6V Batteries

[bcope01]

My two OEM 12V Interstates have kicked the bucket. I think I want to replace them with two Trojan 6V T-105 Plus deep cycle batteries wired in series. The limited research I've done on the internet showed that these batteries have jumped in price from ~$65 to ~$125 each in the last 18 months. Wow, I should have been investing in lead instead of real estate.

Bill

[Brent]

Hi Bill, I can't comment on the price; but I put the same two batteries in my unit several years ago. They work great!

The two batteries take a deep discharge and recover well. I boondock a lot and use my inverter, which of course pulls on the batteries. I'm surprised they aren't standard issue with a new BF. Just be careful if you are jumping with cables to hook up correctly.

Also it is a tight squeeze to service the batteries, so I installed the hoses that just fit on the tops of the two batteries and you use a pump to service - very easy to do; I would recommend it.

Brent

[BornFree_n_Now]

Upgraded a couple of years ago to the Trojan T-125 batteries, believe they are the same size or close to the same size as the T-105’s, but with additional capacity. Also put in a watering system (camping world) ~~ would not be without either :>)

[bcope01]

Brent and Larry, I'll be out to the local shops pricing batteries tomorrow. Whether I get the 105s or 125s will probably boil down to cost. The new "Plus" series of these Trojan batteries have a new flip-top vent cap; a built-in maximum level indicator in the vent well; and embedded terminals. I had the Camping World pumper system you mention on my Interstates until I changed out the old battery tray with the new design offered by Born Free. The new tray allows the battery tray to extend all the way out exposing completely all of the batteries. With this new tray I decided to do away with the pumper system since checking and filling them manually wasn't a big deal anymore.

Bill

[bcope01]

Had two Trojan T-105 Plus batteries installed today. Cost was $238, including tax. Everything fit and the existing cables worked fine. Replacing batteries is not an inexpensive ordeal anymore.

Bill

[kent0826]

As a potential Born Free owner how long can you boondock on the batteries before having to recharge? I assume it depends on what's being used and for how long it's being used. Can it be expressed in total wattage consumed? And a follow up -- how long does it take to recharge? Thanks much.

I attended the Richmond RV Show and spend a good bit of time looking at the BFT and 24RB in Casual Elegance. What a beautiful coach.

--Kent

[Brent]

Kent, you can calculate the use per appliance, time used and compare with the capacity of your batteries. I've not gone to this length.

I have used interior lights, the TV, maybe a computer for the evening and left something on all night. The batteries didn't really register a heavy discharge on the monitor.

Now if you use things like hair dryers, toaster oven and heavy use appliances I would think it would draw down much faster. If I get to setting in one spot and want to use the batteries until they discharge, I may get a 100 watt solar panel put on the roof so I can recharge without the generator. So far that has not been an issue.

[whemme]

Kent,

If you plan on doing a significant amount of dry camping where AC shore power is not available, then battery capacity and time to recharge using your generator will become an issue. I have two Interstate deep cycle batteries in my BF coach with rated total capacity of 210 amp-hours. I have found that that the furnace fan running on a cold night to be the biggest draw on battery capacity. My experience is that you can run only two days & nights including some TV watching before my batteries are basically depleted and need recharging. If you have an inverter and run some high power devices such as a hair dryer or a toaster oven off of your batteries, they will be depleted even faster.

The other problem is the time it takes your generator to recharge your depleted batteries. Most BF coaches in the last several years were equipped with a Magnetek/Parallax 7345 charger/converter. The battery charger in this device is only a single stage unit and you would need to run your generator for approximately 3 days to get your batteries back to a full charge condition.

Because of this slow recharge problem and that most people would not be happy to have to run their generator that long to recharge the depleted batteries, some owners (including myself) have replaced the 7345 charger/converter section with a 3-stage charging unit. The one I chose to install as a replacement was the Progressive Dynamics PD9160A charger/converter with the optional Charge Wizard. This unit is much faster at recharging your batteries via the generator and will bring the batteries back to full charge in approximately 4 hours rather than 3 days. The other option is to install a solar panel system on the roof of your BF coach as Brent suggests above and hope you have some sun light during the day to recharge your batteries when your are gone.

You can look at my post titled CONVERTING PARALLAX 7345 CHARGER/CONV TO PD9160A in the Coach Modifications section on this forum for complete details on how to install the PD9160A.

[bcope01]

Bill, I also replaced my Born Free OEM Magnetek/Parallax charger/converter with a 3-stage charger/converter. I replaced it with a 55-amp IOTA model using your excellent conversion/installation instructions that can be found in this forum. Thanks for providing those.

I know I can use my generator to recharge my coach batteries, and with the new IOTA 3-stage charger/converter it will be faster than the OEM system. But isn't it even more efficient (faster yet and more fuel efficient) if I just idle the chassis engine and let the alternator charge the batteries?

Take for example a 110-amp Ford alternator (I'm not completely sure what we have in our coaches, they may come with a higher output alternator than this). Amperage output at idle (650 engine rpm) is 64 amps. At a raised idle of 1,700 engine rpm, the alternator output ramps up 91 amps.

Obviously, the alternator output amperage beats most installed chargers/converters. The big question is what consumes more fuel, the coach generator or the chassis engine running at idle, but for less time. My gut feeling is that idling the chassis engine will recharge the coach batteries quicker and at less cost in fuel. Do this make any sense?

Bill

[whemme]

Bill,

My opinion would be that yes the motorcoaches engine alternator would probably recharge your coaches batteries faster than a 3-stage charger/converter but not by much. The alternator on the Ford V10 is rated at 130 amps according to my spec sheet.

The reason I say that the V10 alternator will not charge that batteries much faster is based on the following observations: I have both a voltmeter and an ammeter in the charging circuit on the output of my PD9160A charger/converter. When my coach batteries are essentially depleted and I start my Onan generator to recharge them, the charging current starts out at 60 amps, the full rated output of the PD9160A charger/converter in its boost mode output at + 14.4 vdc. However, that 60 amp charge rate only lasts about 10 to 15 minutes before it starts to trail off. That is because the batteries no longer will accept a 60 amp charge rate with a +14.4 vdc charging voltage. I would submit that under these same conditions except recharging from the 130 amp engine alternator you would experience a similar result. The alternator will charge the batteries faster than the PD9160A but only for the first few minutes before the charging current drops below 60 amps.

My guess would be that the engine alternator might possible shorten the time to total recharge a set of depleted coach batteries by at most 5 or 10 minutes. Therefore, it still would take the engine alternator approximately 4 hours to fully recharge the batteries - not just 2 hours.

I also think that the Onan generator will take less gas than the V10 would idling to do this recharge job. My Onan burns approximately 0.6 gallons/hour when the output is in the 1000 watt range according to its manual. An that 1000 watt output is close to what it is putting into the PD9160A when it initially is charging at its full 60 amp rated output but then it slowly drops off from there. I really think that the V10 would be burning quite a bit more than 0.6 gallons per hour at idle - just my opinion.

[rv4fun]

I also replaced charger/convertor on my coach following Bill Hemme's excellent directions for making the changeover. While it might be faster to charge the coach batteries by idling the V-10 engine and using the alternator, I don't think it will be as efficient. It will probably burn a lot more gasoline to do this than to run the generator for 4 hours. I believe I read somewhere that the generator uses around 1 gallon per hour or maybe a liitle less. Running the generator for 4 hours would then burn around 4 gallons of gas. I'm not sure how fast the V-10 engine consumes gas on idle, but I'm thinking that it's a lot more than 1 gallon per hour.. Larry

[bcope01]

Yes, but what if only took one or two hours (or less) at engine idle to achieve what it took the generator 4 hours to accomplish? It would be interesting to measure volts and amps coming from each and do the calculation of the time needed to bring a discharged battery up to fully charged. Then the fuel consumption of each would need to be measured. Both calculations way beyond my capabilities.

FWIW, I tend to idle my engine if I just need to charge my batteries (charges both coach and chassis batteries at the same time) and my generator when I need AC (with the added benefit of charging my coach-only batteries). As I only boondock periodically, and not often for more than a day or two, I don't normally need to do any supplementary charging since driving between camping spots usually keeps the batteries fully charged.

Bill

[Randy Wilson]

Based on my experience trying both methods of recharge while dry camping, the V10 engine appears to be much more costly. It recharges at a high rate, but not so much higher than the Progressive Dynamics converter/charger. My generator consumes only about 1/2 gallon per hour charging while carrying other small 120V loads. While I don't have an exact consumption on the V10 idling, my fuel usage vs. usual expected fuel consumption indicated usage at least twice that of the generator. I monitor the batteries with a Xantrex XBM system and compared fuel consumption based on extensive, detailed record keeping of fuel consumed. Admittedly, this is not exact, but the difference was clearly in favor of the generator with a multi-stage charging system.

[whemme]

Sorry but I left my posting above dated Wed Feb 13, 2008 12:16 pm uncompleted earlier. It now has been completed with the other info that I wanted to put into that post.

[whemme]

I test drove our 2002 BF 26' RSB coach later today in preparation for our leaving for Phoenix on Monday. I have a Scan Gauge engine monitoring system and I was able to measure the fuel flow of my V10 engine at its normal 800 rpm idle speed. The fuel flow toggled between 0.8 and 0.9 gallons per hour. I actually was suprised that is was that low. That would compare to the 0.5 to 0.6 gallons per hour that the Onan generator would use to recharge the coach batteries.

The 1.0 gallons/hour that Larry Rayher speaks about in his post above is with the Onan generator fully loaded generating 4000 watts. The Onan will be generating on average approximatley only 500 watts to recharge the coach batteries which will result in the lower 0.5 to 0.6 gallons/hour fuel usage.