Hopefully, this should save someone having to replace a battery. After I managed to kill the OEM jar on my TT, here are some lessons I'm passing on. Right now, I just replaced the battery with a generic deep cycle from a local auto parts store, but once this festival rolls around, that battery will be used for the macerator pump, and I'll be getting two AGM jars. My lessons:
1: My single stage RV converter did a decent job at boiling the battery at 13.8 VDC. Replacing the converter isn't a priority, although if I did want to keep my trailer, I'd pull that converter and install either a better, three stage one that is gentler on the batteries, or a complete inverter.
2: If using a furnace, "one battery, one night" as a rule of thumb. Even if the furnace came on every couple minutes per hour to keep the temperature at 40, the 7-10 ampere-hour drain resulted in a dead jar while stored, even with running a generator for a few hours weekly to charge it.
3: If one doesn't want to be bothered with watering the cells, probably the best thing to do is get two Optima Blues in parallel, and that solves that. Of course, these are fairly expensive ($200-$250, although I found one place that sells them for $125 or so with a coupon), and have about 75% of the amp-hours that other AGMs do (75 Ah each), but supposedly these batteries are extremely hard to kill, other than leaving them for months in a completely discharged state. Where I live, it is hard to find any other good AGM battery other than the Optimas.
4: Schumacher chargers do an OK job charging, but once charged, they will go into float mode. However, if the battery starts getting drained, they seem to remain in float mode, and won't go back to a normal charging mode unless manually nudged. This did the coup de grace on my old battery, as I was expecting 10 amps/hour coming into the battery, so I could leave the furnace set on 40. Lesson learned: Have a 40A charger plugged in and on the battery as well when running off the generator.
5: When I put my TT back into storage, it is going with an 8A Battery MINDer, and with some access to shore power. That, or I just disconnect a cable.
Thousands upon thousands of RV'ers charge their batteries with a single stage converter without boiling their batteries.
Don't blame your maintenance negligence on the converter. I charge my "jars" with a multi-stage charge controller. Yet I need to fill water several times a year.
If the battery doesn't gas, then it's not getting a full charge.
If the battery doesn't need water then it's not getting a full charge.
It isn't the converter that killed them (I killed the battery by letting it completely discharge multiple times). However, a multi-stage converter is a lot easier on batteries than a single stage.
What is interesting is how relatively inexpensive good converters are. If I felt more confident, once my TT is out of warranty, I would pull the old one and put in a more sophisticated model that works better with AGM batteries.
One of the solar sites sold me my four Concorde Lifeline agms about 6 years ago. I can vouch for their ruggedness and durability.
The 4C battery size is the largest agm that can be shipped by regular UPS. When I bought mine I could not find a reseller for three states around me that could match the shipped price of the online dealer.
Those Optimas are rugged but really for folks who do not need many Ah's. Not even close in price per ah when I got my "gold standard" Concordes.
mlts22 wrote: ... I would pull the old one and put in a more sophisticated model that works better with AGM batteries.
It depends on which brand/model of AGM. One forum member here swears by his 7345 13.8v single stage for his AGMs because his AGMs are spec to that voltage. AGMs are all over the map for what voltages they require.
2003 Chev 2500HD Gas, 2003 Komfort 26FS 5er
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