Why wireless?

[hack-n-cough]

I was thinking of a 510 mod that used a wire to the battery pack, which could be on your belt or pocket (maybe use some decent gauge headphone wires on a self-retracting reel).

I realize that at these small voltages there's a significant drop on even a few feet of run, but it doesn't seem to hurt the usb passthrough, which is what I plan to build off of. I mean, a 2X AA case rewired for parallel (not series, though that would be an option for the hi volters) would give a hell of a lot of Ah, and even a 4X is still smaller than a cell phone.

Sure, there's a wire, but IMHO it's better than sucking on the end of a flashlight. Anybody try going in this direction?

 

[warp1900]

I was thinking of a 510 mod that used a wire to the battery pack, which could be on your belt or pocket (maybe use some decent gauge headphone wires on a self-retracting reel).

I realize that at these small voltages there's a significant drop on even a few feet of run, but it doesn't seem to hurt the usb passthrough, which is what I plan to build off of. I mean, a 2X AA case rewired for parallel (not series, though that would be an option for the hi volters) would give a hell of a lot of Ah, and even a 4X is still smaller than a cell phone.

Sure, there's a wire, but IMHO it's better than sucking on the end of a flashlight. Anybody try going in this direction?

You have a lot of reading to do in the forum


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[framitz]

Sure, there's a wire, but IMHO it's better than sucking on the end of a flashlight. Anybody try going in this direction?

Hmmm, maybe 30 or 40 people, maybe hundreds have this setup.
It's discussed and done by many all the time.

 

[a2dcovert]

I mean, a 2X AA case rewired for parallel (not series, though that would be an option for the hi volters) would give a hell of a lot of Ah, and even a 4X is still smaller than a cell phone.

I would be very cautious putting 2 of these batteries in parallel. You would need to install a protection circuit to prevent problems. Running any type of batteries in a parallel circuit can be dangerous. These Li Ion batteries would make a big boom.

Kevin

 

[hack-n-cough]

I searched but couldn't find anything, so I posted to confirm that somebody must've thought of this before (since it's so simple), or to see if there was some major issue I wasn't seeing. Thanks, I'll keep digging - no need to reinvent the wheel.

I would be very cautious putting 2 of these batteries in parallel. You would need to install a protection circuit to prevent problems. Running any type of batteries in a parallel circuit can be dangerous. These Li Ion batteries would make a big boom.

Kevin

I definitely need to learn more about Li Ion safety, and pardon me if this is a stupid question, but if I'm keeping the voltage the same (parallel), can't I use individually protected batteries?

 

[tdstrike]

takes a lil bigger belt but...

or some folks use a kensington and a passthrough if they wanna be a wee bit more discreet.

 

[a2dcovert]

I definitely need to learn more about Li Ion safety, and pardon me if this is a stupid question, but if I'm keeping the voltage the same (parallel), can't I use individually protected batteries?

That's not the type of protection circuit I was talking about. When you connect batteries in parallel you need an isolation circuit to prevent the batteries from interacting with each other. If they are not exactly the same or if one pulls more current than the other the batteries will attempt to equalize. If one shorts out it will be able to overload the "pack" and all batteries in the "pack" will go to ground. The isolation circuit will prevent the batteries in the "pack" from effecting each other.

I know it seems at first like the same thing would happen if they were connected in series but, that is not the case. Batteries in series either connect the circuit or break the circuit if one goes to open. This is why you seldom find battery packs that are parallel. Most use the serial circuit method because of safety.

Kevin

 

[warp1900]

That's not the type of protection circuit I was talking about. When you connect batteries in parallel you need an isolation circuit to prevent the batteries from interacting with each other. If they are not exactly the same or if one pulls more current than the other the batteries will attempt to equalize. If one shorts out it will be able to overload the "pack" and all batteries in the "pack" will go to ground. The isolation circuit will prevent the batteries in the "pack" from effecting each other.

I know it seems at first like the same thing would happen if they were connected in series but, that is not the case. Batteries in series either connect the circuit or break the circuit if one goes to open. This is why you seldom find battery packs that are parallel. Most use the serial circuit method because of safety.

Kevin

Interesting Kevin, I have had a lot of luck with my parallel 18650s without knowing it, I will have to look into that. I don't remember anyone mentioning that here before.


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[a2dcovert]

I was made aware of this while planning a solar power system for my house. I got a battery system that was given to me that consisted of 20 12 volt sealed lead acid batteries. I thought I could build a real powerful 12 volt battery. I am a Ham Radio Operator so it's real good to have plenty of 12 volts around to run my radios off of.

Another Ham friend of mine shot holes in my plans by explaining the possible problems caused by paralleling batteries. It was eye opening and I still have 20 12 volt batteries doing nothing. By the time I added the isolation circuits the total voltage would have dropped to about 11.5 volts. Most 12 volt systems are really designed to run at 13.8v with no load.

You can search the web for info. Some sites will just casually mention the possibilities of fire resulting from running a parallel battery pack. You may run circuits like this with no problems. But you know Murphy, if it can happen, it usually will and at the wrong time.

Kevin

 

[framitz]

If in doubt, check this out:
Serial and parallel battery configurations

 

[a2dcovert]

If in doubt, check this out:
Serial and parallel battery configurations

Thanks for the link. There's some eye opening info on Li Ions there. They're more scary than I thought.

Kevin

 

[mnealtx]

Interesting Kevin, I have had a lot of luck with my parallel 18650s without knowing it, I will have to look into that. I don't remember anyone mentioning that here before.


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No worries if you're using protected batteries - another reason why Nicowolf and others keep harping on it.

 

[mnealtx]

Re: 12v stack for Ham.

I wouldn't be TOO worried about it - the individual batteries will self-equalize. You *do* want to spend the scratch on a GOOD charger/inverter, however.

There's literally THOUSANDS of RV'ers that do exactly what you're describing, but with 6v cells instead of 12v. Hundreds of thousands of diesel trucks do the same with 12v batteries in series-parallel.

 

[crazyhorse]

My diesel pickup runs two in parallel to make a bigger 12v. My old military jeep runs two in series to power a 24v system.

 

[a2dcovert]

I guess you guys are right. There is a big difference between paralleling 2 protected 14500 and the 20 12 volt batteries I was comparing it to. Charging these 14500 would be done outside the box anyway.

My project could be done if I would buy the very expensive charger/inverter. I'm too cheap to do that right now. I'm not a tree hugger so any alternative energy system that doesn't save money is not a good idea to me, ha ha.

I may try one of these 1800 mah nicosticks too.

Kevin

 

[crazyhorse]

Kevin, I've been running a triple engine NicoStick for months without a problem. They're PCB 14500's @ 900mAh each and are charged as a gang using external charging posts.

 

[mnealtx]

Parallels are easy, Kev - check out my parallel nicostick thread to see how the pads go.

CH - triple battery parallel? Nice... you should be getting almost 3 days with that!

 

[me5647]

I've seen 3.7v 6000+mah packs on the various battery websites. It looks like they use a single pcb for the whole pack but it dosent say anything about a balencing pcb just the over/under/current protection. I dunno if it safer that way (with just one pcb) or more than likely just cheaper.

 

[a2dcovert]

I am worried about these Trustfire and Ultrafire batteries period. The quality control seems to be very lax. I bought 4 Trustfire protected 14500 and one came in DOA. It looks like the protection circuit failed resulting in an open circuit. I bought 6 Ultrafire 14500's and one of them is intermittantly open on the protection circuit. What are the chances that one will fail due to a short?

I'm certainly not impressed with the design so far.

Kevin

 

[crazyhorse]

CH - triple battery parallel? Nice... you should be getting almost 3 days with that!

3-5 days, depending on how much business I send to my single engine NicoStick. I usually recharge the big'un every third night and swap out the battery in the little one every other day.