Need some more help please. Maggie and I did the Mississippi Pecan Festival this past weekend. They furnished us a camp site with 30 amp power. We ran the genset up there for the A/C and when we pluged in and checked the house batteries they were full. Later that night we noticed that the interior lights were not as bright as they should be and when I checked the house batteries they were half charged and stayed that way through the whole weekend. I could hear the converter humming but it never charged the house batteries up more than half full. If I run the engine they charge up full then drain down to 1/2 and the samething when I use the genset. Is the converter going bad or does it have something to do with the fact the the Barth is 50 amps and it's only pluged into 30 amp's. Same thing happens here at the house. Suggestions please.

Ron

50 A power plugs into 240 VAC (1x +120VAC leg, 1x -120VAC - across the two 120VAC legs gives 240VAC.

The converter runs only on 120VAC, so it would either work or not, regardless of the source of shore power or running the genset. The humming would indicate that it's getting power, but not that it's working properly.

This sounds like either a bad battery (a shorted cell in one battery would bring the whole bank down) or a bad converter.

Because you're getting the same symptoms whether the engine alternator or the converter is used, the first call would be a bad battery.

This should be fairly easy to trace. Let the converter run for a day (should be plenty to charge the batteries). Disconnect shore power. Then right away, disconnect the house batteries from each other and check voltage on each battery.

The good batteries should show around 11.8 to 12.6V. A bad cell in a battery would be indicated by voltages in the 9.5-10.5V range.

If this reveals nothing, have the batteries load-tested (the only sure way unless something is really amiss, like a bad cell).

I'm pretty sure that the culprit is one or more bad batteries; maybe one of the other forum members has another suspicion.

I'll agree with Rusty on the batteries being a good place to start.


I am a crank on hydrometers. The battery gauge in most RVs is not accurate. I believe all RVers should have a hydrometer and a digital multimeter.

To check a battery, give it a good charge on a known good charger. Then read it with a hydrometer.

An auto parts store can check it if they have a conductance meter. If they have a load bank, it will not give a useful test for a deep cycle battery.


Another good test is to fully charge it and let it sit disconnected for 24 hours and read the voltage with a known good digital voltmeter. Subsequent readings a day at a time later will tell you how well it holds a charge. The voltage readings can be seen at http://www.trojan-battery.com/Tech-Support/BatteryMaintenance/Testing.aspx

Are you sure your battery has been receiving a full charge? Many converters do not charge well. The converter that came in my Barth said so in the manual. The engine alternator does not deliver a full charge, either, due to the voltage drop in the isolator. Many battery meters will read a surface charge and tell you it is full when it is not. That is why the 24 hour waiting period is recommended for taking a voltage reading. If it has not been receiving a good charge, the batteries might still be saved if you leave them on a good charger for a while.

I agree with Bill - the quick-disconnect method I suggested will detect a bad cell (which is #1 on my suspect list), but not other issues.

Some converters do quite well charging the battery. The info in the Barth manual is for a two-output converter, where when 120VAC is available, the converter powers the house 12V directly, and charges the battery through a second circuit. The chargers on these converters are both primitive and wimpy. The old one in my SOB was rated at 60A, but the charger circuit was only 15A.

Newer converters are one-output, where all the output goes to the battery, and the house 12V takes the power from the batteries. These converters (at least the Intellitec with Charge Wizard) do a much, much better job - the Intellitec has a desulfating cycle as well.

quote:

Originally posted by Ron & Maggie:
Suggestions please.

Have you tried to plug into 240v and see if it helps any?

If one of your legs is dead going into the coach from a bad adapter plug or there's corrosion in the wire, plug end, adapter etc that could limit your 120 voltage.

It could also be the 50 amp supply cord is bad. If one of the legs is dead in your cord your only getting the 120v supply to one side.

Does both of your roof air conditioners work? If only one is working suspect the cord or plug. With it plugged in try the roof air conditioners one at a time and not both at once. If you have two roof air conditioners they seperate them on different legs. By using the air conditioners your causing a load and it may help you track down a loose wire. Does both roof air conditioners work with the genny and does it sound different on generator power?

If it's not that then what Rusty and Bill H. is saying makes more sense. Charge up your batteries and have them load tested. Check static voltage after a charge to see if one battery is lower.

Bill N.Y.

quote:

Originally posted by Bill N.Y.:
Charge up your batteries and have them load tested.
Bill N.Y.

Load testing is good if it is a load test designed for a deep cycle battery. Most places will not know how to do this and will use a load test designed for a starting battery. A proper load test for a deep cycle battery take time, too. Some good deep cycle batteries will fail a starting battery load test.

I'm still gonna wave the hydrometer flag here. It gives you an instant reading of state of charge and will find a bad cell almost as quickly as the old cell testers.

Even a four-ball eyedropper can find a bad cell pronto.

Thanks guys. You've given me some great direction and I'll start on it tomorrow by getting a hydrometer and a multimeter. I was looking at an Inteli-power converter/charger w/a charge wizard. Is an 80 amp over-kill? Just looking in case I have to replace it. I'll go the battery checks first. I just bought a 50/30 amp pig tail and I'm using a good 25' 30 amp cord which is also new. The converter is the original one so maybe that could be the problem. We'll see tomorrow and I'll let you know. Sack time and I'm beat. Until then........Thank you all.

Ron

Oh yah, one other thing. Our 28' Regal only has one roof A/C and I ran it for over four hours today and the the house batteries never dropped below 1/2 full.

Ron

Unfortunately, that would have no bearing on the battery-charge issue (although you're at least comfortable....)

quote:

Originally posted by Ron & Maggie:
I was looking at an Inteli-power converter/charger w/a charge wizard. Is an 80 amp over-kill? Just looking in case I have to replace it. Ron

Short answer:

80 amps is just about right for two golf cart batteries that are not discharged below 40-50%.

Long answer: I don't know what batteries you have, but my 75 amp converter/charger is just right for my two golf cart batteries.
Some of converter sizing depends on how low you run your batteries. If you run them really low, you will get the full 80 amps into the battery, which could be a little much. The rule of thumb of 13% of rated capacity can be pushed to perhaps twice that with GC batts. 25% of 210 amps is 50 amps. Anything over that is going to shorten the life of the batteries. However, if you never get below 50%, you will see around 40 amps max charge, which is 20% of capacity of two golf cart batteries. For dry camping, it is good to have as large a charger as possible to avoid long genset runtime with the resultant wasting fuel and making noise.

Does your plug on the new cord look like it could plug into this?



This is a 30 amp service. This is 120v.

Or does it look like this?



This is a 50 amp service. It is capable of delivering 240v. Because you wouldn't really need 240v it is just supplying you with 2 - 120v sources of power on the same cord.

Think about it like this. If you had (you don't) two roof air conditioners the circuit breaker would pop a lot on the 120 - 30a service. You wouldn't put two window ac units in your house on the same circuit. To combat this the 50amp 240v supply is broken down into two supplies. Your not running 240v. Your running two 120v supplies into your coach.

You stated earlier that you had a 50amp service. Now your telling us you have a 30amp cord that's 25 foot long. If you have a 30 amp service then you only have one leg supplying power and not two.

I'm a little fuzzy on you having a 50amp service. You stated that if you ran the genny your batteries got charged up but then lost it's power and if you were only plugged in it wouldn't go over 1/2 charge. Why would the genny give you more charge and not the line supply power? Does you genny have it's own alternator? Then your really just charging your batteries thru the genny alternator.

If your roof ac unit (only one) ran better or faster with the genny then I would suspect a "shore supply power" issue. If the ac unit sound the same on shore or genny then I would ignore everything I typed on voltage supply.

If you have a voltage supply problem and your batteries get replaced and you install a new charger etc. you will eventually ruin your new batteries because they wouldn't get there full charge either. Lower line voltage = lower charge voltage.

Plug a voltage gauge for house (alternating current) and read voltage with genny and voltage with shore power. Check each outlet to include the one that's plugged into your battery charger.

Read this for an explanation of rv voltage supply and plugs.

http://users3.ev1.net/%7Ecrossstitch/RVWiring/wiring.html

My house plug to the rv looks like the second one up top. I only use 120v in my coach on two legs. The same outlet that my coach plugs into can also supply my 240v welder (Rusty's welder is bigger ) and I have also used this to reverse feed a 240v generator to power up my house before I got a whole house generator with an automatic transfer switch.

Bill N.Y.

quote:

Originally posted by Ron & Maggie:
...when I checked the house batteries they were half charged and stayed that way through the whole weekend.

Just so were clear. Half charge is 12.1 volts. What voltage were you at?

Bill N.Y.

OK,

New data. I went out and bought a hydrometer, pulled out the battery tray and tested both house batteries. Neither of the house batteries registered on the hydrometer. I put my charger on one of the batteries and will charge it up until tomorrow then check it again. If I can't get a charge into it then I guess I'll be going to Sam's club and buy two new ones. Once again my neighbor brought over his multimeter and checked the "new" battery that Lazy Days put in and it read 12 volts which is low is it not? We also checked all the receptacals and they read 119 and 121 volts. Maybe I'm wrong but it sounds like it might be the converter/charger. Camping World has them in stock for under $300.00. How hard is it to change out the converter if I have to? I'll wait and see what happens with the batteries first. I'm going to Lowe's tomorrow to get a good digital multimeter. Any other thoughts?

Ron

I forgot to say that we checked both of the house batteries with the multimeter and they both read 8 amps. Ron

quote:

Originally posted by Ron & Maggie:
New data.

Good, we love new data.

quote:

Originally posted by Ron & Maggie:
(with shore power) I could hear the converter humming but it never charged the house batteries up more than half full. If I run the engine they charge up full then drain down to 1/2 and the samething when I use the genset.

This statement made me tell you to check line voltage. Now that your telling us 120v lets move on.

quote:

Originally posted by Ron & Maggie:
Maybe I'm wrong but it sounds like it might be the converter/charger...

Yes, only if you can get the batteries back up. If not then replace them too with some good deep cycle batteries.

quote:

Originally posted by Ron & Maggie:
...Any other thoughts?

Nope, sounds like Rusty and Bill H. has you on the right track.

Bill N.Y.