Newmar inverter output problem

[MarioG]

We have a 2500w Newmar inverter/charger. It has worked for us trouble free for over a year now. Last week we had a generator starter get stuck in the ingauged postiton. this was very scary which caused the starter to burn and short out with lots of smoke and sparks. since then the inverter output duration has been severaly shortend. I assumed it was due to bad batteries which was further damaged by the genny starter short. I replaced ALL the batteries yeasterday with new Rolls Surrettes for the house/inverter and dekas for the starboard engine. today we went out for a dinner cruise to local restaruant, when we returned to the boat the inverter panel was in "Low input voltage" which usually indicates the batteries voltage is below 29.1 volts. total time on the inverter use was less than 3 hours. In the past (before short) we would get 8 to 10 hours+ with the old (bad) batteries. the inverter was in charging mode (3 stage) yeasterday after battery instalation and today when I arrived at the boat the charger was in float mode as I would expect. both engines turn over fast and start easly. Could the newmar inverter/charger been damaged or do I have a battery capacity problem?

 

[Pascal]

i dont' see how a starter problem could have affected the inverter.

How many batteries do you have for the inverter, how many AH total? what are you running on the inverter? fridge, some lights, stereo/TV? was anyone cooking? using any appliance like electric grill, toaster, toaster oven?

need to figure out how much you were pulling out of how many amp/hr battery bank.

 

[MarioG]

no cooking onboard. just the salon lights and the stereo and fridge. 4 Rolls batteries with 275 AH capacity total, one day old. three hours of use and the inverter tripped off.

 

[dwaynec]

Is your inverter mounted in the genny room where smoke could have gotten to it and maybe caused some damage?

 

[Pascal]

that should be plenty of battery capacity... 275AH @ 32v is almost what i have (880 AH @ 12v) and we last about 20 hours with the fridge, TV, lights, etc..

the first thing i'd look at is charging. Make sure they your batteries are fully charged. Can you temporarily disconnect the inverter/charger and charge them with your on board charger (assuming you have a separate charger for the starting bank, do you?). Check condition with an hydrometer

do you have a remote panel that shows you how many AMPS you are pulling while inverting? that will give you an idea of you actual consumption, taking into account that the fridge cycles on and off. You may have something in the boat that's left on an pulling a lot of juice, how about block heaters?

Check your DC loads as well since that bank is shared with house.

After I installed the inverter on Charmer, the 70 footer i captain, I noticed that we were not getting the full 20 hours out of the 16 golf cart batteries. I started checking amp draw circuit by circuit and realized that the fluorescent lights in the ER were pulling almost 50AH (@ 12V)


btw, if like us you have incadescnet 110v lights, replace them with the CFLs... you'll use up a lot less battery especially with kids and guests who usually leaves all the lights on... and if you get the soft bulbs (NOT the daylight bulbs), there is no visual difference.

Not to try to beat that old horse again (we're all tired from beating the other horse with battery cables...), but this is why i like to have my inverter and inverter bank completly separated from the house /starting / genny side. easier to troubleshoot and i like redundant and isolated systems.

 

[MikeP]

Is it possible you have a poor DC connection somewhere or a faulty cable? Perhaps the starter short compromised a cable or a fitting.

Otherwise, maybe the batteries were never properly charged initially or, as Pascal noted, a circuit is turned on that you are not aware of.

 

[GJH]

I'm with Pascal, the issue is likely on the battery side and how charged were to begin with. Sometimes new batteries need extended charging before they come fully up to snuff. Run the inverter again with the same loads, measure the beginning voltage, measure the amp draw (do you have a battery monitor installed?), then measure the voltage at the batteries as you go along. You might get a rough idea if by some odd chance the inverter is at fault by seeing if it is drawing watts out of the batteries at a higher rate than its efficiency rating would justify (that is the number of extra watts the inverter requires to deliver the wattage demanded by the AC loads put on it). Call NewMar, they are usually very helpful.

Would be a good time to take hydrometer readings too. It sounds like a dumb question, but are you sure the batteries are topped up with water?

 

[sgharford]

Just another thought – if you’re the starter on your generator is hooked up to same battery bank inverters run off of then maybe your starter acted as unregulated alternator when it got stuck engaged and shorted something on inverter out?

 

[Pascal]

mike has a point about the cables/wiring... check all connection, crimps, terminals, back of the switches, etc... to make sure they're all clean, solid. a massive starter problem can cause some wiring issues (been there, done that)

and double check those block heaters, i think you mentioend that you have block heaters...

 

[Will]

Might the problem with the generator have blown a diode in the inverter? That would result in reduced output.
Will

 

[MarioG]

Thanks for the replys guys! I turned off the block heaters before I started the engines. when I reinstalled the cables i inspected every terminal first. as for being fully charged, all the new batteries were charged at DC Battery the night before delivery. after I installed them I turned on the charger/inverter and it went to "3 stage" charge mode as it normally does and i went home. when I arrived yeasterday at the boat, the charger was in "float" mode. I'll check the density and water again today. and I'll triple check the wires again.

 

[GJH]

Mario, just out of curiosity, what did DC charge you for the batteries and what model #s were they?

 

[MarioG]

I just got off the phone with tech support at Newmar. he says that I have all of the indications of a new set of batteries that need "conditioning". he explained to me that deep cycle batteries that have been stored for extended periods of time when new sometimes need to cycle a few times before they are able to absorb full charge and put out max capacity as intended. the tech guy said to try usuing it again today and see what it does if the problem continues, he said not to worry yet because the inverter/charger has a battery conditioning feature that should solve the problem.

 

[MarioG]

DC charged me 385.80 with trade in

 

[doc g]

Mario, I assume you are using inline "T" type fuses on the positives of the batt cables?? If so I had a situation that I found on my inverters where the one of the fuses was conducting (ie. not open )when tested with a meter but was not allowing full current to go thru. I diagnosed it with a meter by testing the battery voltage at the batt terminal before the fuse and then testing the v after the fuse and found there was a significant difference . I confirmed with a DC Amprobe . I would check with an amprobe each cable under a constant load and see if you have both good connections and fuses . If you don't have inline fuses you should . You can check all this without disconnecting things ,so don't make yourself more work than you have to. Those "T " fuses are some kind of a semiconductor fuse and have presented me with problems several times. I hope this helps , I know how aggravating inverter problems can be to figure out..............................Pat

 

[Brian Degulis]

Mario Make sure you don't have a wiring flaw someplace that's draining the system to ground. Sometimes after a major short or overload something cooked that you don't know about. I would shut down everything on the battery bank then try disconecting one cable and checking for any current flow. It's important to check for this not only for battery life but also because a substantial current leak can cause rapid and severe electrolisis.


Brian

 

[SKYCHENEY]

Maybe things have been changed on your boat, but OEM was to start the genset off of the stbd starting bank. Most inverters were then installed on the port house bank. If this is the case, then I doubt a short in the start circuit of your genset would have anything to do with the inverter bank as they are totally separated except for the shared ground.

 

[MarioG]

Re: Newmar inverter output problem UPDATE!

Finally we figured out the problem. After carfully observing the batteries today while on inverter power, we discovered that one of the 8v Rolls batteries would suddenly drop to 2.5v after 3 hours of use. The other 3 batteries in the bank were at a steady 8.25v on average. total battery voltage was 27.25v. the inverter is programmed to turn off at 29.1v.

New battery on order tomorrow.