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It may not display this or other websites correctly. You should upgrade or use an alternative browser. Thread starter kidthorazine Start date Apr 11, Status Not open for further replies.
I have a dremel that uses nicad batteries but their pretty much dead. I can replace them with some NiMH rechargable batteries but the only way to recharge them is by using the dremel nicad charger. Can I use the dremel charger to recharge the NiMH batteries?
Click to expand Last edited: Apr 11, So a Ni-MH battery must have the charging turned off when it is fully charged which is usually done with a battery charger IC. How do you know when it is fully charged? For Ni-MH cells, the gas released will be hydrogen, which will burn violently if ignited. A severely overcharged cell can explode if the vent fails to open due to deterioration with age or corrosion from chemical leakage. For this reason, batteries should never be overcharged until venting occurs.
In later sections, information is presented which will enable the designer to detect full charge and terminate the high-current charge cycle so that abusive overcharge will not occur. Again, the NiCd cells are more rugged, so it is not intrinsically dangerous to charge them with a NiMH charger.
But keep an eye on the time spent under charge! The end-of-charge circuit might not be able to detect that the NiCd cells have been fully charged and so it might overcharge them. An overcharge that is relatively limited in time could simply shorten your NiCd cells' useful life, but if you overcharge them for hours and hours they could vent and be damaged badly! See the section of that application note about the end-of-charge detection for NiCd vs. NiMH for further details. Here's a glimpse of its content:.
Most high-performance charging systems employ at least two detection schemes to terminate fast-charge: voltage or temperature is typically the primary method, with a timer as the back-up in case the primary method fails to correctly detect the full charge point. NiCd and NiMH have similar charge and discharge characteristics. If the pack voltage and capacities match, then it's worth a try. Sign up to join this community.
The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Ask Question. Asked 3 years, 7 months ago. Active 1 year, 11 months ago. Viewed 17k times. Now I just went and bought a new pack with a charger anyways, and it's NiMH. To counteract this danger, some quick chargers are designed with a fan to keep the batteries cool. Can you overcharge rechargeable batteries?
Don't overdo it. Disconnect chargers and devices with rechargeable batteries after the battery reaches full charge. Overcharging occurs when the device or battery is plugged into a charger after full charge has been reached and may reduce battery life. Can NiMH batteries explode? The biggest danger with NiMH is overcharging. At elevated voltages, the negative electrode evolves hydrogen. Heat is also generated during charging, and as the heat and voltage increases, so to do side reactions that produce oxygen, so you end up with cells that are pressurized and contain an explosive atmosphere.
How do you know when NiMH battery is fully charged? The way the charger knows a NiMh battery is charged is the "delta V" which is the amount the voltage has to drop from any peak for the charger to turn off or change to trickle. The standard is 3 mV or.
If the cell is good, you should know, by the capacity and size of the cell, what the chemistry of the cell is. If the batteries have a covering on them and it's green, then it's NiMH. Unless it's a Sanyo or Panasonic industrial NiCd cus a lot of them had green wrappers too. Do Nicad batteries go bad?
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