I just purchased a "new" 1972 Barth. Very pleased with this machine, however I'm wondering if my old-looking deep cycle battery should be getting this warm.

It is rigged with a copper "shutoff" switch, and with the switch on or off, the battery seems to get warm, when the shoreline power is applied.

Should it get hot? Or should I replace the battery. I'm thinking that it could be a bad battery.

Recommendations?

Thanks!
Tim Grimes
1972 22-foot Barth
350 engine, roof A/C, no provision for generator
gas refrigerator, water heater, etc.
57,000 miles
Just driven from Columbus, OH with good success.

You have an unknown battery and probably an old converter.

Do you have a hydrometer? You should.Test the battery with a hydrometer. It should read 1.275 corrected when fully charged.

Do you have a charger in the garage? You should.

Chances are your converter is overcharging the battery. Do you have a digital voltmeter or multimeter? You should.

Mandatory safety warning: When messing with batteries, wear eye protection. One spark can be a disaster. Batteries are at their most dangerous when they are in the final stages of charging, when they give off hydrogen gas. Hydrogen is explosive. (Army tank crews used to keep an eagle eye on the voltmeter) It was a rule at my employer to wear a full face shield and have either an eye fountain nearby in the hangar, or have a spray bottle at hand on the ramp. I mean so at hand you could find it with your eyes closed.

I keep a squirt bottle and a Polish Diving Helmet in the battery compartment of the Barth. Same for the jumper cables in all my vehicles. I also have a dedicated battery terminal wrench. All but the head is double insulated with shrink tubing and polyurethane, to avoid sparks. The rule is to disconnect the ground connection befoe touching the positives, but who knows what could happen?

I assume you've checked the water level in the battery.

A normal battery might get a bit warm when charging at a high rate due to being discharged, but it would take a while to warm up due to the mass of lead and electrolyte. An overheating battery is usually the sign of an internal short, but this may not be all the issue.

The cutoff switch cuts power from the battery to the coach's 12VDC circuits, so it doesn't come into play when examining the converter's operation.

If you have the original converter, it's most likely a dual-output. When the coach is on shore power, the converter directly powers the coach's 12VDC through one section of the converter, while a second section charges the battery. As an example, your converter may be rated at 45 amps (total), but the charger section may only be 15 amps.

Usually, if there's an internal short in the battery, the converter's charger section isn't of high enough current output to heat the battery, and more likely a fuse would blow.

The quick check for whether yours is a dual-output is to disconnect shore power and listen for the transfer relay to click as it shifts the coach's 12VDC from the converter to the battery.

With a single-output (newer) converter all the output goes to the battery, which powers all the 12VDC coach circuits, whether or not shore power is applied. A single-output converter could have ample output to heat a battery with an internal short (As could a dual-output converter improperly wired - this condition should be corrected at once, because the coach output of the dual-output converter doesn't have a circuit which limits the charge rate - it'll attempt to keep voltage constant).

The reason I bore you with these details is to make sure the converter isn't causing the problem.

These are only preliminary checks: Check the voltage with the shore power off then with it on. With the converter on, normal voltage (assuming the battery charged well when driving to GA) should be about 13.6 to 14.5 V. With it off, 12.5 - 13.6 V. Readings less than 11.5 V with shore power off would indicate a bad battery. Readings higher indicate a bad converter. But a battery could be bad and still show a decent voltage.

Unless you have a battery tester, it's best to take it to a parts store, or better a local alternator shop, and have it load-tested.

Replace it if necessary, charge the new one with an external charger (most alternator shops can top it off before you take it home), then check the voltages as above with the shore power off then on.

It is also a good idea to visually check the converter for type and correct wiring.

Thanks Rusty & Bill...I've got some work to do. I sincerely appreciate your expertise. Tim

Are you going to be in parks with power or in places with no power?

I'm shored-up behind a hangar, using 110.

What "specification" should I use for a replacement house battery in this rig? Currently, the house battery in this rig is a marine battery. It has evidence of swelling on the side. All power is disconnected to it now. I've taken everyone's advice on safety. I appreciate everyone's wisdom, and I don't deserve it. Thanks, Tim

What battery to buy depends on your usage and your space. You only need enough to get from one charging opportunity to the next without depleting your battery below 50%.

If you use a fair amount of power, and have the room, a pair of 6 volt golf cart batteries is best. They are a little taller.

If you don't have the room, or are a light user, a single 12 volt battery is probably adequate. It needs to be a deep cycle battery. Many batteries sold as marine batteries are intended to do dual service, starting and running lights, appliances, etc. Unfortunately, some batteries sold as deep cycle are not. For example, a deep cycle battery that quotes CCA or starting amps or something like that, is not a true deep cycle, and will not last as long.

My definition of a light user is one who does not use the furnace or many appliances. You can determine your usage by buying a Kill a Watt and connecting it to your power cord and then using only 12 volt appliances from one anticipated charging opportunity to the next. We attend events that actually have generator-free areas. So, a long weekend there requires solar or a bigger battery. I suspect you could use your chassis engine to charge your batteries, too, but that can be inefficient unless you do a few mods. Even with the mods, a 454 is a little big as a battery charger.

The definition of charging opportunity will depend on how much you want to run your genset, and how much your camping neighbors hate you for running it. And campground rules.If you buy a 12 volt battery, Trojan makes some good deep-cycle ones. There are also some good 12 volt batteries used for trolling motors. Hang around some fisherman and see what they like.

Swelling could indicate freezing or overcharging. The heat of overcharging combined with a little pressure can bow the sides.

On the subject of converters, the bigger the converter, the less fuel you will burn and you will make noise for a shorter time during charging. If you use the genset to charge a lot, a big converter will pay for itself in fuel savings.

If you are teetering on a choice of one battery or two, perhaps some single battery users here can contribute their experience and opinions.

quote:

Polish Diving Helmet

Okay, I'll bite. Polish Diving Helmet?

quote:

On the subject of converters, the bigger the converter, the less fuel you will burn and you will make noise for a shorter time during charging. If you use the genset to charge a lot, a big converter will pay for itself in fuel savings.

Indeed it will, but you may have to rewire the run from the converter to the battery with appropriate-sized wire.

quote:

Originally posted by Noob Goldberg:

quote:

Polish Diving Helmet

Okay, I'll bite. Polish Diving Helmet?

Plastic bag.

Sorry.

I was envisioning a plastic face guard.

Plastic bag is even better!

As a new-bee here, I had envisioned Bill's Polish Diving Helmet as some monstrous heavy duty solid brass protective shell with integrated glass lenses...perhaps stored in two halves in Barth storage bays. I really like the plastic zip bag idea much better. :-)

I appreciate everyone's recommendation on my battery change. I purchased a deep cycle marine battery at Wally World last night, installed it in its compartment, but have yet to connect the old leads. I used shoreline power last night for A/C, because I had some questions.

I am trying to determine if my 22-foot Barth has some "unique" wiring with respect to its battery setup, and if it is wired properly - at least in the battery compartment?

The engine battery is also new (as of last week)... a very robust commercial battery with 975 CCA, so I'm pretty happy with it. However, that engine battery is so large, that I couldn't also buy a giant house battery. But the deep cycle battery I bought seems robust enough for the task.

Here are my questions...all with respect to the wiring to the house battery....

Obviously with respect to both engine & house batteries (I suppose), black goes to black, and positive goes to positive, but I also have a brass cutoff throw switch, that was installed to the positive lead of the old house battery. When that switch was closed, the house lights were full bright.

Why would I have any lighting at all (albeit dim) in the coach, with that cutoff switch open? As is (or was, before I changed house battery), before I closed the switch, the house lights were extremely low. I would have expected for there to be no coach lights when the house battery throw switch was open?

Second question...There are three smaller wires leading to the house battery. One goes from what appears to be a house ground to the house battery negative. The other two smaller "red" wires lead to either side of the brass throw switch on the house battery's positive side. I assume that those two small red wires connect to all the coach lighting, and so forth?

Third question...I assume that the converter & charging system is provided "only" to the house battery? Is that true? Also, if the house battery throw switch is left closed while the motor home is being driven down the road, what effect does this have on the house and/or engine battery (when the throw switch is closed, while driving), and if that switch is closed (while driving), is this a problem for the engine battery?

Sorry for so many questions, but electricity has always mystified me.

Last goofball question...do those red and green chemically treated battery washers do anything good for the battery? I like them simply to remind me which is positive and negative. Just wondering. Thanks to everyone for all the excellent knowledge.

Thanks, Tim

quote:
Originally posted by Tim Grimes:
Here are my questions...all with respect to the wiring to the house battery....

I also have a brass cutoff throw switch, that was installed to the positive lead of the old house battery. When that switch was closed, the house lights were full bright.

Why would I have any lighting at all (albeit dim) in the coach, with that cutoff switch open? As is (or was, before I changed house battery), before I closed the switch, the house lights were extremely low.


There are usually two places where the positives of the coach and chassis battery are connected. One is the isolator, the other is the emergency start relay. Chase the wires and disconnect them at each one at a time to see when the problem goes away. It could be either one, but I would try the relay first. It is probably near the batteries. The relay is not really necessary unless you somehow run down your chassis battery, so it, and its wires, can be removed if you don't want to replace it. Do you have a multimeter? One of us can walk you through testing the isolator if it is the culprit.

This will not be wasted time, as it is always good to remove and clean connections.



quote:

Second question...There are three smaller wires leading to the house battery. One goes from what appears to be a house ground to the house battery negative. The other two smaller "red" wires lead to either side of the brass throw switch on the house battery's positive side. I assume that those two small red wires connect to all the coach lighting, and so forth?


Assume nothing. Follow them and disconnect them and see what happens.There is no telling who did or what goes where without following the wires yourself. It is typical for a knife switch to have one side connected to the battery and the other side connected to the loads and charging sources. I am sending you a wiring diagram for my 84 gasser. It is 12 years newer, and who knows who did what to your coach, but it is a generic Barth Regal diagram that applies to many models, lengths and years


quote:
Third question...I assume that the converter & charging system is provided "only" to the house battery? Is that true?


Likely.


quote:
Also, if the house battery throw switch is left closed while the motor home is being driven down the road, what effect does this have on the house and/or engine battery (when the throw switch is closed, while driving), and if that switch is closed (while driving), is this a problem for the engine battery?


Again, assume nothing. Find out just what that switch does. It could been installed by a previous owner to shut off all coach loads for storage or to parallel the batteries for better charging down the road. I have seen both. One Barth for sale right now has one for paralleling.

As a general rule, you want your batteries connected both to the coach and the alternator 9in parallel with the chassis battery) while driving, so they will be charged by the alternator and be available for lights, water etc. The connection to the alternator is most likely through the isolator.


quote:
Last goofball question...do those red and green chemically treated battery washers do anything good for the battery?


Yes

So.......find out what wire goes where, clean the connections, and, by disconnecting, locate the culprit on the dim light thing.

.

quote:

Obviously with respect to both engine & house batteries (I suppose), black goes to black, and positive goes to positive, but I also have a brass cutoff throw switch, that was installed to the positive lead of the old house battery. When that switch was closed, the house lights were full bright.

Why would I have any lighting at all (albeit dim) in the coach, with that cutoff switch open? As is (or was, before I changed house battery), before I closed the switch, the house lights were extremely low. I would have expected for there to be no coach lights when the house battery throw switch was open?

Here's the usual basic 12VDC wiring layout:

1. The engine alternator charges the chassis and house batteries through an isolator, which prevents the batteries from backfeeding into the other. A paralleling relay, closed by the emergency start switch on the dash bypasses this isolator. Likewise a manual switch can also bypass the isolator.

2. The converter, when powered by 120VAC (shore power or generator) charges the house battery (only) and supplies 12VDC to the coach.

Refer to my prior post regarding dual-ouput vs. single-output converters. Yours is probably a dual-output, and and the dim lights could signify the charger section is drawing current to charge the battery, lowering the available output to the coach 12VDC circuits. Unless the new house battery is at a very low charge state, this would be abnormal.

If the the house battery is wired correctly, there typically would be a heavy red for powering coach 12VDC circuits, maybe another for paralleling the batteries for emergency start. There could be a third (smaller) from the isolator driven by the alternator, and a fourth (smaller) from the charger section of the converter.

But heed what bill h mentioned - this wiring has obviously been "messed with" by the prior owner, and many don't know really what they're doing, or do, and don't document it.

Those wires need to be traced. I do this with a jumper, a 30' piece of #16 stranded (harvested from lamp cord (a/k/a "zip" cord) I had laying around. Alligator clips adorn both ends.

I then trace the wires visually as far as I can; many times several of the same color disappear into a single harness.

With all batteries' leads disconnected, I'll clip one end of the jumper to the suspect wire's origin, the other to a 12V battery-powered circuit tester. Then I touch the tester to the wires coming out of the bundle. A light narrows it down. To make sure I'm not getting backfeed, I disconnect that wire and test again. Then I label both ends with white electricians tape and a Sharpie, then reconnect.

quote:

So.......find out what wire goes where, clean the connections, and, by disconnecting, locate the culprit on the dim light thing.

I'm leaning towards a defective converter. What happens when you throw that switch with shore power disconnected? The "right" answer is that the coach lights will go out. If they don't, bill h's suspicion that the switch is to parallel the batteries is more likely, or that the converter's defective.

I also second bill h's suggestions on accessories needed for the motorhome owner, and add:

1. Multimeter
2. Circuit tester
3. Battery terminal protector (aerosol spray to seal electrical connections)