okay here are my 2 questions: 1 if i have a optima battery rated a 870cca, 120 reserve capacity, capacity c/20 rate of 55, how long could i use it to run a electric fan drawing 4 amps before i would have to recharge it? is it 30 hrs? 2 if you attach a 6 volt alternator rated at 65 amps to the above battery, would it act as a trickle charger when nothing is drawing from the battery? or would this drain the battery faster? i know i ask alot of dumb questions but you gotta learn somehow.
1........ red or yellow Optima? 2........ NO. Yes. You'll ruin your alternator / regulator. Theres no dumb ?s
I really, really, really wanted my last red top Optima battery to NOT be a POS, but what I wanted didn't matter. My son's last Optima did not last 2 years and neither did my last one. My son warantied his, I replaced mine with an Interstate. So, back on topic to your post, while it may or nay not stay up for 30 hours, I doubt it will last very many of these charge/discharge cycles anyway....
okay im learning. so i know that i dont want to charge that battery ever 12 hours that i use it. Because it will be so infrequent i will forget. What i want to do is place a suplemental electric fan in my car so when it starts to get hot in stop and go traffic i can help cool it down. but there is no reason otherwise to upgrade from my perfectly functional 6v system. Could i buy a step up unit that produces 3 amps @12volts and use it as a trickle charger on the battery
You can put a 12v extra battery in your car just to run the Fan (and maybe a Stereo) but the 6 volt system will NOT charge it. Have to plug into a trickle charger when you get home to keep the 12v topped up.
A 6V alternator won't work. The "overcome" voltage on a regular 12V battery is 13.2V nominal soooo what that means is you need to introduce AT LEAST 13.2V for a 12V battery to accept the charge.
What ever happened to those 6/12 volt batteries.. they were made for 6 volt cars but a relay on them jumped it to 12 volts for starting.. the 6 volt system kept them charged.. Haven't seen one in years.... On that note,, Could you run 2 6volt batteries thru an isolator and use a relay to pull 12 volts when needed. a diode in line would keep the fan from feeding 12 volts back.. I dunno.. Just brain farting here..
I haven't done it, but I have heard that people put a pulley wheel on the driveshaft and mount an alternator off of it. Isolates the circuit and it would charge the battery when the driveshaft is turning. http://www.jalopyjournal.com/forum/attachment.php?attachmentid=156217&d=1138004942 This thread http://www.jalopyjournal.com/forum/showthread.php?t=89519&showall=1
you can still get the inverters, but the only produce 2-3 amps & 12v at high idle. i agree it is a punny fan, but know the electrical issues i was running into i knew i counldt get a 17 amp fan from summit. the radiator is good, it has been flushed and tested and is the stock heavy duty version. i dont have a problem 95% of the time, but in july, in rush hour, the temp gets high.
one more question. could you use the step up transformer to power the fan and use the battery as supplemental power to cover the short fall and supplement the convertor? or is this a canidate for disaster? so instead of lasting 10-12 hours between charges pulling 4 amps , pullin 1-1.5 amps for 40-50 hours?
OR you could get a 6 volt electric fan like these; http://www.fifthaveinternetgarage.com/parts/parts_counter_3.html http://www.macsradiator.com/6voltelectricfan.aspx
Or,,, Just convert to 12V, takes care of virtually all compatibility issues... It is relatively cheap and easy.
but a pain and kinda point less when 95 % of the time the 6 volt works just fine. i will just do the 6 volt fan. pay a little more, but it will be easier.
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