First battery build and first RC charger questions

Hi all. Got my toolpack batteries from doc all pulled apart, and my hyperion 1420i charger arrived yesterday. My holiday project will be to turn this pile of bits into a 14s/as many as I can-P pack.

First - for the charger, I'm planning on using a deep cycle 12v RV battery for starters because I have one. Can I leave the battery attached to a 12v charger/maintainer while I attach the hyperion to the battery? Tried to google this, without success.

Second - for the balance leads, I'm planning on using 2x7s balance taps because the charger supports this (why I picked this model). Are there places I can purchase prewired 7s connectors that are long enough so I can just solder the loose end but not have to fuss with crimping all those little wires? Should I go with JST-xh standard? Charger also supports the hyperion standard but that appears less common.

Third -for the wiring of the balance leads, does the 8th wire on each connector terminate on the same place and measure the full pack voltage? I kind of assumed this, but could only find lipo balance wiring diagrams for single connectors - none that show multiple balance connectors on a pack.

Your deep cycle rv battery will need a charger attached to it and running to run your charger. You may still have to set the amps of your charger very very low to keep the charger from shutting down when the battery voltage drops.

I tried that at first too, thinking a big trolling motor battery would charge my pack for another ride when out at the desert. NOPE, It would put in 1 ah, then quit. I ended up using a cheap 10 amps 12v charger with the battery, and quickly burned out the cheap charger.

Get a good power supply to run your charger asap, rather than buy a larger charger for your lead.



I found hobby king, or Ep buddy to be good places to get Jst plug pigtails. Generally at least 6" long, but some places might have longer ones if you need them.


Wiring the jst's. This is how the cells are labeled on a cellog 8. #1 is the negative lead of the whole pack. #2 is the positive of cell 1 and the negative of cell 2. And so on. Get it, the numbers are all indicating the negative side of the cell. The last positive wire has no number. It's just labeled +

So your 7s section of the battery will have 8 wires. 1234567 and+

Working up the 14s pack, and using 7s plugs, the + wire of cell 7 will be spliced to the negative wire of cell 8. Remember, the + wire of cell 7 is not the wire labeled 7. that # 7 wire is the negative side of cell 7. The wire you splice to cell 8 is the last one, the one that you labeled +.

1. A 24V 30A psu is needed to get the total 550W output. With a 12V supply you will be limited to about 300W iirc. Yes, you can use a 12V battery with a charger attached as a power source, but don't exceed the max amps of the charger when you set the Hyperions input voltages and amps or you may fry the charger. I got lucky and bought a used 600W 24V psu for $20 shipped. Been working great for almost 3 years now.

2. http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1313&_nkw=8+pin+jst&_sacat=0 I bought these iirc.
http://www.ebay.com/itm/2510-2-54mm-8-Pin-JST-Connector-Plug-w-Wire-x-5-sets-/121213718184

3. http://scriptasylum.com/rc_speed/lipo.html

I was planning on using the 12v battery as charger just during the build, when I'll be first charge paralell groups to full voltage, then checking the individual cells with a rough IR measure, I understand the 1420 does IR measurement with newer firmware. It may not be that accurate, but may help sort a few.

Once I've got the battery balanced and built I was thinking of one of the paralelled server PSU's off ebay for ongoing charging. I think it is an ES member who has a line on old server PSU's and packages them in various configs. Whoever it is has 100% pos feedback on Ebay.

Once I've got the battery balanced and built I was thinking of one of the paralelled server PSU's off ebay for ongoing charging. I think it is an ES member who has a line on old server PSU's and packages them in various configs. Whoever it is has 100% pos feedback on Ebay

Click to expand...

You might want to look in the used listed on the forum. Lots of great deals here. I know there were some a while baack.

Dan