My paraboard is 3 fuses on the top each that say "40" on top. and another fuse on the side where the red and black wire comes out that says "50" on it. Is this what you are referring to?

ohhhh ok got it. And yes, I forgot my charger is limited to 20amps. Sooooo 350*80%) divided by 12.6 = 22.2max amps. BUT, my charger will only do 20 since that is the chargers limit. So basically just set my charger at 20amps, 10,000mah when im charging my two 3S 5000mah batteries. So it would be charging 10amps per battery. (double what I was getting before on my cheap charger only doing 1 battery at a time ) ha

Edit. Ignore the mad face at the top of this post. Not sure how that got there, nor do I know how to get it off now. haha. Time for me to go to bed, all this is making my head hurt. Finally got it all figured out tho. Thanks Dave!

Yes, I believe the whitish ones down on the board in the rows of 3 are polyfuses to protect the balance connections. Those will reset on their own once they cool I think it is.

The red ones sticking up are for the main large wires, those I believe are automotive type fuses that you would need to replace. Suggest picking up a small container of them to have on hand. (if you have them you won't need them, Murphy's Law! lol)

As long as your lipos are rated for 2C, which most are these days.

The way I see it (and someone please correct me if I'm wrong)
:
You are only limited on the number of packs you can charge at once by the board you use, which I see connectors for four packs.
You should be able to charge up to four of any cell count from 2s to 6s simultaneously.
The math comes in to play when you try to figure what max charge rate you can set for a given number of packs, and cell count, the limiting factors being the max wattage from the power supply, max charger charge rate, and lipo battery c rating.

Yup, My Gens ace can be charged at 5c max I believe. But I wouldnt ever go that high anyway. I Ordered some SMC batteries as well, I think they can do 3c? not 100% sure. 2c for sure tho. Thanks again!

Yes, some of the high power chargers require a certain minimum supply voltage to achieve maximum wattage, due to input current handling limits.

Don't know if that applies to this charger. Best I can tell it's spec'd for 11-15V input, it might need something close to 15V, don't know. Generally it's an issue for chargers over 500W and with ~24V input capability, but again just speculation, not familiar with this puppy.

Worst case for the OPs situation, since the 3S tops out at 252W compared to the 300W rating, I'd expect it to be fine in this case with at least a 12.6 volt supply. (252/300 * 15V = 12.6V)

Seems reasonable.

Earlier post mentioned the balance board not being able to handle 20amps. How true is this? The wires coming from the paraboard a just slightly bigger than the ones going from the balance board to the charger. There are fuses on the paraboard, but nothing to protect the balance board. Should I be worried about the wires on the balance board? Most of the high amps goes through the red and black wires into the battery correct? How much power actually gets sent through the balance wires?

If you charge one battery at 20 amps, finishing quicker, you can avoid the whole parallel charge fiasco! Some simple logic to consider: If you parallel charge 2 batteries and don't have 2 more batteries to charge while you're running the first 2, your charger would be sitting there doing nothing. You will run the 2 batteries down, then charge them simultaneously and wait for them to finish.

This is the same as having a single battery and waiting between charges only with longer intervals... I like to charge one fast, and run it while charging a second pack. Gens Ace easily handle 5c charges.

This may not be your scenario. I know you have two 3s and two 2s so you can keep your charger busy no problem. Still charging a single battery means you would need to own fewer batteries as long as you could charge them as fast as you drain them.

If your charger is maxed out, you're not charging your batteries as fast as they will allow which to me reduces my time out running my cars. I have one battery that has a 2c max charge rate and it really throws me off...

Just my 2c...

The balance board shouldn't need to handle more than 20 amps or even 5 amps for that matter. The majority of the current flows through the thick +/- leads. A smaller current flows through the balance port. That's determined by the charger's rated balance current.

This would work when using my stc truck. But this is primarly for my hpi vorza, which uses 2 batteries in series.

Ah yeah.. makes sense. thats when para charging comes in handy =P

So when im charging 2 batteries that are 5000mah and I set my charger for 10000mah. Does the charger know to keep 5000 per battery or will it just charge until it reaches 10000 total? What if it over charges a battery once its at 5000 and the other isnt there yet?

The batteries voltage will equalize when hooked up in parallel. That's why it's important to have fairly close starting voltages. Current will flow from one to the other to equalize. If you parallel charge a 5000mah pack and a 10000mah pack, the voltages will still equalize.

It will charge until the voltage hits whatever your charger is set to stop at regardless of how many mah has been put in.

I'm trying to think of the analogy but can't recall at the moment.

edit: think of it like filling one small glass and one large glass from 50% to 51%. it will take more liquid to fill 1% of the larger glass. the batteries will charge from 4.1v to 4.2v but the larger capacity battery took a larger share of the current to fill that .1v