Anything wrong with this charging scheme ?

bertus

Joined Apr 5, 2008
21,324
Hello,

As the three DC/DC converters are not isolated, the proposed scheme will not work.
If you want to use the proposed scheme, the DC/DC converters must have isolation between input and output.

Bertus
 

Thread Starter

Externet

Joined Nov 29, 2005
1,588
Thanks. I thought those were isolated... reading again and observing the (-) trace, they are not, as you stated.
 

bertus

Joined Apr 5, 2008
21,324
Hello,

From the give page:

Input 2.5~4.1V ; Output 4.2V600mA DC-DC Power converter Apply Module Booster
Input DC: 2.5~4.1V
Output DC: 4.2V 600mA
Size:15X19X4mm
Weight: 10g
Design level: technical grade
Efficiency: 65% - 89%
Full load output ripple: Vpp<70mV
Output accuracy: ±0.1V
No-load current: 0.2mA
Cooling Mode: natural cooling
Operating temperature: -40℃ ~ +85℃
Relative humidity: 20-90%
Circuit isolation: No
Shutdown Control: Yes(High-EN; Low-DIS)
pre-delivery aging test: 72h
Aging test: 720h

Bertus
 

Bernard

Joined Aug 7, 2008
5,783
I under stood that LiFePO4 were roughly similar to NiCd in operation, so used 2 in lighthouse.
All was well for 6 mo. when 1 cell lost capacity. Only 1000 mA hr. in a A size, 50 mm X 17 mm.
Think I will reset hi & lo V & go to NiMH batteries.
 
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