Leisure Battery and Solar Log

Who this is for

How the batteries cope, day by day. Each day off hook-up you write the morning and evening readings from your own monitor, what did the charging, how much sun there was and what you ran. After a week or two the pattern shows whether the set-up keeps up or needs changing.

Caravan, motorhome and campervan owners who stay on sites without hook-up, wild camp where it is allowed, or have fitted solar or a battery upgrade and want to see how it performs.

What this helps you track

• The battery reading morning and evening on each day
• Which source did the charging: solar, hook-up, engine or generator
• The hours of sun against how well the batteries recovered
• Which loads were running on the days the readings dropped
• How many days in a row you managed off hook-up

How to use it

1. Write the vehicle, the battery bank, the solar fitted and the type of monitor at the top.
2. Take a reading at the same times each day, first thing and in the evening, in whatever unit your monitor shows.
3. Note the charge source, a rough count of the hours of sun and the main loads you used, such as heating fan, fridge, inverter or laptops.
4. Number each consecutive day off hook-up so you can see how long a stretch the set-up managed.
5. Use the observations space to record changes made, such as a new panel or charger setting, and compare the days either side.

Formats

• Printable PDF (A4 and US Letter)
• Fillable PDF with form fields
• Fill in online, saved in your browser

The printable is laid out inside a box that fits both A4 and US Letter, so the two files are identical and neither one is scaled. The fillable PDF has real form fields. The online version keeps what you enter in your own browser and builds the completed PDF on your device.

How to print

Download the A4 or US Letter file to match the paper in your printer, open it in a PDF reader and print at 100% — not "fit to page", which shrinks the writing space. Both files leave a 14 mm margin, which clears the unprintable edge on home printers. To print the online version with your entries in it, use the Print this sheet button, which prints only the sheet and none of the page around it. More on printing.

Questions

What reading should I write down?

Whatever your monitor shows: voltage, state of charge as a percentage or amp-hours used. Use the same one every time and write which in the monitor field, because the numbers are only useful compared with each other.

What reading is too low?

That depends on your battery type and maker, so the sheet gives no figure. Check the battery maker's guidance and your charger or monitor manual, and note the level you work to in the observations.

Why take readings at fixed times?

A reading straight after charging or under heavy load looks very different from one at rest. Taking it at the same times each day makes one day comparable with the next.

Does the log calculate anything?

No, it is a written record. The pattern comes from reading down the columns. If you also track gas and water off-grid, the water and gas usage log sits alongside it.