Charging batteries problem

Yes any decent auto parts store will have those for replacement.
Get the 30 amp version.

PSU,

What is above is not wrong, but it is incomplete. On the other side of that breaker should be battery voltage. If that is like 7-1/2V, something is wrong. I suggest that you get a largish 12V bulb and socket and put one each across those breakers. The light will (should) not light, but it will allow the battery to be charged slowly. Give it a few days (no Joke) and measure the battery voltages again.

It is my suspicion that you have more wrong than just those circuit breakers. It may be a bad battery and if you replace the breakers now, you will just have to replace them again later.

Matt

Yes Sir, what Brett tells you is correct. They are Automatic reset, circuit breakers. They have bi-metal springs inside them that get's burnt and causes carbon, suit and other non-conducting materials between the contacts. So, that's what appears to be your issue. You can, temporarily, do a test to confirm this. Simply disconnect the terminals from them and put the wires together.

Then check your voltage at your house batteries. It should be the same as the output of the charger, whatever type charger you have that is. It might be down by a tenth of a volt or so, due to voltage loss of the distance and or any connections. But, if it's way up from your present voltage, you've found the problem.

And, as has been suggested, just cruise on down to your local Auto zone or, any auto parts store, and pick up a couple. You really don't need an RV supplies or service center for them. They're common in the industry. Good luck.
Scott

Replace them-- they are inexpensive. The reduced voltage coming out of the resettable breaker suggests internal resistance/poor connection.