Maintenance & Restoration

jwcolby54 · 10-21-2013, 12:24 PM

Quote:

Originally Posted by Ian G.

It is actually exactly the opposite, as a battery discharges the acidic content of the electrolyte decreases (the electrolyte become closer to water). A fully charged battery has a higher acidic concentration. This is why a fully charged battery will not freeze where as a discharged battery will.

Thanks Ian, I stand corrected.

AFAICT the discussion of damage from maintaining even a partially discharged state still stands.

Sulfation and How to Prevent it - Battery University

This web site is a fascinating read and I am working my way through it. Much of it is about other technologies which have little relevance for us RVers.

My problem is that I live in my caravan, connected to AC, so the batteries are charged however much they are charged and then sit at that charge for long periods. Given that, I would prefer that my batteries are fully charged. It isn't clear whether I need to periodically use them some amount, and if so what that amount might be.

What is clear is that the built-in charger in my converter does not use a remote sense, does not use a remote temperature sense, and according to the converter manufacturer simply times the bulk charge phase. And according to the manufacturer, the voltages that they use seem to be selected based on a "do less harm" algorithm, i.e. avoid overcharge at all costs. Given that they do not use any type of remote sensing it becomes clear why they follow this strategy. Given that they are not programmable at all, i.e. battery type or environmental temperature, the fact that I have a pair of 6v batteries pretty much guarantees that their "do less harm" algorithm is badly maladjusted for my needs.

Thus I choose to spend extra money to go third party.

Since I don't drink, and thus haven't a benchmark such as "a good bottle of wine a year", I tend to simply equate the cost of a third party charger to the cost of a pair of batteries.

I only need to avoid one battery replacement cycle to recoup my costs.

Bob Miller · 10-21-2013, 01:34 PM

"I tend to simply equate the cost of a third party charger to the cost of a pair of batteries."
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Blanket statements to the effect that none of our RV batteries are being fully charged and are without (necessary?) benefit of sensing and temperature compensation, might lead some owners to question the condition of their own equipment and unnecessarily spend on other equipment that may not correct a problem that may or may not exist,

Perhaps you could share the name and price of the battery charger that CAN correctly charge an RV battery. Then cost vs. benefit can be weighed, and we can get off this horse once and for all.

multi-task · 10-21-2013, 01:38 PM

Quote:

Originally Posted by Carol H

Humm do you not have at least some lights that are 12volt? Would think unless someone changed the wiring on your trailer that every time you turn one on its pulling from the battery - plugged in or not. So you battery really is not sitting and doing nothing when you are plugged in.

If by plugged in he is referring to plugging in a converter, the converter will be providing the 12v power, not the batteries. I've tested this on two different converters and a tri-metric meter. The converters increase their output as appliances/lights/etc are turned on. This is also why you can remove the batteries and the converter should still power everything.

Of course I can't speak to how well his converter operates. If it can't keep up the batteries will be used.

Carol H · 10-21-2013, 02:02 PM

Quote:

Originally Posted by multi-task

If by plugged in he is referring to plugging in a converter, the converter will be providing the 12v power, not the batteries. I've tested this on two different converters and a tri-metric meter. The converters increase their output as appliances/lights/etc are turned on. This is also why you can remove the batteries and the converter should still power everything.

Of course I can't speak to how well his converter operates. If it can't keep up the batteries will be used.

Drew your right .... wasnt thinking ..... to avoid the big concern the op seems to have in regards to boiling the battery when plugged in long term depending on the converter they might be able to just pull the fuse out of the converter that looks after the charging function.

honda03842 · 10-21-2013, 02:13 PM

We switched from our motorhome to a trailer and while traveling in the trailer would leave the motorhome plugged in with the convertor on. When we came home after 7-8 months we would have to add water, maybe an inch or so, to our Trojan 105s but they were in no way damaged, at least they still worked well.

Our convertor was a PDI with smart charger.

multi-task · 10-21-2013, 02:39 PM

Quote:

Originally Posted by Bob Miller

"I tend to simply equate the cost of a third party charger to the cost of a pair of batteries."
---------------------------------------------------------------

Blanket statements to the effect that none of our RV batteries are being fully charged and are without (necessary?) benefit of sensing and temperature compensation, might lead some owners to question the condition of their own equipment and unnecessarily spend on other equipment that may not correct a problem that may or may not exist,

Perhaps you could share the name and price of the battery charger that CAN correctly charge an RV battery. Then cost vs. benefit can be weighed, and we can get off this horse once and for all.

I happened to search for something like this the other year. The only one I could find that had the same features as my solar controller (programmable set points, temp compensation, allows equalization) was this one:

Battery Charger - TBS Electronics - Manufacturer of Inverters, Chargers and Battery Monitors!

However the cost of it made no sense. My solar controller cost 1/4 the price and if you add in the cost of panels you'd accomplish the same thing with the added benefit of not needing a plug in site.