 Report Share Posted February 17, 2011 Awesome write-up, BR. I second the suggestion of pictures. I plan on upgrading Katy's old bike as soon as we have the resources. Kace's will be good on the stock batteries for a while yet. Quote Link to comment Share on other sites More sharing options...
dmx84 Posted February 18, 2011 Report Share Posted February 18, 2011 Nice write up, and looking forward to the other mods! Quote Link to comment Share on other sites More sharing options...
mikedufty Posted February 24, 2011 Report Share Posted February 24, 2011 Really good write up. How were the results, does the bike go any better? I've just put a Shorai LiFePO4 starter battery in my road bike. I've wondered if they would be an easy upgrade for the OSet too. They claim to be set up to work with a standard 12V bike lead acid charging system, they are similar size to the standard oset batteries, so could possibly just be dropped straight in. I just wonder if they are as good in a power battery application as they are as a starter. Not sure I should trust the oset charger that has already killed a set of Pb batteries with expensive batteries. Shorai market their largest as 18AH pb equivalent, but it seem like they are actually only 6aH. Not sure if their equivalence calculations apply when it is being used for continuous power. Quote Link to comment Share on other sites More sharing options...
betarambo Posted February 25, 2011 Author Report Share Posted February 25, 2011 I would think that Life battery would work. I would go ahead and get a real charger for it. I wonder if the one you are talking about exposes the ballancing plug. It would last longer and perform better with a real charger and a balance charge. My daughter's bike shouldn't be any faster, but she swears it is. I think the old batteries must have been weak. I just got the 3 cell LIPOs today to run in series with the 6 cells. This will give use 36V so that should make it a bit faster. We'll see how the 24V controller and motor react. They tell me it will be fine. I'll let you know hopefully this weekend if I can get time to do some soldering and let her try it out. I also got my watt meter so I can see how much juice she is pulling and use it like a gas guage to see when the batteries are almost done. Quote Link to comment Share on other sites More sharing options...
gwhy Posted February 25, 2011 Report Share Posted February 25, 2011 Lipo is the way to go.. as they can discharge at such a high rate there will be very little voltage drop under load unlike SLA so it will be a double wammy higher top speed longer running time and a lot, lot lighter. I have been using lipo for over a year now in my bikes and would never consider anything else. But care do need to be taken when charging, once in use they are as safe as any other battery. The 2 main things that can not be abused with lipo is never, never over charge them and never, never let them be discharged to lower than 3.2v per cell. A constant voltage/current charger must be used to charge them and I would recommend balancing the battery once in every 5 cycles. Ideally you need to monitor the cell voltage when in use to make sure no 1 cell goes below the danger zone. Quote Link to comment Share on other sites More sharing options...
mikedufty Posted March 30, 2011 Report Share Posted March 30, 2011 Do you monitor the cells while in use? How would you do that? A voltage display for each cell doesn't sound practical. Quote Link to comment Share on other sites More sharing options...
gwhy Posted March 30, 2011 Report Share Posted March 30, 2011 Do you monitor the cells while in use? How would you do that? A voltage display for each cell doesn't sound practical. Personally I dont monitor at cell level when using my bike any more, I just monitor the whole pack (44.4v) and stop riding the bike hard when the battery voltage gets to around 40v , you start to get a feel for how well the pack is behaving by how quick it discharges. You can get cell level monitors in different shapes,sizes and functions and I used to use 2x6 cell monitors ( I use 12 cells ) that gave a voltage readout on a lcd screen with all 6 cells ( 12 cells in my case ) being shown at the same time and also has a audible alarm that can be set for a low cell each device was about 2"x1"x0.5" and was around Quote Link to comment Share on other sites More sharing options...
betarambo Posted March 31, 2011 Author Report Share Posted March 31, 2011 I don't montior the cells while riding. With the Oset the bike pretty much stops moving before they get too low. Just tell your kid to let off the throttle when it stops moving and you are fine. You can get some monitors that show all 6 cells at once. I bought one from Hobby King for like $5 but I only use it in the garage. I got the 12V batteries the other day to try the 36V setup but haven't tried it out yet. I did at least make the series cable I need for it and swap the connectors on the batteries. We have a trials this weekend so maybe I can try it there. I have gotten distracted lately modifying my WRX for serious off road abuse, but that's another story for an entirely different forum... Quote Link to comment Share on other sites More sharing options...
trix Posted April 2, 2011 Report Share Posted April 2, 2011 Hi there, what about something like this... http://cgi.ebay.co.uk/24V-10Ah-Lithium-Battery-LiFePO4-Aluminum-Case-/170606969844?pt=US_Batteries&hash=item27b8f7c3f4 Would this work ? Quote Link to comment Share on other sites More sharing options...
gwhy Posted April 2, 2011 Report Share Posted April 2, 2011 Hi there, what about something like this... http://cgi.ebay.co.uk/24V-10Ah-Lithium-Battery-LiFePO4-Aluminum-Case-/170606969844?pt=US_Batteries&hash=item27b8f7c3f4 Would this work ? It would be a improvement on sla's but only for the weight of the pack, LiFePO4 battery's can not deliver very high currents ( normally 2C about the same as sla's ) over extended periods, The pack in the link say's 10A Continuous discharge and only 25A Instantaneous Maximum Discharge so They are not really ideally suited to be a high performer but the pack will weigh about halve the weight of equivalent sla's and about halve the size you would need 2 of these LiFePO4's packs wired in parallel to really make them worth while on these little bikes . You can discharge them at higher rates but this will make them warm/hot and also make them deteriorate faster, So the extra cost may not be worth while. Where as a small 10Ah 22.2v lipo battery (15C or higher ) pack would be something like 150A Continuous and 300A Instantaneous Maximum Discharge so they should not get hot in use and the weight and size is about a third of sla's. Quote Link to comment Share on other sites More sharing options...
mikedufty Posted April 4, 2011 Report Share Posted April 4, 2011 Good stuff, I just put in an order with Hobbyking. Quote Link to comment Share on other sites More sharing options...
gwhy Posted April 4, 2011 Report Share Posted April 4, 2011 Good stuff, I just put in an order with Hobbyking. Just thought I will ask, But dont forget a charger as well ( You can not use a normal sla charger ) and also another bit of very good kit from HK is a watt meter , ( Im sure they do a cheaper Higher spec meter than this one but I cant find it ) This will give you running/pack voltage, AH used, max watts pulled and min voltage drop from the pack. If you want more detailed info on how to use/make the most of lipo's safely then drop me a PM. Quote Link to comment Share on other sites More sharing options...
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