battery ah?

[bsedwebt]

DEEP CYCLE marine batteries are the only way to go - be aware of the amp hour ratings and how they are figured - some rate at a 1amp load others as much as 5amp load. The WallyWorld ones use 1amp load if I recall correctly. That being said I have found the Trojan to be a superior battery but at a superior price and hard to find locally. The Interstate battery appears to be a good compromise - I got one at the local Gander Mountain on sale a couple years ago for less than $100 - I believe group 27 for the 17' Casita

[Jon Vermilye]

Originally Posted by BatDude

Thanks all!

Yes, I did "cite" incorrectly AH figures.

Yes freezing insulin essentially "Kills it"
When on the road for many months it is important that my insulin lasts.

One does not need to toss it after 28-30 days as many advocate, if keep refrigerated. So both my long acting and rapid acting vials will last 3 months if cared for. Short term a vial can be "cool" and I have used a small evaporative cooling pouch when I was doing field work in the jungels of Belize for weeks at a time.

I had to bring a years supply with me every year when we had our 30 day home leave to buy peanut butter (now off my menu as a diabetic), socks and have our annual medical tune ups.

I did do more reading last night and have a better understanding of "Marine" vs true deep cycle batteries.

Hi Byron, I do recall set up in Death Valley from a few winters back, but failed to remember the AH of your battery. Yes, the Honda is only used as a Shore Power supply.

The challenge will be to find a place to purchase one within a week or so.
There are many boat shops here in quasi-rural Michigan. Wallyworld lists a number of what appear to be deep cycle batteries but not for store pick up.

I imagine shipping on a 45-60 lb battery will be a fair amount.

Cheers all.

One of the problems with many RV refrigerators is temperature regulation. My Dometic RM2510 will often go below freezing on a cool night, then swing into the 40's on a hot day. A good way to help average temperature swings is to keep your insulin or other refrigerated meds is a styrofoam ice chest in the refrigerator. You can find them is all sizes since they are used to ship products by mail. I use a large one to keep my non refrigerated meds from extremes in the trailer, but a smaller one would probably help inside the fridge....

[Glenn Baglo]

This new Trojan battery looks interesting. Weighs a ton and is rather large.
J200-RE | Trojan Battery Company

[BatDude]

Took a bit of phone tag and Internet searching, but I found a realtively low cost replacement battery for our Scamp.

Interstate 24M SRM24 $127.87 including Mi. sales tax. It will be ready for pick up Wed. AM about 20 minutes away.


Specs: Cranking Amps:690; Cold Cranking Amps:550
Voltage:12
Termination:Common Code M
Weight (lbs):46.3; Width (in):6.88; Length (in):11.00; Height (in):9.50
ReserveCapacity:140 amph

WET

Thanks all for the discussions, suggestions and links. Given cost and charging system it does seem wet is best as long as it is on our "Check-list" of things to monitor.


Also saw this:

This Battery Will Self-Destruct in 30 Minutes


This Battery Will Self-Destruct in 30 Minutes - Science Friday

Cheers all,

Bruce

[The Minimalist]

ReserveCapacity:140 amph

Note: Reserve Capacity and amp hours are not the same. Reserve Capacity is the time a battery will deliver 25 amps at 80 deg F before dropping to 10.6 volts, and is given in minutes.

Amp hours is the time a battery will give useful amps over a period of time. Once again useful amperage is considered exhausted when the battery drops to 10.5 volts. The standard test for deep cycle batteries is 20 hours. As an example, in the standard 20 hour test, if a battery is listed as 100 ah@ 20 hrs, that battery theoretically will produce 5 amps continuously for 20 hours. (100 ah/20 hrs)

Whether or not the amp hour rating is listed on the battery, it is best to check with the seller, and have him show you the spec sheet. At the top of the amp hour column there should be a note indicating the test hours. If you can't certify that the AH is based on a 20 hour test you can go by the reserve capacity by multiplying it by .61. This will give you a fair approximation of the 20 hr amp hour rating.

I'd be cautious of any seller that can't give you the information you need to make a fair comparison of batteries.

[BatDude]

Hi all,

I am re-thinking the Interstate battery.
Canceling that order.

Byron said he uses Trojan (he indicated 100 APH). I called the Batteries Unlimited shop just to the south of us and the fellow indicated he could get one in a few days. However, he indicated that he has "Better luck" with RV owners using DEKA wet cell deep cycles both the 27 and 31 types are used.

The Trojans are a lot more $ and have not lasted any longer than the Deka.

I will use recycle/the old Scamp battery (24EV) for our small boat trolling motor as long as it lasts.

Bruce

[Wizard765]

I've been looking at batteries as well and what I've come up with is 2 6V batteries that they use for golf carts etc.. seems a lot of people go this way and get way more time out of the batteries

[Civilguy]

Bruce,

I ran across an interesting thread about batteries and discharge rates some time back:

https://www.physicsforums.com/thread...attery.482113/

There are several threads on FGRV that discuss how to get an alternator's power delivered more efficiently to the trailer's battery. There are also several threads that mention Peukert's curve.

Personally, I am still at the stage of trying to better understand "what I have" with my substantially stock Casita. (This actually applies to all of the trailer's appliances, equipment and systems.)

The battery is an newer Interstate Group 27 with about 95AH capacity, same as was supplied stock.

I am currently focusing on small incremental changes with a focus on the "load side" of the equation.

I have installed LED lamps which use about 16% of the power of the stock incandescent lamps. I have also mounted a Hella marine fan on a small plywood base. It can be very effective while drawing substantially less power than the Fantastic fan; it uses about 40% of the Fantastic Fans' low-speed draw.

Most batteries generally have a broadly similar capacity per a given volume (which correlates to weight). So, adding additional capacity whether by battery, solar or generator, can quickly become expensive in terms of money, weight, and space.

You might be able to acquire some "additional capacity" by monitoring and adjusting the loads and usage.

I'm sort of thinking like Jimmy Carter in his cardigan sweater here...

[DeBreez]

I recently replaced the original battery in our Casita with a Trojan 27TMH, which is a group 27, 115 amp hour battery. There are other models as well, size can be an issue in small trailers (I had to change the terminals to make it fit) so measure carefully.

I got on their website and called their nearest distributor, who referred me to Atlantic Battery in Miami. Just a little hole in the wall place but super nice people and only $145 with the old battery. Much cheaper than any of the online sellers.

[Joe Romas]

A little clarification is needed here.
The reason the trailer battery is not charging properly with the refer on going down the road is NOT the amperage of the alternator!
It's the voltage loss in the close to 50 feet of wire between the alternator on the TV and the trailer's refrigerator.
The TV's alternator charges it's battery at the proper voltage of around 14 volts but every connection and inch of wire between the TV's battery and trailer's battery presents a small voltage loss, add them together and there's not much left by the time it gets to the trailer's battery when you add in the load of 14 amps the refrigerator takes the voltage in the trailer is reduced considerably.
Chevy trucks up the charge voltage when the load/haul button if equipted is pushed. Some claim that hurts mpg's because of the shifting but my silverado does not shift any differently when the button is pushed. I've also read turning on the head lights ups the volts too but have not checked that.

Joe