There are some factors that need to be considered when charging LiPo's and especially when multi-charging.
Most of the 'kits' available for multi charging especially for DJI are based on SEQUENTIAL ... that means the total time to charge the packs is similar to individual charging regime.
A number of solutions do offer SIMULTANEOUS charging and that is the real advantage looked for.
Another factor is the charge rate - we all want faster charging - but DJI packs are designed for about 5.5A max rate at the 4S HV setting. Basically it means that unless you are willing to risk damaging the charge control board in the DJI battery - you should stay at designed rates.
I see in other threads / forums people who suggest the multi connect board that is powered by the DJI charger. Honest opinion ? a) Its sequential, so no real saving in time, b) its at DJI power block rate anyway. So only advantage is you plug in all 3 or 4 batterys at once. But still you have to wait total time.
If you have a simultaneous multi charger powered by DJI power block - then your charge rate is divided across the packs - so very little time advantage ...
I know this is old hat to many ... but new guys on the scene may not be aware of the above.
The ANBEE system that I linked to above : Simultaneous charging of 3 packs, each at the full designed rate. No need for any additional power pack. Price is extremely attractive - well it had to be because I'm a scrooge !! I will not spend out unnecessary cash !
Yes you can buy other setups - price ? Does it actually do better ?
About $45 ... charges 3 packs and Pro / Adv controller at same time (not like DJI who say do them separate) .... try getting a DJI single charger for that !!
I've been using mine for some time now and it does a good job ... and many here know I am a dedicated Programmable Charger advocate ... well the Anbee unit has my vote ...
Nigel