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I am planning to hook two 2600 mAh Li ion batteries up in parallel (keeping the voltage at 3.7V). I will be using an accessory battery with a PCB to avoid over charge/discharge that could cause battery explosion/battery death.
With 5200 mAh (original equipment is 2200mAh) the unit should run more than twice as long, if the amps don’t fry it.
Has anyone tried this yet?

The chargers for the DC 30 show a max of 5 volts and 1 Ah. So, I am going to keep it a little under 1 amp hour and right at 3.7 volts. I will let yall know if it works.

I've thought about it some, I'm not sure what your asking about the amps?

The Circuit controls the current needed not the source. When the power supply says 1amp that's just the max current that the power supply can supply.

Interesting I've thought about it some, But it's like replacing just one battery in a truck if one is weak, you want to replace them both.

V/R = I In other wards Voltage/Resistance = Amps..

I spent a bunch of hours looking for a larger battery. That would fit the case. Never thought about trying to find 2 batteries to fit. No go on a single. That I found.

You are talking about not modifying the case at all right?

Another idea I've thought about is running a 5 volt Battery to the charger port. That way it would charge the collar until it died, then it would run on the 3.6v battery.

Once the piggy back battery dropped voltage below 5v or what ever voltage was not sufficient then have it switch a relay off so it stops charging and then starts to run on the battery. Might need to build a break out board, or you might not?

Personally I don't think it's really worth it too much but since you are thinking about trying it, it's another option for you to look into that you might not have thought about, And it Might be easier than trying to tie two batteries.

You can find Cell phone batteries chargers pretty easily, You'll want a Portable power battery, since most cell phones charge on USB.. (Which by the way happens to be 5 Volts.)

You would look for Something like this.. http://www.duracellpower.com/portable-p ... orola.aspx

Then just wire on the DC30 Charger to plug it in?

Buddy

In a way I find this funny. Since I recall all the complaints about how heavy these collars are when they first came out.

If a guy is going to start running wires out of the collar, or to it. Might as well just put a bigger battery on a harness. Can use as big of a battery as your hound could carry. Could even then make it run for almost ever with the addition of a small solar charger on the top of harness.

Thanks Buddy for the good ideas! I hadn't thought of the 5 volt 'charge' battery.
To answer the question about case modification, I plan to hook a 6600 mAh Li ion battery (weight 5.6 OZ) to the front of the collar via gorilla tape, drill a hole (to be sealed up with silicone) through the front of the battery compartment, and wire it in parallel to a new 2600 mAh Li ion battery. It will all charge together off the original charger port.
The concern with increasing the amps is that I thought too high an amp battery source might fry the unit or cause it to shut off (if there was an overload circuit).
I can tell you from hiking 30 hours with 4 hours of sleep last year in the Idaho wilderness (snow pack 8' on the mountain passes, every creek was 5-6' deep) that having an extra 2-3 days to find hounds before the battery on the GPS collars runs out would be huge! I run radio trackers also, but the mountains bounce and block signal so severely that telemetry is very challenging.

I don't think you can wire two different size batteries in Parallel. I'm not a battery expert by any means, but you might run into some problems. Because it's would want to draw on them symmetrical, and your smaller battery would drain quickly. Then you would have an imbalance, (one dead battery and one Live battery) which will place a load from the collar to the Dead battery.

So If your going to go in Parallel, I would go with two similar batteries, Although depending on how the Battery packs are built it might not make any difference.

The second issue that I haven't fledged out is the third wire. I believe (Just guessing) but I think it's an EEPROM or D/A You may cause some confusion with the Charging or Battery Indicator with that.

Just thinking out loud, I have little to NO experience with batteries especially LiOn.

I think you are right Buddy. The batteries need to be of similar capacity. The battery pack that I selected is 6600 mAh, but it is made of Three 2200 mAh batteries connected in parallel. I am hoping it will function like Four 2200 mAh batteries. The configuration for weight balance may work best with individual 2200 or 2600 mAh batteries with individual leads going to the main battery pack connection point.

What I am really hoping is that I can figure out how to make it work, get you going on it, and send money with collars to you for modification.

Here is a pic of the attached battery. I plan to shrink wrap it to the collar and silcone the ends. I am testing battery life now. So, far it hasn't blown up! It charges, pics up and sends sends signal... hopefully it will last a little longer. I thought about the varried capacity issue. I think that would only be a factor if the batteries are in series -one dead one and the unit is done. If it works, I am going to start using a smaller (5200 mAh Li) battery that will fit more easily. http://www.ebay.com/itm/Li-Ion-18650-3- ... 4aaa13560e

46 hours of running with 5 second updates and I am still picking up signal at 3.3 miles with trees and a mountain in the way

The battery ran the DC 30 for 58 hours with 5 second updates. The combined battery gave 9200mAh. The auxiliary battery pack weighed 4.62 oz (even though the advertisement stated 9 oz). I soddered red to red and black to black on the 2600mAh replacement battery pack (this was + with + and - with -). I am going to silicone the wire going into the battery compartment, shrink wrap the auxiliary battery to the collar, and cut a square out of the back for the charger.

Pluses: longer battery life, greater likelyhood of finding your hounds, uses the same charger, DC 20, DC 30, and DC 40 use the same batteries (so this should work with the DC 40 as well)
Negatives: voided waranty, extra weight, possible reduction of water resistance if you are not very precise in putting it back together
I hope my experiment will help the hounds out there spend more time looking cool on the back of the rig with dead stuff to show off!
If you aren't gifted with electronics but you really want one of these rigged up, I would ask Buddy if he might be persuaded to give it a whirl.

Now wouldn't it be cool to have a solar pannel and a windmill on the dog's back....

Bearbain
Does the batt indicator still work...How long does it take to charge it fully?

Battery pack fully charges in 5 hours. The battery indicator shows 2 of 4 bars when fully charged. It drops to low battery after the first 24 hours and continues to run.
My only thought on a reason for this is the accessory battery may run closer to a true 3.7V were the original batteries run 4.3V at full charge.

Let me know if you try it and have any ideas on an improvement. I read on Marshal's sight that Marshal is planning to release a gps/tellemitry collar the end of the summer. I hope it has better battery life than the DC's!