Pros/Cons to running refrigerator all the time?

I normally leave the TM set up at home between camping trips. The only time it is "lowered" is just before I depart on a trip. I usually have the TM connected to shore power while at home.

Does any body have any bits of wisdom on whether to leave the refrig running all the time or shutting it down?

I have the Dometic 3 way.

Thanks
Rocky

Never thought about checking the battery water level and removing the fuse!!!

Where is the fuse located?

Thanks
Rocky

Question TX_Camper, If you remove the fuse will the battery charge? I have read some where that the converter will not allow over charging because it will not allow the battery to fully charge with the old series (6300 I think) and the new series (7300 I think) will allow the battery to top off, but not over charge since it has over charge protection built in. Is that information incorrect?

[Bill]

John and Rocky -

Texas_Camper has a good handle on this situation.

Running the refrig full time should have no adverse effects. Most Dometic models, in fact, are designed to be used full-time.

Pulling the battery fuse is also not a bad idea. With the fuse pulled, the battery will not charge, but it also will not discharge - nor will it overcharge, as T_C pointed out.

The old 6300-series converter will overcharge your battery quite readily, as evidenced by gassing and spitting. There is an adjustment inside the 6300 series that sets the cutoff level, so if you have a 6300 series that won't bring your battery to full, then the adjustment needs a tweak. But as described by T_C in his second post, the choice for an idle battery is undercharge or overcharge - there is no middle ground. If you don't use it, you'll likely lose it.

A good charger is described as a three-stage charger. The 3rd stage actually has a LOWER charge voltage than the first two stages. The ability to switch to this lower voltage - and to know when it is appropriate to make the switch - is lacking in the 6300 series converter.

The 7300 is a better converter than the 6300 in some ways. Reduced RFI (radio frequency interference) has been discussed quite a bit on this board. But as I read the manufacturer's literature, overcharge of an idle battery is still a problem. Like the 6300, this is not a three stage charger. So once again, I agree with T_C - pull the battery's fuse to avoid overcharging.

BTW, good three-stage chargers are not expensive. On the advice of HappyTrails, I bought a Guest 2610 10-amp charger on ebay for about $40. I leave it attached to my TM battery 24/7. Due to my wife's broken ankle, our TM has been in the garage for nearly four months now, with the Guest charger connected and powered. I opened the TM yesterday, checked the battery water level and specific gravity - it is in perfect condition. My wife has improved to the point where we plan our first trip next week. I am mighty glad to find the battery in good shape.

Hope this helps.

Bill

Thanks Texas_Camper for the info on where to find the fuse. I located it.

Thanks Bill for your information as well. I hope your wife's ankle continues to mend. However, I could not think of a better way of recuperating than camping in my TM!

Rocky

If I leave my TM connected to shore power in my driveway, but I check my battery water level once/twice a week, am I likely to avoid the problem of overcharging and drying out the battery? I probably will use some DC appliances from time to time but not that often.

[Bill]

[quote author=TWMetzger link=board=22;threadid=1836;start=msg13042#msg1304 2 date=1081998298]If I leave my TM connected to shore power in my driveway, but I check my battery water level once/twice a week, am I likely to avoid the problem of overcharging and drying out the battery? I probably will use some DC appliances from time to time but not that often.[/quote]

Your question is a good one, and there is surprisingly little information out there. I put the query to another forum where I am active, and one expert whom I trust gave me kind of a mumbled answer. The answer was basically "Not good. Overcharge causes bubbling and outgassing, and the gas is basically water which has been dissociated into hydrogen and oxygen. If there is any possibility of the hydrogen building up (which is really pretty hard to do), then you have a potentially explosive situation. Beyond that, you have the possibility of forgetting to check the water levels. As soon as the plates are exposed to air, damage happens rather quickly. Beyond that, if the overcharge rate is severe, heat may build up, which will warp the plates and ruin the battery." And then some non-specific mumbling about shedding the active material off the plates - I couldn't find anything more specific on that.

One other thign to consider is that if you are going to be continually adding water, it must be distilled water every time, or the minerals in the water will build up in the battery, and that WILL kill it.

So overall, I gather that continual gentle overcharging is not a catastrophe if you watch the water, but is not recommended, either. But really, a good 3-stage charger costs about half as much as a new battery. Why take the chance?

Bill

The operation sheet for my 6300 series converter says, "The rate of charge will decline as the battery reaches full charge. After the battery reaches full charge, the charging section will drop back to maintenance level. It will not resume active charging until the battery again falls below full charge". Does this mean that overcharging shouldn't be a serious problem to worry about?

[Bill]

Sounds like it, doesn't it? And it is a good start. But look further down in the same sheet. It says that if you leave the charger connected, you should check the battery water once a week. Loss of water is a sign of overcharging. I refer you to my post above on three-stage chargers. Feel free to ignore it.

The short answer is that the converter is fine when your camper is in active usage. And it is OK to leave the converter connected for medium-term storage (a week or two). And it is probably OK to leave it connected for long-term storage (say for several months over the winter) as long as you check the battery once a week. However, if you leave your TM in storage for months, and leave the converter connected, and don't check the water, you will likely come back to a low-water overcharged battery. If this is your storage situation, it is better to fully charge the battery, and then simply disconnect it. The battery will hold its charge well, especially in cold weather. But be sure to actually disconnect the battery - the TM contains a couple parasitic loads (devices which draw current even when everything is nominally turned off) that will kill the battery if they remain connected.

Bill

[rotor_wash]

Check out Water Miser Battery Caps. They help delay the time between water additions to your battery. There is even some thought as to reducing venting problems as well. We solar junkies very commonly use them as we are in the charging business whenever the sun is shining.

One of many sources as well as a good explanation of how it works:

http://www.solar-electric.com/batwatmiscap.html

Greg