Understanding house batts and charging them

[camaraderie]

Heh...good you know now but I hope the 10 was a typo!! Never run your batts below 12.2V before you recharge them unless you wanna replace them like everready D cells!
Enjoy!!

[Superchief]

Anything for science! ;-). That was the low battery reading on the inverter, not what volts the batteries were actually at. While it is not recommended to take them down that far, Interstate does list 10.2 volts as the lowest. Thanks for the help!!

[camaraderie]

Heh...science thanks you!
This might come in handy... left side is number of cycles...right side is % discharged.
10.2 is 100%. Science is your friend....LOL...All best!




Your next mission should you choose to accept it Mr. Phelps is to advise the group how long a 10.5V nominal charge will take to drop to 10.2V with a 5amp load. Science awaits your results!

[boowho]

Just finished installing the Battery Monitoring module for the Magnum 1212. Install was quite easy; mostly plug and play.

It took the system right at 20 hours to get an accurate reading on State of Charge. While waiting the display simply reads "Thinkin'" !!

Paid $170 for the kit (with shunt), but almost $60 additional for stuff they do NOT include.

Going to experiment/test it out over the next week or so, to determine exactly how much good it does for me. Initially, I think it will be a great asset.

Boowho??

[camaraderie]

Ooof...that is quite a price to pay...what was the additional stuff that added up to so much? Kit price is in the ballpark with other quality monitors...only thing I had to get with my victron was a short negative cable to run from shunt to batt.

[boowho]

Originally Posted by camaraderie

Ooof...that is quite a price to pay...what was the additional stuff that added up to so much? Kit price is in the ballpark with other quality monitors...only thing I had to get with my victron was a short negative cable to run from shunt to batt.

Short cable same as you.... Then fuse holder, extra hook-up wire, phone splitter and cable, wire terminals, extra short cable (not really neccessary, but opted to improve my battery hook-ups a bit), some nuts and bolts (mounting hardware) plus a couple of other things I can't remember at the moment.

I have two output circuits of the battery stack; posts are so short the nuts would not screw all the way on with three lugs on them. After installing the shunt, I had only two lugs attached to the negative post instead of three. I decided to fix the positive post the same way, so that was maybe $15 of the extra cost.

They used to "nickel and dime you to death"; now it's $5 and $10 you to death.

Boowho??

[boowho]

After installing the BMK, I turned off the charger four days ago. Tonight, the SOC was standing at 81%. Disconnected the shore power and watched TV for an hour. SOC dropped to 76%.

So, looks like I used approx half of my stack capacity using the parameters stated above. The Magnum BMK is quite nice; among several of it's readouts is the total AH's that have been taken from the batts, since the stack was last disconnected. Could this be a guide as to how much service life is left in the stack??

Boowho??

[I-RV]

Originally Posted by boowho

Just finished installing the Battery Monitoring module for the Magnum 1212. Install was quite easy; mostly plug and play.

It took the system right at 20 hours to get an accurate reading on State of Charge. While waiting the display simply reads "Thinkin'" !!

Paid $170 for the kit (with shunt), but almost $60 additional for stuff they do NOT include.

Going to experiment/test it out over the next week or so, to determine exactly how much good it does for me. Initially, I think it will be a great asset.

Boowho??

Boo; Your installing the Magnum BMK makes sense for you because you already have the Magnum ME-RC ($190) remote control installed which I believe that is needed before the BMK is installed. Also for sure the ME-RC gives a lot of Magnum control.

I would just like to point out to other readers that there is another more economical monitor for those that do not have the Magnum ME-RC. It is the VoltMinder Battery Sentry which has a programmable alarm setting which gives an audible alert. I described it in the following thread........

http://www.forestriverforums.com/for...ing-60104.html

[boowho]

Originally Posted by I-RV

Boo; Your installing the Magnum BMK makes sense for you because you already have the Magnum ME-RC ($190) remote control installed which I believe that is needed before the BMK is installed. Also for sure the ME-RC gives a lot of Magnum control.

I would just like to point out to other readers that there is another more economical monitor for those that do not have the Magnum ME-RC. It is the VoltMinder Battery Sentry which has a programmable alarm setting which gives an audible alert. I described it in the following thread........

http://www.forestriverforums.com/for...ing-60104.html

Noted. Obviously, considering the cost of the Magnum accs, I probably would have gone a different direction myself, had I not already owned the rest of the Magnum system. I know others here have mentioned several alternatives in other threads.

And BTW, I paid (a year ago) $225 for my Magnum remote control. I hope their stuff is primo, cause their prices sure are!!!

Thanks again to everyone for ALL the great thoughts/ideas.

Boowho??

[camaraderie]

Originally Posted by I-RV

Boo; Your installing the Magnum BMK makes sense for you because you already have the Magnum ME-RC ($190) remote control installed which I believe that is needed before the BMK is installed. Also for sure the ME-RC gives a lot of Magnum control.

I would just like to point out to other readers that there is another more economical monitor for those that do not have the Magnum ME-RC. It is the VoltMinder Battery Sentry which has a programmable alarm setting which gives an audible alert. I described it in the following thread........

http://www.forestriverforums.com/for...ing-60104.html

I think that unit is entirely unsuitable for boondocking use. ALL it shows is voltage which in no way corresponds to the actual condition and capacity of the batteries or PRESENT draw which you MUST know to plan properly.
The ONLY way to do this is with a device that has a shunt and measures amp use...remaining battery CAPACITY...TIME remaining at current amp use and actual state of charge as opposed to instantaneous and faulty voltage readings.
These types of monitors sell in the $150 range and the most popular are by Victron and Trimetric.

[I-RV]

Originally Posted by camaraderie

Heh...science thanks you!
This might come in handy... left side is number of cycles...right side is % discharged.
10.2 is 100%. Science is your friend....LOL...All best!




Your next mission should you choose to accept it Mr. Phelps is to advise the group how long a 10.5V nominal charge will take to drop to 10.2V with a 5amp load. Science awaits your results!

Camaraderie; your own post, shown above has a chart for voltage versus battery capacity. Accurate steady-state voltage reading at the battery terminals or specific gravity readings of the cells, are two highly used ways of determining the capacity of the batteries.

As an analogy to water, water-flow like amps, tells you the flow rate, but does not tell you potential back at the reservoir (which is voltage). You can get 10 gal/min from a 55 gallon drum and also from a reservoir. But you need to know the potential of the source (tank), which is voltage.

When you are dry camping at a rally and running your heaters all night because it is 35 degrees out, your not going to sit up at night without sleeping to be watching the current draw.

The VoltMinder that I suggested is a very economical and accurate way (if connected directly to the battery terminals) of knowing the capacity of the batteries. It has a programmable audible alarm as well.

[boowho]

food fight!!!!!

[camaraderie]

Yes...correct...STEADY STATE VOLTAGE is a good indicator of battery condition. Now please explain how when living in your coach and using electricity...the necessary UN CONNECTED time to record an accurage voltage may be obtained.
VOLTAGE readings in a operating coach/trailer tell you one of two things accurately...your battery is being charged...OR...your battery is dead. It is neither an accurate reflection of the state of your battery, the capacity remaining, the amp HOURS remaining at present use rates, OR the 50% point when you better recharge if you don't want to lose cycle life.
When you can SEE and know the currrent draw of your heaters and KNOW that you have enough capacity to last the night you may sleep soundly and warm. Otherwise...you know to run the genny before going to sleep OR that you better add battery capacity if you want to stay warm in the future.
I repeat...VOLTAGE meters are cheap unaccceptable substitutes for REAL battery monitoring and preservation for those who boondock.

Now...if you want to know the STATE of your batteries...charge them fully...disconnect the negative wire and WAIT 24 hours before taking a reading at the terminals...or use a turkey baster in the same manner to take a spec grav. reading. THAT is a steady state reading.
Anything below 12.6V says capacity diminished. Anything below 12.4 says capacity significantly diminished...start saving for new ones. Anything below 12.2 says install new ones if you're gonna be camping dry.

As an analogy to water, water-flow like amps, tells you the flow rate, but does not tell you potential back at the reservoir (which is voltage). You can get 10 gal/min from a 55 gallon drum and also from a reservoir. But you need to know the potential of the source (tank), which is voltage.

Nice try. You might actually want to read the manual from a Victron or Trimetric before you tell us about water and reservoirs and what you need...and what YOU don't have....and are deep cycle batteries rated in volts or amp hours???? Wonder why that is???

[camaraderie]

Originally Posted by boowho

food fight!!!!!

[I-RV]

Camaraderie
I believe that the FR forums are not for arguments or who is right. You gave your opinion and I respect that. I gave my opinion and I wish you hadn't belittled it and respected it.
I have not more to say on this subject.

Please, have a good day!

[garbonz]

Camaraderie speaking the truth.

[Superchief]

The forum for me is a vehicle to get information and get peoples opinions on issues and to see what others are doing and who has had success or not. It is my responsibility to make an informed decision based upon the information presented here. I haven't found an "expert" on any subjects here. I like to have alternatives. JMHO. Craig

[camaraderie]

I think that is true Superchief, when it comes to opinions, though I do think there are some great experts in certain things here that blow me away & educate me which is why I show up.
What I also think is that there are absolute facts and poorly informed opinions and that where one knows an opinion is wrong and will cost people money or time or inconvenience, the facts must be clearly stated and the incorrect opinions debunked.

Others of course, may decide who makes the stronger factual case for their own purposes.

[Herk7769]

"Old Wives" tales are debunked all the time.

We still get posts about not keeping a battery on concrete and that has not been true since they stopped making battery cases out or rubber (about 50 years now).

I would listen to Camaraderie as he is pretty sharp on matters of 12 volt usage.

Just my opinion of course...