EMS model 900 issues (electrical gremlin)

Question

Seems that I have an electrical Gremlin. I have kept my RV plugged up to 120 v power ( extension cord) all winter to keep the batteries charged. I started hearing my LP detector beeping. It was beeping from low voltage. My EMS display was blank. I noticed that I had power to the TV's in the rig, so that told me that it was isolated to the 12v. system. I got after the issue by unplugging the 120 v. cord from power and plugging it back in to start with. After a few times of this, I had to go into the rig and turn the main breaker off and then back on again. this would reset it and all would be fine for a day or so. Now, I am only getting 5 volts from the inverter, that is until I flip the main breaker, it gives a shot of 12 volts, the ems display fully lights up for about 1.5 seconds and then the power drops. when I flip the main breaker back on, I get the same thing, other than after the 1.5 seconds the EMS display shows 0 amps, and the "0" is very dim. it will not cycle through the normal cycle. I have the unit unplugged at this time, but have not disconnected the batteries yet. I noticed that my battery disconnect switch is not working either. I have no power to anything that requires 12 volt at this time with the batteries still connected. Anyone's advise is greatly appreciated. I have done this for many years in the past to keep everything charged and maintained, and have recently moved into a new place hopefully I will have 50 amp service to my RV garage soon, but this gremlin has me frustrated.

thanks,
Jason

sam_spade · Answer

Some simple tests should show that your batteries have failed.
Either there is an internal open or several cells are shorted, causing the inverter to shut down.

This could be due to a corroded connection too or to a failed inverter.

In addition to some voltage checks, a good place to start would be to check the water in the batteries (you did do that every 4 weeks or so, right?) and connect an external charger to them for a while.

After you get the main problem solved, you should check the float voltage output of your converter/charger. If it is too high it can damage the batteries over a long period.

canadian_rainbi · Answer

I think that the first thing you should do is physically disconnect the batteries. TAKE A PHOTO OF THE CABLING FIRST then follow Sam Spade's advice.

If unsure how to check the batteries:

Check fluid level. IF below the plates in any cell you have damaged the battery. How much depends on how far below the plates.

Add just enough distilled water to cover the plates and just a bit more. (not FULL--just enough to be able to suck electrolyte into the hydrometer for an accurate reading) then charge with and external battery charger.

Check the SG in each cell.

After a rest of several hours check battery voltage. If not at above 12.6 you have not charged them long enough or they are dead/dammaged.

Clean all battery terminals and ends, including the battery ground connection to the chassis. This step is often missed.

jhubble · Answer

Thank you Gentlemen. I will do this, this evening. I replaced the house batteries at the end of last year (season). The Chassis battery may be the main culprit. I will check these and report back. Thank you again.

Jason

d_e_bishop · Answer

I know it may not be convenient but, most repair shops and chain type auto parts stores will do a battery check for free. If taking them to a remote location the are several battery testers available for a small fee.

I have 6 vehicles that I either fully maintain or partially maintain and I broke down and purchased a HFT OBD II a Battery checker a couple of spare DMMs that I keep in a soft tool bag. In fact I bought our daughters a OBDII reader after each one spent $40 to find out the gas cap was loose.

I would have the batteries load tested first and go from there.

jhubble · Answer

Gentlemen, I thank you for tips and knowledge. I put a charger / tester on the chassis battery, and it showed bad. I turned the charger to 12 volt high and plugged the rig back to shore power. Everything worked as it should. I will replace the battery tomorrow and install. Thanks again, y'all saved me a whole lot of gremlin chasing. BTW, the house batteries looked and showed good.

Sincerely,
Jason

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EMS model 900 issues (electrical gremlin)

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