diff --git a/CHANGELOG.md b/CHANGELOG.md
index 14b1d7798..427d2673d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@
 
 ## Bug fixes
 
+-   Update the default variable points to better capture behaviour in the solid particles in li-ion models ([#1081](https://github.com/pybamm-team/PyBaMM/pull/1081))
 -   Fix `QuickPlot` to display variables discretised by FEM (in y-z) properly ([#1078](https://github.com/pybamm-team/PyBaMM/pull/1078))
 -   Add length scales to `EffectiveResistance` models ([#1071](https://github.com/pybamm-team/PyBaMM/pull/1071))
 -   Allowed for pybamm functions exp, sin, cos, sqrt to be used in expression trees that
diff --git a/pybamm/models/full_battery_models/base_battery_model.py b/pybamm/models/full_battery_models/base_battery_model.py
index d499d08d2..fef75e178 100644
--- a/pybamm/models/full_battery_models/base_battery_model.py
+++ b/pybamm/models/full_battery_models/base_battery_model.py
@@ -113,15 +113,19 @@ class BaseBatteryModel(pybamm.BaseModel):
     @property
     def default_var_pts(self):
         var = pybamm.standard_spatial_vars
-        return {
+        base_var_pts = {
             var.x_n: 20,
             var.x_s: 20,
             var.x_p: 20,
-            var.r_n: 10,
-            var.r_p: 10,
+            var.r_n: 30,
+            var.r_p: 30,
             var.y: 10,
             var.z: 10,
         }
+        # Reduce the default points for 2D current collectors
+        if self.options["dimensionality"] == 2:
+            base_var_pts.update({var.x_n: 10, var.x_s: 10, var.x_p: 10})
+        return base_var_pts
 
     @property
     def default_submesh_types(self):

Increase default r_pts
I think we should increase the default r_pts from 10. E.g.
```python3
import pybamm
import numpy as np

model = pybamm.lithium_ion.DFN()

chemistry = pybamm.parameter_sets.Ecker2015
parameter_values = pybamm.ParameterValues(chemistry=chemistry)

var = pybamm.standard_spatial_vars
npts = [10, 20, 25, 30, 40, 50]

solver = pybamm.CasadiSolver(mode="fast")
t_eval = np.linspace(0, 3800, 200)

sols = []
for N in npts:
    var_pts = {var.x_n: 20, var.x_s: 20, var.x_p: 20, var.r_n: N, var.r_p: N}
    sim = pybamm.Simulation(
        model, solver=solver, parameter_values=parameter_values, var_pts=var_pts
    )
    sol = sim.solve(t_eval=t_eval)
    print("N={}: {} s".format(N, sol.solve_time))
    sols.append(sol)

pybamm.dynamic_plot(sols, ["Terminal voltage [V]"], time_unit="seconds", labels=npts)
```

gives 

N=10: 0.15861007800413063 s
N=20: 0.235911022995424 s
N=25: 0.29073380999761866 s
N=30: 0.31032642299396684 s
N=40: 0.4951283990012598 s
N=50: 0.5220356229983736 s


![Figure_2](https://user-images.githubusercontent.com/43040151/85523692-37762900-b5ff-11ea-9139-933e013cc036.png)

My vote would be somewhere between 20 and 30 

diff --git a/tests/integration/test_solvers/test_solution.py b/tests/integration/test_solvers/test_solution.py
index 487f8016f..c764feb05 100644
--- a/tests/integration/test_solvers/test_solution.py
+++ b/tests/integration/test_solvers/test_solution.py
@@ -84,8 +84,11 @@ class TestSolution(unittest.TestCase):
         # solve model
         solver = model.default_solver
 
+        var = pybamm.standard_spatial_vars
+        Nr = model.default_var_pts[var.r_n]
+
         T_av = 0
-        c_s_n_av = np.ones((10, 1)) * 0.6
+        c_s_n_av = np.ones((Nr, 1)) * 0.6
         external_variables = {
             "Volume-averaged cell temperature": T_av,
             "X-averaged negative particle concentration": c_s_n_av,
@@ -111,7 +114,7 @@ class TestSolution(unittest.TestCase):
         t_eval = np.linspace(0, 3600)
         sol = solver.solve(model, t_eval, external_variables=external_variables)
         np.testing.assert_array_equal(
-            sol.inputs["Volume-averaged cell temperature"], np.zeros((1, len(sol.t))),
+            sol.inputs["Volume-averaged cell temperature"], np.zeros((1, len(sol.t)))
         )
         np.testing.assert_array_equal(
             sol.inputs["X-averaged negative particle concentration"],
diff --git a/tests/unit/test_models/test_full_battery_models/test_base_battery_model.py b/tests/unit/test_models/test_full_battery_models/test_base_battery_model.py
index 635ccc04f..d7d90e0cd 100644
--- a/tests/unit/test_models/test_full_battery_models/test_base_battery_model.py
+++ b/tests/unit/test_models/test_full_battery_models/test_base_battery_model.py
@@ -76,6 +76,24 @@ class TestBaseBatteryModel(unittest.TestCase):
             )
         )
 
+    def test_default_var_pts(self):
+        var = pybamm.standard_spatial_vars
+        var_pts = {
+            var.x_n: 20,
+            var.x_s: 20,
+            var.x_p: 20,
+            var.r_n: 30,
+            var.r_p: 30,
+            var.y: 10,
+            var.z: 10,
+        }
+        model = pybamm.BaseBatteryModel({"dimensionality": 0})
+        self.assertDictEqual(var_pts, model.default_var_pts)
+
+        var_pts.update({var.x_n: 10, var.x_s: 10, var.x_p: 10})
+        model = pybamm.BaseBatteryModel({"dimensionality": 2})
+        self.assertDictEqual(var_pts, model.default_var_pts)
+
     def test_default_spatial_methods(self):
         model = pybamm.BaseBatteryModel({"dimensionality": 0})
         self.assertTrue(
diff --git a/tests/unit/test_simulation.py b/tests/unit/test_simulation.py
index 3222383c7..896decf8b 100644
--- a/tests/unit/test_simulation.py
+++ b/tests/unit/test_simulation.py
@@ -244,8 +244,11 @@ class TestSimulation(unittest.TestCase):
         model = pybamm.lithium_ion.SPMe(model_options)
         sim = pybamm.Simulation(model)
 
+        var = pybamm.standard_spatial_vars
+        Nr = model.default_var_pts[var.r_n]
+
         T_av = 0
-        c_s_n_av = np.ones((10, 1)) * 0.5
+        c_s_n_av = np.ones((Nr, 1)) * 0.5
         external_variables = {
             "Volume-averaged cell temperature": T_av,
             "X-averaged negative particle concentration": c_s_n_av,

pip install -e .[dev]
parse_log_pytest
requirements.txt
pytest numpy>=1.16.0 pandas>=1.0.0
apt-get update apt-get install -y gcc
3.9
requirements/base.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
anyio==4.9.0
anytree==2.12.1
argon2-cffi==23.1.0
argon2-cffi-bindings==21.2.0
arrow==1.3.0
asttokens==3.0.0
async-lru==2.0.5
attrs==25.3.0
autograd==1.7.0
babel==2.17.0
beautifulsoup4==4.13.3
black==25.1.0
bleach==6.2.0
casadi==3.7.0
certifi==2025.1.31
cffi==1.17.1
charset-normalizer==3.4.1
click==8.1.8
comm==0.2.2
contourpy==1.3.0
cycler==0.12.1
debugpy==1.8.13
decorator==5.2.1
defusedxml==0.7.1
exceptiongroup==1.2.2
executing==2.2.0
fastjsonschema==2.21.1
flake8==7.2.0
fonttools==4.56.0
fqdn==1.5.1
h11==0.14.0
httpcore==1.0.7
httpx==0.28.1
idna==3.10
importlib_metadata==8.6.1
importlib_resources==6.5.2
iniconfig==2.1.0
ipykernel==6.29.5
ipython==8.18.1
ipywidgets==8.1.5
isoduration==20.11.0
jedi==0.19.2
Jinja2==3.1.6
json5==0.10.0
jsonpointer==3.0.0
jsonschema==4.23.0
jsonschema-specifications==2024.10.1
jupyter==1.1.1
jupyter-console==6.6.3
jupyter-events==0.12.0
jupyter-lsp==2.2.5
jupyter_client==8.6.3
jupyter_core==5.7.2
jupyter_server==2.15.0
jupyter_server_terminals==0.5.3
jupyterlab==4.3.6
jupyterlab_pygments==0.3.0
jupyterlab_server==2.27.3
jupyterlab_widgets==3.0.13
kiwisolver==1.4.7
MarkupSafe==3.0.2
matplotlib==3.9.4
matplotlib-inline==0.1.7
mccabe==0.7.0
mistune==3.1.3
mypy-extensions==1.0.0
nbclient==0.10.2
nbconvert==7.16.6
nbformat==5.10.4
nest-asyncio==1.6.0
notebook==7.3.3
notebook_shim==0.2.4
numpy==2.0.2
overrides==7.7.0
packaging==24.2
pandas==2.2.3
pandocfilters==1.5.1
parso==0.8.4
pathspec==0.12.1
pexpect==4.9.0
pillow==11.1.0
platformdirs==4.3.7
pluggy==1.5.0
prometheus_client==0.21.1
prompt_toolkit==3.0.50
psutil==7.0.0
ptyprocess==0.7.0
pure_eval==0.2.3
-e git+https://github.com/pybamm-team/PyBaMM.git@712ed9b1a1455751c53d60b3828ae0e4c1b411c3#egg=pybamm
pycodestyle==2.13.0
pycparser==2.22
pyflakes==3.3.1
Pygments==2.19.1
pyparsing==3.2.3
pytest==8.3.5
python-dateutil==2.9.0.post0
python-json-logger==3.3.0
pytz==2025.2
PyYAML==6.0.2
pyzmq==26.3.0
referencing==0.36.2
requests==2.32.3
rfc3339-validator==0.1.4
rfc3986-validator==0.1.1
rpds-py==0.24.0
scikit-fem==10.0.2
scipy==1.13.1
Send2Trash==1.8.3
six==1.17.0
sniffio==1.3.1
soupsieve==2.6
stack-data==0.6.3
terminado==0.18.1
tinycss2==1.4.0
tomli==2.2.1
tornado==6.4.2
traitlets==5.14.3
types-python-dateutil==2.9.0.20241206
typing_extensions==4.13.0
tzdata==2025.2
uri-template==1.3.0
urllib3==2.3.0
wcwidth==0.2.13
webcolors==24.11.1
webencodings==0.5.1
websocket-client==1.8.0
widgetsnbextension==4.0.13
zipp==3.21.0

name: PyBaMM
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=3.0.16=h5eee18b_0
  - pip=25.0=py39h06a4308_0
  - python=3.9.21=he870216_1
  - readline=8.2=h5eee18b_0
  - setuptools=75.8.0=py39h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - wheel=0.45.1=py39h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - anyio==4.9.0
      - anytree==2.12.1
      - argon2-cffi==23.1.0
      - argon2-cffi-bindings==21.2.0
      - arrow==1.3.0
      - asttokens==3.0.0
      - async-lru==2.0.5
      - attrs==25.3.0
      - autograd==1.7.0
      - babel==2.17.0
      - beautifulsoup4==4.13.3
      - black==25.1.0
      - bleach==6.2.0
      - casadi==3.7.0
      - certifi==2025.1.31
      - cffi==1.17.1
      - charset-normalizer==3.4.1
      - click==8.1.8
      - comm==0.2.2
      - contourpy==1.3.0
      - cycler==0.12.1
      - debugpy==1.8.13
      - decorator==5.2.1
      - defusedxml==0.7.1
      - exceptiongroup==1.2.2
      - executing==2.2.0
      - fastjsonschema==2.21.1
      - flake8==7.2.0
      - fonttools==4.56.0
      - fqdn==1.5.1
      - h11==0.14.0
      - httpcore==1.0.7
      - httpx==0.28.1
      - idna==3.10
      - importlib-metadata==8.6.1
      - importlib-resources==6.5.2
      - iniconfig==2.1.0
      - ipykernel==6.29.5
      - ipython==8.18.1
      - ipywidgets==8.1.5
      - isoduration==20.11.0
      - jedi==0.19.2
      - jinja2==3.1.6
      - json5==0.10.0
      - jsonpointer==3.0.0
      - jsonschema==4.23.0
      - jsonschema-specifications==2024.10.1
      - jupyter==1.1.1
      - jupyter-client==8.6.3
      - jupyter-console==6.6.3
      - jupyter-core==5.7.2
      - jupyter-events==0.12.0
      - jupyter-lsp==2.2.5
      - jupyter-server==2.15.0
      - jupyter-server-terminals==0.5.3
      - jupyterlab==4.3.6
      - jupyterlab-pygments==0.3.0
      - jupyterlab-server==2.27.3
      - jupyterlab-widgets==3.0.13
      - kiwisolver==1.4.7
      - markupsafe==3.0.2
      - matplotlib==3.9.4
      - matplotlib-inline==0.1.7
      - mccabe==0.7.0
      - mistune==3.1.3
      - mypy-extensions==1.0.0
      - nbclient==0.10.2
      - nbconvert==7.16.6
      - nbformat==5.10.4
      - nest-asyncio==1.6.0
      - notebook==7.3.3
      - notebook-shim==0.2.4
      - numpy==2.0.2
      - overrides==7.7.0
      - packaging==24.2
      - pandas==2.2.3
      - pandocfilters==1.5.1
      - parso==0.8.4
      - pathspec==0.12.1
      - pexpect==4.9.0
      - pillow==11.1.0
      - platformdirs==4.3.7
      - pluggy==1.5.0
      - prometheus-client==0.21.1
      - prompt-toolkit==3.0.50
      - psutil==7.0.0
      - ptyprocess==0.7.0
      - pure-eval==0.2.3
      - pycodestyle==2.13.0
      - pycparser==2.22
      - pyflakes==3.3.1
      - pygments==2.19.1
      - pyparsing==3.2.3
      - pytest==8.3.5
      - python-dateutil==2.9.0.post0
      - python-json-logger==3.3.0
      - pytz==2025.2
      - pyyaml==6.0.2
      - pyzmq==26.3.0
      - referencing==0.36.2
      - requests==2.32.3
      - rfc3339-validator==0.1.4
      - rfc3986-validator==0.1.1
      - rpds-py==0.24.0
      - scikit-fem==10.0.2
      - scipy==1.13.1
      - send2trash==1.8.3
      - six==1.17.0
      - sniffio==1.3.1
      - soupsieve==2.6
      - stack-data==0.6.3
      - terminado==0.18.1
      - tinycss2==1.4.0
      - tomli==2.2.1
      - tornado==6.4.2
      - traitlets==5.14.3
      - types-python-dateutil==2.9.0.20241206
      - typing-extensions==4.13.0
      - tzdata==2025.2
      - uri-template==1.3.0
      - urllib3==2.3.0
      - wcwidth==0.2.13
      - webcolors==24.11.1
      - webencodings==0.5.1
      - websocket-client==1.8.0
      - widgetsnbextension==4.0.13
      - zipp==3.21.0
prefix: /opt/conda/envs/PyBaMM

tests/unit/test_models/test_full_battery_models/test_base_battery_model.py::TestBaseBatteryModel::test_default_var_pts
tests/integration/test_solvers/test_solution.py::TestSolution::test_append tests/integration/test_solvers/test_solution.py::TestSolution::test_append_external_variables tests/unit/test_models/test_full_battery_models/test_base_battery_model.py::TestBaseBatteryModel::test_build_twice tests/unit/test_models/test_full_battery_models/test_base_battery_model.py::TestBaseBatteryModel::test_default_geometry tests/unit/test_models/test_full_battery_models/test_base_battery_model.py::TestBaseBatteryModel::test_default_spatial_methods tests/unit/test_models/test_full_battery_models/test_base_battery_model.py::TestBaseBatteryModel::test_default_submesh_types tests/unit/test_models/test_full_battery_models/test_base_battery_model.py::TestBaseBatteryModel::test_get_coupled_variables tests/unit/test_models/test_full_battery_models/test_base_battery_model.py::TestBaseBatteryModel::test_options tests/unit/test_models/test_full_battery_models/test_base_battery_model.py::TestBaseBatteryModel::test_process_parameters_and_discretise tests/unit/test_simulation.py::TestSimulation::test_basic_ops tests/unit/test_simulation.py::TestSimulation::test_discontinuous_current tests/unit/test_simulation.py::TestSimulation::test_drive_cycle_data tests/unit/test_simulation.py::TestSimulation::test_get_variable_array tests/unit/test_simulation.py::TestSimulation::test_plot tests/unit/test_simulation.py::TestSimulation::test_reuse_commands tests/unit/test_simulation.py::TestSimulation::test_save_load tests/unit/test_simulation.py::TestSimulation::test_save_load_dae tests/unit/test_simulation.py::TestSimulation::test_set_crate tests/unit/test_simulation.py::TestSimulation::test_set_defaults tests/unit/test_simulation.py::TestSimulation::test_set_defaults2 tests/unit/test_simulation.py::TestSimulation::test_set_external_variable tests/unit/test_simulation.py::TestSimulation::test_solve tests/unit/test_simulation.py::TestSimulation::test_solve_already_partially_processed_model tests/unit/test_simulation.py::TestSimulation::test_solve_non_battery_model tests/unit/test_simulation.py::TestSimulation::test_solve_with_inputs tests/unit/test_simulation.py::TestSimulation::test_specs tests/unit/test_simulation.py::TestSimulation::test_step tests/unit/test_simulation.py::TestSimulation::test_step_with_inputs
pybamm/models/full_battery_models/base_battery_model.py CHANGELOG.md
pybamm/models/full_battery_models/base_battery_model.py CHANGELOG.md