diff --git a/crud.py b/crud.py
index 8c0b7f0..9179d9a 100644
--- a/crud.py
+++ b/crud.py
@@ -95,10 +95,18 @@ async def create_charge(
 
 
 async def update_charge(charge: Charge) -> Charge:
-    q = ", ".join([f"{field[0]} = ?" for field in charge.dict().items()])
     await db.execute(
-        f"UPDATE satspay.charges SET {q} WHERE id = ?",
-        (*charge.dict().values(), charge.id),
+        """
+        UPDATE satspay.charges
+        SET extra = ?, balance = ?, pending = ?, paid = ? WHERE id = ?
+        """,
+        (
+            charge.extra,
+            charge.balance,
+            charge.pending,
+            charge.paid,
+            charge.id,
+        ),
     )
     return charge
 
@@ -116,12 +124,6 @@ async def get_charge_by_onchain_address(onchain_address: str) -> Optional[Charge
 
 
 async def get_charges(user: str) -> list[Charge]:
-    await db.execute(
-        f"""
-    UPDATE satspay.charges SET last_accessed_at = {db.timestamp_now} WHERE "user"  = ?
-    """,
-        (user,),
-    )
     rows = await db.fetchall(
         """SELECT * FROM satspay.charges WHERE "user" = ? ORDER BY "timestamp" DESC """,
         (user,),
diff --git a/models.py b/models.py
index 1f42501..adf7a3e 100644
--- a/models.py
+++ b/models.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import json
+from datetime import datetime
 from typing import Optional
 
 from fastapi.param_functions import Query
@@ -60,8 +61,8 @@ class Charge(BaseModel):
     zeroconf: bool
     balance: int
     pending: Optional[int] = 0
-    timestamp: int
-    last_accessed_at: Optional[int] = 0
+    timestamp: datetime
+    last_accessed_at: Optional[datetime] = None  # unused, TODO: remove
     currency: Optional[str] = None
     currency_amount: Optional[float] = None
     paid: bool = False
@@ -91,6 +92,7 @@ def public(self):
             "completelinktext",
         ]
         c = {k: v for k, v in self.dict().items() if k in public_keys}
+        c["timestamp"] = self.timestamp.isoformat()
         if self.paid:
             c["completelink"] = self.completelink
         return c
diff --git a/static/js/display.js b/static/js/display.js
index 99a9f09..6f3f7c4 100644
--- a/static/js/display.js
+++ b/static/js/display.js
@@ -35,7 +35,8 @@ new Vue({
     hasEnded() {
       const chargeTimeSeconds = this.charge.time * 60
       const now = new Date().getTime() / 1000
-      const timeSecondsLeft = chargeTimeSeconds - now + this.charge.timestamp
+      const then = new Date(this.charge.timestamp).getTime() / 1000
+      const timeSecondsLeft = chargeTimeSeconds - now + then
       return timeSecondsLeft <= 0 || this.charge.paid
     }
   },
diff --git a/static/js/utils.js b/static/js/utils.js
index 89b2c69..048f24c 100644
--- a/static/js/utils.js
+++ b/static/js/utils.js
@@ -22,9 +22,10 @@ const mapCharge = (obj, oldObj = {}) => {
       ? JSON.parse(charge.extra)
       : charge.extra
   const now = new Date().getTime() / 1000
+  const then = new Date(charge.timestamp).getTime() / 1000
   const chargeTimeSeconds = charge.time * 60
-  const secondsSinceCreated = chargeTimeSeconds - now + charge.timestamp
-  charge.timeSecondsLeft = chargeTimeSeconds - now + charge.timestamp
+  const secondsSinceCreated = chargeTimeSeconds - now + then
+  charge.timeSecondsLeft = chargeTimeSeconds - now + then
   charge.timeLeft =
     charge.timeSecondsLeft <= 0
       ? '00:00:00'
diff --git a/views.py b/views.py
index 74c37be..241a6d7 100644
--- a/views.py
+++ b/views.py
@@ -43,7 +43,6 @@ async def display_charge(request: Request, charge_id: str):
         raise HTTPException(
             status_code=HTTPStatus.NOT_FOUND, detail="Charge link does not exist."
         )
-
     return satspay_renderer().TemplateResponse(
         "satspay/display.html",
         {