How to charge using deep cycle batteries.

[flint723]

Originally Posted by kirby_

Ok, so now I'm thinking more about doing this with separate batts rather than the car's 12V battery. I ran some quick back-of-the-envelope estimates on charging needs for a busy day at the field and I came up with just under 600 watt-hours. I did that by looking at the batteries I fly most and doing:
mAh * 80% * 4.2V * "S" count, then figuring out how many flights of each batt I would want to charge. I over estimated quite a bit, a typical field day will be less than 500Wh. My biggest heli right now is a Gaui X5 that I fly with 3300-4000 6S packs. Lately I've been flying some 3S quads and planes. I didn't factor in charger efficiency. Its a DPL8, so pretty reasonable.

So, I like the idea of a 24V battery bank, and to get 600Wh from 24V I need only 25Ah. So I started looking around and found the UP12350 from UPG. They're about $120-$130 for a pair and about 25lbs each. Both will fit with room to spare (7.68Wx5.16Dx7.13H) in the rolling crate Xrayted posted, or maybe another rolling bag from Home Depot or Harbor Freight.

Am I figuring this right? Two of these in series gives me 24V, if I plan on a worst case current of 16A (that's two of my 6S X5 batts at 2C each), that's only 8A per battery, which doesn't seem too harsh.

These seem, cheap, light, and enough capacity for my needs. I find 1 or 2 year warranties depending on the price point. Any reason these won't work?

Those are not marketed as deep cycles (says right on them to not deep discharge) but they may work ok. Probably just be careful not to let them go ~11.5v resting and they would last a while.


This looks like the same thing except they call it a deep cycle? Who knows if there is any difference.
https://www.amazon.com/ML35-12-Batte...dp/B00K8E0WAG/

[kirby_]

I'm not sold on those exact ones. They just seemed to show up everywhere when looking for an inexpensive AGM 12V 35-40Ah battery. I'm open to suggestions. Either mail order or local pickup.

[flint723]

You're right, that one or ones that look just like it are about all you find in the 35-40ah range for a reasonable price. I'd give them a try I think. If it seems like it two aren't enough capacity you can add another one later and run 36v on the dpl8 (If they can fit in your crate thing).

[Slyster]

Just for comparison keep in mind I have two 12v 110Ah deep cycles and can get 16 (or so) 6s5000mah lipo charges. you can do the math from there. You don't want too little deep capacity.

[kirby_]

Originally Posted by Slyster

Just for comparison keep in mind I have two 12v 110Ah deep cycles and can get 16 (or so) 6s5000mah lipo charges. you can do the math from there. You don't want too little deep capacity.

Agree, but they're heavier, bigger, and more expensive. I've followed this thread, but I don't have a place I am willing to make the batts permanent. Maybe I should look at sizes on 50Ah batteries.

[Ohio AV8TOR]

Originally Posted by Slyster

Just for comparison keep in mind I have two 12v 110Ah deep cycles and can get 16 (or so) 6s5000mah lipo charges. you can do the math from there. You don't want too little deep capacity.

So I use 6S 3300's so is my estimation right below?

16*5000/3300=24 so if I used a single 12v battery would I get (12) 6S 3300 charges? I would be happy with 6-8 is why I ask.
Thanks

[Slyster]

It will be less efficient since the charger will have to boost the voltage to 24v which the double the amp draw. Will have some capacity loss. But I'd say 8 3300's would be probable.

[ACITceva]

Sort of a related question... Does anybody know if its possible to use an icharger 106B as a simple voltmeter to check the voltage of a PB battery?

I realize it has a setting for charging PB but it's unclear as to whether I can just do a voltage check.

[GimpyGolden]

Sure can. Connect PB's to main leads and press and hold stop. After a few seconds you'll get a screen showing Input V which is your PSU, Temp and Output V which is your PB's voltage.

Alternately you could connect the charger as the source Voltage and do same thing but then look at the Input readout. Just remember 106 is 18V max so don't connect to PB is series.

[ACITceva]

Originally Posted by GimpyGolden

Sure can. Connect PB's to main leads and press and hold stop. After a few seconds you'll get a screen showing Input V which is your PSU, Temp and Output V which is your PB's voltage.

Alternately you could connect the charger as the source Voltage and do same thing but then look at the Input readout. Just remember 106 is 18V max so don't connect to PB is series.

Thanks Scott I will give that a try. I figured there must be some way to see the voltage of the input source but couldn't figure it out from the icharger documentation.

[CrashNburn420]

It's been a while since I used a 106 but I thought you could also scroll with the arrow keys during a charge to see the input voltage. The voltage will be sagged down a little compared to resting.

[ACITceva]

Originally Posted by GimpyGolden

Sure can. Connect PB's to main leads and press and hold stop. After a few seconds you'll get a screen showing Input V which is your PSU, Temp and Output V which is your PB's voltage.

Alternately you could connect the charger as the source Voltage and do same thing but then look at the Input readout. Just remember 106 is 18V max so don't connect to PB is series.

Originally Posted by CrashNburn420

It's been a while since I used a 106 but I thought you could also scroll with the arrow keys during a charge to see the input voltage. The voltage will be sagged down a little compared to resting.

Thanks guys - all of these suggested solutions worked for me.