Your EnergyCarts from EU store the amount which is based on IC2 Exp.
Could you add a ModDetection (via modID) that adjust the EnergyStorage to the old values if IC2 Classic is loaded?

Tell me what values you want.

The orignal ones.
BatBox: 40k Storage 32 Transfer (should be like the same but just to list them all)
MFE: 600k Storage 128 Transfer
MFSU: 10M Storage, 512 Transfer.

MFSU cart was removed.

ok did not know. But since the MFSU cart is a little bit bigger in then the MFE cart from Exp it should be enabled then... Maybe changing the CESU Cart to an MFSU cart if classic is loaded :3

Why not just copy the NBT data directly from the power storage unit used to craft the power cart. that way it will always have the proper capacity regardless of which ic2 version your using and it will also remember how much energy was stored in the device so you wont have that annoying issue where a full MFE looses it's charge when placed in a cart FYI modern IC2 energy storage devices now remember their charge when wrenched

Though in a perfect world the electric loco would have a item slot for energy / lapo crystals hint hint

@mikeloeven that would require custom recipe handlers to transfer the power levels over to the cart. Is it even possible to query an item for the max capacity?

@CovertJaguar i am closing this because i already did the patch.
But there is 2 things i want to say:

• 1: Do you keep EU Support in Railcraft?
• 2: Yes it is possible to make that happen what he said. The Item that has to be used has to be implementing IElectricItem of any kind to make that happen. IC2C Energy Storages do not implement that in item form because it would cluster your inventory in general....

Anyway thanks for letting me add the MFSU cart when Classic is installed XD

EU support isn't going anywhere. The changes to the API for 1.9 were pretty minor so far.