Why do we care about your chargers? There is info for Don's charger by simply searching for "Thunder AC6 Dual Power". It says it has 'Auto'. When charging or discharging, the smart charger offers an AUTO function that sets the feeding current or the cell count of the Lithium battery automatically.
That auto means it automatically adjust current to get each individual cell equally charged. What Don implied that B6 can determine the battery cell configuration and adjust the voltage for proper charge the battery.
Have you wondered why b6 requires you to confirm the cell configuration before it starts charging.
I looked thru my manuals (I had 4 different b6 suppliers) and downloaded the one from the net http://ittgroup.ee/files/IMAX_B6_manual.pdf, I could find the "auto" feature you mentioned. In fact, if you care to look at page 4, it clearly said the balance plug must be connected to the charger. You surely have one of the kind b6 charger.
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In the workshop, we use a bench power supply with constant voltage at 16.75V and 3A. In the field, we use a 12 to 110V inverter with the stock charger. If the b6 can work directly, it is worth looking into.
Yeah, you figure if the B6 will do the CV/CC output it makes sense to utilize it for the Solo batteries too. The only issue I run into is the B6 will only go to 5k mah. The Solo batteries are 5200. So you don't get a complete charge. You get all but one led.
I use IMax B6AC v.1 and v. 2 (both Genuine) for several years and I could share some experience with you (though I have not tried to charge Solo's batteries with them).
IMax B6AC has several functions in terms of charging - Balance Charge and simply Charge. Using Balance charge you need to have the balance connector plugged in Imax B6AC. Using Charging you don't need to have the balance connector plugged in. On both methods you need to set battery type to LiPo 4S.
Solo's battery is smart (it has a built in BMS) so Solo's charger supplies CC/CV and Solo's battery BMS makes the Balance charging of all 4 cells of the battery.
Having that in mind - you don't need to use the Balance Charging when using Imax B6AC, but use the Charging and Solo's Battery BMS will do the other part of the job.
Hope this helps.