Nedavno Ban napisa:
> I can not find this diode where I am, so can you suggest a
>> substitute? I guess I can not just put regular 27V zener diode here?
>>
>
> Yes put a 3-5W 27V zener.
Local parts store only has ZY 27 (27V 1,3W), and ZX 27V (27V 10W) which is to expensive to buy for making something that may not work, just as a pastime.
If diodes use the zener effect, they are always very fast, because no
> charge needs to be removed. This is valid for z-diodes above 8V
> rating. The circuit discharges the battery, in one year with more than
> 30Ah, together with the self discharge rate there will be 0 capacity
> left after a year for a normal 45Ah, this is certainly not a good idea
> and won't prolong battery life at all.
I wouldn't let it connected for a year. Perhaps a month or two, and then recharge it. I used to do that, but as soon as the battery is out of the car, unused, it dies quickly. I tried to connect my charger to a timer that switched it on for a 20 min three times a week. Unfortunately timer died while I was away for a three weeks, car battery got charged all that time, and it died.
Better to get a trickle charger
> and keep the battery fully charged during the storage time.
What sort of voltage / current do I need? Do you have any links to a good proven trickle charger design?
I've found different ones from small ones (like the ones for mobile phone), to 1A. But isn't 1A (when battery is fully charged) cause electrolyte to boil?