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Robert, RV Mechanic
Category: RV
Satisfied Customers: 13362
Experience:  18 yrs. RV experience including Cummins North West, Country Coach, Monaco Coach - vendor certified.
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I have a 1994 Thor ambassador I seem to be over charging

Customer Question

Hi I have a 1994 Thor ambassador I seem to be over charging the houe batts could the be the Shore supply inverter being at fault? The over charge is making the batts Warm and gas off how do I check the 240/12 v inverter (UK) regards paul
Submitted: 2 years ago.
Category: RV
Customer: replied 2 years ago.
Also although new the batts seem to have little charges in them for now I have put an isolating switch in line so I can stop any charging whilst driving.
Expert:  Robert replied 2 years ago.
Hi my name is Robert..
Do you have the problem when when the alternator is charging the battery or when you are plugged in? What is the make and model of the inverter or converter... An inverter takes the DC battery voltage and makes the AC voltage so you can have AC power when unplugged, a converter will not do that.... Robert
Customer: replied 2 years ago.
Hi Robert,Thanks for this, so allow me to perhaps explain a little better, first I have 3 batteries of my RV one for the engine start and two deep cycle for the 12v on board, a couple of week ago one of the deep cycle batteries was gasping off and would not hold charge so I changed it, however when I have completed a 5 hour run one of the deep cycle was starting to gas off again without being plugged in to the shore supply (240v UK).So for now I have installed an isolater switch to isolate the two deep cycle batteries from the system so not to damage or cause the gas to enter the cab whilst running, whilst I was away last week and the 240 shore supply was connected both of the batteries appeared to behave however when back home show very little power in them.Please understand I have no electrical circuit drawing so not sure what has been fitted when this was shipped to the UK, this said there appears to be an inverter/converter mounted at the bulk head with the batteries connected to it this looks original from manufacture in 1994, at this present time I do not have the make and will look at this this evening when I get back to the RV after work.Do you think I could send a photograph of the set up so you can better understand? I have found a transformer at the rear of the RV which the 240V enters and appears to be stepped down to 11Ov to feed the RV systems.Sorry to ramble however this is what I have at this present time.Kind regardsPaul M
Expert:  Robert replied 2 years ago.
Yes you should be able to add a photo in your reply, should be a paper clip icon for that...
Need to know the make and model of the converter or inverter, it is directly responsible for charging the batteries when you are plugged in. When the engine is running then a battery isolator is used to charge both the chassis and house battery.
One thing I want to mention is you should always replace the batteries in sets when they are wired together OR the new battery might get depleted faster.
As far as it gassing with the engine running it could be a bad isolator... I will try my best on this, it is an older unit.... Robert