Thunder AC680 Charging 4s2p In Parallel?

[rwhitfield]

All-

I am wondering what opinions the forum might have on using the Thunder AC680 charger (80W/6A) to charge in parallel a 4s2p 10600mwh 30C configuration? I realize the C rate on the parallel charge would be < than 1C (.67C or so I think) based on the limitations of the charger wattage / amps, BUT.... I am actually questioning the potential benefits of having a parallel balance going on with one charge vs charging each 4s1p separately at the nominal 1C rate? I am trying to understand how the two parallel packs would ever be balanced as a "team" when rigged up for use if they were not actually charged togeher in parallel too?

I guess the CON of the parallel charge method is that the charger can only balance on an assumption that no weak or bad cells exist.... given the balance plugs have to be in parallel too right?

If someone just says "buy a second charger for the other 4s pack and quit being complicated" I just might do that as well. No need for LiPo fires in my garage! :confused2:

Rick W

[JimClark]

That charger is only good for 6 cells

[rwhitfield]

Jim-

When charging a 4s2p (2-4's in other words) .... wouldn't I simply be able to tell the charger it is a single 4s pack with 10600 mah? Once the circuit were in parallel, it simply becomes an issue of charging rate / capacity I figured?

Buying another cheap charger and letting them go in solo might be the easiest thing, but I still wonder about balancing it back up when rigged in parallel for running use?

RW

[JimClark]

You are correct. What batteries and connectors are you using

[rwhitfield]

Jim-

The batteries are Ace Gens 4s1p packs @ 5300mah 30C. My set up currently uses Deans Connectors to the ESC.... but I figured with this much amperage going over any contact points for both the chraging and the run times, that I would go ahead and solder up all 4mm - 6mm bullet connectors from end to end. The only thing that bothers me on the Ace Gens is that the wires going to the batteries themselves are a bit on the weak side IMO. I guess you get what you pay for.

Do you think a Deans Connector set up would be okay, as that would be easiest on me.... but I rather do it right and spare myself a burn out later that might damage EVERYTHING. I suspect the bullets would help dissapate heat transfer better too, given things would not be so "tight".

Thanks,
Rick

[JimClark]

I would change to bullets. You can balance the batteries while charging also you just need to get the correct harnesses. I assume those batteries use the use the same balance tap as turnigy, Zippy ect batteries do
here is the balance adaptor just pick your conectors
http://www.progressiverc.com/parallel-2x-balance-adapter.html

Here is a charge adaptor
http://www.progressiverc.com/adapter-cables-and-boards/parallel-cables.html

[rwhitfield]

Jim-

Thanks for all of your time on these replies! It has been a lot of years for me to rekindle the hobby, but I can tell I am going to get hooked once again. As a teenager, my cars and planes cost me at least 3 girlfriends, given I never had money for the women -- but plenty for the hobby! I will check these harnesses out for sure, and the prices look reasonable vs my time to make them up myself. The AceGens have a 4mm bananna plug stock if the website is right.... so do you think I could go all 4mm bullets on such a current draw? I tend to think so, and with an ESC rated at 60A I might actually benefit from a bit of "natural" resisitance in the system.

This is my first cut with Lipos... am I right that when not charging, that both balance plugs in a 2 pack 4s parallel circuit (10600 mah total) are just "sitting there" unconnected? These are NOT linked during parallel run time are they???

Rick W