Charging Rate of Honda 2000

SoundGuy wrote:
.. because the battery "experts" here on the forums, whenever the subject ever comes up of dual 12 volt batts in parallel vs dual 6 volt batts in series will always insist that the chances of one 6 volt going dead while the other doesn't and therefore rendering the pair useless for powering the trailer is so rare an occurence as to be not worth considering.

That has to do with a catastrophic failure, not poor maintenance or old age.

Hi pnichols,

My (limited) understanding is that starved acid batteries run out of "working fluid" before the plates are fully discharged. i.e. there is no acid left in the battery, only water--but if there were more acid available that another 20% discharge could be done. That allows the sales pitch to say they can be totally discharged and may recover totally. It may also limit damage to the plates.

That leaves the group 31 susceptible to freezing. It also (guessing) probably means that charging profile demands are a bit squirrely.

Group 29 are not the same design as group 31 or so I have been lead to believe. i.e. the group 29 is not starved as much. That may be untrue.

My own batteries are a telecom design with a specific gravity of 1.300 and are surplus acid. This means I must treat them as if they are regular flooded batteries, with the exception of no equalization and take them no lower than 50% of fully charged. If I flatten them totally I'll damage the plates and permanently reduce capacity.

On my own system I have to limit charging to no more than 110 amps for 556 amp-hours of battery bank. i.e. 27 amps per jar. Fortunately, my Magnum inverter/charger allows me to control that parameter.

I guess what I'm trying to say is that you need to investigate what the maker recommends and follow it. If you don't then you may be treated to a shortened life span, with early loss of capacity.

Because I chose surplus acid jars I investigated them as much as I could. I do not consider myself an expert on AGM in general.

pnichols wrote:

pianotuna wrote:
The Group 31 is a starved acid format. 31's are not forgiving of errors. I'd lean towards group 29 myself.

Don ... would you explain this comment in a little more detail?

In other words:

1) Isn't any size of 6V AGM battery and any size of 12V AGM battery starved acid?

AND

2) Isn't any size or voltage of wet acid batteries not starved acid?

(However, I may not know what you meant by "starved acid"!)

Hoppypoppy wrote:
Just for the sake of closure to any who may give a hoot. One battery was dead. Other good. Thanks again.

??????

sure, seems both have been mistreated.

pianotuna wrote:
The Group 31 is a starved acid format. 31's are not forgiving of errors. I'd lean towards group 29 myself.

Don ... would you explain this comment in a little more detail?

In other words:

1) Isn't any size of 6V AGM battery and any size of 12V AGM battery starved acid?

AND

2) Isn't any size or voltage of wet acid batteries not starved acid?

(However, I may not know what you meant by "starved acid"!)

Every time one of the 12V batteries in my Ford F250 7.3 diesel died, you replaced both of them. I'd do the same with a pair of 6V batteries, the other cells were abused, each 2 volt cell, pulling load for the weak sister 2 volt cell, the whole time. YMMV, that's how I'd do it.

pianotuna wrote:
Hi SoundGuy,

I prefer 12 volt jars--but not for the reason of redundancy.

The Group 31 is a starved acid format. 31's are not forgiving of errors. I'd lean towards group 29 myself.

We're not normally dry campers so deep discharging measured in hundreds of cycles that 6 volters are so famous for isn't an issue for me but significant voltage drop under heavy load from my inverter is, ergo my preference for a pair of 12 volt G31s which will offer about the same reserve capacity as a pair of 6 volt GC-2s but are less likely to suffer as much voltage drop under heavy load as will a pair of 6 volts. Since I "know a guy" I can buy a set of RV Care branded, Deka designed batteries distributed here in Canada by East Penn at just slightly over cost. I appreciate your caution about the G31 size but since there are no G29 versions offered in this particular lineup I'll have to go with the G31 as the next size down is the G27.

Hi SoundGuy,

I prefer 12 volt jars--but not for the reason of redundancy.

The reason one of the OP's six volt jars failed is because they were repeatedly deep cycled, and rarely brought to 100% state of charge. One happened to measure ok and the other did not. But we don't know what testing was done. I suspect that if he had treated the 12 volt jars the same as the 6 volt, that the results might be the ame--one battery dead and the other "passing" (probably by the skin of its skinny skin teeth).

The Group 31 is a starved acid format. 31's are not forgiving of errors. I'd lean towards group 29 myself.

SoundGuy wrote:
Personally, I'd rather not be left with one live and one dead 6 volt so when I upgrade this spring from my existing single G27 I plan to do so with a pair of 12 volt G31s that together will offer similar capacity to a pair of 6 volt GC-2s but which can each power the trailer on their own should I so choose.

Hoppypoppy wrote:
Just for the sake of closure to any who may give a hoot. One battery was dead. Other good. Thanks again.

I do. ;) Five long pages ago in your original post you indicated these were dual 6 volt batteries, one of which you're now saying is dead while the other is still OK. That's interesting because the battery "experts" here on the forums, whenever the subject ever comes up of dual 12 volt batts in parallel vs dual 6 volt batts in series will always insist that the chances of one 6 volt going dead while the other doesn't and therefore rendering the pair useless for powering the trailer is so rare an occurence as to be not worth considering. Your report is just one of quite a few I know about in which 6 volt battery owners have reported the same problem ... I suppose the question now for you is whether to replace just the one dead battery with a new one or to replace both so they're both the same age. Personally, I'd rather not be left with one live and one dead 6 volt so when I upgrade this spring from my existing single G27 I plan to do so with a pair of 12 volt G31s that together will offer similar capacity to a pair of 6 volt GC-2s but which can each power the trailer on their own should I so choose.

Maybe no one else will say it ... but thanks for the update! :B

Just for the sake of closure to any who may give a hoot. One battery was dead. Other good. Thanks again.

Since we don't charge at 12 volts but rather at 14.4 (or more) and we have 1800 watts of which only 80% should be used on a continuous basis, 100 amps is a better guesstimate than 150. Of course, some converters (PD for example) have a power factor of 0.7 so that eats into the 100 amps as well.

In real life my PD 40 amp draws 723 watts when it is running flat out.