2 or more batterys

[JerryS]

I am working on the idea of building an adapter were I could atache two or more batterys and then have it run the radio.

My question is, am I going to want isolate each battery from each other, so that if I have one of the batterys drain faster from the others that is does not drain them, or if I have a battery gobad it wont hurt the others.

What would be the best way to isolate them or should I just run them together?

Thanks
JerryS

[tvsjr]

I don't get the point. If I were trying to build a packset type arrangement, I think I'd be looking at a battery eliminator with a switch-mode regulator and an SLA (or one of the LiPoly packs) to provide the juice.

[thebigphish]

...and to piggyback on terry, the SLA idea is leaps and bounds better, as you are only limited to runtime by the SLA capacity, rather than the piddling amounts of standard radio batteries.

Mayhaps you have a specific reason in which to want to frankenstein together some batteries?

[JerryS]

Just thinking outside the box.

[thebigphish]

ok, so what was the problem you wanted to address? Limited runtime on batteries? Scalability?

[JerryS]

OK guys, to tell you the truth this "project" that I have started. is starting to get out of hand. I think of one issue, get it figured out then something else comes up. So i am going to sit back and think about it for a wile. How it started was that I have serval Li-ion cells that I have been able to fit in to a battery case, to make things short I am taking a step back and think about it.

JerryS

[JerryS]

I have been looking for the last 3 weeks for a soultion to my idea. I have called almost every supplyer in the states and have email as many overseas but have come up empty. What I have been looking for is the empty battery casket for the saber radio.

So. I am working on the idea of having them made. They would be made in such a way that the base would be removable i.e. screws, they would be the same depth but would be 6 to 7 inches long so you could cut it to size for as many cells you want to put in it. It would have a base that fits in side the case that you could glue it in. There are some other mods that would be done.

My question is would you be interested in something like this?

JerryS (Dr. Frankenstein)

[Tom in D.C.]

Jerry,

Unless you can tolerate lugging a battery that is truly monstrous in size, it's a lot, and I mean a LOT, easier to get two 4000 mAh Saber batteries, charge them both up, and then put one on the radio and the other one in your pocket until the one on the radio quits. You should be able to run for many, many hours on this basis and all you have to do is shell out some bucks one time for the two batteries.

I've been handling Sabers for a long, long time, and I've yet to come across any source for empty Saber battery cases.

Regards,

[JerryS]

I have been doing alot of research about different types of batteries, different cell technologies, weight to rate comparison, cost, run time, and architecture.

The casket would not only be used for a radio. I have other items that i could use them with. In different sizes not only would I be able to add higher and or different capacities larger or smaller cell size, or different technologies all together to fit my needs. I would also be able to add different charging technologies as they come out.

I am looking at this from a long term prospective. Having the base removable gives me the opportunity to maintain the battery, change cells, and one idea that i have is being able to analyze each cell as to its performance. so if i have one cell go bad I don't have to buy a whole new battery. i would only need to change the one cell.

I am working on a mounting base that would be able to allow me to place them in parallel or series to obtain different voltage or amperage, and would be used to charge them, I could throw this in to a backpack or shoulder bag like the maxpedition jumbo versipack.

I have looked at SLA and they just don't fit plans.

Dr. Frankenstein

[Bill_G]

Why not tell us your total concept. Then maybe we can weigh in with ideas.

In your first post you wanted to put two (or more) batteries together to run a radio, and your primary concern was whether they needed isolation or not. My two cents is - no - let them self equalize.

Later you said these batteries would run other devices as well as a radio meaning you needed more capacity. You wanted the batteries modular as evidenced by your request for a "casket" that would house standard sized cells.

You aren't willing to carry two charged Saber batteries, but are willing to carry numerous batteries as evidenced by your comment about a backpack, but sealed lead acid batteries do not fit your plans.

So, it's been asked before, but bears asking again - what are you trying to do? We all like to dink. We all like to do cool stuff. But, maybe you're beating yourself up over an idea that is easier done another way. Let us know.

[JerryS]

OK so you want to know.

Thur some of my sources I have been able to acquired over 110 prismatic lithium-ion cells (the flat ones), rated at 3.7 volts, and 1000mah. I first thought that that were 800mah and cell phone cells but they are set up differently ( plus on one end and neg on the other). I can fit 6 cells into the casket, 3 in parallel to to act as 1 cell then 2 cells in series to achieve 7.4 volt at 3000mah. The cells cost me around $0.85 ea (plus a good bottle of Scotch). I have found a charging circuit that will charge them the correct way for around $4.00. So for around $10.00 and the cost of used DOA batteries I can build 1 battery. All of the components fit in to a NTN4595 casket just right. So for $10 to $15 bucks for the components a little of my time I have a 7.4v, 3000mah lithium-ion battery that if I was to buy this retail it would cost me over $100.00 for each battery, not to mention the cost of the dedicated charger and no way to monitor or analyze each cell.

I still have the opportunity to acquire more of the prismatic lithium-ion cells. In the near future I will be acquiring some lithium-poly cells and they will be in the 3.7 volt, 6000mah range, but the caskets need to be longer. That is the reason for looking at having longer caskets made.

The reason for the special mount is to be able to use more then 1 if i need longer run times and then be able to charge them with the same mount.

Like I said the cost of doing it this way is far less costly and weight wise then carrying a SLA

So now you know.

Dr. Frankenstein
AKA JerryS

[Bill_G]

Ok. Thanks Jerry. Sounds like you have it under control.

[JerryS]

Well received the first batch for DOA batteries.

I have been able to open up a couple so far with my miter saw, by removing 3/32 of an inch witch leaves me a 3" and 7/8" casket. Some of the battery flex were burned up by what looks like a major shorting or over drawn of current. I was able to salvage the buttons and it looks like I will be making some flex of my own.
It looks like I have to go down to the local hobby shop to get some small plastic bags to put the spent cells in before they go for recycling. I don't need them to short out, as some of them still have some charge in them.

[JerryS]

Well the process has started. The design is in the hands of the engineers.

I would like to take a poll. If it were you what color besides black would you have the caskets made in?

I am toying with either red or yellow.

So let me know.

Thanks
Dr. Frankenstein