C5 Help > Tried & Tested : Share your good,or bad, experiences

My LiPo Oldham retrofit.

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AJ Johnson:
Hi all.
Not sure if this has been covered before, but I thought I would post some pics of the battery I have just put together using 14.8V LiPo's for RC cars. These are "Hunger" brand 4s 25c packs I sourced from China for about AU$40 each delivered.

Remember if you attempt this yourself, batteries contain nasty stuff (lead and sulfuric acid). Wear protective equipment and check with your local authorities on how to dispose of their contents correctly.

First i had to split the lid off the original Oldham battery. Twisting the battery posts back and forth will snap the lead rod or break it off the plate. Either way, the desired result is achieved. Then, a block of wood and a hammer does a good job of loosening the plastic welds apart. The lid did crack slightly in some places but some lines of Loctite 406 sorted that out.


A nice long flat blade screwdriver does a good job of prying the rest of the lid off. Keep a big bucket underneath to catch the contents.


The crusty old plates. The lid came off quite cleanly.


A "Renovator" or oscillating cutting tool cuts through the connecting links between each tank.


Then with a firm grip of some pliers and some jiggling, the plates slide out.


The empty case. Just about to have a thorough clean.


So we've jumped a few steps but I used 4x5000mAh packs for a total of 20Ah. Unfortunately they were just a little too wide to fit in each "tank", so i cut out the center divider and stripped the heatshrink and some thin aluminum that was stuck to the sides of the packs for a snug fit. Also, cable passages have been cut in the top of the tanks and insulation inserted between the tops of the packs to stop any arcing. The ends of the packs have PCB's with nice solder sections, so two pairs of packs are paralleled using 12AG/4mm wire and out to 6mm crimp lugs. These seem to handle the current draw okay. The original posts have been drilled through where the original lead posts entered the case and M6 bolts with large washers (in stainless of course) connect the lugs and affix the terminals to the battery lid.
The balance charge wires have been paralled as well and the wires extended to reach the charger through a hole drilled in the side of the battery case.


The lid is secured back on using 4 peel rivets on the ends. This way I can drill them out if and when I need to access the packs or add more at some stage for longer lasting fun ;)


And here it is all strapped up with the lid. Weighs in at 3.1 Kg.


I've only managed a 5km run with a few inclines on this pack so far, which seemed to use about 1/4 capacity after recharging. Top speed is much better. I was cruising at 18km/hr on gel cells but now I'm doing 29-30km/hr. Current draw was around 22 amps cruising.

Now I'm not sure what I'm in for as far as how long the standard electrics and gearbox will handle this boost in power but I guess I will cross that bridge when I get to it.

dansretropod:
Nice work, it's great to see you re-using the old battery case like this ;D

I used to run my C5 on a 20ah lifepo4 battery and would get about 15 miles out of it, they're great batteries and because of the light weight make hills much easier ;D

As for using these batteries with existing C5 electronics I think you'll find the power gauge LEDs stay fully lit until very near the end and then go down quickly.  Also I'm not sure if the 5v regulator in the control box will need a bigger heat sink to deal with the extra voltage plus I'm guessing its pretty hot down there in Newcastle so you may need extra cooling in the CB :D

Ton C5:
WOW thats brilliant .
i am going to try that this spring.

top mod in my book

alecjw:
Nice! How did you get rid of the plates and contaminated acid? I know halfords take whole planté cells but I wasn't aware of any way of getting rid of battery innards. I might consider doing this with my 60Ah lithium mod.

C5 ENTHUSIAST + RESTORER:
Well done what a great idea must try it one day ... bye Chas

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