Can you over charge battery for the gpx4500

Can you over charge battery for the gpx4500

Eureka wrote:Can you over charge battery for the gpx4500

No Tim, Once the battery is fully charged the light will be solid green and that is the end of the charging cycle, having said that I wouldn't leave the charger on for days.

Minelab can. By nearly a couple of hundred $

I mean over charge it on the battery recharger.

Many thanks for your replies.

Cheers,

Tim Eureka

ferrousfinder wrote:Minelab can. By nearly a couple of hundred $

Over charge......

Ferrousfinder

Top Call!

BREVITY IS THE ESSENCE OF WIT...............

Eureka wrote:Can you over charge battery for the gpx4500

I always take mine of the charger when the light has gone green (or as soon after as I notice it). I never leave it on for over night or for a few days.

cheers dave

One dealer told me ages ago that as soon as it turned green, take it off charge.
Paul

Hi
Love the over charge joke a good way to start the day
Regards Neale

Just wondering has anyone dismantled a 45 battery. How many milliwatts or amp hours are they ?

Maybe about 7.8 ah = 7,800 mah.

Well they used ta be , dun know abart nar but.

They have a capacity of 9.2ah and max. discharge is 1a

Charging Lithium-ion

Charging and discharging batteries is a chemical reaction, but Li-ion is claimed as an exception. Here, battery scientists talk about energies flowing in and out as part of ion movement between anode and cathode. This claim has merits, but if the scientists were totally right then the battery would live forever, and this is wishful thinking. The experts blame capacity fade on ions getting trapped. For simplicity, we consider aging a corrosion that affects all battery systems.

The Li‑ion charger is a voltage-limiting device that is similar to the lead acid system. The difference lies in a higher voltage per cell, tighter voltage tolerance and the absence of trickle or float charge at full charge. While lead acid offers some flexibility in terms of voltage cut‑off, manufacturers of Li‑ion cells are very strict on the correct setting because Li-ion cannot accept overcharge. The so-called miracle charger that promises to prolong battery life and methods that pump extra capacity into the cell do not exist here. Li-ion is a “clean” system and only takes what it can absorb. Anything extra causes stress.

Most cells charge to 4.20V/cell with a tolerance of +/–50mV/cell. Higher voltages could increase the capacity, but the resulting cell oxidation would reduce service life. More important is the safety concern if charging beyond 4.20V/cell. Figure 1 shows the voltage and current signature as lithium-ion passes through the stages for constant current and topping charge.



Figure 1: Charge stages of lithium-ion. Li-ion is fully charged when the current drops to a predetermined level or levels out at the end of Stage 2. In lieu of trickle charge, some chargers apply a topping charge when the voltage drops to 4.05V/cell (Stage 4).

Courtesy of Cadex

The charge rate of a typical consumer Li-ion battery is between 0.5 and 1C in Stage 1, and the charge time is about three hours. Manufacturers recommend charging the 18650 cell at 0.8C or less. Charge efficiency is 97 to 99 percent and the cell remains cool during charge. Some Li-ion packs may experience a temperature rise of about 5ºC (9ºF) when reaching full charge. This could be due to the protection circuit and/or elevated internal resistance. Full charge occurs when the battery reaches the voltage threshold and the current drops to three percent of the rated current. A battery is also considered fully charged if the current levels off and cannot go down further. Elevated self-discharge might be the cause of this condition.

Increasing the charge current does not hasten the full-charge state by much. Although the battery reaches the voltage peak quicker with a fast charge, the saturation charge will take longer accordingly. The amount of charge current applied simply alters the time required for each stage; Stage 1 will be shorter but the saturation Stage 2 will take longer. A high current charge will, however, quickly fill the battery to about 70 percent.

Li-ion does not need to be fully charged, as is the case with lead acid, nor is it desirable to do so. In fact, it is better not to fully charge, because high voltages stresses the battery. Choosing a lower voltage threshold, or eliminating the saturation charge altogether, prolongs battery life but this reduces the runtime. Since the consumer market promotes maximum runtime, these chargers go for maximum capacity rather than extended service life.

Some lower-cost consumer chargers may use the simplified “charge-and-run” method that charges a lithium-ion battery in one hour or less without going to the Stage 2 saturation charge. “Ready” appears when the battery reaches the voltage threshold at Stage 1. Since the state-of-charge (SoC) at this point is only about 85 percent, the user may complain of short runtime, not knowing that the charger is to blame. Many warranty batteries are being replaced for this reason, and this phenomenon is especially common in the cellular industry.

Avoiding full charge has benefits, and some manufacturers set the charge threshold lower on purpose to prolong battery life. Table 2 illustrates the estimated capacities when charged to different voltage thresholds with and without saturation charge.

I doubt you could over charge the ML GPX battery, i have noticed with the 4000 and the 4500 battery if you disconnect it soon after the green light appears, the voltage is about 8.2v, left for another two hrs roughly and its 8.4v.

Just what i have observed.

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries