thanks all for input responses so far...
JiminDenver wrote:
It's going to take longer than 12 hours to fully
charge your batteries with your converter. I usually plug the batteries in for a few days when we get home, A day long top off charge once a month and then a few days before we go out. At this point your batteries may need some care to get them back up.
the casita trailer group noted that their manual said 8 hours to
charge a battery w/ P 7300.
when i charged 6 days ago, the 1st 8 hrs were w/ RV plugged into shore. next, with battery disconnect on STORE and a separate charger connected to house batt. the BIRD then allowed both batts to trickle and a battery full light came on in 4 hrs.
is it OK to charge both house and chassis via BIRD in this manner -- using external charger w/ BIRD?
as noted, the 1 y/o batteries' dropping from 12.75 to 12.5 in a week
is not making me happy.
i saw no voltage between house ground terminal and ground wire w/ battery disconnect in STORE.
i am reluctant to do same check on chassis batt since it might reset
computer. thoughts on this? is there a 30 min delay before chassis
batt disconnect resets computer?
ScottG wrote:
Hate to say this but that is a terrible
converter/charger. It's charging profile is terrible and the only time it isn't under charging it's over charging.I swapped mine out while it was still perfectly healthy for a Progressive Dynamics because of the superior charging and storage ability.
a lot of people have as reported in dozens of threads i have plowed
thru. but the P 7300 is still in a lot of RVs with happy owners. the
manual says it lowers the amps after charging a while, but maybe at
13.8 volts, which many say is cooking level. but if you put
disconnect on STORE after 12 or 24 hours?
and doesn't a 14 v alternator maybe do same thing?
pnichols wrote:
It sounds like you have regular wet cell batteries
(batteries with liquid acid in them) in your RV.
The voltage level coming from the stock Parallax 73XX converter in
your RV once it has fully charged your batteries - if you then
continue to leave your converter connected to the batteries - is too
high of a level to be kept on regular wet cell batteries continuously.
However, the voltage level coming from your converter will bring
them up to full charge whenever they are low - but just take longer
than other types of equipment designed to put out a higher voltage
level for faster charging. Many RV owners replace the stock
converters that come in their RVs so that the resulting voltages from
their new chargers are better suited to their wet cell batteries for both long term storage and faster charging.
All the above being said, there are different models of dry cell RV
batteries available that do much better with stock RV converters.
We have those kind in our RV and they are many years old with still
most of their capacity left. Our RV sits in the back yard when we're
not using it and with our model of dry batteries, the converter can be
connected to them almost continuously without damaging them.
Hence our batteries are always in full charge whenever we start out
on a trip. Our batteries also charge faster than regular batteries, so
the converter brings them up to around 90 % of full with only a few
hours on our small quiet generator when charging in a campsite.
When traveling between campsites, the main engine alternator (our
RV is a motorhome) will bring our batteries up to full charge in 4-5
hours of travel time. RV converters are not always worthless, even for camping without hookups ... as they do play well with certain types of batteries.
i am OK with a slow charge at home and then disconnect. but i not
sure how long and how often. i think, contrary to what some report,
a whole month is too long. even every 2 weeks may be stretching it.
i think i may have already done some harm to these new batts by
not doing weekly 12 hr chargings.
smkettner wrote:
Costco group 78 is a deep cycle? I think you are
better to just leave it plugged in. Best would be a PD4645
replacement converter charging at 14.4, 13.6 then float at 13.2
volts.
group 78 is what chevy uses in lots of vehicles. it has 850 CCA and
side terminals. they are maintenance free from costco.
we are always on shore power at cg, so no need for deep cycle
house batt. i do not think the 850 CCA harms onan, which needs
450 CCA. so having 2 identical maintenance free batts seemed like
a good idea.
smkettner wrote:
Alternator will initially charge at 14.6+ volts and as it heats up with the rest of the engine will drop into the 13.8 to 14.2 zone. This is great for the chassis battery but the house battery is often connected through a relatively long wire isolator etc that will drop voltage a bit and provide a slower charge.
You can get an aftermarket regulator that does a specific 3-stage
charging routine. More popular in the boating world.
Not sure how much off-grid camping you do but also consider 100 to
300 watts of solar instead of the converter upgrade. No more worry
about plugging in.
thanks, i was not sure, but suspected that is how they perform. the
P 7300 seems to work along exact same lines as the alternator.
