Charging at the track
 

let me get straight to the point, i use my real car battery to charge up my rc lipos at the track and it is killing my gas mileage, i saw other people using big batteries, but on close inspection they were using marine and RV batteries,
I was thinking of doing this, but what type of marine or RV battery?

- how many CCA (cold creaking Amps) should i get?,
-should i get a high end one or cheap?

Because i would like it to last long, also what charger for the boat or rv battery, and how many amps should i be charging it at? is it safe to charge this in my room?

any suggestion would be great, thanks alot.:yes::yes:

How is it killing your gas mileage? Are you saying the load on the alternator on the way back is really that significant?

maybe not that much, by the gas consumed is still a good amount. what do you do to charge your batteries? the car, or an alternate battery, if so what kind?

Just spring for a small 4 stroke generator..

+1:yes:

I don't get the mpg thing. I can't see it making any noteworthy difference on a tank of gas unless you are leaving it running all day while you are at the track! Kinda like not driving at night because it uses more gas to run the headlights. If you wanted you could pickup a jump box, and have it to charge your batteries, and would double around the house if you ever need to give something a jump box. They are nice to have around. A marine battery is just designed to be ran down slowly, and farther than a car battery without damage from doing repeatedly. You can charge off it all day long, and if you run it way down it can be slowly charged back up without damage. As long as you are not killing you car battery should really have a problem with it though. I don't know how many classes you race, I might would just pick up a few more packs so you don't have to do so much charging at the track.

http://www.harborfreight.com/cpi/cta...emnumber=66619

My track has power... when im out bashing i run my chargers DC off my car battery. and jumper cables just in case i charge too much:lol:

Sounds to me like he is letting the car sit there and idle while he is at the track charging...:neutral: Thats the only way I can see it costing any gas milage.

Buy a decent deep cycle marine battery (about $100). If you have a power supply at home to run your charger off you may be able to charge the battery back up with your RC charger, as long as it has a mode for lead batteries. Charge at about 4amps is good. Otherwise get a decent jumper pack, I like the ones that have built in power inverters, also about $100 for one with an inverter but is very useful!

that is what i was doing, i read some of the suggestions, they are great, the harbor freight portable genenator is a good i idea, i will have to look in to that.

thank you so much:yes:

You don't have to let the car run the whole time you are charging, just check it every hour or so make sure you are not running it down too much. If its a little slow to crank let it run for a few minutes. I would have though someone at the track would have let you know there is no need to run it constantly. You may find you really don't need to spend any more money, unless you want too!

should i run the car while charging a lipo battery, and then next lipo charge don't run the car ?, would it be ok to do that. the lipo takes about an hour to charge. i am trying to find out what the most cost effective and efficient way of charging my lipo packs at the track.

Me too.. and idling for long periods is BAD for any engine, you risk carbon build-up and other issues. Ideally you should have a separate battery, as mentioned. But try not to idle more than 5-10 minutes per hour while charging.

car batteries are 50+Ah thats plenty for standard trackside charging. The bigger the car, the bigger the battery.

you dont have to run your car while charging.

however if you are afraid you wont be able to start just get jumpstart cables or spare battery :)

Ditto that. Do not run your car while charging - it could possibly be bad for your charger, and possibly your cars electrical system. I believe I read in my Hyperion instructions some warnings on this.

To the O.P. have you any reason in particular that you chose to do this? Did you run a battery down? If so, you'd be better off investing in a new battery for your car/truck. If your cars charging system is not re-charging the battery, get that looked at too. Better money spent that way.

If you do get a new battery, I'm a fan of the Optima's.

Sears Die Hard Platinum, One of the Best batterys I ever bought.

thats great, how much are they, what are the Cold Creaking Amps on it.? are they like the marine or RV batteries?

A marine or RV battery is your best bet, they can better tolerate a deep discharge. Just keep it topped off and it will easily handle a day at the track.

A generator will require gas and maintenance, way too complicated IMO.

Actually, a small generator is not a bad idea at all. When not being used for R/C, you can use it in emergencies if power goes out. 800W is not that much, but enough for lighting or maybe even heating the house (only if gas heat where it just needs power for ignition and the blower).

A regular generator produces 120v, which is stepped down to 12v via a PS, then stepped back up for whatever the charger needs. Why not cut out the middle-man and produce 12v right at the generator? Since only ~200w is needed for almost all but the strongest chargers, a weedwacker engine running a car alternator to produce the needed 12v. Put a 0.5F cap on the output to smooth the DC pulses (car alternators are actually three-phase generators rectified via bridge or fullwave diodes). :smile:

if noise of generator is an issue at your track, you want awesome efficiency, and money isnt an object (starts at about a grand), these hondas are AWESOME! we have 4 of these for our boat, RV, and tailgates. Virtually Silent!

http://www.hondapowerequipment.com/p...&category=play

i think u should just get a car battery 800cca shold be more than fine, charge it in the garage before u go to the track and it should last all that u need to use it for the day, most likely more than that, then all u have to do is charge it again before next time and if it does for some kind of reason get to low then all u have to do is open your hood, but i doubt your draining that much in one day

There are some other really good ideas here, consider them all befor you drop the coin.

http://www.sears.com/shc/s/search_10...ame=Automotive

i read somewhere that charging off your car for long idling periods will cause carbon build up in the cylinders and it isn't good. any suggestions if this is true? should i stop all together on charging my lipos off my car if this is damaging it.

your input is greatly appreciated.

shoot i can go 8+ hours on my car with 2 chargers going without starting it

Dude, put down the Scooby Snacks a minute, it was in post #13 of this very thread..

Idling won't destroy your vehicle, it's just a bad idea. And wasteful!

Diesels don't care really. but gasoline engines like to be worked in their normal operating range to stay clean internally.

I love that car alternator idea! But instead of a weed whacker motor I say just use that nitro motor that most of us have no use for now. lol.

Kidding on this... Damn nitro fuel cost would kill ya if you actually tried it.

Yeah, nitro is wayy expensive these days.

Did a little more reading on alternators and found it wouldn't be a good idea. They need a battery to set up the stator field (until the alt is running, and then it powers itself). Probably easier to use a larger outrunner motor instead.

so after all this conversation, i guess i might buy a marine battery or RV battery (deep cycle), or borrow the ones that my friends have at the track , also how long can i charge off my car battery when it is not running, or what math do i need to figure this out?

thank you for your input,

I see people at the drag strip with an old pressure washer frame/motor assembly with some bracketry rigged up to run an alternator. They use them on cars without alternators to speed charge the battery in between passes. Always wondered if one could make some kind of generator out of it, but I guess by the time you add in batteries, and and inverter it wouldn't really be worth it.

that depends on your battery. But i believe it is safe to say u should have no problems charging the whole time u are at the track if u have a good battery. and u should not have to start it. and when idling your car it really should not sit longer than it takes to warm up as it will cause more carbon buildup or overheating issues.

Car batteries are built for delivering short high Amp bursts (ie starting your motor) and beeing recharged constantly. Applying a constant load (recharging your RC batteries) for a rather long period of time and maybe depleting your battery over half its capacity will degrade its capacity and cycle life in a short amount of time. Running your engine while recharging is the better option (when you don't want to degrade your cars battery).

As _paralyzed_ has already mentioned
-> A marine or RV battery is your best bet

should i replace my car battery with a marine or RV battery? and then charge my lipos off of that while it is idling , is that better? my car has no overheat issues, it warms up and than it stays at perfect operating temp. but this carbon build up thing, should i be concerned?

thank you for your advice and suggestions

Ok, D8, I'll say it again. Dont run your car while charging. It's just NOT needed. The draw from your charger is low enough that it will not drain your battery to a point that you will cause any damage to it. If you feel you must do something, buy a set of jumper cables just in case you do draw it down enough so that it doesn't start. If your drive home is 1/2 hour or so, your car will charge the battery enough so it will start again in the morning. IF then you have more issues with your battery, buy a new battery for it. I've charged lipos for three days straight without starting my truck, and it fired up fine.

i can give it a try, i need to bring so jumper cables and a volt tester to be safe. this battery has some years (about 5-6) on it,

Might be time for a new battery either way then!

what brand of deep cycle battery should i go with?, seventy to ninety bucks is what some people toll me they are priced at.

These are the best, but cost a lot:
http://www.1st-optima-batteries.com/index.html

Ditto:mdr: it seems to me its time for a new battery if it is over 5yrs old, especially if u have cold winters

The optimas are the best but interstate has the greatest, if u really feel u need a large amp hour battery just buy the biggest one u can fit in your battery tray. I use my battery in my jeep just a stock interstate 850cca and never have drawn it down unless i leave my head lights on over night and a charger doesnt use near as much juice as them and i charge 6s at 5amps

i think i understand what all of you guys that are helping me out are saying, that if i get a great quality marine or RV battery and replace it with my car battery, and then when i go to the track to charge my lipos, i should have the car turned off. what voltage is the bear minimal to start the car successfully, i am going to charge up my slash packs a few times and several 4s lipos for my xb808e, i guess these (deep cycle)batteries can handle it no problem.

thank you for your input.

u can buy a load tester from harbor harbor freight they are a great way of seeing how low your battery is under load.
http://www.harborfreight.com/cpi/cta...emnumber=90636