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RE: NEWBEE HOUSE BATTERY QUESTION
Had an interesting experience with a camping neighbour's dead battery which was at about 12volts but hydrometer showed to be all water. Put my Vector smart charger (20/10/2) on it and at first the Vector only showed 4 something amps. Almost gave up, but then noticed the amps were slowly rising!
The amps kept rising slowly for about half an hour and got to over 15amps when I had to go to do something else and take the charger. (he was going to finish charging the battery later at home now that he knew it could be saved) I expect the amps would have reached the 20 max for the charger and then continued until the battery had reached enough SOC to make the amps taper down in the normal way.
I never knew charging amps could rise like that, the opposite of tapering down. Weird. The OP's batteries could be in the same shape.
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BFL13
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10/13/08 07:46pm |
Tech Issues
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RE: Trojan Better ??
Longevity is all very well, but the real measure is supposed to be the number of deep cycles it will do.
In "Managing 12 Volts" Barre gives a table for this by battery type:
-Starting 25-50
-Low cost deep cycle 150-200
-Moderately priced deep cycle 250-300
-Gel cell and AGM 500
-6v Golf cart 700
-High quality deep cycle 900-1700
So how does that relate to years of service? I know in our case where we go off- grid for say 60 days a year and do a 50-80 each day that's 60 cycles a year not counting a few other times.
So if a 12v 27 is "moderate" we should get 5 years from that or at least twice that,10 years, from a golf cart type. So if the golf cart costs twice what the 27 does we break even.
I have no figures for different brands of 6v golf carts but it hardly matters if one can do a few more cycles than the other when fitted into that comparison table?
Individual calculations for own camping style must be made of course when choosing battery type.
Those who report their battery longevity in years should also report their number of deep cycles (to 50% SOC) per year. If they are on solar and stay above 80% SOC all year they should say so too.
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BFL13
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10/13/08 04:58pm |
Tech Issues
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RE: converter / charger replacement
The tech looked at it so he is probably right, but your post referring to "shorepower into the rig" leaves the possibility for instance, that you just popped the main 30amp breaker in the AC dist panel and that the converter itself is ok. Can you clarify?
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BFL13
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10/13/08 12:48pm |
Tech Issues
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RE: I thought I knew how to properly charge my batteries
15.4v is the upper limit for the Norcold fridge controls according to the manual. The high voltages even with low amps once the batteries are charged will cause water loss. Is the solar controller working right?
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BFL13
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10/13/08 11:42am |
Tech Issues
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RE: NEWBEE HOUSE BATTERY QUESTION
Ok, I got it now. So charging current is reaching the battery, the disconnect was not interrupting. Good.
I think the Charge Wizard timed out at 4 hrs on the 14v boost and went to normal. I am unclear if that means the batteries took a charge this time or not. They may be just badly sulfated instead of having a bad cell or ISTR the Charge Wizard voltage would not go back to normal?
As others say, isolate the battery from its charger after the recharge and wait till the surface charge dies down to get a true voltage. But in this case where the batteries are suspect:
Disconnect shore power or turn off the converter (circuit breaker or unplug) and run a load of lots of lights and fans as soon as you finish the recharge. If the batteries collapse in voltage under load, you do need new batteries as you were suspecting. (I doubt desulfation will do any good if they have been so low for so long, but who knows? IMO better to start over new so you know what you have there. The converter seems to be working properly.
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BFL13
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10/13/08 11:18am |
Tech Issues
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RE: NEWBEE HOUSE BATTERY QUESTION
How could you discharge the batteries completely when they were already at 11.7? How did you then start the "recharge" that didn't work? Where are you taking those Charge Wizard voltages from--the battery posts or elsewhere?
You need to read the voltage at the battery posts to see if they are getting a charge from the converter with the battery disconnect in the right position.
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BFL13
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10/13/08 07:32am |
Tech Issues
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RE: NEWBEE HOUSE BATTERY QUESTION
In your rig does "shutting off the main DC switch" not cut off the converter (which charges the battery) from the battery?
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BFL13
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10/13/08 05:58am |
Tech Issues
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RE: Help with 12 volt mod
You already have the inverter, so just attach it to your battery bank up front and plug in shore power (first turn off the converter)
You don't need a 2000w inverter for that. We do it with a 400w inverter and use the 110 receptacles inside to watch TV/DVD.
How much wattage you need for the inverter depends on what the watts are for the AC device you are trying to run. How long that will run then depends on how much battery bank you have.
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BFL13
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10/12/08 03:07pm |
Tech Issues
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RE: What's the difference in 12-v monitors?
IMO solar vs gen has a lot to do with the need for a monitor. With solar you try to stay even with your daily amphrs in and out and stay in the high SOC of the battery since the usually low amps of the solar (Except for certain Texans :)) does not allow for a fast recharge, and you don't want to be stuck staying even at a lower SOC or you will get sulfation. With the varying input and output you need one of those fancy monitors to keep track and make adjustments to your useage to match your input .
With the gen, you run the batteries down for however long that takes and then recharge them back up all at once in the shortest time you can. You only need to know when you are down to where a recharge is needed and when to stop recharging. Don't need a monitor for that.
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BFL13
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10/12/08 01:07pm |
Tech Issues
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RE: What's the difference in 12-v monitors?
Other folks who weekend camp a few times a year, and have the rig plugged in while stored, will not understand the need
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Everything is relative they say. We camp off grid for ten day to two week stretches.
For those ten to fourteen days we do 50-80s with no need for a monitor. I can see where the solar guys staying out weeks and weeks at a time would want to have more accurate figures though. With a generator and a fast charger you just don't need all that precision.
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BFL13
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10/12/08 10:52am |
Tech Issues
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RE: What's the difference in 12-v monitors?
WOW! 50% is really bad for battery life!!
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Depends on how long is "bad" I guess. The usual advice is not to go below 50% except rarely and they will last "long enough."
The reason to go down to 50% is to get them in the zone where they will take high amps for a fast recharge, to save gen time. If you try to operate in a high SOC range, the low amp acceptance rate will mean running the gen forever. It is ok for the solar users who have lots of time but no good for the generator folks.
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BFL13
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10/12/08 10:35am |
Tech Issues
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RE: Trojan Better ??
I saw a Trojan ad that claimed their 105s have a superior sort of separator than the ones in U2200s, so equal weight is not the only factor it seems. Another thing might be the amount of antimony used to harden the plates from vibration/shock damage. No idea.
We have U-2200s that have done four seasons now and have taken a real beating IMO, but they are still going ok. A rough test last Spring showed they were about 90% of their original amp hr rating. Worked as usual this past summer of off-grid camping doing 50-80s. I can't see how having Trojan 105s instead would help any.
I now have a pair of 12v 27s at 120ah each and tried them instead of the U-2200s doing 50-80s and they acted the same way for recharging times and how long they last between recharging. Can't see any difference for actual camping. supposedly they will only do half the number of deep cycles the 6v pair will though, so that is a cost factor.
While waiting for the U2200s to up and die, I use all four as a bank so not to waste the two 27s in the meantime. This creates way more amp hrs than we need for our style of camping and I now have so much electricity I don't know what to do with it all :)
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BFL13
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10/12/08 10:16am |
Tech Issues
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RE: What's the difference in 12-v monitors?
. Am I reading the voltage wrong?
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The range hood (or where-ever) monitor idiot lights tell you all you need to know for when to recharge the batteries at about the desired 50% SOC point. You look for the "bounce back" not the actual static light showing.
When you are in the green (unloaded) and you turn something on it drops to yellow. (loaded voltage) Turn the fan (whatever) off it goes back to green. After a while, it stays yellow after the fan is turned off. When that happens, it is time to recharge. Too easy.
I have tested this at home to see if this occurs at the resting voltage of about 12.2 and it does. Also while camping you can pick a time when not much is on and it will be around 12.2v when the light stays yellow.
You don't need to get exact SOC and amp hrs. You only want to know if you have to recharge today or can it wait till tomorrow? If you are that close to getting through another night or not, you will recharge anyway to be safe.
The other problem is when to shut off the gen when you have recharged "enough." Converters do not have ammeters so you can monitor when the amps have tapered down to such a low number it is not worth the gen time. We use a portable charger that has an amps read-out and do not use the converter for recharging when off-grid, so that problem is solved for us.
If we only had the converter, I am unclear how you can know when enough is enough, but I expect you learn from experience (ie the hard way) and probably overdo the charging times just to be sure.
When you have got your time to recharge figured and time to stop charging figured "close enough" without having the fancy monitor for exact numbers, you don't need the fancy monitor.
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BFL13
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10/12/08 09:19am |
Tech Issues
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RE: 12 volt confusion
Since your problem comes from the battery being connected to the converter, just disconnect it :)
Then it won't overcharge, and you won't need to replace the converter to get a lower float voltage.
You just need to keep the battery in good shape on stand-by for when you move your rig or if there is a campground power failure. IMO let the disconnected battery self- discharge over a few weeks and re-connect to re-charge it every month say. Also you should run the battery down to 50% SOC about every two months and recharge it fully to "exercise" it.
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BFL13
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10/12/08 08:41am |
Tech Issues
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RE: Low 12 system voltage
If you are on shore power and the converter quits, you should not notice anything until the battery gets low. Therefore your battery is low. Since the converter won't charge it up, the battery has a fault or the converter does.
First charge up the battery (make sure there is water in it) by other means--portable charger, or booster cables from a car, whatever. If it won't take a charge, replace it. If it will take a charge then the converter is suspect.
To go camping with no converter where shore power is available, take along a portable charger and just get your 12v from the battery, while getting AC from shore power and to run the portable charger as required. If dry camping, use the portable charger off the gen.
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BFL13
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10/11/08 06:58pm |
Tech Issues
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RE: Parallax/Magnetek 7345 Shut Off Switch
When you trip that breaker the lights should auto-switch to battery power and stay on, perhaps a bit dimmer, but they should stay on, if, that is, your battery is connected
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In our 5er there are three AC lights (one big one over the dining table and a couple of cheesy looking wall lights by the sofa ) on the "receptacles" circuit. There are also the usual DC lights. The OP seems to have something similar.
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BFL13
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10/11/08 08:56am |
Tech Issues
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RE: Parallax/Magnetek 7345 Shut Off Switch
If your 7345 is wired like my 7355, the converter shares its circuit breaker with the AC receptacles' circuit. That circuit also has the AC lights on it. The receptacle outside that the fridge is plugged into is one of the receptacles too.
As suggested above, you have to look at the wiring of the breakers. Each has a black (hot) wire with its white (neutral) wire going off to a bus at the side. The converter black and white wires come up from below and there is no negative wire with them. You can install a switch in the converter's black wire before it gets to the breaker, or snip it from the receptacle circuit's black wire and splice it to a different black wire going to another breaker for something you don't need or give it its own breaker in a spare slot.
But why? There is no advantage in turning it off except when you are off grid and want to use the receptacles by plugging your shore power cable into an inverter clamped to your batteries. Then you must turn off the converter, but still want the receptacles to work.
At home with no battery in , you can still run the water pump etc from the converter-supplied DC.
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BFL13
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10/10/08 07:17pm |
Tech Issues
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RE: Parallax/Magnetek 7345 Shut Off Switch
The 7345 is a converter not an inverter. It does not have a switch, but you can use its circuit breaker on the AC dist panel as a switch if you like.
The battery disconnect switch if fitted, goes on the positive wire from the 7345 to the battery. This will isolate the converter from the battery but not the battery from all its loads, since some loads go directly to the battery (LP alarm, stereo, slide motor , breakaway brakes, some inverter installations)
Your best battery disconnect switch is you taking the negative wire off the battery post and putting it back on as required.
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BFL13
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10/10/08 09:57am |
Tech Issues
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RE: Aux start switch and Magnetek 6345 converter
Where do you get that info?
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Managing 12 Volts, by Harold Barre.
p85, "A battery in the float stage should be at 13.1 to 13.9 volts depending on temperature: 13.1 volts at 90F to 13.9 at 50F for a wet cell battery. If the voltage is high for the temperature, the battery may be overcharged resulting in high water loss and reduced battery life."
Elsewhere he says the float charge is to prevent self-discharge, and that you should still exercise the battery every two months when it is floating.
I see though, that he says a normal 12v starting battery has mostly lead plates which do not self- discharge much while deep cycle batteries with antimony in the plates to harden them make for increased self discharge rates. So the need to float the house batteries would be greater than the need to float the engine battery based on that.
I do find here in the winter that leaving the batteries on the 7355 at 13.7ish is insufficient to keep their SG up, and of course we go well below 50F--around freezing at night and say 40F during the day.
I have no use for a converter that would do 13.2 since I do not have a "storage" period when it is above 50F :)
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BFL13
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10/10/08 09:47am |
Tech Issues
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RE: Help with 12 volt solution
You can just get a cheapo 400w inverter and clamp it to the batteries outside and plug the shore power cable into it. (turn off your converter first) This makes your regular receptacles "live", is cheap and there is no wiring to do.
If the converter is on the same circuit as the receptacles then you have to put them on different circuits or put a switch in the converter's power line before it gets to the circuit breaker it shares with the receptacles.
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BFL13
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10/10/08 08:49am |
Tech Issues
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