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Charging on 12v car battery

Charging on 12v car battery

Old 05-21-2004, 11:33 AM
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Default Charging on 12v car battery

Does anybody have any data-no matter how subjective of how many 6-cell gp3300 packs can be charged on a 12v battery-import car size-not a big marine battery.

In a nutshell I need to know if the average car battery can charge up (from a deadshort) a minimum of 12 packs in one day.

And also do the occasionla motor run in and run a lathe etc.

I have never raced a full day without a power supply to charge on-so this is all new to me.

Ray
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Old 05-21-2004, 11:50 AM
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ray we use to use 12v batteries back in the day because when we race at parking lot races some of us didnt have a generator, talking back in like 85 thru 88.
I would use something like a 600 to 700 cca amp batt it would last about 10 charges and honestly i cant remember if the mah rating matterd on the battery but but higher mah rating on the car battery is batter just means it will last longer.
charge the batt at a slow rate over night.
and enjoy.
do me a favor let me know how many charges you get with the 3300's we did this with the 1200 and 1500's of the day.
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Old 05-21-2004, 11:57 AM
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Hey SpeedXL-how goes it?

Well-the problem generally with charging on another battery I have found is you dont really know when the car batteries has given up the ghost without watthing it like a hawk!! I thnk it will false peak and then you'll go 2 minutes in a qualifier and dump!!

Thats what I am trying to avoid. I guess I will pre-charge every battery for practic and then re-charge them without traying if I dont tie inot a generator. All y packs will run flatter than usual-but oh-well. I am NOT buying a generator.

Keep the info coming!!
Ray
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Old 05-21-2004, 12:02 PM
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I have a super small 12v battery (starter box battery) and tried to use it as a line charger/bump pack and if you werent careful-youd de-charge your RC battery using it.
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Old 05-21-2004, 12:17 PM
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Like speedxl, "back in the day", I used to charge up to 12 packs of 1200 and 1400s on the car battery, and no problem starting afterwards. If there are problems, you could always run the car for awhile to keep the charge up.
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Old 05-21-2004, 01:37 PM
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You could go to Wal Mart & for 39.99 get a deep cycle marine trolling battery, i assume you have a automotive battery charger, charge it the night before a race, and your R/C car packs and you wont have to worry about getting a jump start!
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Old 05-21-2004, 01:46 PM
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Ray,myself,Zach and Bob used to charge our battery packs all day long at steves for our 3 tc's and 2 mini coopers.All but one set of cooper packs were 3300's.if you need a marine battery for tommarrow night,let me know,I have 4 of them in the garadge for my boat.I will top one off and you can pick it up on your way to the track.You will pass my house on your way

Ray
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Old 05-21-2004, 03:26 PM
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Thanks everyone,

I am actually not exactly opposed to spending money on this sport as shold be obvious, but this week I am broke so no going and buying a battery.

Ray-if you see this-lets hook up and I'll swing buy and pick-p the battery from you. I will be coming down rt.3 so call me with the rest of the directions!!!

Thanks,
Ray
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Old 05-21-2004, 03:39 PM
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I used to charge off batteries all the time. I did conserve though. When the charger is not running, I'd disconnect it. The most I've done is 8 charges on one battery and on the 8th one the charger gave me a voltage drop error because it was too dead. I had charged the car battery @ 2 amps for a full day before hand so it had a full charge. Just make sure you have some kind of a back up plan.
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Old 05-21-2004, 03:41 PM
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I was charging off a Neon last year, and I started the car every couple of hours and idled it for 10 minutes. It worked fine, the packs were charged and the car started at the end of the day.

Dont know about using a stand alone battery though never tried it.
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Old 05-21-2004, 04:32 PM
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You-know this is why I love RCTech!!! Sometimes I am the one who tries to help others, and whenever I need help-theres always great help. Thanks

Grizzly is going ot loan me a deep cycle marine battery for the day!!

But I will take it under advisement that my battery has 6 to 7 charges in it-MAX!!
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Old 05-21-2004, 11:04 PM
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Like as stated previous Deep Cycle Marine Battery is the best. You can use a automotive battery but they don't like being dumped too far and can damage their lifespan.

Another good purchase I got lucky on was catching a sale on a Radio Shack Inverter. It comes with a fan and a outlet plug. I use mine usually to hook up an AC soldering iron instead of using a Beutane one. I even use it to hook up my tv on long trips. Also made my wife happy when we had 3 hours of blackout, I dragged out the inverter, Marine battery and hooked up the TV until the lights came back on...

I would consider too charging all practice packs before you get to the parkinglot. Just to save precious power and time.
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Old 05-22-2004, 03:46 AM
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My son and I both use the same battery to charge all our packs
After aout 10 packs give or take the battery dies. One time I was using my inverter for my solder gun and killed the battery in my van too. There I sat, Dead spare batterey and van battery. I had cables though so I got a boost.

Its fine to use your car battery, but run the car every hour or two for 10 minutes because it really doesn't like to be deep cycled. The computer in your car doesn't like it either. Carry Cables. I have only needed them once in 3 years.

David Root
I am a mechanic and I do play one at work.
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Old 05-23-2004, 03:46 AM
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I'd say for totally flat 3300's, you'd be looking at maybe half a dozen packs on a standard 12v car battery, depending on the charge rate too.

The best long term solution is the deep cycle marine cell, it can handle the abuse of being discharged(although most chargers will shut off before the 12v is damaged anyway)and they are usually quite large-more capacity. A normal small 12v would be fine as a temporary measure but the number of packs you'll charge will come down.

Last edited by Simon K; 05-23-2004 at 04:01 AM.
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Old 05-23-2004, 08:43 AM
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A medium sized 12V battery for a luxury family sedan usually has about 80Ah in it. Non-luxury models can have a smaller battery and the spacesavers in little import hatches... probably 40-60Ah. Big truck battery.. about 100Ah (they double them for 24V).


Don't like deep cycles so only plan on using 1/2 those numbers.

eg that 80Ah will give you about 10 charges.


And those are for "new" batteries too... using hand-me-downs taken out of your car when it ain't up to the task of cranking the engine over usually also means they don't have the juice for charging anymore.
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