diff --git a/hardware/power.md b/hardware/power.md
index c76b59e..dc688aa 100644
--- a/hardware/power.md
+++ b/hardware/power.md
@@ -1,26 +1,41 @@
 # BATTERY
+* 1S LiIon/LiPo (3.7 V nominal)
+* 18650 for easy ubiquitous availability (~3,000 mAh each)
+* connect cells in parallel until we get the capacity we want
 * lipo can charge at 1C
-* 5900mAh -> 5.9A
-
-Strawman design proposal: 1S LiPo, 18650 for easy ubiquitous availability
-(~3,000 mAh).  Add cells in parallel until you get the capacity you want.
 
 ## CELLS
 [INR18650-35E](https://lygte-info.dk/review/batteries2012/Samsung%20INR18650-35E%203500mAh%20%28Pink%29%20UK.html)
 
+
+# POWER BOARD
+[Adafruit 6091](https://www.adafruit.com/product/6091)
+* $7
+* 5-18V input, USB-C or PV/DC
+* CC at 1.0 A, 0.5 A, or 0.25 A
+* handles LiPo/LiIon or LiFePo cells
+* optional thermistor to reduce charge current when battery overheats
+* battery under voltage protection disconnects the battery from the load at 3 V
+* [schematic](https://learn.adafruit.com/adafruit-bq25185-usb-dc-solar-lithium-ion-polymer-charger/downloads#schematic-and-fab-print-3188140)
+
+Max charge rate is 1 A at 3.7 V nominal battery voltage, which is 3.7 W.
+
+
+# PHOTOVOLTAIC PANEL
+
+Anything 5-18 V should be fine, the charger can't use more than 3.7 W.
+
+Trying this one: <https://www.amazon.com/Soshine-6w-Performance-Monocrystalline-Cellphone/dp/B09ZL3F7CT?th=1>
+
+
+# ALTERNATIVE POWER BOARDS
+
 ## CHARGERS
 1. [5V 2A USB-C](https://www.amazon.com/DWEII-Converter-Step-Up-Charging-Protection/dp/B09YD5C9QC/)
 2. [5V 2A](https://www.amazon.com/Ruiwaer-Discharge-Integrated-Adjustable-Charging/dp/B08QHVW5J8)
     * have on hand (i think)
 3. [Adjustable](https://www.amazon.com/Lithium-Battery-Charger-Charging-Converter/dp/B089NG9TFW)
     * combine with [heatsink](https://www.amazon.com/Printer-Heatsink-Thermal-Conductive-Adhesive/dp/B07RKHRHJV)
-4. [Adafruit 6091](https://www.adafruit.com/product/6091)
-    * $7
-    * 5-18V input, USB-C or PV/DC
-    * CC at 1.0 A, 0.5 A, or 0.25 A
-    * handles LiPo/LiIon or LiFePo cells
-    * optional thermistor to reduce charge current when battery overheats
-    * [schematic](https://learn.adafruit.com/adafruit-bq25185-usb-dc-solar-lithium-ion-polymer-charger/downloads#schematic-and-fab-print-3188140)
 
 strawman: charging up to 4v with the INR18650 (see `CELLS:INR18650-35E` for the discharge capacity graph, and `CHARGERS:3` for 4V cutoff w/ a 5V panel) gives us ~3000mAh, or 88% of the 3398mAh tested battery life.
 
@@ -31,4 +46,3 @@ strawman: charging up to 4v with the INR18650 (see `CELLS:INR18650-35E` for the
 * mppt charge controllers:
 1. <https://www.amazon.com/Waveshare-Solar-Power-Manager-Regulated/dp/B0CT2ZBML9>
 2. <https://www.amazon.com/4-4-6-5V-Lithium-Battery-Charger-Controller/dp/B08DY28BXW>
-