DIY Battery Box

Well some of the rechargeable batteries advertise a 2700 mah rating. Which should give me about 14 hours. Which is plenty for what i do.

I'm starting to do the research on the ff/battery box combo for the future of my outback. I've read quite alot about the blue box, or the cabelas battery. I think I could churn out the cabelas bat box and rig in a couple days, buy everything local. The blue box might take awhile, due to shipping and a little more work cutting/splicing. Have you guys that have switched found it that much better than the larger heavier batteries? Is it worth it for someone to start off with the blue brick ya think?

 I had my wife look up that blue box on Chinese websites, since that is where its made. She said the cost in china is just under 20 bucks with current exchange. so, not to much of an up-charge considering shipping. She goes back end of the year for abit so if people are interested then, can make her lug some back for me  Just hope she don't find this post.

It is a pretty project, and I hesitate to point this out, but ...

An AA battery weighs about 24.5g and 12 of them, 294g.  I have an similar otter box so I estimate your weighs about 350g.  That puts your design weight at 644g (1.42 lbs) without considering the breadboard, switches, wires, holders, and connectors. 

The entire blue brick design above including the Hobie gearbox, lid, foam, and connectors totals 727g (1.6 lbs). 

So if your primary design goal was to save weight ...

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The entire blue brick design above including the Hobie gearbox, lid, foam, and connectors totals 727g (1.6 lbs). 

So if your primary design goal was to save weight ...

+1
I bought the blue brick after reading "some" of this thread, goin to cabelas and checking out other options and it seamed the most reasonable outside of the three weeks it took to arrive.. I was lazy to rig a water tight box so i just stuffed it in a dry bag for now... the whole setup, FF, battery, transducer & the well I made for it is still +\-  5lbs

I wanted to save weight and wanted a power supply that was readily available. So i settled on the aa "a fair compromise of both worlds"that gave me both a light weight power source and something i can get literally anywhere. If you go out fishing and your blue brick happens to loose its charge and you didnt bring your back up your screwed. Now i could have bought a couple of the "blue bricks" and waited for them to arrive however if something were to happen to them it would be another month without a fish finder or have to rig up something temporary until they arrived.

I use a tupperware container with 8 rechargeable AAs.  It works all day for me.  I used to have it set up where two more rechargeables would attach in series so I could run 8 regular or 10 rechargeables.   I found that unnecessary one day when I could not find the two battery holder. I don't know how long one set-up of 8 2300 mah batteries run, but it lasts longer than I do.  I have used it for as long as 8 hours, but my FF is nothing fancy.  It is black and white with no gps function.   If I do run out of charge, it was so cheap I have a spare. 

Can someone explain how to charge the blue brick? I got the one with the charger but misplaced the directions (if there were ones). The charger has a red and green light. Do I need to switch the brick's power button on to charge it? It seems the red light is always on, when I plug the brick in to charge it and turn it on both lights come on. I charged it over night and the voltage increased but the red light is still on? Does the green light only show once it's charged? Does it take more than 12 hours to fully charge? What should the final voltage read when fully charged? Thanks in advance.

plug it in, turn the battery switch to on.  When it's done, charger light will show green.

Thanks

I had slow charging issues with the charger that came with my blue brick.  Start reading at post #84 for the details.

Thanks for the help, Demonick. A few more dumb questions,

What exactly is a "smart charger"? I assume its a charger that shuts down when fully charged? I have a motorcycle trickle charger I use for my other batteries, is this the same thing?  Will this work for the brick? If I were to plug the trickle charger into the output leads on the brick, would it work? Is over charging a concern with either the standard charger or a trickle charger?

Fascinated with the blue brick design, but I don't paddle a peddle craft.  Right now I've got a waterproof box and a small lawnmower battery.  This kit serves me on my inflatable river boats as the source of power for inflation.  Since I have it and wanted to save $$ I added some bolts to allow pretty quick connection to my electronics and cam strapped the whole mess inside my boat to the two forward most scuppers.  Seems to be good for now.  I'm sure it is heavier than the blue brick.  No idea of the weight.

What exactly is a "smart charger"? I assume its a charger that shuts down when fully charged? I have a motorcycle trickle charger I use for my other batteries, is this the same thing?  Will this work for the brick? If I were to plug the trickle charger into the output leads on the brick, would it work? Is over charging a concern with either the standard charger or a trickle charger?

Li-ion batteries are not like Lead-Acid batteries.  While Li-ion have many advantages they are more sensitive to over-charging.   Li-ion batteries have a particular charging profile and require their own type of "smart charger".  Start reading at post #67. 

The blue bricks have built in over-charge protection.  But it doesn't hurt to have double safety.

Maybe I missed it in the thread somewhere, but is there a low voltage cut off anywhere in the system?

The easiest way to hurt Lipo cells is running them too low. If that happens they lose their stated capacity and may even puff and ooze. (btdt)

I use these cells a lot in my RC toys and they are awesome, just need to keep some things in mind for maintenance:

• *Don't overcharge or charge too quickly. (1 x capacity is rule of thumb for normal charge)
• *Don't run the cells too low. (3 volts per cell should be a cutoff - or 9 volts for packs like this one)
• Don't store for long periods at full or low charge. (minor rule, but still best to store at 75-80% charge if longer than a couple months. Otherwise you can permanently lose capacity.)
• Balance Charge the cells, another housekeeping rule for longevity

Do check out some of the online RC websites as these batteries can be found ridiculously cheap online. (same or better quality for a fraction of the price)