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Old 04-03-2015, 08:46 PM   #1
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Default Car battery to charge in the field

I've been reading but I need a better understanding of how to do it with a car battery. I purchase a car battery and a car battery charger, connect the two than use than use my charger? What car battery charger should I use that I can purchase locally?
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Old 04-03-2015, 09:30 PM   #2
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What your describing will work and you would want a charger that puts out more current than you will be charging at or you will be discharging the battery. Since you will be plugging into power anyway, why not just by a power supply? It would be a lot cheaper and easier than using a battery and charger in my opinion.
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Old 04-03-2015, 10:01 PM   #3
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Kind of confused of what you are saying.

You want to buy a car battery, and a car battery charger and hook the charger to the battery while you use it to power something???

Or are you asking how long can you use a car battery as a power source before you need to charge it?

If its the second one, it all depends on what you will be running off it. I have run a starter box, engine heater and my charger for a race day without having to be jumped off that night.
Now mind you, the heater and starter box was not constantly running for the 12 hours we were there but I did charge four 4s LiPo's, four 2s Lipo's and 2 RX packs for my nitro cars. And the charger was hooked up at the beginning of the day and was one of the last things disconnected. My truck started up just fine.

If you want to do something like this, I would buy a standard 51 series battery for $75 or splurge for a Optima Blue top Deep Cycle for $240. And you can charge it one of 2 ways. Buy a trickle charger and leave it plugged in all day and over night before you use it or mount it as a duel battery set-up in your vehicle. Just go positive to positive and negative to negative so you will still be running a 12V system.

Easy day. Good luck.
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Old 04-04-2015, 05:14 AM   #4
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Assuming you intend to charge the battery ahead of time and then use it for the day, go with a marine or deep discharge battery. It will last longer than a regular car starting battery for this type of use (meaning last for more days, not longer each day). Modern starting batteries are designed for high starting current, but don't like being heavily discharged so much. Generally at similar prices, can always spend more of course.

For charging it get a 'smart' charger, Battery Tender, Schumacher, Black & Decker, and others offer them. It probably can be a fairly small one, especially if you only need the battery once or twice a week, as you can let it run in between outings. Before I broke down and got a generator I used a 2 amp model I paid around $20 for, worked great.

Both are available at local auto parts stores, wally world, etc.
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Old 04-04-2015, 10:32 AM   #5
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If I was to do it, I would use a deep cycle battery like the Optima Yellow Top and keep it hooked up to a battery manager (battery tender available on Amazon) during the week to keep it in the 'float' state.
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Old 04-04-2015, 02:38 PM   #6
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Well I want to charge my 3s and 2s packs and a RX pack. At the track there is no electric power. Would a lawn mower battery due?
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Old 04-04-2015, 08:49 PM   #7
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Most likely not. You definitely want a deep cycle battery then. You might want to look into a small two cycle generator and a power supply, it will probably be about the same cost.
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Old 04-05-2015, 02:57 PM   #8
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Quote:
Originally Posted by Dave H View Post
Assuming you intend to charge the battery ahead of time and then use it for the day, go with a marine or deep discharge battery. It will last longer than a regular car starting battery for this type of use (meaning last for more days, not longer each day). Modern starting batteries are designed for high starting current, but don't like being heavily discharged so much. Generally at similar prices, can always spend more of course.

For charging it get a 'smart' charger, Battery Tender, Schumacher, Black & Decker, and others offer them. It probably can be a fairly small one, especially if you only need the battery once or twice a week, as you can let it run in between outings. Before I broke down and got a generator I used a 2 amp model I paid around $20 for, worked great.

Both are available at local auto parts stores, wally world, etc.
+1 From personal experience don't use anything but a marine battery or deep discharge battery. Back in the day, I made the mistake of buying a car battery (Sears best Die Hard). It would die(wouldn't hold a charge) in less than a month. I went through a couple (thank you warranty), and finally learned about marine batteries.
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Old 04-05-2015, 03:44 PM   #9
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Even using marine batteries, it is important to recharge the battery as soon as you get back from the track. Even deep cycle lead-acid batteries don't like to be left discharged for long. My first one only lasted 2 years because I didn't know this and waited to re-charge it the day before race day instead of right after race day. Once I learned, I get like 6-7 years out of each battery.
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Old 04-05-2015, 06:56 PM   #10
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I agree a lawnmower battery may not be enough. And ta_man makes a good point, keep the battery charged as much as practical.

Remember lead acid batteries give off a little gas, and can leak acid if something goes wrong. Best to use & charge in a ventilated area. Consider a cheap battery box for a little protection from spilled acid, I have one similar to this. Bonus, the handles make it easier to move.

Supposedly this has been fixed with modern case materials, but in the old days it was recommended to store the battery off the floor on something non conductive, like a block of wood. Prevented/reduced electrical leakage and discharge in storage. I still do it out of habit.
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Old 04-05-2015, 07:27 PM   #11
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Good advice here. You can buy car "battery chargers" pretty cheap now a days. Harbor Freight has some on sale all the time. Go to a rural store for deep cycle batteries at a good price. Golf cart batteries are the same thing.
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Old 04-06-2015, 06:00 AM   #12
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So buy a car battery (deep cycle preferably) and a vehicle battery charger. What to charge the car battery at and how long? Or this info is on the charger? Do anyone know approx. how many pack I can get on a car battery?
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Old 04-06-2015, 06:13 AM   #13
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get a lithium ion battery instead. I used to carry a 12V car battery to our local track and it can only charge 6-8 packs of 6000mah 2s batteries. The lithium ion battery i have is 50000mah and can charge almost 20 packs. Much lighter and no need to worry about damaging the battery if you go below voltage.
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Old 04-06-2015, 09:47 AM   #14
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Quote:
Originally Posted by cyba888 View Post
get a lithium ion battery instead. I used to carry a 12V car battery to our local track and it can only charge 6-8 packs of 6000mah 2s batteries. The lithium ion battery i have is 50000mah and can charge almost 20 packs. Much lighter and no need to worry about damaging the battery if you go below voltage.
Got a link?
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Old 04-06-2015, 10:07 AM   #15
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i got it locally in Taiwan... link to seller below. You can use google translate.
These are very popular a lot of RC guys are using these and it comes in different specs. Mine came assembled exactly what you see in link with volt meter.

http://goods.ruten.com.tw/item/show?21503335917111#auc

price is $200 US dollars. Not sure if ebay have similar item but I heard these batteries came from electric bicycles. If you can get your hands on the battery then just build a case yourself with plugs etc.
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