New 6 volt batteries, problem?

[ryanPSD]

Hey everyone,

Hoping for some input on the new battery situation. We have a 2015 class C, about one year old next month. I’ve replaced the converter in my WFCO 8955 with a Progressive Dynamics 9270 already.

In the last week I purchased two new 6 volt US Battery 2200’s to replace the factory 12v’s house batteries that came with it. Date stamp on the new batteries was Feb (IIRC) 2016. When I installed them, voltage on each was around 6.2, and 12.4 when wired up. I figured no problem, and left the RV connected to shore power for about 3 days before our trip this weekend.

Upon unplugging and driving to our campsite today (less than 20 miles), my volt meter shows still 12.4 on the batteries. Any idea what gives? Shouldn’t I be seeing 12.7+ on a full charge still with two 6v batts in series?

I did notice the other day that the electrolyte level on the new batteries was not close to the bottom of the fill neck, but about halfway down to the plates. I estimate 1/2” above the plates, and 1/2” below the fill neck. I did not get a chance to top them off, but assumed they would be fine for the moment. I assume this should be the typical 1/8” or so just below the fill neck on these as well? The RV was level while charging, and is level at the campsite.

I did not check voltage after unplugging from shore power, before leaving. I only did prior to unplugging and the PD9270 was in storage mode at the time, it was around 13.2v if I recall, but I know it charged these batteries in all stages. The converter had no issues charging the previous 12v batteries.

Had to run back to work for the rest of the day but will be back this evening to see how they are doing, with the family using them. I don’t have a hydrometer but I think that may be next on my list.

Thank you for any input!

[DrewE]

That's a rather larger voltage drop than I would expect for those modest currents. I would check that your connections are all clean and tight and your wires and terminals are all solid and good. It would also not hurt to check the voltage output at the converter when charging (with a non-trivial charge current) and at the battery terminals. I'd also check for the off chance that there's a bad cell in one of the batteries.

Assuming the voltage dip is due to an ohmic resistance, you might see a voltage of somewhere around 8V when attempting to crank the built-in generator (if you have one), which could well be insufficient for the task...and, if it's a bad connection, it would be getting pretty hot pretty quickly.

[ryanPSD]

smkettner wrote:
US Battery is known to need 20+ cycles to reach full capacity.
Although voltage does sound low. As long as the electrolyte covers the plates you are fine.

Was the alternator charging the battery in transit?
Is the 12.4 holding well or still dropping while in use?

Thanks, that might just be the case here.

I can confirm there were no loads on the batteries, and wife drove immediately after unplugging. Confirmed alternator is providing charge to house batteries.

When I left the site today at 1:00pm it was at the 12.35-12.4. Wife sent a picture of volt meter at 4:00pm of it at 12.46. Just got here to camp at 6:00pm and it is 12.47v.

A 5 amp load drops down to 12.26v. 8 amp drops to 12.08.

I hope I answered everyone's questons.

The guy I got them from is taking care of me, and said he would replace them if I desire. He got a new, more recent, shipment of 2200's in. He said he would also up me to the US 125 green top for a few more AH if I want. We are already set up so I will keep a close eye on things and see how they go.

Thank you all for your help and input. Any further thoughts are greatly appreciated!

[time2roll]

US Battery is known to need 20+ cycles to reach full capacity.
Although voltage does sound low. As long as the electrolyte covers the plates you are fine.

Was the alternator charging the battery in transit?
Is the 12.4 holding well or still dropping while in use?

[ryanPSD]

I keep going back thinking about when I replaced the batteries, and looking at the picture I took, and really don't think I missed anythng.

http://i65.tinypic.com/141jcev.jpg

Messy, I know. Some of it is temporary until I find more room for a proper bus bar etc.

The two large cables coming up between the batts are #4 direct to the converter for charging. The two smaller ones going off to the right are a temporary 350 watt inverter. The two large cables going up top are the original that go to chassis, 12v distribution, alternator isolated charging, etc. Cat5 provides power and connection from shunt to volt/ammeter.

Thank you all for your input this far. I will hopefully know more through tonight and tomorrow.

[ryanPSD]

MrWizard wrote:
sounds like
something is wired wrong
dropped / lost a wire during the battery change out
you have 'house loads' running and NO charging from the battery isolator alternator circuit
blow fuse in charge circuit ?
dropped missing wire ?

what was on inside the RV, put fridge on LP not electric not auto
batteries should not have dropped that much, just running CO detector and fridge LP controls, unless you have a residential fridge powered by inverter ?

Thank you, I'm going to double check all wires are there and connected properly. I took a picture of the batts after install and it looks good, but will double check in person.

The alternator circuit has always charged the house without issue, and I cannot think of any loads that would have dropped the batts in the couple hours between unplugging and getting to our site, but will think about this more. The vehicle charging would have normally brought the batts up to showing 12.7 easy in the drive to the site.

Fridge is on auto and switched to LP properly, but is still on auto as it's always been. My wife unplugged actually and drove to the site, actually, but she knows what she's doing, nothing was on that could have done that, and they would have normally charged up in the drive... I will double check her process. She just loaded, unplugged and drove.

[ryanPSD]

I will try that if I can when I get to the campsite. No major draw, it was no more than 1.5 amps when I noticed it, just the fridge cooling fan off. The load rests around .7 amp when the fan goes off.

I am using the amp meter I linked in my converter thread a while back.
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28823708/print/true.cfm

It has proven quite accurate comparing amps with my DC clamp meter, and voltage to the same clamp meter and my Fluke.

[MrWizard]

sounds like
something is wired wrong
dropped / lost a wire during the battery change out
you have 'house loads' running and NO charging from the battery isolator alternator circuit
blow fuse in charge circuit ?
dropped missing wire ?

what was on inside the RV, put fridge on LP not electric not auto
batteries should not have dropped that much, just running CO detector and fridge LP controls, unless you have a residential fridge powered by inverter ?

[ryanPSD]

Posted before I saw your edit, I believe the PD charge wizard does an equalization every 21 hours at 14.4v for 15 minutes. RV was plugged in for near 3 days before leaving. I feel I may wind up trying an exchange after we get back from this weekend.

[2oldman]

Hmm.. it sounds like the charger is working properly. Is there some draw on these batteries you're not aware of? Can you unhook them when (supposedly) fully charged, let them sit for a half hour and check voltage again?

[ryanPSD]

2oldman wrote:
Assuming your VM is accurate, you did buy under-charged batteries, but that shouldn't be a big deal. Electrolyte sounds fine - as long as it's above the plates.

I'm a bit confused as to whether you've checked the voltage at the batteries when plugged in and charging. Next I'd be considering doing an equalization charge, or exchanging them, assuming your voltmeter is correct.

Thank you for the quick reply. Sorry, typing on my phone and it may not have come out right. I checked voltage when I first plugged in to charge, and saw around 14.4v, indicating the PD's bulk charge. After a couple days, today, before unplugging, voltage showed around 13.1v-13.2v. Did not check after unplugging, before driving. After driving to campsite, voltage showed 12.35v-12.4v.

[2oldman]

Assuming your VM is accurate, you did buy under-charged batteries, but that shouldn't be a big deal. Electrolyte sounds fine - as long as it's above the plates.

I'm a bit confused as to whether you've checked the voltage at the batteries when plugged in and charging. Next I'd be considering doing an equalization charge, or exchanging them, assuming your voltmeter is correct.