A123 packs outlast Deep Cycle Lead Acid Battery???

[kyleservicetech]

I've been flying four models with the A123 packs. Three with 6S2P A123's and one with 4S1P A123's.

Last week, after flying 5 flights on the 6S2P A123 packs, my home built charger showed that my 10 month old Walmart Deep Cycle battery was down to only 10.3 Volts DC, ending flying for that day. That battery should have lasted for 15 flights or more.

Next, that lead acid deep cycle battery was tested with one of those glass float type battery hydrometers, all cells showed dead, dead, dead. The battery was recharged, using an Astroflight whattmeter in series with the deep cycle battery charger. My 120 Amp Hour deep cycle battery only took 46 Ampere Hours, and still all cells showed nearly dead with the hydrometer.

What the heck happened?? (The battery clearly states the original receipt is required for any warranty. Lost it.) :o

Take a look at the following web site:
http://jgdarden.com/batteryfaq/carfaq.htm

I don't know who Bill Darden is, but he has a very detailed web site on these lead acid batteries, and appears to know far more about these batteries than I. :o

But, buried in this web site he points out that some of these lead acid deep cycle batteries come in two different types. "Deep Cycle", and "Engine Start/Deep Cycle". And, he points out that some of these "Engine Start/Deep Cycle" batteries are nothing more than a standard automotive battery with carrying handles. And these "Engine Start/Deep Cycle" batteries may only have something like a 50 charge cycle life span. Which is how long mine lasted.

And, my failed battery was labeled "Engine Start Deep Cycle Battery".

So, my brand new deep cycle battery for my electric models is plainly marked as "Deep Cycle Battery", 120 Amp Hours. Hopefully, this "Deep Cycle Battery" wil last for more than 10 months. Will see this time next year!

Oh yeah, my three 6S2P A123 packs now have about 250 Ampere Hours cycled through each of them for the past year and a half, and all have the same exact performance they had when they were brand new.

[everydayflyer]

With Pb deep cycles the most important number for our useage is reserve Minutes. That is the time it can deliver 25A before reaching 10.5V or 100% depth of discharge. My two 125 Ah ea. deep cycles are rated 210 Reserve minutes. Next you should not discharge a deep cycle over 50% if you expect to get more than a hundred cycles fro it. 210 min. equals 3.5 hrs . 3.5X 25=87.5 Ah and half of that is 43.75 Ah so that is the max. I should use from one of my 125Ah deep cycles. that is why I use two in parallel and rarely use more than 50 Ah from the pair before recharging them. They are now two years old and stll going strong.


Charles

[kyleservicetech]

everydayflier
Good to know, I was discharging them down by about 40-50 Ampere Hours routinely, and didn't know that was a good cut off point! But, I thought I still had some 120 minus 50 or 70 Amp Hours left. Wrong!

[BradT]

When I bought my travel trailer 7 years ago, I had a 2nd deep cycle battery (Dyno brand, never heard of them before) added in parallel to match the 1 that came with it. A single battery is not enough for extended dry (no hookups) camping trips. After 7 years of camping, hunting, and fishing trips, and many hundreds of 3S, 4S, and 6S lipo charges, from 1800 to 5000 mah, they are still going strong. When the trailer is not in use, the batteries are in my shop, hooked up in parallel, with a maintenence charger feeding them. They have never been drawn down below 11V, AFIK. You should certainly get a lot more than 10 months out of any true deep cycle, if it's treated well.
Brad.

[Matt Kirsch]

I know a lot of people with campers who believe the "Deep Cycle" and/or "Marine" type batteries are absolute garbage. They don't get very good life out of them.

They're really not much more than a standard automotive battery with a different sticker. Automotive batteries are not meant to be continually cycled; they give a quick burst of power and get charged right back up.

I've been told that it's because the lead plates are perforated. You can get the same power with a lot less lead, at the expense of the longevity and robustness of the battery.

Check out Golf Cart batteries. You need two 6V batteries connected together but they're a lot tougher and designed to be drawn down to rock bottom and recharged many times.

[kyleservicetech]

matt kirsch
Golf Cart Batteries
Yes, I saw those batteries at our local "Farm and Fleet". Will see how long my 120 Amp Hour Farm and Fleet Deep Cycle battery lasts, if its NG by this time next year, will definitely check into those Golf Cart batteries.

Thanks for your response.!

[e-sailpilot86]

What about the Optima deepcycle batteries?