Batteries

[RCaerobat]

Hello,

I have read that the best batteries to use in the TM are two 6v golf cart batteries. Is there a certain brand that seems to be better and where is the best place to buy these? Also, what is the best method for charging? I read in the owners manuel that is the TM is plugged in, it will top off the battery. But, I imagine that is not the most effecient way to charge them. So, what charger do you recommend?

Thanks again,
Emory.

[B_and_D]

I can't tell you about the best way to charge, still trying to perfect this ourselves, but we got two 6 volt Trojan 105's from our local Interstate Battery store. They were really helpful about info on hooking them up/cables, etc. They were about $70 each, without sales tax, etc. What they didn't have we found at a local auto store.

We put wing nuts on them so that we could easily interchange them with our 12V deep cycle battery when we need to switch.

I would really like to invest in a solar charging system, and also buy a Honda generator for those times that there isn't enough solar power to charge. When we were in Lake Almanor this summer, our neighbor had one of the 1000 models, and it was pleasantly quiet. He thought that it didn't have quite enough "oomph" though, and wished that he'd bought the 2000 model. We are "newbies" to the world of boondocking/electrical camping; we ended up just buying a set of jumper cables from the ACE hardware store in Chester, taking our batteries off the TM, hooking them up to our truck battery, and charging off the truck battery while it was running for 20 minutes or so. We tried charging the batteries with our converter by idling the truck, connected via the 7 prong plug, and they didn't charge up at all.

I've read that you shouldn't idle your vehicle that long to charge your batteries, but it worked for us. In the meantime, before we invest in a generator or solar rig, I'm planning to buy a battery charger that we can run off of our inverter while we're driving around and charge the batteries (we'll have to take them off the TM) in the tool box of the truck. You don't want batteries inside your TV unless you have ventilation, they give off harmful gasses.

I am not an expert at this stuff, still learning here, so hopefully someone else with some more expertise at these matters on the board will also answer. Please take my ideas with a very large grain of salt.

I did buy the book called "RV Electrical Systems: A Basic Guide to Troubleshooting, Repairing and Improvement" by Bill Moeller & Jan Moeller and I've found it very helpful in understanding a lot about our TM's electrical system. We keep it in the TM and read it every time we venture out.

D'

[Bill]

B_and_D wrote: We got two 6 volt Trojan 105's from our local Interstate Battery store.These are widely accepted to be very good batteries, especially for the price. They are widely used in RV systems like our TM systems, and are also widely used in applications like solar power for homes, where battery efficiency, capacity, and longevity are very important.

and We tried charging the batteries with our converter by idling the truck, connected via the 7 prong plug, and they didn't charge up at all.Yup, isn't that annoying? The problem is that the TM battery is at the end of a long wire, and there is a lot of voltage drop in that wire. The voltage regulator in the truck's engine compartment cuts off the alternator when the truck's battery is charged, but the TM battery is at a lower voltage - ie, not charged. And if you have any appliances in the TM turned on (ie, refrig), the problem is even worse.

and ... taking our batteries off the TM, hooking them up to our truck battery [with jumper cables], and ... running for 20 minutes or so. I've read that you shouldn't idle your vehicle that long to charge your batteries, but it worked for us.I think this warning is left over from the old days when the truck's engine would get a lot of carbon in the cylinders if you left it idling too long. Today's computer-controlled engines shouldn't have any problem. And your batteries charged better because you brought them right up to the engine compartment where the voltage regulator could see them - and used big wires (the jumper cables) to connect them.

and finallyI'm planning to buy a battery charger that we can run off of our inverter while we're driving around and charge the batteries in the tool box of the truck.This will work, but be aware that a standard garage-type battery charger will happily overcharge your battery. You might consider buying a 3-stage charger, which will not do this. I bought a Model 2610 from Guest Industries (http://www.marinco2.com/searchProducts.asp?c=Onboard+Chargers). It charges at 10 amps, and properly changes the charge rate to match the state of charge of the battery. (A model 2620, at 20 amps, would charge faster). I mounted mine permanently in the battery compartment of my 2720SL, and when the TM is at home or in storage, I leave it plugged in 24/7/365. You can't do this with a garage-type charger. You might want to keep yours unmounted, so you can carry it in the truck.

You are on the right road to battery happiness - let us know where you go.

Bill

[paul street]

:new_newbi
Regarding battery charger, what is a "Float Charger"?

See http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=42292

Not an expert but this sounds a little like what others have mentioned.

:new_newbi

[RockyMtnRay]

:new_newbi
Regarding battery charger, what is a "Float Charger"?

See http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=42292

Not an expert but this sounds a little like what others have mentioned.

:new_newbi

Well, the item is indeed described as a "float charger" but is totally absent any specifications to confirm that...or any indications of what kind of current it puts out. To be honest, the price seems waaaaay too low for it to be a reliable, safe charger that I'd trust a battery to. At that price point, I have major doubts about the sophistication of the circuits and quality of the voltage controller and transformer, not to mention the quality of the wiring. The old saying of "you get what you pay for" is usually true...quality float chargers like the one that Bill recommends...or the "Battery Tender" models from Deltran...seem to retail around $25 to $50 at merchants who know what they're doing and carry quality merchandise. Yes, Harbor Freight is a low overhead operation but they also tend to sell bottom of the line merchandise.

I'd look for a better quality unit that has been reviewed by an RV publication...or by a motorcyle publication since motorcycle batteries have the same winter storage considerations.

[Denny_A]

Bill,

That was the best Batt Charging tutorial I've seen - ever.

A big HIGH FIVE!

:D Denny_A

[paul street]

:new_newbi

I agree. That was great Bill.

But, I am still somewhat confused.

In your earlier posting, you alluded to, if I read it correctly, that the TV hook-up, via the Bargman connection, and it's alternator, would not re-charge the TM battery sufficiently ... or at all.

I was under the impression that the converter tackled that problem; ie, discharged 'house' battery; and accomplished this while driving 'on the road', etc..

Please help this confused NEWBIE out.

Thanks :new_newbi

[RockyMtnRay]

In your earlier posting, you alluded to, if I read it correctly, that the TV hook-up, via the Bargman connection, and it's alternator, would not re-charge the TM battery sufficiently ... or at all.

I was under the impression that the converter tackled that problem; ie, discharged 'house' battery; and accomplished this while driving 'on the road', etc..

The converter can recharge the house battery only when the "shore power" cable is plugged into a 110V AC source like a campground electrical plug or a generator.

A converter is so named because it converts 110V Alternating Current "shore power" into the 13.8V Direct Current needed for a TMs DC appliances and lights and for recharging the battery. The converter's only source of 110V AC is the shore power cable. While driving down the road, there is no 110V AC source available to the converter. Ergo, the converter does nothing while driving.

Actually, the "12 Volt" line from the tow vehicle through the Bargman plug will in most cases provide some recharge to a discharged house battery, particularly if a heavy load like the refrigerator is not running on DC. The recharging current is not large...around 5 to 10 amps...and the maximum recharging voltage is often not much over 12.5 (due to resistance in the wire and connectors). It's not enough current to fully recharge a badly discharged battery in the few hours of a typical trip, nor is it a high enough voltage to bring the house battery to a full state of charge (around 13 volts). But it will usually partially recharge the house battery...before I installed solar panels on my TM, I would leave a campground with an almost completely discharged house battery and by the time I got home (after about 5 hours of traveling) the battery was up to around 60% of full charge.

[RCaerobat]

Good stuff so far. Thanks. So far, I have a vote to buy the Trojan 105 batteries and a Guest 2610 charger. Any other good options?

Emory.

[paul street]

Thanks for this information. Helps with the muddy waters. Guess what confused me, since I am new to the trailer concept, is that in our self contained RV, when driving, it's set-up does re-charge the 'house' battery.

Is there no way to accomplish this that you know of?

Paul :new_newbi




The converter can recharge the house battery only when the "shore power" cable is plugged into a 110V AC source like a campground electrical plug or a generator.

A converter is so named because it converts 110V Alternating Current "shore power" into the 13.8V Direct Current needed for a TMs DC appliances and lights and for recharging the battery. The converter's only source of 110V AC is the shore power cable. While driving down the road, there is no 110V AC source available to the converter. Ergo, the converter does nothing while driving.

Actually, the "12 Volt" line from the tow vehicle through the Bargman plug will in most cases provide some recharge to a discharged house battery, particularly if a heavy load like the refrigerator is not running on DC. The recharging current is not large...around 5 to 10 amps...and the maximum recharging voltage is often not much over 12.5 (due to resistance in the wire and connectors). It's not enough current to fully recharge a badly discharged battery in the few hours of a typical trip, nor is it a high enough voltage to bring the house battery to a full state of charge (around 13 volts). But it will usually partially recharge the house battery...before I installed solar panels on my TM, I would leave a campground with an almost completely discharged house battery and by the time I got home (after about 5 hours of traveling) the battery was up to around 60% of full charge.

[RockyMtnRay]

Is there no way to accomplish this that you know of?


:confused: :confused:

Did you mean "is there any other way to accomplish this?" If that's what you were trying to ask, then there are at least a couple of other ways to get a house battery recharge while driving.

Probably the least expensive/complicated is to run a dedicated and very heavy gauge wire (8 guage or larger) from the tow vehicle's alternator to the hitch, thence through a dedicated very heavy duty connector to more heavy duty wire that connects directly to the trailer's house battery. By using very heavy duty wire and one low resistance connector, the full voltage produced by the tow vehicle's alternator will reach the trailer battery and a very substantial (20 to 30 amp) charging current is enabled.

Another is to go through the considerable complications and expense of installing a generator on the trailer that could be operated while traveling. One TMO member did mount a propane powered genset on his TM's hitch that could theoretically have been used to do this. Advantage: Puts out enough current to run the refer and recharge the battery! Disadvantage: Costly, heavy, and needs a source of fuel while traveling.

Another option is to mount about 400 watts of solar panels on the TM's roof...a 400 watt array will produce roughly 20 amps of current which is enough to run the refer and recharge the battery. That large an array will cover most of the roof though...and will cost around $2000. Unfortunately, solar panels only produce their rated power in full, bright sunshine...even slightly cloudy skies will drop their output by as much as 80 to 90%.

[Larry_Loo]

Bill, that was an excellent note about the different types of battery chargers that are available.

I have a Century Mfg. Co. 10 amp. battery charger that I purchased from a Good Guys auto store for about $40 several years ago. If I set it at a 10 amp charge rate for my depleted 12 volt AGM battery, it will show an initial charge around 10 amp. Then its charging current gradually diminishes to as low as zero (as shown on its ammeter). I've left it on for a couple of days when the battery was quite discharged but no longer than that. From your description my charger must be capable of stages 1 and 2 at least. I'm not sure about it going into a stage 3 since there's no voltmeter on the charger's panel.

[paul street]

RockyMtnRay......
When you say .....
"thence through a dedicated very heavy duty connector to more heavy duty wire that connects directly to the trailer's house battery."
.....what kind of connector are we talking about. I know very little about this subject and need all the help I can get. Are we talking about something similiar to the presently existing Bargman connector from the tm to the tv?

I like your suggestion of being direct connected to the tv battery in order to re-charge the house battery while driving; and will like to pursue it more; of course along with getting a desulfator and isolator also.
Paul
:new_newbi

[RockyMtnRay]

RockyMtnRay......
When you say .....
"thence through a dedicated very heavy duty connector to more heavy duty wire that connects directly to the trailer's house battery."
.....what kind of connector are we talking about. I know very little about this subject and need all the help I can get. Are we talking about something similiar to the presently existing Bargman connector from the tm to the tv?

I like your suggestion of being direct connected to the tv battery in order to re-charge the house battery while driving; and will like to pursue it more; of course along with getting a desulfator and isolator also.
Paul
:new_newbi

Well, first of all, since I have the distinct impression that you've not yet gotten much if any actual experience with the electrical characteristics of your specific Tow Vehicle (TV) and specific TrailManor, I would suggest you do nothing to the recharging system for the trailer until you do. Yes, as Bill noted previously, he's experienced a fairly large voltage drop in the recharging wire to his 2720SL's battery. I, OTOH, have experienced only a fairly small voltage drop (around .2V) between the voltage at my TV's alternator and the voltage at my TM's battery when it's recharging a fairly depleted battery. Yes, .2V is a fairly significant difference when you're talking maximum charge state but it's not that huge if the charge state of the battery is still low...and as the battery charge state rises, its voltage rises causing the charging current to decrease, which in turn causes the voltage drop over the charge wire from the TV to also decrease. The bottom line is a less-than-optimum charge circuit will recharge the TM's battery...if the TM refrigerator is NOT running on DC...it will just take longer to do it.

The important qualifier is whether or not the the refrigerator is running on DC. Turn off the refrigerator and nearly all charge circuits (even those with high resistance) will recharge the TM's house battery while driving. Run the refrigerator on DC and some TV/TM combinations will fully recharge the TM battery, others will almost achieve/hold a full charge on the TM battery, and others will allow the TM battery to discharge/not recharge at all. You really should determine where your specific TV/TM fits on this spectrum of capability before you start doing a lot of rewiring.

After several towing trips, you may determine you really do NOT need to improve your TV/TM's recharging capability. But if you do, before you get toooooo carried away with special connectors going back to the trailer (the more wires and connectors, the more likely you'll trip over something or forget to hook something up), you can do something you'll need to anyway...install heavier duty wiring (~8 to 10 gauge) directly from the TV battery (with or without an isolator) to the rear of the TV and from the TM's hitch area back to the battery compartment on your 2720SL. To be honest, I'd do the latter first as I suspect there's more resistance in the trailer's wiring and internal connections than in most TV's factory wiring harness. The Bargman connector actually is pretty well designed and is probably about as good a connector as you will get anyway. That assumes, of course, that the terminals on the TV's Bargman connector were properly connected to the wiring...quite often they're not if the TV end is an after-market add-on.

As for an isolator, that, IMO, is a fairly optional piece of equipment and you may not even need it. When I wired my previous TV (a Jeep Cherokee) for towing (it did not have the factory towing package), I did not install an isolator and simply ran a 10 gauge wire straight from the the Jeep's battery back to the Bargman connector with only a 30 amp circuit breaker for protection. In two years of towing, I never even came close to discharging the Jeep's battery. However, once I got on the road with the TM hooked up, I also never stopped longer than about 20 minutes enroute so there was never enough time for any significant discharge to happen. Furthermore, both the Jeep and TM batteries were very healthy and both had plenty of capacity to power the TM's refrigerator for several hours at its normal 11 amp usage rate. I'm sure I would have had a different story to tell if I had stopped enroute for several hours...or if either battery was very marginal. My current TV (Toyota Tundra) does have an isolator...my thought is it's a nice but unneeded feature given my traveling profile.

The bottom line is if you are likely to make long (over an hour's duration) enroute stops...and your TM's refrigerator is running on DC, then an isolator is a reasonable way of insuring you will be able to restart the TV. But isolator or not, the constant drain from the TM's refrigerator (if it is running on DC) will steadily discharge your TM's house battery anyway. If your trip does call for a multi-hour enroute stop, the smart thing to do is to simply open the TM and switch the refrigerator off DC...either completely off or to propane for the duration of the stop. Then when you're ready to resume your trip, re-open the TM and put the refrigerator back on DC again. Once cooled down, the refrigerator will...even when off...hold food cold enough to prevent bacterial growth for several hours. Leaving it off for several hours, however, may allow some frozen food to at least partially thaw or melt. So it all depends on your traveling style...and whether or not you like to tinker with things even if you don't need to. Me...I fix what really needs to be fixed, follow the KISS (Keep It Simple Stupid) principal, and believe in the "if it ain't broke, don't fix it" concept.

As for a desulfator/charger, I've had excellent experience with this BatteryMINDer (http://www.batterymart.com/battery.mv?p=VDC-12112). When in storage it acts as both a float charger and a desulfator. I store my TM in my garage and simply leave it hooked to this unit constantly between trips. Although the maximum 1 amp charging rate isn't huge, it will bring a half-discharged house battery back to full charge over the course of about 72 hours. It's float charge characteristics are quite good...even after 6 months of winter storage, I find I lose only a small amount of water from the cells yet the battery stays fully charged. Well worth the moderately high cost.