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Old Jan 08, 2008, 03:11 PM
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I went down to AutoZone and got their second largest deep cycle marine battery for field recharging. But I don't really understand the ratings on them.

If I got a deep cycle marine battery with 750 CCA (Cold Cranking Amps) does that mean that I can pull 750 amps out of that thing when recharging my packs? I have a two 6S 5000 mah packs run in series for a 12S 5000 mah pack.

How many times could I recharge that thing from this marine battery, and how FAST can I charge it with this DUO charger off of a Deep Cycle battery... in other words, are there any amp draw restrictions?

The marine battery is only 12 volts, and my pack is 4 times that. How does the lipo voltage difference affect how much amperage gets put back into these lipo packs?
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Old Jan 08, 2008, 05:26 PM
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First off that sounds like a combination starting / deep cycle which is really not what you need. You need a striaght Deep Cycle and yes they are different.

Learn about Pb batteries here:
http://www.solar-electric.com/deep_c...attery_faq.htm


Cold cranking amp means nothing for our use. The important number is RC .

My 125Ah are 310 RC. This means they can supply 25A cont. for 210 minutes before reaching 10.5 under taht load.


Chargers step up the volts. A 6S LiPoly =25.2V and 5000 mAh (5Ah) at 1C is 5A.

5X25.2=126 watts per battery. If Pb holds 12.2 under load then 126/12.2=10.32 amps. (load). Chargers are not 100% efficient so it will take more than this per charge.

As a guide line 2300 mAh A123 Rracing cells require approx. 0.66Ah per cell per charge,so a 6S A123 2300 requires 3.96Ah per charge.


Charles
Old Jan 08, 2008, 05:43 PM
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Hmm. I read through that page, Everydayflyer. I'm going to need to look at my battery, it may be a hybrid. I just want to know how many times I can safely draw these packs from the marine battery. I'll find out exact specs and post them later.
Old Jan 08, 2008, 06:11 PM
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Another approach that perhaps is simpler for you to understand.

3SLiPoly equals 12.6V same as fully charged deep cycle.
5000 mAh = 5Ah so ruffly charging 3S5000 mAh would require 5Ah fro deep cycle.
You have 12 cells so 4X5=20Ah per charge plus extra which is used by charger(not 100% efficient). ball park figure. each 12S 5000 mAh charge will require 25Ah from your deep cycle.

Big electrics require a lot of Ahs to charge their batteries and that is why I have two 125Ah in parallel as my field power source.

Charles
Old Jan 08, 2008, 06:29 PM
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So according to that page you posted, if your battery is a deep cycle you can go down to as low as 20% draw, which means with your 125 you'd be able to get 4 charges roughly for my 12S 5A pack. 4 charges at 25 A= 100 amps drawn, which leaves 25 Amps on the source battery.

Whereas if you had a regular battery or hybrid, you'd only be able to regularly get down to the 50% draw, so I'd only be able to charge that 12S pack 2 times before I start hurting the car battery. 3 times would put it down to 40%ish, which would probably be okay, but not if I did it frequently.

Is that an accurate evaluation?

That sucks for me. If the battery I bought isn't truly a deep cycle battery (and that write-up says there's no way of really knowing without ripping the battery apart due to false advertising by most marine battery manufacturers), that means I can only fly this thing at the field twice, and it won't leave me much juice to charge other packs.

So I need another field charger. Any recommendations for a TRUE deep cycle battery that I can use to feed my new 0610i Duo Hyperion charger? (see how I threw the charger name in like that so people would think I'm still on thread topic? )
Old Jan 08, 2008, 06:44 PM
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My Deep cyle duel Thread

https://www.rcgroups.com/forums/showthread.php?t=728847

battery numbers in there somewhere.

Biggest Deep Cycle / RV battery Sam's Club sells. Available at some Wal-Marts also.

My 125Ah have 310 RC only. 25AX3.5hrs.(210min) =87.5 Ah at that load.
The 125Ah capacity would be at approx. the 20 hr. rate (6amps.) .Rememer I said the RC number is the one most important to us.

For decent life no Deep cycle should be discharged great than 50%. Discharging 80% means a soon death and 100% is a sure way to need new ones very frequently.

Charles
Old Jan 08, 2008, 06:49 PM
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You won't be pulling 750 amps charging your batteries

Your looking for a stat called "Amp Hours" it should be on your battery somewhere. For instance 50 amps hours, you would be able to pull 50 amps on that battery for 1 hour. In reality you don't want to discharge your deep cycle fully, I would say never go below 40 percent charge for the longest life.

Anyway for some easy calculations if you will want to convert everything to the same unit of measure. In this case we will use watt hours. Assuming 13.2 volts at 50 amp hours we get (13.2 x 50) 660 watt hours.

To fully charge a 6 cell Lipo lets assume 4000mah and we will putting 80 percent back into the pack (3200mah or 3.2amp hours). Assume 22.2 volts for the 6 cell pack that gives us (3.2 x 22.2) 71.4 watt hours per charge. Also assume you will lose some energy in the charging process due to running the charger itself. So assume about 75 watt hours per charge.

Now keeping to the 40 percent rule a fully charged 50 amp deep cycle battery is good for about 5 charges.
Old Jan 08, 2008, 07:12 PM
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Quote:
Assuming 13.2 volts at 50 amp hours we get (13.2 x 50) 660 watt hours.
Kinda unreal IMO. Fully charged a Pb is close to 12.6 and under a 20Amp. load a 50Ah would do well to hold 11 volts .
Many found out quickly that a charger such as the TP1010C (220 watts) would suck their deep cycles dry in short order charging big packs wide open at that was only 5amps. for a 10S LiPoly.

charles
Old Jan 08, 2008, 07:24 PM
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Guys please keep this thread on the DUO charger subject.
Old Jan 09, 2008, 01:00 AM
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Quote:
Originally Posted by Mike_Then
It shouldn't cost anything to ship a Duo charger from ALL e RC -



Taken from their front page. I've ordered a bunch of stuff from them (including all of my Hyperion chargers.... two EOS 5i DP, two LBA10 balancers, and a EOS 1210i), and plan to order the Duo from them as well.
You can also use coupon "google10" for 10% off.
Old Jan 09, 2008, 01:17 AM
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Quote:
Originally Posted by newracer
You can also use coupon "google10" for 10% off.
Cool. I'll keep that one in mind!!!

I got charged shipping when I got my 1210i from AlleRC, but I also requested faster shipping than normal, and I guess I missed the free shipping deal.
Old Jan 09, 2008, 01:35 AM
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The 610I Duo chargers are on their way to us via FedEx.. we hope to receive them here at ALL e RC some time this Friday.
Silent, you are correct.. our policy has always been free STANDARD shipping on any order over $100 going to any USA address. We also offer other options for faster delivery, but since that increases our shipping costs, the 'free shipping' does not apply in that case. Standard shipping is generally either USPS 1st Class, Priority, or UPS Ground, dependent on the size and/or weight of the packaged order. All orders received before 3 PM on any weekday are shipped that same day. Orders arriving over the weekend (when we're closed) are actually processed on Sunday night for shipment on Monday.
Old Jan 09, 2008, 10:10 AM
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What is going to be the price? Same as Aircraft-World? $269?
Old Jan 09, 2008, 10:45 AM
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Yeah, bummer. I should have waited and ordered from allerc. Ah well, such is life. $25 isn't gonna kill me - though it's that attitude that gets me paying extra for everything I order, which is a lot when you add it all up. If Allerc had known when the Duos were coming when I called last week, I'd have waited, but they didn't. Could have been weeks, could have been more.

Regardless, I'm excited about the product. Now if we could get them to make a 0610i QUAD. I could throw out my PolyCharge4 altogether. As is, when at the field charging, 4 packs at a time is the norm for me.
Old Jan 09, 2008, 05:42 PM
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The 610 Duo's have landed.. now available on our web site at www.allerc.com .


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