BHPian x-o-b recently shared this with other enthusiasts: Hey fellas, The OEM original 8 year old car battery in my Thar CRDe started to show signs of degradation and I had fun trying to experiment with its lead acid chemistry in various “stupid” yet insightful ways to revive it. I will post a separate detailed account of my adventures with that battery soon. The original battery was rated at 72 Ah, 600 CCA. I dropped in my 35 Ah 500 CCA rated Gypsy battery just for kicks and as expected, the Thar didn’t even crank. All I heard was the clicking solenoid switch – dud!! The 35 Ah wasn’t good enough? But wait, what has Ah got to do with the cranking anyways, it shouldn’t have mattered. What matters is the CCA (Cold Cranking Amps) and 500 Amps should have been sufficient. Hmmm, something’s fishy here. I pulled out the starter motor and yikes the copper bush in the front had badly worn out. It wasn’t the battery after all. I came to realise that perhaps it was this worn-out bush, in the first place, to cause excessive current draw (overload) in my older battery and this continuous overloading had caused it to snap. Whatever. Anyways, so I repaired the starter motor and my “puny” and tiny battery from the Gypsy could now easily crank my massive Thar. Happy? Not quite. I have always hated the lead acid batteries on cars and have tried to explore ways to get rid of it. I hate that it is chemically corrosive, has lead in it, is so bulky, has limited lifespan, etc., etc. I needed something better. A LiFePO4 or LTO would be nice but it doesn’t quite work in a car. It requires a good BMS and the alternator spikes may simply damage the electronics. Also, since the lead acid battery in a car acts like a nice ballast or buffer load – consider it a wonderful shock absorber of electrical spikes – for the car, other than simply a DC power source. LiFePO4 or LTO simply can’t do that. Hence brewing of a plan began. Experiment time fellas. The plan is to use the smallest Ah sized lead acid battery (but 12 volts rated). That should handle the ECU and various “essential” electricals in the car. For cranking, a dedicated capacitor bank. Sweet. Here is the plan Need to find capacitors: here I got 6 capacitors each rated 500 Farads 2.7 Volts to be connected in series A pack of 6 is adequate but what the heck, I’ll add 6 more in parallel Copper wire – really thick one for interconnection Ready to solder Capacitor packs, when connected in series, need a voltage balancing board Since the voltage of the car alternator is capped at around 14.5 Volts, it will never be able to charge my pack rated at 16.2 Volts. That’s my boost converter for charging the pack to 16.2 Volts Connectors The balance board connected Reverse current protection diode (high current rated) Finalized and ready to crank Let’s use my reliable Nokia 5 Volts charger to charge the pack, for now I’ll add more pictures from under the hood. This is work in progress and I need to build a good case for it. I have used an EC5 connector to make this pack as portable and “plug and play” as possible. Now, the moment of truth. Did it work? Was the pack able to crank my Thar without the battery assisting it? Oh yeah, it worked like magic. The beauty in this setup is that even a near dead battery in my car can sufficiently charge my capacitor pack (thanks to the wide input voltage range on the boost converter module). Thanks for reading through fellas, so long. Check out BHPian comments for more insights and information.
