Batteries

[anthem4us]

What is the recommendation of this forum in regards of testing your batteries and what are the best ones to use to replace the old ones. I have an 2004 coach and have not replaced them yet. Would you be able to save money if they were purchased in Quartzite, or are their some other places that compete?

[anthem4us]

What is the recommendation of this forum in regards of testing your batteries and what are the best ones to use to replace the old ones. I have an 2004 coach and have not replaced them yet. Would you be able to save money if they were purchased in Quartzite, or are their some other places that compete?

[bigfish]

Have not replaced my batteries yet but have looked up the spec on my Intersate U2400 wet cell and compared them against other brands with comparable models. None that I found have the reserve capacity or AH rating of the Interstate U2400.

6V Intersate Workaholic U2400,
251 AH
562 MINUTES @ 25A/154 MINUTES @ 75A RESERVE CAPACITY
10-1/4" L X 7-1/8" W X 11-7/8" H
70 LBS
Cost may be around $125 ea.
May want to pay particular attention to the length as 10-1/4" L would be the max. 7-1/8" W is also a consern, as it may be difficult to get the hold down bars all threads w/nuts secured to frame.

For a cheaper wet cell, may want to consider the Interstate U2200 @ around $80.00 ea.
6V Intersate Workaholic U2200,
232 AH
474 MINUTES @ 25A/122 MINUTES @ 75A RESERVE CAPACITY
10-1/4" L X 7-1/8" W X 11-1/8" H
63 LBS
If money is no object & no battery maintenance is a priority, need to check out the AGM type of batteries

[BryanL]

The best means of testing batteries is by usage. See how well they do for you.

Hydrometer testing is often touted as the only way to determine state of charge but that is so ancient. Measuring specific gravity is a hazardous process that has a very high risk of causing contamination. These days, a digital volt meter is much safer and more convenient and will tell you enough.

The tables and such for voltage are for a battery that has been off line for a few hours - in reality, much the same conditions as for measuring specific gravity properly.

But you can measure voltage live and learn about not only the state of charge but also the condition or health of the battery by watching how the voltage changes as you turn on lights or apply other common loads to the battery. Old timers used to tell about their battery condition just by watching how the lights dimmed.

As for which batteries, get the biggest and heaviest that will fit in the space available and are intended for the service. Buy from a reputable retailer. I'd suggest not going for an AGM unless you need the specific capabilities that type of battery offers (reduced ventilation, large current draw, rapid charging). Do wire properly and keep connections clean.

For your batteries to last a long time, get enough batteries so you don't run them down more than 50% (past 12.2v resting). Typically, your batteries should handle 3 days and 2 nights with a few hours of furnace without trouble. Charge with an intelligent 3 stage charger than is rated to provide 20 amps for each 100 AH of battery capacity. Use a maintainer that will provide a good float charge and do equalization and desulfation if you have the batteries out of service for more than a few weeks.

There are meters that calculate the state of charge of your battery bank. I call the Trimetric type electron counters although the newer models may make some accommodation for current draw. The smartguage is one that compares the voltage changes to its battery model to determine how the battery is doing. These kinds of meters are quite a bit more expensive than a DVM but some folks really like to have instrumentation to worry over ;-)

[Dale777]

Alpine4us,

I had Lifeline AGM batteries installed at the WRV factory on my 2006 coach, as a special option. Compared to dealing with the headaches of normal wet-cell batteries that I had on my 2001 Alpine Coach, these AGM batteries are wonderful, wonderful, wonderful!

The extra cost for AGM is easily offset by the lack of headaches in dealing with monitoring for water, watering, corrosion, cleaning, and the time involved with all of this. I don't worry about splashing acid on me, bending over in a tight space, peering in with a flashlight to see if any watering is needed, then watering, or trying to get an automatic watering system to work properly.

I just forget these AGM batteries exist - other than to check periodically for connections and any other visible problem.

[Jim&MaryJo]

For a "thrifty" solution, here's info from a previous post:

Just an FYI and "library log"...

My coach batteries expired on my last trip (the week after warranty expiration).

After shopping around, I chose the Costco/Johnson Controls "GC2 golf cart" batteries for ~$60 each.

Based on an apparently credible post, these batteries are actually US Battery model US-2000 rated for 210AH (105 @ 12v).

I decided to sanity check my Xantrex Freedom 458 inverter/charger settings.

I found the settings to be the default settings, which were wrong.

--Battery bank was set for 400AH, I set to 600AH (6 batteries X 105AH). I believe this "tailors" the charge cycle.

--Idle was set to 5A, Xantrex website manual now contains a footnote for a "0" setting for RVs.

--Battery type was default set for "wet cell", but take notice if you ever use an AGM or Gel battery, this setting must be changed to service a critical difference in the way such batteries are charged.

Please let me know if I missed something or messed up the math...

[Ted III]

Is there not a concern with one AGM going bad and they all go bad? It seems that was an issue in the marine situation? I truly know very little about batteries except when they are dead. Then I become very knowlegeable

[dgerstel]

Ted,

I don't think one battery going bad will make the others go bad. The problem that I am aware of is that anytime batteries are run in parallel a low one will drain down the others. This is why it is very important that all of the batteries in a group that is in parallel are "matched" All of the same age and rating. I have 8 6 volt batteries, 4 parallel banks of a pair in series. My concern with using AGM batteries is that if one goes bad I can't just replace that one and have a matched set. I don't know an easy solution to this. Even the high, high end coaches that use the large batteries run more than one in parallel, so that if one fails you should replace all in that bank. That is why I just stick with the "golf cart" batteries and use the Hydro caps.

Dale

[bigfish]

Specs for the US battery US-2000;
6V DEEP CYLCE US BATTERY US-2000,
216 AH
445 MINUTES @ 25A/114 MINUTES @ 75A RESERVE CAPACITY
10-1/4" L X 7-1/8" W X 11-1/8" H
59 LBS

BTF

[BryanL]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The problem that I am aware of is that anytime batteries are run in parallel a low one will drain down the others. </div></BLOCKQUOTE>

This isn't usually the case. It might be if cell shorting was the main cause of battery failure but 80% of the time or so battery failure is due to sulfation. That makes the battery weak which doesn't pull down the rest of the bank - it just doesn't add as much as it would when healthy.

As far as battery maintenance and adding water and that stuff - if you take care of your batteries, this should be a minimal nuisance. Having to add water frequently means your batteries are being overcharged.

As noted, you need to pay particular attention to the charge and maintenance settings no matter what type of batteries you have. If you have these settings right and don't abuse your batteries they should last a long time (5 years or so).

As for the capacity specs - you'd probably do better just to consider weight. How you use the battery, how you have them wired, the operating temperature and such things can make as much as a 30% or so variance in the spec sheet rating.

[dgerstel]

BryanL,

A weak battery hooked in parallel with an other batteries will drain down the other batteries. What happens is the batterie that are of higher strength will try to charge the weak battery.

http://sierranevadaairstreams.org/owners-guide/understa.../battery-config.html

I guess that I am more concerned than others due to the fact that most of the battery failures I have had in RV's is one cell going bad, requiring replacement of the whole bank.

Dale