Can you connect multiple chargers to a 12V car battery?

[Finsta]

Is it possible to connect 2 lipo chargers to a car battery and charge 2 6s 5000 (or similar) lipos? If not, how do you guys charge multiple battery packs at the field? I am awaiting my T-rex 600 and want to maximize flight time. Looking for tips. Thanks! Also, from normal flying, probably some flips...etc, nothing too crazy, what flight time can I expect from TP 5000 packs?

~Finsta

[Trooper Sam]

I've done it for charging multiple 3S packs, but I think charging 2 6S 5000 packs would be a really big draw. You might get two packs charged.

[WillJames]

You can run 2 chargers off a battery no problem. Just make sure you have a high enough capacity battery. Chargers tend to false peak with dropping input voltage, so be aware that as your battery gets discharged, your packs may not be fully charged.

[kgfly]

Regular car batteries are not much use for charging large 6s packs. Charging a 6s (22-25V) 5000 mAh lipo at 1C from a 12V battery draws about double the current or around 10-12A. Car batteries are designed for short bursts of high current and no more than around 20-30% discharge with almost immediate recharging. That is very different to what happens when charging large lipos.

If you want to get multiple 6s 5000 recharges without killing your car battery you need a separate deep-cycle battery designed for up to 80% discharge, something like 80-120Ah.

[eurylokhos]

The way to do it is to hook it up to the battery in your car and leave your car running so the battery is charging at the same time as you putting juice back into your packs. That works very well, but don't try it without the car running, or after a couple charges, you won't be able to start your car. Of course, with the cost of gas being what it is, you're probably better off getting a deep cycle.

[Finsta]

Thank you everyone for the replies. Ken, I am glad you replied as I had a quesiton I wanted to ask you specifically. But before I get to that, so does everyone bring a deep cycle battery with them to the field? Is that how everyone charges their larger 6s and up packs? Also, what about a generator? Would that produce enough power? My direct question to you is, I recently seen a post you made regarding the e-STATION BC6 'Dual Power' charger and that it was a little under powered. How will that affect performance? Will it take longer to charge? Reason I ask, is that is the perfect charger for me. I will not go over 6s and I want to charge at both the field and at home and most other chargers require a power supply with min of 20amps and I just bought one with 18 for my other smaller charger. I would like the TP charger, but at 300.00 each and then a power supply for like 160 each, that is just too much. 300 for both chargers w/ balancerr and AC, seems great. Is this a good charger? -Thanks so much everoyone. ~Finsta

[kgfly]

Finsta - A generator can be a great solution. Some come with both AC and DC outputs but some have found the poorly regulated DC output is dangerous (blows up the chargers) so just use the AC output into a DC power-supply which then drives the chargers. There are some cheap and probably quite noisy 2-stroke generators on Ebay (and elsewhere for) $100 or less. The cream of the crop is probably a Honda 4-stroke. Kipor is a well regarded alternative to the Honda, similar performance but much cheaper. I suggest you review these threads on field charging, they should answer most of your questions:
http://www.helifreak.com/showthread.php?t=41352
http://www.helifreak.com/showthread.php?t=43216

The BC6 is a great little charger and is 2s-6s but since it is limited to 50W output power it cannot charge 6s above 2.1A. That means it will take 2 hours (or longer) to charge a 6s 5000mAh battery. That's too long for me. There are lots of options for charging a 6s lipo but you cannot escape from needing a charger with at least 150W output power and a DC supply with at least 180W if you want to charge at 1C.

There are many options. Probably the cheapest high-performance field charging solution is the FMA BalancePro (2s-6s, integrated balance charger, 240W/10A output) for around $105, a 800W 2-stroke generator for around $100 and a DC switch-mode power supply from eBay for about $40. Throw in a WattsUp meter (since the BalancePro does not have a display) and the whole setup will cost around $300. You can use the charger + pwr-supply at home from a wall socket or at the field from the generator. Another option would be a 125Ah deep-cycle battery plus a suitable charger to keep it in good condition, and the charger/balancer of your choice, perhaps a BC8 if you want a really convenient and simple setup. That's likely to be more like $400 I would guess.

[Finsta]

Thanks so much Ken. Looks like I would have made a mistake with the BC6 cause I do not want to wait 2 hours to charge a battery, so #@$@# that! So thank you. I do like the FMA charger and will probaby go that route then. I want 2 chargers, double. I just looked at some yamaha generators that look really cool. About 700.00, but very nice, small, light and quiet. I live in FL, so I can pass this one off to the wife as a Hurricane expense ;). How do you feel about the TME Xtrema LiPo Charger/Wattmeter? I have some credit due to me @ tower hobbies and they sell them there, plus the breaks you usually get. Not sure how quick that would charge a 6s batt. I was hoping for less than 1hr