Born Free Leap'n Lions RV Club Info & Discussion Forum

Born Free has for years equipped their coaches with either one or a pair of Interstate SRM-27 deep cycle batteries. Owners needing to replace them due to age may not know that the house battery carrier used in the Born Free will actually fit the somewhat larger Interstate SRM-29 battery that has increased capacity.

The SRM-27 has a 85 amp-hour rating at a 5-amp rate whereas the SRM-29 has a 105 amp-hour rating at the same rate. Currently, the suggested retail for the SRM-27 is $97.95 and it is $111.95 for the SRM-29. Therefore the SRM-29 provides a 23.5% increase in capacity for a 14.3% higher cost. The SRM-27 weighs 53 lbs and the SRM-29 weighs 61 lbs.

Those doing significant dry camping and needing new batteries may want to consider the SRM-29 as a replacement.

Bill : How would this compare with a couple of 6 volt Golf Cart batteries ?

bill crommett,

No doubt that a set of Trojan 6 v golf cart batteries would have significant higher quality and have longer life capability. Trojan golf cart batteries are noted for being 'hell for strong' with a price to match. However, their physical dimensions do now fit the Born Free house battery carrier very well in my opinion.

Two Trojan batteries that would work if you changed the carrier would be their T-105 and T-125 6 v batteries. There are actually 7.125" wide verses the 6.750" width of the Interstate SRM-27 and SRM-29 batteries. The extra 0.375" width is what would cause a pair of them not to fit into the carrier.

However, the length of both the T-105 and T-125 is shorter (10.375") vs the length of the Interstate SRM-29 which is 13.0". Overall the Trojan batteries are smaller in total volume at 803.9 cu-in versus 877.5 cu-in for the SRM-29.

Even though the Trojans are smaller batteries overall, both have higher rated capacities over the SRM-29. At a drain rate of 25 amps, the T-105 is rated for a life of 7.45 hours, the T-125 is rated for a life of 8.13 hours and the SRM-29 (assuming two in parallel) are rated for a life of 7.0 hours.

The T-105 has a list price of $200 but I found online prices that varied from $139 to $159 depending on the vendor. The T-125 has a list price of $231 but I found online prices that varied from $158 to $179. This in comparison to the list price of $112 for the SRM-29 battery.

Just to add to this issue, I have recently committed to buy a BF 24RB and it will have AGM batteries. I will go with 4 6V and a total of 440 AH capacity. These batteries make even Trojans seem quite inexpensive and represent, IMO, a considerable bet that it is the way to go. And yes, two AGMs would fit in my tray on 2001 23RK that will be replaced.
Ralph

Thank you, Bill, but since converting to the progressive charger I have had no problem with the batteries. But I have not done much Boondocking, either. So th amp capacity has not bee an issue. Your posts have pointed the way for better Boondocking if desired.

If you have one of the newer style battery trays, a pair of Trojan T-105 Pluses fit nicely. And notice the easy access to all the cells for easy filling!

Bill

...and all tucked away.

Bill

bigdipper wrote:Just to add to this issue, I have recently committed to buy a BF 24RB and it will have AGM batteries. I will go with 4 6V and a total of 440 AH capacity. These batteries make even Trojans seem quite inexpensive and represent, IMO, a considerable bet that it is the way to go. And yes, two AGMs would fit in my tray on 2001 23RK that will be replaced.
Ralph

I would add this advice to those considering the investment in AGMs. 2-stage converters pose a significant risk due to the required frequent monitoring, the potential for forgetfulness, and are simply hard on your expensive AGM batteries. It would be wise to also invest in a 3-stage converter/charger when upgrading to gel cells.

Even with the most conscientious care, 2-stage chargers are hard on batteries and lack desulfination modes.

Mike

Mike & Jean Bandfield wrote:I would add this advice to those considering the investment in AGMs. 2-stage converters pose a significant risk due to the required frequent monitoring, the potential for forgetfulness, and are simply hard on your expensive AGM batteries. It would be wise to also invest in a 3-stage converter/charger when upgrading to gel cells.

Even with the most conscientious care, 2-stage chargers are hard on batteries and lack desulfination modes.

Mike

Mike, I am not aware of any 2-stage charger/converters used in Born Free coaches. I am aware of the OEM single stage Magnetek/Parallax 7345 unit and the various 3-stage Progressive Dynamics units and the WFCO 8945 and 8955 replacement units - but not a 2-stage unit that you speak of. Specifically what brand and models of 2-stage units are you referring to?

Sorry I may be getting thread off-topic. My postings based on the future BF will be more meaningful after I have the unit and am living with it. Sometime in the fall, or perhaps in 2011, I will provide the board a review of a rather unusual electrical system. For what it is worth, the configuration of the 12V and 120V system, that includes AGMs, being built in by BF is based on design approved by an Oregon company AM Solar which seems to be well-regarded on the subject. All parties know and understand more than I about the nuances of "3 stage, progressive, or whatever" converter chargers.
Ralph

Oops! You're right Bill. 'Didn't engage my brain. I was thinkin' 2nd generation and typing 2-stage.

Anytime the topic comes up about how much better the 3rd generation chargers are I'm thinkin how much better the 2nd generation (7300 series) chargers were than the 1st generation (6300 series) and how I must be an old codger now that I've seen that much progress. I hope I haven't confused anyone other than myself.

My point was that the 7300's are hard on batteries plus it's too easy to forget to disconnect the battery when its fully charged or when putting the RV in storage. And do you want to risk expensive batteries on a 7300 with the new 3-stage chargers now available.

Mike

Bill Cope,

I do have the newer style battery carrier in my 2002 BF 26' RSB. I stand corrected since I did not think a pair of Trojan T-105 or T-125 batteries would fit because of the extra 0.750" width of a pair of those over the width of a pair of Interstate SRM-29 batteries.

I checked my coach today and there is barely a free space of 0.750" width available with my SRM-29s. Tell me if the Trojans fit into your carrier snugly or are they a real tight fit?

Bill Hemme, they are snug but by no means jammed in. You can see I re-oriented them side-by-side as opposed to the one-behind-the-other OEM configuration. Configured the way I have them, I still have a 1.5" gap in the front of the battery tray, so a longer battery would also fit.

Bill

When I first read these posts I did not have my BF at home to check my records on what I paid for two Trojan T-105 batteries. I checked today and I paid $99.95 each for two from a local battery dealer in August of 2007. At that time I thought this to be a very good price compared to other sources I checked. I am suprised that either they have increased in price so much or that I got such a good buy! I do have the new style battery tray and they fit very well as stated above. I only had to make a spacer to fill in the extra space.

Dallas, I think all lead-acid batteries took a big jump in price shortly after you bought yours. I was told something about the skyrocketing price of lead, etc. Personally, I think the prices were artificially inflated.

An example:

Jan 4, 2008 - "Johnson Controls said the increase was not linked to volatility in the lead market, but that costs of other materials such as sulfuric acid and polypropylene had jumped as much as 200 percent in the last six months."

Bill