This week I am starting a new category called Random Rants. I will be adding random thoughts in this blog. To start with I thought I will add something that I am going through this week.
So it all started with a dead battery in my car. My Toyota CH-R kept on getting discharged every two days. So instead of bringing my truck to jumpstart every time, I thought of just buying a jump starter. Apparently things changed a lot with jump starters. Last time I checked they were all Lithium battery based. Now I see there are new models based on capacitors. I was interested in those and got one of the supercaps (super capacitors). I bought one of them from Amazon for jump starting my car but it really aroused my curiosity. This blog is about what I found about them.
Pros/ Cons for a Supercap jump starter
- Supercap jump starters use capacitors, which means they have:
- Longer shelf life, no need to keep it charged
- It does not need to be pre-charged to use
- Higher total number of recharge cycles
- Can work in extreme weather conditions without problems
- However they will also not retain charge as capacitors will discharge
- Safer to use than battery based one as there are no chemicals, and no fire hazards
Overall we do see that using a capacitor based jump starter definitely has a lot of advantages over a lithium battery based jump starter.
How much battery capacity is needed?
When getting a jump starter, one thing that you need to know is the CCA (cold cranking amp) for the car battery. SAE (Society of American Standards) JS37 from June 1994 defines CCA as the measure of output amperes for a 12V battery for 30 seconds while maintaining 7.2V at 0 degrees Fahrenheit.
The cold cranking amperes required by the vehicle is proportionate to the engine displacement for the car. According to one of my reference sites, rule of thumb is that you need 1 CCA for every cubic inch of engine displacement (for diesel it is double of that). You can always find the engine displacement from the vehicle manual. For example, the car I had trouble with had a 2.0L engine which is equivalent to 121 cubic inches of engine displacement. So, we will need a jump starter that can give at least 121 cold cranking amps to minimally jump start the vehicle.
Normally what you see when you buy a jump starter is what is the maximum vehicle capacity it can start. So they may say something like 8L gas and 5L diesel engines. You will also find similar rating for the super capacitor based jump starters.
How does a supercap work?
These type of jump starters rely on the property of capacitors to store charge and then release it quickly when needed. They rely on the assumption that a battery that cannot cold start an engine still has enough juice to charge a bank of capacitors so as to send it back to the alternator when cranked.
Normally these will provide alternate ways of charging too for completely dead batteries. You can charge it using a car cigarette lighter port or a USB C battery pack. Of course charging time with a battery pack will be higher.
For these to work, you will attach the capacitor to the car battery and charge flows from battery to the capacitor. This process will take less than 3 minutes. After the capacitor is fully charged, you will press a button that activates the capacitors in discharge mode and it powers back the car. You can now go inside the car and crank it up.
The jump starter I bought claims to be 500F (farad). In one of the videos it also shows a bank of five capacitors connected. I would assume that it has five 100F capacitors connected in parallel. This should give it a total capacity of 500F.
My experience with the Jump Starter
I used this jump starter for quite a few days while I waited to change the car battery. My battery showed 6.8V, but even with that I did not have any problems charging up the jump starter to 100%. After I click the button for it to discharge, I did not have any problem with the car to ever start. It started up fine every time (that would be about seven times in approximately five days).
On a whole, I had very positive experience with this jump starter. This is a keeper and I plan to add this to my car toolbox as well. Just to complete the blog, I think I will mention the super capacitor I got. On Amazon, you can find it by searching Buture 500F supercap jump starter. Ciao for now!