Battery lost a cell. Desulfating or refurbishment possible?

[bryanl]

The 'golf cart' batteries are usually a bit taller but with a smaller footprint and wind up being maybe 5% or so bigger than a group 27. That makes a difference in how it will fit in the box but is insignificant as far as energy storage capacity. Other than that, the 6v is just an extra $10 for no gain in performance.

As for needing water a few times every year, you might look at upgrading your battery maintenance equipment. You should seldom need to add water if your charging and maintenance is being done properly.

[Skater]

Originally Posted by masseyfarm

In my search to answer whether AGM's need an upgraded ALTERNATOR setting, I found the following site quoted here http://www.airforums.com/forums/f449...tml#post943179

A lot of good answers in about 5 pages of info.

Dave

I've never heard of touching the alternator for AGM batteries. I know plenty of people that use Optimas (AGM battery) that use stock alternators. Actually, I'm one of them...I have an Optima Blue Top as the house battery in my camper, and it charges fine off the alt.

I do think a 3-stage converter is a good idea, though. The older one-stage models will cook batteries, and AGMs are especially susceptible, especially if you're like me and keep the camper plugged in all the time. Check out Optima's website and their limits on charging the batteries. The newer models might be better but I wouldn't trust it.

[masseyfarm]

[QUOTE=Skater;943539]I've never heard of touching the alternator for AGM batteries. I know plenty of people that use Optimas (AGM battery) that use stock alternators. Actually, I'm one of them...I have an Optima Blue Top as the house battery in my camper, and it charges fine off the alt.


Everyone knows by now my preference for the T105's for cost vs output/life, for the average RV user.
For those with smaller units, AGM is a questionable investment.
If your stock alternator may 90 to 100 amps @ 13.8 volts. This is far too small to run a bank of AGM IMHO. Even with wiring upgrades to the charging system, it will send the alternator into a constant charge, eventually leading to failure. (AGM's are rated over 14V)
If you are running through an isolator there is furthur drop in voltage. This results in the AGM's never reaching their potential charge unless you are on shore power or running the aux.
Please correct me if I'm wrong. No one wants to answer this simple fact.
The next question is life of electronics and bulbs and LED's with the higher VOLTAGE?????????????????????
Check out the LED threads to see the failure rate of LED 50000 hr lamps.

Dave

[Keyair]

Interesting...

I was reading my RV Maintanence book this evening...
The Author says very clearly that Deep Cycle/Marine batteries are a compromise, and that Golfcart Batteries are "True Deep Cycle" with the thicker plates and deeper reserve capacity.

[ROBERTSUNRUS]

Originally Posted by masseyfarm

Please correct me if I'm wrong. No one wants to answer this simple fact.
The next question is life of electronics and bulbs and LEDs with the higher VOLTAGE?????????????????????
Check out the LED threads to see the failure rate of LED 50000 hr lamps.

Dave

Hi, this may not be the answer that you want to hear, but as an automotive electrician, I always said that you can not put any time on anything electrical; Electrical items can blow out the instant that they are connected, or last one thousand years.

[Mexray]

Here's some data on hooking up the 6 volt DC batteries in a Series-Parallel system...check out the 'yellow' diagram - you can just eliminate two of the batteries in this diagram to get a picture of a 4-battery system...

RV Battery Wiring - Solar RV Panels

Note how the POS cables and the NEG cables running from the battery bank to your fuse panel (& ground) are attached at OPPOSITE ends of the system....these is a small amount of 'resistance' in each battery connection, and hooking the cables in this manner tends to 'even' out this resistance during the normal discharge/recharge operation...

[masseyfarm]

Originally Posted by Keyair

Interesting...

Originally Posted by Keyair

I was reading my RV Maintanence book this evening...
The Author says very clearly that Deep Cycle/Marine batteries are a compromise, and that Golfcart Batteries are "True Deep Cycle" with the thicker plates and deeper reserve capacity.

Yes, if it says "deep cycle marine" it is for starting and storage, and would be a compromise.
Trojan Deep Cycle Battery

What I am saying is: for the money,($125.ea), weight, life, and satisfaction, for the small to medium RV owner, I think the T105's do an adequate job. Yes, they need to be serviced, more if they are overcharged by a poor charger.(which could ruin the more expensive AGM)
But if setting up a system, spend the money on the charger, solar, wire upgrade, etc, etc, and if after the T105's have run their course in 4-5-6 years and you are comfortable with the rest of the system, then plan an upgrade to all the batteries.
Again, I would not want to mix AGM with my existing wet starting batteries and expect long term satisfaction from the chassis alternator.
Comes down to how much money you have to spend.

Dave

[Keyair]

Mexray:
Awesome link, great info!
Thanks!

Massey:
I am maybe a few months away from my big battery purchase, as I have a lot to do before I am ready.
I will be ripping that rusty crap outta the tray, and I just needed to grasp what batteries I should make accomodation for.

Here is my thought process at this time....
Remember, I have no 110V access where the AS is stored...

I am assuming I am going to run with 6V's, say 2 pairs, but I might add another pair to that if I can afford it..
By adding at least 100W of solar, and living and traveling in SoCal, I have a system that will be charging the batteries while in storage, and ready to go at any time. If I have 6 x 6V batteries wire as per the diagram in the link Mexray posted, I should have 600+AH on tap. More than enough for a couple of days boondocking let alone the "top-up" charging the batteries are getting on route, and when parked during the day.
The DC charging from the engine maybe would be better just feeding the engine battery, and not online with the coach batteries at all?
Another thought....
Maybe my money would be better spent adding another solar panel/panels to my 100W starter panel, and not even bother with a intelligent charger for the AC to DC circuit?

Mmmmmm!

[nti06]

if you really want to go all out for some batteries, go to your local O'Reilly auto parts and ask them to order an AGM31T.

Or an 8D3 (as big as the battery box). More than likely the 31 group series Marine battery that they should have in stock will be fine for what you need.

You can charge your coach and engine batteries while driving with a battery isolator.

[Keyair]

Thanks NTI.
The 31T you mention is a truck starting battery, and looks a fine battery, but its not a deep cycle. The other one is a monster, but not easily replaceable if something went wrong.
I am decided on the 6V option.
I realize that the Engine will charge the batteries thru the isolator that is already mounted.
I was just "thinking out loud" that maybe I should leave it alone to do what a normal 105A alternator was designed to do, that is, recharge starter battery and provide power for the basic chassis. Asking a 105A alternator to provide enough power for the chassis, lights, engine fans, HVAC and its fans would be enough, let alone asking it to charge a big couch battery bank.
Now, if it went bad, then a 180A Alternator would be a option...
I guess I just feel that there are multiple redundent systems, overlayered on each other, and each adding to the wiring, and complexity, and possibility of a failure.
Lets use a prime example I had this week... My 1984 Mercedes 190D Alternator died... I replaced it with a remanufactured unit, that failed within a week... The first time I realized something was wrong was when it failed to start... a jumpstart got it going, but I noticed that the battery was way too hot. A quick check with a Multimeter revealed a chargeof 18V! Next day, I tested the battery and it show a rested reading of 2V... dead. I returned the alternator(lifetime warrantee), but it had killed a perfectly good battery, and the Bosch 1000CA replacement was $150.
How many times have I heard this... Univolts failing and boiling batteries, Alternators killing batteries... Why have 3 ways to charge a battery when I have bright sun I can utilize?
I think I will bring this up over in the M/H forum!

[masseyfarm]

Originally Posted by Keyair

Thanks NTI.

Originally Posted by Keyair

The 31T you mention is a truck starting battery, and looks a fine battery, but its not a deep cycle. The other one is a monster, but not easily replaceable if something went wrong.
I am decided on the 6V option.
I realize that the Engine will charge the batteries thru the isolator that is already mounted.
I was just "thinking out loud" that maybe I should leave it alone to do what a normal 105A alternator was designed to do, that is, recharge starter battery and provide power for the basic chassis. Asking a 105A alternator to provide enough power for the chassis, lights, engine fans, HVAC and its fans would be enough, let alone asking it to charge a big couch battery bank.
Now, if it went bad, then a 180A Alternator would be a option...
I guess I just feel that there are multiple redundent systems, overlayered on each other, and each adding to the wiring, and complexity, and possibility of a failure.
Lets use a prime example I had this week... My 1984 Mercedes 190D Alternator died... I replaced it with a remanufactured unit, that failed within a week... The first time I realized something was wrong was when it failed to start... a jumpstart got it going, but I noticed that the battery was way too hot. A quick check with a Multimeter revealed a chargeof 18V! Next day, I tested the battery and it show a rested reading of 2V... dead. I returned the alternator(lifetime warrantee), but it had killed a perfectly good battery, and the Bosch 1000CA replacement was $150.
How many times have I heard this... Univolts failing and boiling batteries, Alternators killing batteries... Why have 3 ways to charge a battery when I have bright sun I can utilize?
I think I will bring this up over in the M/H forum!

I hear you!

You are probably going overkill with 6 heavy house batteries. Especially if you are staying in southern sunny climate.
Weight and carrying capacity is usually a problem on most RV's
Another solar panel would be more productive.
The isolator works, but you have no control of it and there is a voltage drop thru it.

Here is what I did on my CLIPPER. (Cummins CT300)
I have a upgraded Delco SI 22 130A alternator, charging 2 X HD wet cell starting batteries, bank #1, (soon to be replaced with the same type), and have removed the ISOLATOR because of the voltage drop.
I have installed a SurePower 1315-200 SEPARATOR.(replaces the isolator) and allows charging both ways over 13.2V.
I have installed a cockpit controlled solenoid between the chassis and the ISOALTOR so I can manually control the combined or separate charge.
I have 4 X 6V T105's for the house bank #2.
I have one Trojan deep cycle wet cell 12V up front for the electronics. This has a charge line from the house battery circuit and another tie to the chassis circuit, which both have manual switches in the cockpit that I control as needed.
Xantrex Freedom Inverter Charger 2000 Watt 12 VDC 3 stage charger for the house #2 battery bank. (will charge all if switches and solenoid activated. AUX diesel 7000W slightly used.
All system are monitored in the cockpit with DIGITAL VOLT GAUGES.
SOLAR: 20W polycrystalline, charge controller, manual switch (to feed chassis or house depending on the need) Can be left on either, depending on solenoid setting between battery bank #1 or #2.
253W polycrystalline panels (4) run thru a MMPT controller to the #2 battery bank.
2 X 5.5W monocrystaline panels (no charge controller) to the #3 battery up front. Powers a 400W invertor for the electronics.

My experience with this setup is:
While camping, if the sun is shinning next day, I can boomdock overnight and leave the house batteries on all the SOLAR and they will completely charge. (in this case I have the solenoid between 1&2 bank connected so that any solar over capacity goes to the chassis battery. If not using the #3 invertor I will tie this panel in also to the house.

When travelling during the sunny day after boomdocking, I will separate the #1, #2, #3 banks. This allows SOLAR to charge the #2 and #3 and the Delco to run the chassis load of DRL, AC, fans, etc.
In theory I should get better fuel mileage as the alternator is not running the # 2 or #3 if not necessary.
NOTE: THE SOLAR WILL NOT PRODUCE IF YOU ARE CHARGING FROM THE ALTERNATOR AT THE SAME TIME AS THE CONTROLLER WILL SIGNAL THE BATTERY IS AT CAPACITY.
ALWAYS DOCUMENT UPGRADES SO THAT FUTURE SERVICE WILL BE POSSIBLE WITHOUT UNNECESSARY EXPLORATION COST.
Dave

[Keyair]

Thats a good setup Dave...

[masseyfarm]

Lots of good advice here.
U.S. Battery - Care & Maint p.1

Note item #15
If you can't charge the batteries fully: "Avoid continuously operating batteries in a partially charged condition. This will shorten their life and reduce capacity"

THE POINT IS YOU HAVE TO MATCH THE SYSTEM. AN EXPENSIVE AGM IS OF NO VALUE IF THE REST OF THE SYSTEM CANNOT PRODUCE TO THE NEEDS OF THAT EXPENSIVE BATTERY.
Now if you need the AGM for safety reasons due to location, then the extra cost may well be justified.
Dave

[Keyair]

Reading up and trying to make sense of all the info...
A question..
Many charge controllers have a "Dump" option...
Sounds like a good idea to use the excess voltage to heat water via a 12V element... but I have been unable to find this elusive beast...
Also, as my AS is stored in the heat most of the time, could I rig a vent fan as a dump too?

[arodriguez60]

If you are only going to have 100 watts of solar you do not need a dump. 100 watts is not enough power for 600 amp hour storage. It would be under powered. you would need some where around 600 watts!

[arodriguez60]

How many watts do you need? For the first the "rule of thumb" is between 5% and 13% of the battery bank's Amp hour capacity. Some battery manufacturers recommend more, but generally 10% is a good "target". As in:

200 Amp hour battery charged at 20 Amps. This is multiplied by the system charging Voltage to get the need Wattage;
20 * 14.2 = 284 Watts, 20 * 28.4 = 568 watts, et cetera.
You then have to figure in a certain amount of panel "derating", as a panel's actually averaged output over the "equivalent good sun" hours will be less than nameplateThat's where it gets tricky. Your actual site location will determine the derating. I use 77% as "typical" just to get in the ballpark. But if you're at higher altitude the panels will do better. Lower altitude or other factors decreasing the insolation will adversely effect panel output.

[Keyair]

I am planning to start with about 100w of solar and add more panels if I need them later.
As my AS sits in the bright Cali sun light when not in use, I assume that 100w would be enough to charge the batteries fully within 24 with no load.

[arodriguez60]

at ideal conditions you should get about 5 amps for 4 hours a day. other times of the day will be less. Use an MPPT controller to get the full potential