Oset Batteries Lithium (LiPo) Conversion Directions

[gwhy]

This is a great thread but I have to say im still uncertain about what to do. I get the whole series boosts V, parallel boosts Ah. Most of the links to the batteries are not available anymore from HK. For convenience (or utter laziness) would someone be able to make a kit list for 24v and 36V bikes with all the bits and pieces. My sons 36v kuberg trial e should be here soon and I want to make sure he gets his use out of it.

Incidentally, I have a stash of batteries in work (from a UPS, I work in IT). would they work? Ive got 6 x Yuasa NP7-12 (12v,7ah) and 2 x gsb gp12120 f2 (12v,12Ah). From what ive understood from this thread I could series the 12v7ah batteries in 3 to get the 36v but then its still only 7ah. The standard kuberg SLA setup is 9ah. Saying I cant find any more of the 12v12Ah batteries could I series that up with the 7ah one? im guessing not......

Ive got a few of IBM/Lenovo laptop PSU's, im sure I read they can be used as PSU's for the chargers too.

Luckily the free-rider ive got on order comes with lipo as standard so it should be easy to replicate that setup...

/Jon

All the information for a shopping list is within this thread ( im sure it is ) with all the relevant information about the batteries that are needed from hobbyking ( just go to the HK web site and look at the batteries that you need).

You can P 7ah battery with a 12ah battery ( as long as they are the same voltage ) always look at the higher ah battery as the same ah's as the lower one i.e 7ah in P with a 12ah = 14ah ( edit : this should have been a 7ah in P with a 12ah = 7ah )

The free rider is lithium but I doubt it very much that it will be lipo , more than likely to be lifepo4, so it will be slightly different.

Edited September 10, 2014 by gwhy

[jon0881]

All the information for a shopping list is within this thread ( im sure it is ) with all the relevant information about the batteries that are needed from hobbyking ( just go to the HK web site and look at the batteries that you need).

You can P 7ah battery with a 12ah battery ( as long as they are the same voltage ) always look at the higher ah battery as the same ah's as the lower one i.e 7ah in P with a 12ah = 14ah

The free rider is lithium but I doubt it very much that it will be lipo , more than likely to be lifepo4, so it will be slightly different.

Thanks for that. so I could do with tracking down another 12v12ah battery. If ive understood, adding just one 12v7ah will drop the lot down to 7ah. If I can get a set of 3x 12v12ah and then had 6 x 12v7ah I would think that would be enough to keep him going for a while and I wouldn't need to move to lipo yet.

For the free-rider. im sure its lipo, I quizzed the CEO a while back and he didn't correct me when mentioning LiPo. He said it will have a BMS to allow safe charge and discharge of the batteries. The batteries are in a unit inside the bike and are not meant to be removed for charging. I cant wait to have a go on this thing. I only hope that the power and runtime of it lives up to my expectations.

Gwhy, you live in the UK? have you had any problems using either of your ebikes? They are of course more subtle so can be ridden in more places but im sure you can still earn a section 59 if you are in the wrong place at the wrong time.

[gwhy]

I would be interested to know for sure if the free-rider is "lipo" or some other form of lithium based battery as this this is what can get very confusing when looking and talking about batteries, there are subtle differences to the lithium based batteries chemistries.

Upto now I have never had a problem with riding my e-bikes anywhere. I think the real bonus is that they are quite, so unless your out in the open to been seen then there is very little chance of getting caught riding. All of the general public that do see me riding are just interested and fascinated and will stop to ask questions about my bikes but not to complain. I used to regularly visit a local bmx track with my 20" e-bmx and mix it up with all the ( non-electric ) other riders without issue. I think I may have problems if I took the e-sherco to the bmx track but this is just because it looks like, and is a full size motorcycle as opposed to a bicycle and there are a lot of people that walk past the track so I think its a law of average game and you just need to be a bit sensible. The less peeps that actually 'see' you riding ( because they cant hear you ) the less chance of getting caught .

[jon0881]

That's good to know. I should be one of the first people to get my leg over the free-rider so i'll put up a post when its here. There is a cracking little MTB track not far away from me. My plan is to use that when its quiet.

To a total newbie, here is a good write up on lipo's

http://www.rchelicopterfun.com/rc-lipo-batteries.html

Edited July 25, 2014 by jon0881

[rasmus]

Hi,

I am all new to this forum, and have been reading it all - picking some up, and some just confuses me :-) I am a dad to a crazy MX kid, who used to loves his Oset 36v. We have a 20" standing, but he is simply to small to have fun on the bike yet. The power is fine for him, but he is to short. He wants me to boost the 36v, and now I am hoping for your help. I know that we are probably no going to get the the same power of the 36v with Lipo as we have on the standard 48v, but as much boost and longer runtime as possible without a great risk of burning the controller and motor.

Could "Gwhy" help me in this matter? I have nothing but the standard battery and standard charger. What do I need from HK? Batteries, chargers, connectors etc. Could you help me do a list?

[gwhy]

Again, thanks to everyone for the technical advice and the common sense. I'm going to build a 10ah "cassette". That way, I can in the future build another to either swap or piggy back with a couple of parallel leads to get the 20ah distance. So my shopping list currently looks like:

Hobby King

4 x 5000ma 5S1P 15C Zippy - (2.8kg) $160 (ordered a spare, as DOA likely)

1 x Nylon XT60 Connectors Male/Female (5 pairs) $3.19

- 4 x Female replace the ones on the batteries

- 1 x Male replace the OSET power connector

- 1 x Male and 1 x Female for the power meter

2 x XT60 Harness for 2 Packs in Parallel $4

1 x XT60 Harness for 2 Packs in Serial $2

Pack of 3/16th (4mm) shrink tubing

1 x Parallel Balance charging Board for 6 packs 2~6S (XT60) $9 (not sure this needed yet)

2 x Turnigy Accucel-6 50W 6A Balancer/Charger w/ accessories $46

2 x Lithium Polymer Charge Pack 25x33cm JUMBO Sack $5.46

1 x Turnigy 130A Watt Meter and Power Analyzer $24 - On backorder so bought an Eflight Power Meter rated at 120A from my local RC store ($50). This is essential equipment.

Note that HobbyKing doesn't send manuals, web search them.

My miscellaneous shopping list is:

Battery Case (cassette)- used Lock n Lock Food Savers 800ml/27oz

Laptop power supplies for the chargers - This hasn't worked for me they produce 19v, the chargers accept 10v-18v - use a 12v battery hooked up to a charger.

3mm padding (between and around batteries) - Wrapped the batteries in rubber antislip matting.

Zip ties (hold the batteries together) Not required in the food savers.

Grommets to seal around the parallel cables exiting the case - used silicon sealant

Strapping to hold the cassette in the tray - essential - used the old battery bag - not ideal.

Follow-up notes:

Awesome upgrade - some important considerations around LiPo safety. If you are considering this upgrade, then read this extremely important information http://www.rcgroups.com/forums/showthread.php?t=209187

Stuff arrived in about 10 days. I ordered 5 batteries just in case, and one arrived with a cell out!.

Soldering on the XT60 connectors is challenging to begin with, I had to upgrade to a 100watt soldering iron, a gizmo to provide an extra pair of hands, used old style lead based solder. Use the Allen Key heat sink or the plastic melts. Excellent how to video here http://www.youtube.com/watch?v=3Yj-DHxKS6c.

I cut a 3/16th x 3/4in slot in the side of the food savers to allow the cables to exit. Work out where by dry fitting the food savers "cassette" to the battery box on the bike.

Each cassette holds 2 batteries wrapped in the rubber matting very neatly with the XT60 connector just on the outside. The cassette fits across the bike battery case very snug!

I fitted the power meter into another Lock n Lock 180ml/6oz.

Fit the power connectors to the bike into another small Lock n Lock to waterproof.

Findings:

The RC world rates batteries at their minumum voltage, so my 5S1P batteries are rated at 18.5v but when fully charged actually have 21v - so I have ended up with 42v when fully charged - bike speed is up noticeably but motor does not get warm. DO NOT allow these batteries to fully discharge, a safe minimum seems to be 37.9v (30% life remaining) go beyond that and you could destroy the battery. This is where the power meter comes in, mine shows voltage and mA used. For my 10Ah setup I stop at just before 7000ma used. Currently the bike seems to consume 90ma per minute so a working range of 75 minutes. There is no significant loss of power down to that threshold. (Update - blasting around for 30 minutes flat out used average 125ma per minute so range to 30% remaining 55 minutes and to 20% remaining absolute lowest 63 minutes). Trials playing in the yard 50 to 80ma per minute.

Always disconnect the batteries from the bike and power meter so there is no drain while in storage.

Charging - This is where the move from the super safe lead acid to LiPo gets serious. These batteries can be dangerous - if you haven't read the link on safety, read it now. It seems that there are 2 main dangers: Charging at the wrong voltage and physical damage. The charger I have checks the battery, reads the number of cells and says what it finds, then asks for confirmation. I also charge them in a clear space on concrete in a Lithium Polymer Charge Sack and check them regularly and disconnect as soon as they are charged. (BTW LiPos like to be stored partially, not fully charged so the RC folks tend to charge them on the way to their event).

Physical damage - these batteries are not well protected, at one end you can see the individual LiPo cells with a soft foil like material, a nick in this and you will get a fire - but not immediately, just after you have stored the bike in the truck/car and gone off for "refreshment". Hence my wrapping them and putting them in a cassette. Look at your current SLAs and see the wear marks on the sides where they bounce around in the battery case.

Using my 2 small chargers seems to take 150 minutes to charge the 4 batteries from 40%. I could buy 2 more chargers and halve the time.

555555555

all the info that you need is with in this topic but yes its all got a bit crowded.. this is the best shopping list here for reference also with observations and practical usage all in one post.

if you are in the uk then when buying stuff from HK make sure that you get it from the uk warehouse as postage cost can go through the roof for batteries..

Edited September 11, 2014 by gwhy

[rasmus]

Hi Gwhy,

Thanks for this. As our bike is the 36v, would these batteries be correct? Just double checking before ordering? Are these the most up-to-date batteries available for this project? Just want the hardest pull and longest drive time available really....

[gwhy]

Hi Gwhy,

Thanks for this. As our bike is the 36v, would these batteries be correct? Just double checking before ordering? Are these the most up-to-date batteries available for this project? Just want the hardest pull and longest drive time available really....

yes, either the zippy brand or the turnigy brand 5s1p 18.5v 5000mah X4 for a 36v setup.. 15,20 or 25c will be fine its not worth the extra cash for a higher discharge battery on these bikes.. if you get on ok with these batteries but want more runtime then just buy another set of batteries , but dont spend a lot of cash on battery's until you are happy with handling and caring for them as it can be a lot of money wasted if you should ruin them if its your first venture in to using lipo.

[gilles]

Hello,

Looking for upgrade off my son's OSET 16" 36V I found this thread. Great info Thanks!

So if I understand correctly I will need:

2 x 5S1P 5ah series and these 2 again in parallel to have 10Ah?

I also ran into this site for visualization of the linking of the packs:

http://www.scriptasylum.com/rc_speed/lipo.html

Greetings

[redline2097]

My 2 year old outruns the power of his Oset 12.5 24v and the original battery is getting pretty weak. I'm considering to upgrade to lipos, is 4 x 5S1P overkill to 24v oset (37v @ 10000mah)? Or would the 4S1Ps give enough power increase?  Oset is 2013 model.

Edited April 15, 2015 by redline2097

[gwhy]

if you are considering lipos then 4S will be a good jump in power ( 33.6v hot off the charger ).. the only problem is that you will have to monitor the lvc manually as the controller is setup for 24v..  so you will have to power the bike down when the voltage gets no lower than around 27v ,, running the battery lower than this will/may permanently damage the whole battery and make the battery unstable , if you what something that is a little more forgiving and nearer the standard voltage HK now sell lifepo4 battery's these are 4S2P each and are 8000mah each so you will need 2 battery's to make up a 24v 8ah battery.  I dont know what the lvc is set for on the controller on the 24v bikes so you will need to test but if you use the lifepo4 then you need to stop riding when the voltage is at around 18v and the hot off the charger voltage for lifepo4's will be around 29v .. no matter what chemistry you choose always balance charge them using a li balance charger.

[redline2097]

Would this be enough to check the voltage: http://www.hobbyking.com/hobbyking/store/__18588__HobbyKing_8482_Cell_Checker_with_Low_Voltage_Alarm_2S_8S_.html

And is this suitable charger of a that kind of setup (4 batteries in 2x2 in series, 29,6v @ 10000mah) http://www.hobbyking.com/hobbyking/store/__12105__HobbyKing_8482_ECO6_10_200W_10A_6S_Bal_Dis_Cyc_Charger_w_acc_.html

Edited April 15, 2015 by redline2097

[gwhy]

yes just 1 of these will do the job but i would recommend having 2... one of each set of 4 cells ,, but you can not leave it connected to the battery all the time as it will drain the battery's.. you will have to plug it in when you are using the bike and remember to unplug afterwards.. another draw back with these small alarms is the connections are quite fragile and can easily be damaged with the constant plugging/unplugging . but will work..

[gwhy]

if you are confident wiring up batteries then you could purchase a bms ( approx £30 delivered ) to fit to the battery permanently.. and by the correct type of charger to charge through the bms ( approx £30 delivered) 

[redline2097]

Could I add the voltage checkers via witch like this and turn on when bike running: 

 

Or could I wire them via bikes own power-on switch?

Which bms on hobbyking you would recommend?

Edited April 15, 2015 by redline2097