Battery Electrical Information, Any Year, Any Make

[RickHaleParker]

The Li-ion ones work only if the only problem is a dead battery. If the car wont start easily then they could be worthless.

Low battery not dead battery.

The cars made in the last 25 years or so have a protection mode that shut things down and prevent start if the battery gets too low. This prevents the battery from getting seriously depleted and and excessive high current when you try to start it. The Jump Start Packs have just enough capacity to over come the protection mode. The couple of seconds of cranking is to prevent damage to the Jump Start Pack when dealing with a problem it was not designed for, which is a seriously depleted battery.

This is why you don't need to let the battery charge for 30 minutes before cranking like we did with the electro-mechanicl controlled cars. How many jumper cables did you fry on a electro-mechanicl car before you learned to let it charge before cranking?

[850oldschool]

My NOCO Genius GB40 is undefeated. Never tried to clear a flooded engine at -20, though.

[MrAl]

The float voltage is around 13.8 volts.

There are different options on what the float voltage should be.

Some people say as low as 12.4V. I say 12.4 is too low because it only a partial charge. I say 12.8 -12.9 because that is the full charge voltage. Keep it at full charge will prevent sulfation. 13.8V is a charging voltage and can slowly evaporate the water in the electrolyte.

Hi Rick,

I think you meant "opinions" ?

Anyway, i have always read 13.5 or 13.8 volts in that area, but since you live in a warm area you would have to reduce that so maybe that is what you have experiences. The 13.5 or so is for 25 degrees C ambient and i believe my conditioner has that built in.

I have designed quite a few battery chargers in my time but from what i can remember only one lead acid charger for commercial sale. That one was kind of special though and required an inductor that weighted as much as maybe 10 pounds. I cant remember why it had to be so special but it was probably either for industrial or military use.

However, i have charged several automotive batteries for my own purposes using hefty power supplies with regulated voltage and current. Some i found required as much as 15 volts to get it to charge properly while others would charge at 14 volts reasonably well.

I had designed a lot of other chargers though for NiCd and NiHM and Li-ion.
What bothered me about the Li-ion chargers at the time was they were all using linear charge methods, so i wet out to design one that used a switching regulator technique and thus it was much more efficient and did not get hot or even warm. Today they are probably all like that.

One of the NiCd chargers i did was more interesting i think because i used a microcontroller at the time made by MicroChip (now merged with Atmel). I did that because i did not like the way other NiCd chargers worked, especially the single wall wart and resistor type, which charge the cells continuously at 100ma to 300ma all day long seven days a week. That seems to kill the cells in a year.
It started when i purchased a Ryobi portable drill from Home Deblow. It came with not one but with two battery packs. I thought that was great, until i found out very soon later that they were cheap junk and died within 6 months.
Ok so what to do. I went out and got new NiCd cells cost about $40 USD. Replaced the cells, and went on. They died in a year. Ok so i went out and bought a new set, but this time i designed the new charger before using them. The chip was programmed to charge the cells at full charge level, but for only maybe a minute or two (dont remember the exact timing now) and would come on twice per day. The result was the cells lasted for 5 years.
After that i said the hell with it, i connected a very high current diode in series with a 12v lead acid battery rated for 8 ampere hours, and connected that to one of the battery packs after removing the old cells. After that i never had a problem with it and always had full power ready when needed. The big difference was the NiCd cells were rated around 2 ampere hours, while the lead acid was 8 ampere hours, so that's 4 times longer run time, roughly.
I always meant to design a switching regulator for that too to drop the 12v down to 9v but never got around to it. Instead i eventually went out and got a Makita drill that uses Li-ion cells.

Anyway, if you havent checked out "Battery University" yet check it out see what you think. They talk about different battery chemistries including lead acid.