Originally Posted by
JPMacG
Unknown, I don't understand the distinction you are making. When a cell is fully charged it will dissipate any further charge energy as heat. This is an indication that the cell is fully charged. At low charge rates the heat is not damaging to the cell. This is why Sanyo and other manufacturer's state a standard timed charge rate at C/10.
On the other hand, cells can be damaged by use of an unreliable peak-detect charger. Because peak detect chargers charge at a relatively high rate, overcharge is not tolerated well. A missed delta will often cause damage.
In my experience, packs always charged at C/10 or less will have a longer life span than packs charged on a peak detect charger. I realize this is contrary to Battery University. I suspect (just my opinion) that Buchmann is more interested in promoting his company than in being completely honest.
Originally Posted by
JPMacG
Unknown, I don't understand the distinction you are making. When a cell is fully charged it will dissipate any further charge energy as heat. This is an indication that the cell is fully charged. At low charge rates the heat is not damaging to the cell. This is why Sanyo and other manufacturer's state a standard timed charge rate at C/10
The very fact that it is a timed charge is proof that the heat is damaging to the cell - why else have such a solid cut off ? Clearly, Sanyo are aware that to charge for longer WILL damage the cell. It's a low key budget attempt at not overcharging fully discharged cells and makes no allowances for loss of capacity or partly discharged cells.
A Nimh cell can only dissipate so much heat, temperature is not an indiction of state of charge, whereas
rate of temperature change is.
So, anyone who believes that checking if a battery is 'warm' (in relation to what?) to ascertain charge state is sorely mistaken.
I said earlier
While these are all bad things - Nimh do not like being trickle charged - I believe cheap fast chargers are more damaging.
I also believe cheap fast chargers (and even some that are not so cheap) are damaging.
When charging a single Nimh cell I select a C rating and monitor the temperature and delta peak - or rather my charger does. I do not own, use or recommend a Buchmann charger.
You seem somewhat confused on some basic facts:
Because peak detect chargers charge at a relatively high rate, overcharge is not tolerated well.
Different types of chargers use delta peak detection not just fast chargers. In fact, the delta peak is easier to detect with higher charge rates. A fast charger is not necessarily using peak detect.