Etikettarkiv: charge

Lead accumulator charge table


Table is given for 20°C.
Adjust table with 0.022V/°C when deviating from this temperature.

Unloading-end: 11.8V, charge with 13.2-14.4V. Battery will start gassing at 14.4V (do not exceed). Continuus preservation charge max 13.2V. Float charge; 13.4V for gelled electrolyte, 13.5V for AGM (Absorbed Glass Mat) and 13.8V for flooded cells.

Precision of charge voltage is critical to keep sulfatisation at a minimum. An error of 5% may be enough to reduce life substantially.

A newly charged battery will quickly drop to 13.2V and then slowly settle at 12.6V. After full charge let battery rest 20 hours before measuring open circuit voltage. There might be residual surface charges on the conductor plates otherwise.

Equalization charge – maximum 2 hours at 15V. Make sure ventilation is good and battery temperature is constanly monitored.

New Batteries for Cars

One of the biggest problem of using electrical (battery powered) cars is the problem of charging them. The amount of energy needed for a normal trip to work would require several hours of charging the car, it has been estimated to somewhere around 8 to 12 hours of charging. This is of course very different from filling the car with petrol which takes a couple of minutes and the battery charge time of 8 hours or so would work if you charged the car over night, went to work, charged it while working and then returned home.

The problem here is of course obvious – I think a lot of people want to use their cars shopping and transporting and that makes it much harder, not to mention taking a longer trip that is more than say an hour or so that would be difficult in an electric car this way. Imagine visiting even close by relatives and having to stay the night because you have to re-charge your car battery over night just for the trip home. Someone suggested that there would be ”battery stations” where the whole battery pack could be changed in the car, removing the flat battery and inserting a fresh one and then this way save the charge time. Not very practical however because you may imagine the stack of batteries required to fill even a fraction of the energy need normal gas stations fill?

Electrical Cell
A 1,2 volt re-chargeable NiCd cell.

But there is a solution now, the Swedish paper ”Ny Teknik”, new technology, reports about scientists at MIT in the US having come up with a new type of battery that can be charged in about 20 seconds which is incredible. The paper is scarce on the details for it but it is a definite improvement and if this could go into serial production that could save the battery powered car from being nice but not very useful!

One problem they note however is that house-hold electrical outlet would not be able to deliver the charge current necessary, that would require high amp industrial connections which could be put at special ”charge stations” but not really practical at home – it would require changing the electricity system completely between the transformer and the house and the electrical grid is not built to take such currents from ordinary houses.

So a cross between these technologies seems the ideal, a full charge may take say 5 hours or so when at home, over night and at the ”e-station” you can fill her up in about 20 seconds and then continue driving. Enough of these charge stations along the roads and the problem seems possible to solve actually.

It sure is an interesting technology, something I have waited a long time for.