diff --git a/src/components/battery/BatteryCard.tsx b/src/components/battery/BatteryCard.tsx
index af3c2f2..effcc8d 100644
--- a/src/components/battery/BatteryCard.tsx
+++ b/src/components/battery/BatteryCard.tsx
@@ -9,7 +9,8 @@ import { Input } from '@/components/ui/Input';
 import { Select } from '@/components/ui/Select';
 import { useToast } from '@/components/ui/Toast';
 import { useRouter } from 'next/navigation';
-import { Battery, BatteryCharging, Monitor, Trash2, ArrowRight } from 'lucide-react';
+import { Battery, BatteryCharging, Monitor, Trash2, ArrowRight, Pencil } from 'lucide-react';
+import { EditBatteryModal } from './EditBatteryModal';
 
 interface Device {
   id: number;
@@ -36,6 +37,7 @@ export function BatteryCard({ battery, devices }: BatteryCardProps) {
   const router = useRouter();
   const { showToast } = useToast();
   const [actionModal, setActionModal] = useState<'charge' | 'available' | 'assign' | 'delete' | null>(null);
+  const [showEditModal, setShowEditModal] = useState(false);
   const [count, setCount] = useState('1');
   const [deviceId, setDeviceId] = useState('');
   const [loading, setLoading] = useState(false);
@@ -148,6 +150,14 @@ export function BatteryCard({ battery, devices }: BatteryCardProps) {
             </h3>
             <p className="text-sm text-slate-500">Total: {total} batteries</p>
           </div>
+          <Button
+            variant="ghost"
+            size="sm"
+            onClick={() => setShowEditModal(true)}
+            className="text-slate-400 hover:text-slate-600"
+          >
+            <Pencil className="w-4 h-4" />
+          </Button>
           <Button
             variant="ghost"
             size="sm"
@@ -356,6 +366,13 @@ export function BatteryCard({ battery, devices }: BatteryCardProps) {
           </p>
         )}
       </Modal>
+
+      {/* Edit Modal */}
+      <EditBatteryModal
+        isOpen={showEditModal}
+        onClose={() => setShowEditModal(false)}
+        battery={battery}
+      />
     </>
   );
 }
diff --git a/src/components/battery/EditBatteryModal.tsx b/src/components/battery/EditBatteryModal.tsx
new file mode 100644
index 0000000..1b95236
--- /dev/null
+++ b/src/components/battery/EditBatteryModal.tsx
@@ -0,0 +1,137 @@
+'use client';
+
+import { useState, useEffect } from 'react';
+import { Button } from '@/components/ui/Button';
+import { Input } from '@/components/ui/Input';
+import { Modal } from '@/components/ui/Modal';
+import { useToast } from '@/components/ui/Toast';
+import { useRouter } from 'next/navigation';
+
+interface BatteryGroup {
+  id: number;
+  brandName: string;
+  typeName: string;
+  chemistryName: string;
+  availableCount: number;
+  chargingCount: number;
+  inUseCount: number;
+  notes: string | null;
+}
+
+interface EditBatteryModalProps {
+  isOpen: boolean;
+  onClose: () => void;
+  battery: BatteryGroup | null;
+}
+
+export function EditBatteryModal({ isOpen, onClose, battery }: EditBatteryModalProps) {
+  const router = useRouter();
+  const { showToast } = useToast();
+  const [loading, setLoading] = useState(false);
+  const [formData, setFormData] = useState({
+    availableCount: '0',
+    chargingCount: '0',
+    notes: '',
+  });
+
+  useEffect(() => {
+    if (battery) {
+      setFormData({
+        availableCount: battery.availableCount.toString(),
+        chargingCount: battery.chargingCount.toString(),
+        notes: battery.notes || '',
+      });
+    }
+  }, [battery]);
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault();
+    if (!battery) return;
+    
+    setLoading(true);
+
+    try {
+      const res = await fetch(`/api/batteries/${battery.id}`, {
+        method: 'PATCH',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          availableCount: parseInt(formData.availableCount) || 0,
+          chargingCount: parseInt(formData.chargingCount) || 0,
+          notes: formData.notes || null,
+        }),
+      });
+
+      if (!res.ok) {
+        const error = await res.json();
+        throw new Error(error.error || 'Failed to update battery');
+      }
+
+      showToast('success', 'Battery group updated');
+      onClose();
+      router.refresh();
+    } catch (error) {
+      showToast('error', error instanceof Error ? error.message : 'Failed to update battery');
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  if (!battery) return null;
+
+  return (
+    <Modal
+      isOpen={isOpen}
+      onClose={onClose}
+      title="Edit Battery Group"
+      footer={
+        <div className="flex justify-end gap-3">
+          <Button variant="secondary" onClick={onClose} disabled={loading}>
+            Cancel
+          </Button>
+          <Button onClick={handleSubmit} disabled={loading}>
+            {loading ? 'Saving...' : 'Save Changes'}
+          </Button>
+        </div>
+      }
+    >
+      <form onSubmit={handleSubmit} className="space-y-4">
+        <div className="bg-slate-50 rounded-lg p-3 mb-4">
+          <p className="text-sm text-slate-600">
+            <span className="font-medium text-slate-900">
+              {battery.brandName} {battery.typeName} ({battery.chemistryName})
+            </span>
+          </p>
+          {battery.inUseCount > 0 && (
+            <p className="text-xs text-slate-500 mt-1">
+              {battery.inUseCount} currently in use (managed via device assignments)
+            </p>
+          )}
+        </div>
+
+        <div className="grid grid-cols-2 gap-4">
+          <Input
+            label="Available Count"
+            type="number"
+            min="0"
+            value={formData.availableCount}
+            onChange={(e) => setFormData({ ...formData, availableCount: e.target.value })}
+          />
+          <Input
+            label="Charging Count"
+            type="number"
+            min="0"
+            value={formData.chargingCount}
+            onChange={(e) => setFormData({ ...formData, chargingCount: e.target.value })}
+          />
+        </div>
+
+        <Input
+          label="Notes (optional)"
+          value={formData.notes}
+          onChange={(e) => setFormData({ ...formData, notes: e.target.value })}
+          placeholder="Any additional notes..."
+        />
+      </form>
+    </Modal>
+  );
+}