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Honda Insight battery trickle charge/discharge cycle control.

Hi, I'm new to this forum. This question might have been answered? I have built a Honda Insight Nimh battery trickle charger. It charges at approx. 100ma until the battery reaches about 175 volts.
I would like to automatically switch it into discharge mode and discharge to approx. 110 volts. then repeat the cycle. Can you help with with a circuit that will do this? Can a comparator with hysteresis work or are the voltages too high? Oh, counting the number of cycles and complete shutdown after x number of cycles would be nice also but not necessary. thanks in advance.
 
I see this post is a little old and I probably cannot help much, but with shelter-in-place I have some time to offer some comments.
I think Insights have something like a 1kwh battery. Charging that at 100 ma seems pretty miniscule even for a trickle charger. Still more problematic is significantly discharging a 1kwh battery creates a lot of heat that has to be dissipated, although I suppose if it's over a long time period it's doable. However, cycling a battery tends to shorten its life.

Probably the biggest question is why do you want to do this? Am I missing something?

P.S. The high voltage concern that you ask, can be handled by a simple resistor voltage divider circuit.
 
Thanks for the reply. From what I have read on the insight websites, Doing one or two slow charges and discharges over a long time will equalize and possibly rejuvenate all the cells in the battery. Don't know if this premise is accurate but I thought I would try it any way. Any circuit that would switch from charge to discharge at preset voltage values and recycle a set number of times would be greatly appreciated. the battery i have has 120 nimh in series at 6 or 7 ah.
thanks,
Manny
 
To do this right probably requires a microcomputer like an Arduino and a significant effort. However a workable simple solution might be possible. Here are some thoughts.

1. Charging your battery at 100ma after a significant discharge is probably too slow unless you have a lot of time. Especially for multiple cycles.

2. Turning on and off at predetermined voltages might be possible using high voltage zener diodes (100v - 200v) and relays.

3. Instead of turning the charger on/off, just leaving it on during discharge might be acceptable and simplifies things.

4. An adequate and cheap load for discharge can be provided by a couple of incandescent light bulbs in series.

5. Final shutdown after several cycles is a little complicated. There may be some event counter modules that can do that.

Frank
 
Thanks Frank, That is the plan. Slow, long period charge and discharge through incandescent bulbs for two or three cycles. I am close to testing the charge circuit at full voltage soon. Hope it works.
Manny
 
I expect you do could do as you require with some relatively simple hardware. A couple of comparators to determine peak voltage and discharge status plus a simple counter using a 4017 to end the cycle of charge and discharge.
 
Thanks WHONOES, I'll try to find a circuit that would do the job. Can you direct me to such a circuit?
thanks,
manny
 
I'm not aware of any published circuits that would satisfy your requirements.
I expect there is enough knowledge within this forum to help with design.
What sort have equipment do you have to help with your design?
 
Thanks everybody. I think I found a "power line voltage alarm" by Mr. Johnson that i can adapt to my circuit. It lights an led at a present high and low voltage which i can use to actuate a relay. I am not a circuit designer but know how to make my own boards using Eagle. Thanks again.
 
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