Battery's Recharger Question

What do you mean by boost recharger? A switch mode supply?

I would just use a little wall mount supply that delivers 15V to 20V, place a suitable resistor in series and charge at around 10mA or a bit less. That is how most chargers for portable phones work because it is easier on the battery when left connected to the charger even after it is full.

Regards, Joerg.

QOS1 wrote:

"Joerg" a écrit dans le message de news: snipped-for-privacy@removethispacbell.net...

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=== Hello, I'm using NiMh Battery, a boost recgarger is once who charger the battery (accumulator) very quickly contrary to the classic one (it takes 1/4 of the time needed). I need also to use an automatic switch mode supply wich means : the system works automaticaly under 9Vdc, when connecting the recharger the system is automaticaly disconnected from the battery to allow charging them. Charging like you discribe it may take lot of time and in my application i need to charge completely the accu 9V 150mA in 10min. Can anny noe help me ? What can i use to disconect automaticaly the electronic sysem when battery in recharging ? How can i detect the current sens ?. Thanks for all

Joerg schrieb:

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No, this is the worst solution, the current is too low to charge in acceptable time (C/10 = 15mA), a full charge takes more than 20h!!! and to high for trickle charge. Even chargers for portable phones normally employ better charging methods and switch between charge and trickle charge. Perhaps not the cheapest ones. Espacially NiMH is not very forgiving to overcharge.

@ QOS1: I dont know 9V Blocks which can be fast charged in 10min. So normally maximum is 3..5h.

Martin

As Martin said, you cannot charge a 9V rechargeable in 10 minutes. It would be destroyed. However, you can achieve better charge times of around 1-2 hours with a very intelligent charger. I would not build that myself because you can buy them. A very good one is the "Energy" Series from Ansmann. Check out their site:

I think they also have the info in English. Maybe even Francais? Anyways, I bought two Energy 16 chargers for our church because we use radio microphones. These are able to charge a 9V 250mAH battery in under two hours, regardless of how much charge was left in the battery. However, they first check and condition the battery, then charge it rapidly and afterwards go into trickle mode to keep it topped of. The nice thing is they can charge four batteries at a time. They make a cheaper version that can do two 9V block batteries.

You could take a 9V battery connector and connect to you device with a cable. Just make sure the polarity is right. These chargers signal the charging stage so you know when the battery charge is complete. They also sense and signal when a battery becomes faulty, such as the failure of one of the cells in there.

Regards, Joerg.