I'm going to be doing alot of camping in my 98 chevy conversion van. I want to be able to run my accessories without draining my battery. I'm going to have a powerful stereo so an extra battery wont last. I need an inverter that can convert 12vdc to 120v ac. I guess I would have to disconnect the battery to do this. I also thought I could just hook a battery charger up at all times, but I could overcharge the battery. Any help would be appreciated.

duel batt systum with the #2 batt a deep cycle run the inverter from that one that way when it gets low you still can start the van

In the RV world, a device which converts 120v AC to 12vDC is called a Converter.

Your statement about keeping a battery charger connected leads me to believe that where you will be camping, you will have access to grid power, like at home. If this is what you are looking for, I recommend you google 'Best converters' and find a phone number and talk to Randy.

A Converter is designed to power all your 12 volt loads, and charge the battery(s).

If you do not have access to 120 volt grid power, you will need another battery, or 2, isolated from the engine battery as suggested above.

I have a Schumacher Battery 'intelligent' 3 stage battery charger. If the battery is already fully charged, and I am running relatively small loads, it works as a converter, adjusting it's output to keep the battery voltage in float range@ ~ 13.2 to 13.6 volts.

If the battery is not fully charged, or the amp load varies greatly, it will get confused and go into fault mode.

A converter will not so this. It is designed to keep the batteries voltage steady during changing loads.

They come in different amp configurations. Iota and WFCO are the two best brands AFAIK.

But let me say, If you get one of the old school manual chargers, it will just pump out amps and not care about loads. Whether the voltage will skyrocket or not is another matter. Experiment, and see what happens when you shut the stereo off, like in between songs.

If you go over to RV.net and search for Converter, you will find more info than you can process.

Thanks for the info!

I went on to the iota website. They seem to have nice converters. I'm thinking how I should hook it up. I would probably have to mount somewhere inside vehicle. I would not want exstention cords running out of my van. I would need to run a cord thru my floor and install a waterproof GFCI outlet. I would probably put the converter under my front passenger seat and run the outlet farther back. Then I guess I would run my 12V power to my battery. Then run my ground to the frame, or to the battery. Which would be best? I was planning on getting one of those Optima batteries. Is there a specific battery that I need. Will a converter in anyway shorten the like of my battery?

Do not wast your money with Optima.

Oddessey batteries are about the same price but have 15 to 30% more capacity.
Ideally you want the converter mounted pretty closely to the battery(s) over thick wiring. This increases charging rate, and decreases time to reach full charge. Ground the Battery to the frame, but also run a ground wire directly from the Converter to the battery. The installation directions will say to do this. Some Converters have temperature compensation Probes which attach to the battery, and special settings for AGM batteries, like optima or Oddessey.

The only converters which harm batteries are older Magnatek brand ones or similar. They have too high a float voltage and will boil away the water in a flooded battery, and just overcharge an AGM whose electrolyte cannot be replaced if it is severely overcharged.

It is also not good to always leave the converter on, with the batteries always fully charged. Batteries like occasional excersize, and prompt and full recharging.

My 2 cents.. Optimas are notorious for just dying.. I have an RV that has been connected to grid power for a while now. The converter in it is pretty small unit but has about 8 circuts on it all CAPABLE of 30 amps. The unit is small but very powerful. i will ahve ot get you the actual specs on it. If it gets hot, it has fans that kick on thermostaticly. I have tested it out a few times.. i cranked up ALL 40ish 12v lights in the RV as wel as the bathroom fan. It takes about 5 min and the unit kicks on the fans.. all the lights are old incandecents from 1988. When unplugged, the dual 75 amp/hour batteries will drain from the lights in about 4-5 hours. The converter recharges the batteries if left by itself in about an hour. it's a real healthy unit i tell ya..

ON the other hand, in my van, I was running a 1500watt inverter. I also had an all electronic marine battery charger/conditioner connected to the house battery. Whenever i plugged in to grid power, I had all my 120v accessories switch over to grid. then when i would unplug, I'd ahve a fully charged house battery. A 125 amp hour battery will run one of those electronic mini refrigs for an entire weekend no problem. And at that, it only brought the battery down to 40%. that's enough to kick on the low voltage sensor on the inverter. Whne that happens, I just plug it in, or fire up the van. I put a toggle switch in for the solenoid to attach the house batt to the main batt for charging on the road.

Interesting. I'm not sure what I'm going to do yet. I'm kinda thinking of being off the grid altogether. I plan on doing alot of camping, so it would save me money in the long run on campsites. I can't haul around a ton of batteries so solar panels would be he only solution. any of you guys have or had a solar panel setup. I know it's common with RV's.

I have a 130 watt solar panel on my van's roof. It is absolutely great in a sunny environment, but small shadows from trees or power lines significantly reduce output. If your campsites are regularly in the shade, your money would be better spent on a nice quiet Honda 1000 watt generator

It is cheaper and easier to conserve power, than generate it. If you plan on using a huge wattage amplified stereo, your gonna need a lot more than 130 watts, and more than 2 batteries.
And while smaller panels can offset usage, batteries should be recharged at 5 to 13 percent of their rated amp hour capacity(20 hour rate).

You will also need to significantly upgrade the alternator wiring for any auxiliary/ house batteries will not see much amperage through the Stock wiring. Trust me when I say that everybody significantly overestimates their alternator's contribution to the battery(s). Idling the engine is almost futile in recharging the batteries, unless the charging system is upgraded, and the alternator's pulley is smaller than stock.

And for those times when you do have access to the grid you will want to hook up a charger, or plug in a converter to blast some amps into the batteries.

I pretty much live off of 12 volts. Feel free to ask any questions

I will throw my agreement in on the Optima batteries. They are all hype. I have two boat anchors in my garage that died 2 months after the warranty on them expired. They only have a 1 year. The one will not take a charge and the other will not hold a charge. Best to get a large deep cycle battery. I used to have one that was on a Coast Guard cutter and they replace them every two years. Lasted me for another 4 years. They are very heavy, very large and probably around the same money as the Optima's

so what batteries do you suggest that are safe to mount INSIDE a van? that was part of my reasoning behind buying an Optima. no fumes, etc, as I have my second battery mounted in the back, under my bed.

You definitely need an AGM battery for that application. They do make deep cycle versus starting AGM batteries.

These batteries are considered the best in the RV world.
LIFELINE
Odyssey batteries are also considered excellent.
Odyssey

Universal brand batteries(from china) are the cheapest AGM batteries. Here's a group 27 for 180$. I do not know if it is a deep cycle. This was just a quick search.
Universal battery

Make sure you do not get a Gel battery. They have vastly different charging requirements.

If you do get a pricey battery, you need to also upgrade the wiring leading to it so it is not chronically undercharged, sulfates early and dies prematurely.

Also be cautious, I read and saw pictures proving somewhere that all "sealed" batteries are not truly sealed.

On a side note, I have a Optima yellow top. It's been in the truck for 9 years. I must have killed it dead 50 times. It's still going strong...

Generally the only time an AGM battery will outgas is if it is severely overcharged. Even if an AGM battery's case is broken, there is no liquid within to spill.

No battery produces gas when discharging.

Now there are maintenance free sealed batteries that are not either AGM or GEl technology. They are just regular flooded batteries that are non servicable. It is a marketing scam for those afraid to put a little distilled water in their flooded batteries once in a while. The problem with these is they still use water, but it cannot be replaced.

Avoid this type as you would an Ebola plagued monkey.

Make sure whatever you buy clearly says AGM, and is basically twice the price. If you see "maintenance free" and only a 3 to 20% mark up over a similarly sized battery, it is the Ebola plagued rabid baboon.

Diehard Platinum (AGM)batteries are made by the same company that makes Odyssey batteries. They are considerably cheaper and have a loyal following. I don't know if they are built to the same tolerances/ quality.

And about the Optima batteries. There was a period of a couple years starting in 2003ish where they cut every conceivable corner to cut costs, and quality went into the toilet. As they did not lower their price during this greedy binge, and their executives just got fatter like the disgusting wall street schmoes, they should be avoided even now that they claim they have started using virgin Lead again and other measures to bring back quality.

My friend has a 10 year old optima which will not die even after severe abuse. Another friend has a ~5 year old Optima which has maybee 10% of it's capacity remaining despite being cared for and never deeply discharged.

wrcsixeight, your AGM theory is not correct. AGM batteries DO contain liquid, but AGM means Absorbent Glass Mat (or Material) which absorbs and contains the electrolyte (acid) so that it doesn't slosh or spill, and keeps the lead plates wet at all times... this allows the battery to be used in other positions than the normal "upright" way.... like if you put it in a 4-wheeler or jet ski that is often not horizontal. If your batteries plates become exposed to air they oxidize and it reduces the output capacity of your battery.

Otherwise you are correct. Yeah, I used to work at a battery plant and ALL lead-acid batteries create hydrogen when you charge them. Its the chemical nature of the beast. Even a "sealed" battery contains a pressure release vent. If this vent malfunctions and pressure builds up in the battery, it could explode! Or if you vent it somewhere contained (like inside the cabin of a van) where there's a chance of a spark.... kaboom!

BUT, the good thing is the batteries only vent hydrogen under charging. And the "sealed" type only vent under EXTREME charging... like say 200amp or higher... (when we charged them during manufacturing they whistled like birds!). And you might never use them that agressively. So the better choice is the "sealed" (or sometimes called maintenance free).... but by far the BEST choice is just to vent your battery. Build a little box around it with a nice sealing lid and find a way to create a vent to the outside. Better safe than sorry I'd say.

As far as a 100% safe battery for mounting inside your van... I don't know! Even little AA and AAA Lithium, Cadmium (etc) rechargeable batteries are vented. Look at the ends... there's a little pinhole. Just the amount of gas produced is so small because it's such a small battery.

I realise the liquid electrolyte is suspended within the glass matt.

Everything I've read about them indicates that if the AGM's battery case is punctured or breaks, this electrolyte will not drain out as a liquid.
Is this not correct?

A Question. No sarcastic tone intended.

I thought the electrolyte was suspended in gel, so in that sense no 'liquid' would drain. Maybe the mat has the ability to contain the gel? I don't know, never taken a pointy stick to one.

I am wondering how the agm's combat dendrite reversal? Better due to the lack of a liquid or worse because the mat gives them a structure to 'build' in.

...oh, I happen to like Ebola plagued monkee's

I am truly enjoying this thread Lots of good knowledge here.

Does anyone know or remember what color the Optimas were when they first came out for public use in the early 80 s ?

or

what aplication Optimas were originaly designed for ? (PS they failed this application .)

I have sold many Optimas, only because people demanded them, there are many batteries that offer better value. jus my 2 cents

That's ok.

Actually no... it can drain... well somewhat. AGM is a tight weave fiberglass, similar to house insulation, only denser, and with some additional ingredients. SOME will be retained in the matting somewhat permanently due to surface adhesion, but it is porous, so some amount of it will drain out. But much is retained. And often the batteries are overfilled slightly to compensate for any air pockets during the fill too. Any of that excess liquid will also be free to drain out. And the matting does not fill 100% of the battery. There are spaces along the outside of the plates, underneath the assembly, between layers, etc that will contain "free" liquid that was not absorbed. But overall, a great amount of it is contained in the matting. So it is nearly true.

There was a story about one of the sales guys in the plant, that during the inception of AGM batteries whipped out his hand gun and shot the case to "impress" a customer. Needless to say he was a bit embarrassed by the result. Shredding through the matting will release the liquid.

Now GEL batteries are a getting more like your description. The acid is mixed with silicone additive and then filled into the battery. After a short time the liquid "sets" (similar to how jello does) and results in an electrolyte approximately the thickness of molasses. Well THEN the liquid clings in there damn good. But ultimately it is still a liquid.... though it is very VERY thick and slow moving.

Though if you dissect either of these batteries, you will find the mat is wet to the touch. And you will be able to wring a good portion of the electrolyte out of the glass mat, much like a sponge.

I would have to say the only true "non-spillable" battery is a dry cell... and those are made with a "paste" electrolyte. Even that is a little "fluid". The idea is 100% contact with the plates for good conductivity and no air intrusion.

What about dendrite reversal, better or worse?

Dendrite formation happens through lack of use. The dendrites form and bridge a path through the matting from one plate to the other... and create a short. So really the AGM material versus the "standard" separator material wouldn't really make a difference. They are BOTH porous. The only way to eliminate dendrite bridging would be to have an impervious membrane between the plates (ie in place of the glass mat), but you need the porosity for the electrons to flow. Without electron flow you have nothing.

As far as the GEL's effect on dendrite, I'm not sure... we were just getting into that line of battery when I lost my employment there. I had been involved with implementing the line, and we only produced a couple thousand batteries before then. I'm sure that the line prolonged my employment with the company, because once it was up and running, they cut the entire engineering department.

In all, the best way to eliminate dendrite formation is to just give your batteries a workout... don't let them sit. As far as reversal, a shot of high current charging is supposed to "reverse" dendrite formation, but often it just blasts them loose to suspend in the electrolyte, where they can hang up in the matting and bridge right back again. Think of it like a fuse. If you give it a high enough voltage/amperage you can incinerate the whole filament. But mostly you just fry a little gap in it.

So I guess to sum it up, I'm sorry but I just don't have enough input on the battery type's impact on dendrite susceptibility to help you out, but that's about what I know.

My two thoughts, were the mat would act as either a bridge to aid in them or as a barrier preventing them. I always see batteries in reversal that won't take a charge, but of the 5 or 6 agm's I have had this never happened. That's why I asked, just idle curiosity.

Well, you are correct... the mat's original job is to separate the plates, so they don't move and/or contact each other, and short. (On the assembly line it was called separator material.) It additionally helps in that it also packs everything nice and tight inside the case to reduce the possibility that vibrations/jolts would break the active material off the lead grids, or even break the grids themselves. And then lastly, being absorptive helps keep the plates wet (like a sponge), keeping the performance up and battery life long.