No charge battery wont stay charged

the new battery may be fault or have a parasite drain

either have a faulty battery ---or a parasite drain in the unit

How old is the battery? Will it hold a charge if you have it charged by shop or Auto parts place? Have you checked the cell water level? If low use distilled water only, be careful, inside is acid that will burn your skin or anything else. If It is a good battery, you have switches that are staying on, or a short to ground, bare wires next to the frame somewhere.

Check the charging relay if working. You can find it in the fuse box which is either in the engine compartment or under the dashboard on the drivers side legroom.

Alternator ? is the charging light of your car stays on ?

It may be worth checking the battery itself, charge it off the bike, leave for 24hrs. Reconnect to the charger and check that the reading was the same as when you charged it. If it takes another top-up charge, the battery maybe at fault.

the battery wont stay charged? if youre putting in a fully charged battery and your car runs, but then the battery slowly dies, the problem will be your alternator. the alternator is what maintains a car batteries charge. try replacing the alternator. hope this helps.

it sounds like your power adapter isn't supplying enough power to the unit. You should be able to try switching out the adapter with another and see if that helps. If the doesn't help, then there may be a problem with the recharging circuit on your GPS. AT which point you should contact TomTom.

Check Power supply first.
use another one and check if battery is charging.