Our laptop died and then our tablet charger fell apart a few days later. The smartphone charger was compatible with the tablet, but it charges the tablet incredibly slowly. We have been limping along with a crippled tablet getting too little charge during the day and a crappy smartphone.
Last might, my son discovered that using Airplane mode when Wi-Fi isn't available anyway saves a good bit of battery power. We wish we had known this way sooner.
We also routinely keep the brightness turned down and I clear the cache daily on certain apps. At one point, we had some battery minding app of some sort.
We again have a faster, higher amperage charger. But it took a few days to arrange. We hope that using Airplane mode will help extend our battery power enough to make it less of a problem that we can't readily replace the laptop. We just don't have the money.