Vmax batteries

[Fro]

I'm the first to admit I don't know what I'm doing when it comes to the RV.. having said that, I'm clawing my way up the learning curve thanks to the great help and advice from this community.

I have not tested my coach batteries yet, but I'm fairly certain they are toast. I have had this coach less than a year and the previous owner assured me that all batteries were less than 3 years old. I'm thinking his memory is off by a few years. Cummings couldn't get my chassis batteries to hold a charge so at last months service they were replaced. I did have to use the boost a couple times after I got the coach and the weather turned cold, so it really wasn't a surprise.

I am thinking I need to replace the house batteries now. They don't seem to hold a charge anymore either. I have a bank of 4 GC 6v for 834 Ah.

Edit: Just checked batteries with very expensive float thingy from wallmart. It must have cost maybe two bucks..
bat 1: cell one dead, cell 2 fair/50%, cell three Full
bat 2: cell one dead, cell 2 dead, cell 3 fair/ 50%
bat 3 cell one fair 50% cell 2 full; cell 3 dead
bat 4: cell one dead; cell 2 fair 50%; cell 3 full


Normally, I have the coach engergized with 15 amp either at the s&b or storage facility, so had not been keeping tabs on the batteries other than adding distilled water. I have since added 520 watts solar and it isn't long before the batteries on the EMS system show half or quarter charge. This week the inverter shut down due to low voltage. THe days were hot and sunny, panels were in full sun and the only load was the usual phantoms and the residential fridge.

I am wondering if anyone has had experience with Vmax 6v GC batteries. I see amazon has a bank of 4 for $1K.

My system is Freedom 458 charger/inverter, echo charger, and sunrunner 40 mppt controller. I did verify the chargers were both set for wet cells, the only error I found was the xantrex was set for 600 rather than 800 for bank size.

[montyhp]

I have Vmax charge tanks. (4x6vGC version) I put them in in January 2016. So far no problems. Just be sure to set your Freedom 458 for AGM mode.

When I first bought and installed the batteries, I heard a bubbling sound. Called Vmax and they said it was not a problem. Once they initially charged, no problem.

Two or three times I have taken the coach to the shop and left it there for a couple of weeks without turning off the salesman switch (last time the shop turned it back on), so the batteries were totally dead when I got the coach back. They have recharged with no problems.

[jelag]

That's great that you found a battery hydrometer to use to check your batteries and that you've found the results... now what you'd like to hear, but at least it looks like you've diagnosed it correctly....

My 2 bits on this is that all battery manufactures here in the US have a great product... I personally chose wet cells instead of AGM's just because I like to look inside that cell, see how clear the electrolyte is... check the level and know things are OK... some others have a different opinion... and that's great....

For years I've bought my 6 v batteries at Costco.... good price, good return and warranty and no matter where I travel there seems to be one of their stores...

But I'm sure you'll hear from others here... and think through the purchase and do what you feel is right for you...

[Arch Hoagland]

$1,000 for four batteries sounds a bit steep to me. I use $90 Costco batteries and they work just fine.

My coach has a battery disconnect switch right in the battery compartment that completely disconnects them.

The salesman switch doesn't completely disconnect them and they will run down.

Good to see you got a hydrometer, most people don't do that. Good investment.

If you leave your coach hooked to shore power while in storage and you don't disconnect the batteries completely it's important to check the water levels every few weeks.

[bobcovey]

Hmm, I think your AH calculation is off by 2x: they are 6V, so will be in series/parrallel pairs, right? So two pairs yield 470 AH, I believe.

Costco now sells Interstate batteries, which I think are made by Johnson Controls, the same folks who supplied the Kirlkand branded GC2 batteries. Whatever the label, it looks like the same battery: roughly 220 AH each, or 440 AH in the 4 battery config like I use. These cost about $90 each in 2014, or about 1/3 the price of four VMAX AGM units for roughly equal capacity. I check the water level every couple of months, takes about 10 minutes. I couldn't make AGM's pencil out when I bought mine, but other people have different priorities.

When these give out I will look hard at the Trojan J305P or equivalent, roughly 40% more capacity in approximately the same footprint, but a few inches taller.

Cheers,

[Fro]

Hmm, I think your AH calculation is off by 2x: they are 6V, so will be in series/parallel pairs, right? So two pairs yield 470 AH, I believe.

bobcovey, you are absolutely correct. each battery is rated at 216 ah so I really only have 432 a/h @12v when in series/parallel. And if I understand everything correctly, I really only have 216 a/h before I hit 50% at which point I need to either get shore power or crank up the genny. Told ya I didn't know what I was doing

I looked for AGM at Costco, they told me they no longer carry them due to poor quality control in China creating problems for them. I really like the idea of a sealed battery, the hydrogen gas is corrosive and the solar controller and echo charger are in that bay. I'm thinking it can't be too good for them.

Hmm, I wonder If I cut a 3 inch hole in the side or top of the bay and mounted a computer fan in reverse (as if to pressurize the compartment or create positive air flow out the drain/vent hole in the floor) would significantly reduce the outgas accumulation? A 120 mm fan would move air at least 45 cfm. That flow would be more than enough to exchange the air every minute. I suppose the 2 inch drain hole acts like a venturi when the coach is in motion the gas is dragged out, much like pulling the drain on a boat when scooting across the lake?

[TLGPE]

I'll just jump in and mention that many of us use the Pro-Fill automatic watering system for wet batteries. There are other good brands, of course, but the idea is to keep the cells topped off and contain the corrosive gasses.


Buy distilled water (only!) and pump them up once in a while. This saves your batteries and lets you sleep easier.


Tom