WhatsApp backups are tied to the phone number and Google Account they’re created with so syncing with another Google account is not an option AFAIK
Edit: After some experiments, It's possible!(unlike my earlier answer saying it isn't (sorry for that)
The account in the above quote refers to your main Google account (with which you set-up your phone. You can add other Gmail accounts to your phone (create a Gmail ID and add it your phone under the accounts option)
of your phone. I currently have 3 accounts(one main and two others. Whatsapp by default backs up to the main account for backup.
Steps to backup to a different account
From WhatsApp settings menu go to Chats → Chat backup and tap on accounts (it shows the three accounts I have:
Select the account to which you would like to back up.
Tap backup. It would flash an authentication message followed by this pop-up. Tap accept at the bottom
- Backup as usual.
- Delete the backup from old account (see link in next paragraph).
Note: I verified the backup to an alternate account but bear in mind this method would work only if your backup is less than 15 GB (default free account storage). You can check here,the size of your backup on GDrive and option to delete the backup.
Other options are:
If photos take up a lot of storage, you could sync them to a different Google account (that account needs to be on your phone, in addition to your main account). I do that
Use storage management tools of Google to delete stuff and create additional space.
If you have another cloud provider with adequate space, you could set it up to sync WhatsApp data (location) and restore (local backup restore)
when needed. I haven't tried this option. If you don't have a cloud, syncing to laptop using rsync
or adb pull
is a possibility
Buy additional space Google one. IMO,their pricing is competitive and you can then use Google One app to conveniently manage storage by deleting unwanted stuff. I am aware you don't want to pay but leaving it here for completeness.
Disabling backups is not a preferred option going by the number of questions on this site that deal with restoring backups and frantic appeals to help restore data because it contained important information, photos, etc. Especially since WhatsApp does not provide a way (API) to sync backups to another cloud provider.