Can Make Own Battery Pack?

[James connell]

yes, solder them.

NiCd and NiMH have an almost flat voltage/current curve across the whole drain - alkylines do not - they drop in voltage as they discharge, they'll be down to a volt or so 1/2 way though their life.

i recomend 5 rechargables.

 

[pggeek]

Ok, I am not fimilar in what you need theis for but just some hints. Look what is in there if it is nicad use nicad if it is nimh use nimh the reason is the charger is different for each. Totally diff tec. If you charge a nimh on a nicad charger it won't know when to shut off and will fry the batt.

Another thing I noticed, TheAvatar said it was high current? Mah is not a current rating but a rating on how much charge the batt will hold. If you need high current you have to get high output cells or regualr cells will melt themselfs. If you are draining over 3 hours though you should be ok.

Sand the ends slightly before you soder and dont' get the cells to hot. Other than that have fun.

 

[bonmatt]

I'm not sure what you mean, look in there. This is for a camcorder, and I do not have the accompanying battery pack or charger. I just have the specs that the camcorder uses a 6V source, and uses 3.9 Watts. By my math, that's about 650 mA.

I have 4x1.2V rechargeable batteries and 4 cheap, 1.5V alkalines. I was told the alkaline are rated at about 1200 mAh.

So do those specs give enough info, and do the batteries sound like they give enough hiuce, for the camcorder to work from at least, say 10 minutes? (either 4 alkalines, or 4 rechargeables with 1 alkaline).

Thanks

 

[SubMariner]

We use a place called Batteries Plus to build packs for us. When the mfg's pack for our Sea & Sea YS300 crapped out, we were aghast at how much S&S wanted for the replacement... somewhere in the range of what you were talking about for yours.

But we found that Batteries Plus would build us exactly what we needed/wanted for only about $35!

I don't know if you have one local to you, but it would certainly be worth checking out.

Bonne Chance,

~SubMariner~

 

[DavidG]

1.) Although NiMH's may be too expensive for your solution (given the need to also buy a charger) one other thing is that many places say DO NOT SOLDER them as the heat will kill them. More correctly, they can be soldered but you have to be carefull. Technique and a low powered gun have worked great for me.

2.) I am not an authority but I think the 6 volts is the minimum needed to run the recorder. So, 4 x 1.5v = 6v (the minimum and therefore the low battery light. You might get 10 minutes but the voltage is going to drop quickly and I doubt it will operate under 5.5volts.) That's why pdoege says use 5.

One other thing. I've found that with NiMH's, they have a higher discharge capability (amperage) than other types of batteries. When I've built packs I've had to up the amperage rating on fuses. Ex. UK light cannon comes with a 2A and has to be upped to a 3A otherwise the 2 amp fuses blow each time.

Good luck.

 

[bonmatt]

Thanks all.

I think I have it solved.

I will buy one more NiMH AA rechargeable battery to go olong with the 4 (and the charger) I already have (from my digital camera).

I checked the spec sheets, and they should be able to put out 650 mAmps, while maintaining 1.2V each, for at least 2 hours. I will tape the 4 battery holder with the 1 holder together and somehow attach it to the camcorder.

I will get to test it probably tomorrow.

Thanks!

 

[TheAvatar]

Another thing I noticed, TheAvatar said it was high current? Mah is not a current rating

I wasn't talking about capacity! I was talking about (I=P/V) (650mA=3.9W/6V) 650mA... (which is a very high current demand for a series of AA cells (paralell would obviously make things easier). Look at what James' example: "1000mAh battery can't do 2000mA for 1/2 hour." In an ideal system you could, but James is 100% right and batteries are limited in their abilities. Also, always be suspicious of tech data sheets. These are guides, not exact real world performance.

Check what the orginal official battery pack was... NiCd, NiMH, or Li-Ion? Unless the origianl manufacture's pack was NiMH, I wouldn't try to use NiMH AA cells.

This is a very high current application. I think NiCd is really the only suitable rechargable battery for this application... unless you find some Li-ion or Li-polymer batteries. NiMH will probably work, but not nearly as well. NiCd handle high current very well. It is one of the few things they do well (that and lower temperature applications).

Sure NiCd have 2/3 the power density of NiMh and will last for 75% of the charge cycles that NiMh will, but NiCd are cheap. You can probably buy 10-16 NiCd for the price of 5 NiMh. There is no way you should be running the NiCd totally dead on one dive if you have good ones. The NiCd should last 1.5-2.5 hours. NiCd recharge extremely fast. The first set should be recharged by the time you come up from your next dive, assuming they don't finish recharging between the end of your first and the start of your second dive.

If you are using a nonrechargable battery, use a lithium battery, not a standard alkaline. Lithiums handle the high current applications a lot better.

I would not solder directly to a battery unless I knew exactly what I was doing. You could ruin the battery, or if you are stupid about it, cause it to leak. Solder all wire connections, but the batteries should be made to connect via pressure (springs... like every single electronic device out there).

Just in case you somehow forgot, YOU WILL NEED NOT 4, BUT 5 1.2V CELLS CONNECTED IN SERIES IF YOU NEED TO MAKE A 6V BATTERY!

 

[TheAvatar]

Make that I would never solder directly to a battery. The only way to do it right is to heatsink right behind the solder point on the battery which is almost impossible and would make thing a royal pain. Furthermore, how are you gonna swap out batteries if they are soldered in? Cut them out and resolder them each time? Pain in the ass... and will shorten the life of everthing. Have fun getting them into some of the chargers out there if there is a sloppy mess of solder all over the battery contacts.

If you are a true idiot soldering... it's *possible* to blow up the battery... and that wouldn't be much fun.

Also... if you use the same battery type for your homemade pack as the original pack, you might get a more valid reading off your devices built in battery indicator.

 

[TheAvatar]

Bonmatt,
let the board know how this project turns out

 

[bonmatt]

Success... so far. Here's the initial result:

4 rechargeable NiMH AA's plus 1 non-rechargeable alkaline AA - at least 15 minutes of recording time. According to the spec sheet for an alkaline AA, that's about all I can expect.

Once I buy my fifth rechargeable, I think I will get 2 hours or so.

Jim