Zippy Frog Battery

[Deleted member 4366]

My 6S 8000mAH packs arrived today and they're a perfect fit in a frog-type battery case after grinding away some of the internal webs and the charging fuse-holder (which is not needed). This pack will go on my Dahon Jetstream - should make it fly! A useful update for anyone wanting to increase the current in their bike for better hill-climbing. The case only cost a few quid from China

 

[jerrysimon]

Nice job Dave.

Whilst perfectly safe for those who know how to handle these cells, I would still however issue a health warning that Lithium Polymer cells are not for the faint hearted.

They should be treated with the greatest of respect re over charging/discharging and possible fire risks from this or physical damage.

PS All that said I am not sure if the newer cells being made now limit this somewhat ?

Regards

Jerry

 

[piotrmacheta]

Nice. what the dimensions of those battery packs?

 

[jerrysimon]

Details here

Regards

Jerry

 

[Deleted member 4366]

Nice. what the dimensions of those battery packs?

Approx. 70 x 50 x 170mm. You might want an extra 5 or 10mm length for the leads if you can't turn them back along-side.

 

[Scottyf]

Nicely done and a good fit. The Turnigy cells are great and balance really well.
I'm suprised more people dont head down this route and just get a cheap BMS that supports 10s or 12s cells and just solder up the balance leads to the relevanct connection.


Its the same when people have retired old batteries. I'd fill them up with lipo cells and wire up the power and balance leads accordingly.

Lipo really isn't that dangerous proving you have the correct charging methods and stp before the cells resting voltage is 3.65v.

Hell i've even took some cells lower than that and they are still pretty safe. I think there's more scare tactics with it than anything.

 

[shemozzle999]

A couple of questions d8veh.

Are you going to connect the serial junction through the built-in fuse holder so you can remove the fuse and charge them separately through the balance connectors?

Is there enough spare space around them to allow for cell expansion when in use?

 

[rooel]

I have used Lipo for years inserted by me in a Frog casing whose Li ion cells had failed, and have had no problems. However I have two questions regarding the OP's setup: is there no battery management system packed into the cells' outer covering? The ones I use are from Batteryspace and the BMS board is connected to, and bound up with, the cells. The Hobby King photo shows the BMS connector unconnected and there is no BMS board in sight.

The other problem I see for me is that with a 24 volt system the two packs in series would provide only 22.5 volts which would be too low, and in parallel 43 volts which would be too high.

 

[Deleted member 4366]

A couple of questions d8veh.

Are you going to connect the serial junction through the built-in fuse holder so you can remove the fuse and charge them separately through the balance connectors?

Is there enough spare space around them to allow for cell expansion when in use?

I'll run balance leads outside for balancing, and I'll bulk charge through the RCA charge socket. I might also bring out separate power leads for single pack charging - haven't decided yet

 

[shemozzle999]

Thanks for the explaination d8veh, looking forward to see how it works out.
The lipos look if they were made for the case.
I was about to buy a 36v frog but I might convert my old 24v one now.

 

[Deleted member 4366]

I have used Lipo for years inserted by me in a Frog casing whose Li ion cells had failed, and have had no problems. However I have two questions regarding the OP's setup: is there no battery management system packed into the cells' outer covering? The ones I use are from Batteryspace and the BMS board is connected to, and bound up with, the cells. The Hobby King photo shows the BMS connector unconnected and there is no BMS board in sight.

The other problem I see for me is that with a 24 volt system the two packs in series would provide only 22.5 volts which would be too low, and in parallel 43 volts which would be too high.

No BMS. All charging and balancing will be done manually. The two packs are 6S in series making 44v nominal, or 50.4v fully charged.