Playing with A123 20Ah lithium cells

[drmiller100]

i'd be surprised if the prius is as low as 14.0 volts when the starting battery is fully charged and certainly it will not be lower.

Thank you for the research.

It sounds like these would be VERY nice batteries for an electric car. I've gotten a bit of push to build an electric verison of my trike. Sounds like this woudl be a good solution.

[Daox]

These batteries won't be going in the Prius, they'll be used as the starting battery in my Paseo. They'll be replacing the group 24 lead acid battery that weighs about 40 lbs with this which will weigh about 5 lbs.

[Daox]

Darin remembered that there is another EM member using an even smaller lithium pack as a starting battery. Here is the link to his post.

http://ecomodder.com/forum/showthrea...tml#post318908

[Cobb]

So much for the 900 mah that is stamped in the left front corner. Wonder if they are purposely mislabeled for customs reasons?

Strangely after that gorup buy I remember seeing an article about a batch of defected cells that had a crease in them, like those.

Think I got a good dozen of IMA cells that are worth a dam and similar in capacity. I am going to try and make a 14 volt 6.5 amp hour battery out of them for under the hood. Then hook a 5 watt solar panel to that as well.

Then of course remove the 12 volt starter with the lead acid battery.

[drmiller100]

Originally Posted by Daox

These batteries won't be going in the Prius, they'll be used as the starting battery in my Paseo. They'll be replacing the group 24 lead acid battery that weighs about 40 lbs with this which will weigh about 5 lbs.

sorry, I should have read more closely. I understood you were using it as a starting battery for an ICE.

My experience is EVERY modern normal running vehicle has 14.0 to 14.4 or so volts, fully charged, and engine running.

I have a small automotive shop, and we specialize in fuel injection and electrical issues, and battery voltage at idle is something we pretty much always check.

[Daox]

You are correct drmiller. Your post reminded me , so I just went and checked it. The voltage varied from 14.2V to 14.4V, but it mostly stayed in the 14.3-14.4 range. So, we'll say 14.35V as an average.

14.35V gives us 3.575V per cell. That is going to leave these cells pretty much topped off all the time. Max charge voltage is 3.65V per cell and you gain very little capacity between 3.575V and 3.65V according to the charts.

I actually wouldn't mind a slightly lower voltage, but this is what I have. I don't believe there is an easy way to adjust the alternator output. Someone correct me if I'm wrong. But, this should do just fine.

[Daox]

I also wasn't able to find the 'noalox' product at the local store that was supposed to be a distributor. What I did find was this stuff. It claims to improve conductivity and protect aluminum electrical connections.

You're supposed to work this paste in with a wire brush or emery cloth to both sides of the connection, then put them together. Sounds to me like its attempting to stop the oxidation before it starts. This sounds like a different product than the noalox which claims to 'cut aluminum oxide'.

I'd like to test it to see how well it really works. So, I'm thinking I'll cut a bunch of aluminum spacers and stack them together and measure the resistance. Then I'll use this stuff and reassemble the stack and measure resistance. Ideas are welcome for a better testing procedure.

[Daox]

So, to clarify, it looks like Ox-gard and Noalox are fairly similar. I mention this because my Ox-gard was $4 for a 4oz tube vs Noalox at $12 for a 4oz bottle.

Here is the MSDS data for Ox-gard:



And here is the MSDS data for Noalox:

[jjackstone]

Daox,

Don't know that you'll be able to measure much difference in resistance. The big gain with this type of product is that it fills in all the little unseen pits and holes found in most unpolished materials essentially creating a larger surface area. That is why the conductivity increases. JJ

[Daox]

The paste is not conductive. I tested it. I would think the main benefit is from being able to make a solid aluminum-aluminum connection without two layers of aluminum oxide (an electrial insulator) between them.

Small update. I'll finish up testing cell #3 today. Number 4 should be done a couple days after, then I'll work on assembling them into a 12V pack.