So I just picked up two Interstate GC2 6v's from Costco for $94 ea.The sticker states 210Ah@ 20hrs.I dont plan on using them for about another month so I will just store them inside so they dont freeze.I ran them in series on my workbench and get a charge of 12.35So I assume this is at about 70% capacity?I have a 40/120a car shop charger. Would it be ill advised to use this to top off the new batteries, or should I just hook them up to my TT and plug it into the house. The TT has a 3 stage converter/charger power center..Kind of overwhelmed with battery service & maintenance as I go about reading about it. Going into only my second season with my new TT and the house battery from the dealer was a real poc that barely got me through last year.I know I need to pick up a hydrometer and distilled water eventually.Any tips would be great for a newb.

Despite WFCO's claim to the contrary your converter is unlikely to ever deliver a 14.4 volt bulk charge that your two 6 volt batteries in series should see so you're already off to a bad start. Many here would recommend that if you truly care about those batteries that you replace the WFCO with a converter that can properly maintain them.

Use your shop charger and charge them up. Fully charged they won't freeze but you can keep them inside, it will probably make it easier to charge them anyway.

Distilled water "eventually"??? Get it now. People have gotten spoiled the last 40 years or so with maintenance free batteries. 6 volt golf cart batteries need frequent re-watering. You might want to consider the watering systems they sell, especially if the batteries are in a location where looking in the top isn't easy. I'd install them now and let the RV's converter do the job it was intended to do. The upside to the 6 volts is that if you keep them watered and the terminals clean they will usually reward you with 7-8 years of service. Our previous coach had a WFCO and we had no problems with batteries being undercharged.https://www.amazon.com/Trailer-Electrical-Battery-Watering-Stystem/dp/B00MJUP1SA/ref=sr_1_12?keywords=battery+watering+system&qid=1551472761&s=gateway&sr=8-12

garyemunson wrote:Our previous coach had a WFCO and we had no problems with batteries being undercharged.Ignorance is bliss :W - fact is just about every WFCO owner, myself included, who has taken the time to actually measure what their converter is capable of report that it never delivers a 14.4 volt bulk charge to the battery terminals - never. :M I turned mine off and instead use a stand alone charger than does. :B

Don't want to steal the thread but related... I have a voltage meter hooked directly to the battery and a WFCO converter. It reads 13.7 when plugged in to a/c. Sometimes 13.3. It may go higher but those are the readings I have noticed. Does that indicate the charge rate? Is it adequate for GC batteries? I don't have GC batteries but was thinking about it.

New dual 6v's. Need some advice plz | Good Sam Community

35 Replies

deadticket8
Explorer
Mar 09, 2019
Thanks much for the info. I may have to go that way at some point, but for now I ordered a Pro Logix 2320 charger. $89.97 According to specs will go on float at 14.3 volts. That should allow me to run refrigerator(110v) at night along with fan etc. Well see how it goes!
Update: hooked up new charger and charged right up over 14 volts. Very happy! Thank you for educating me on trickle chargers.
time2roll
Nomad
Mar 08, 2019
deadticket8 wrote:
Thanks for the info, but I do not have an RV. I used to though. Now I have a cargo trailer with a solar setup. I am looking for a good charger that can be plugged into a 2000 watt portable generator when I am parked in the shade. Need something that will top off batteries not stop charging at 12.5 or there abouts.
The linked converter will charge at 14.4 volts for 4 hours before it drops to 13.6 volts. There is also a manual override to go another 4 hours in boost mode.

Not high enough? There is a similar model that goes 14.8 volts to match the Trojan GC2 spec.

http://www.bestconverter.com/9200-148-Modified-Deck-Mount

Not fat enough? Get the 80 amp if you want more power.

That CTECH is fine too at 25 amps will take a bit longer.
SoundGuy
Explorer
Mar 08, 2019
deadticket8 wrote:
Now I have a cargo trailer with a solar setup. I am looking for a good charger that can be plugged into a 2000 watt portable generator when I am parked in the shade.

CTEK Mulit US 25000. My 7 amp CTEK does do a proper 14.4 volt bulk charge. :B
deadticket8
Explorer
Mar 08, 2019
Thanks for the info, but I do not have an RV. I used to though. Now I have a cargo trailer with a solar setup. I am looking for a good charger that can be plugged into a 2000 watt portable generator when I am parked in the shade. Need something that will top off batteries not stop charging at 12.5 or there abouts.
time2roll
Nomad
Mar 08, 2019
deadticket8 wrote:
I camp from a cargo trailer now with solar panels. When I charge my batteries from my solar panels they show a charge of up to 14.4 volts. But if I charge batteries off of a trickle charger the highest they get is 12.4. Any suggestions on a charger I can use in shady spots that will take it up? Ill be charging from a 2000w generator.
http://www.bestconverter.com/PD-9260C-60-Amp-RV-Converter
deadticket8
Explorer
Mar 08, 2019
I camp from a cargo trailer now with solar panels. When I charge my batteries from my solar panels they show a charge of up to 14.4 volts. But if I charge batteries off of a trickle charger the highest they get is 12.4. Any suggestions on a charger I can use in shady spots that will take it up? Ill be charging from a 2000w generator.
time2roll
Nomad
Mar 03, 2019
Trailer is good to about 15.4 so just put the shop charger on and let it rip.
ktmrfs
Explorer III
Mar 03, 2019
pianotuna wrote:
You need to know what the battery maker says is the fully charged resting voltage. And that number is *only* correct at 25C (77 f).

As someone else said--a hydrometer is a far better way to measure state of charge.

If we assume that 12.72 is fully charged, then 12.65 is 99.4% of full. Unfortunately that last 0.6% means that the jar may well sulphate.

I'm not sure I'd say 12.65 is 0.6% from full. discharged a flood cell battery is around 11V, not 0.00V so dead to full charge is about 1.7V, and 0.07V is about 5%. so 12.65 V is around 95% SOC. the graph from 10% SOC to near 100% SOC is pretty linear with battery voltage.

and as you correctly point out just because fully charged voltage is XX.X 12.8 or whatever does NOT mean that charging a battery with a 12.8V charger will fully charge it. It Won't and will eventually lead to sulfation. Flooded cell batteries need a period of time with a voltage around 14.6V to fully charge and avoid sulfation. They need to stay at that 14.6ish volts until the charge current drops below a certain % of battery AH capacity. then they can drop down to a float voltage.
pianotuna
Nomad III
Mar 02, 2019
You need to know what the battery maker says is the fully charged resting voltage. And that number is *only* correct at 25C (77 f).

As someone else said--a hydrometer is a far better way to measure state of charge.

If we assume that 12.72 is fully charged, then 12.65 is 99.4% of full. Unfortunately that last 0.6% means that the jar may well sulphate.
jkwilson
Explorer III
Mar 02, 2019
brianosaur wrote:
Okay so after 24 hours of rest inside my house I got a series reading of 12.64v.

12.7v is full correct?

What should my new Costco Interstate's be reading so I know the difference between a bad charger and a bad newly manufactured 6-month-old battery?

I just put them in the garage and clipped the shop charger to them.
Charging now at 14.78v. All six cells are bubbling while charging, the trailing battery in the series was doing so a bit more so than the leading one. ...not sure if that matters.

To confirm what everyone is saying (and as previously posted) my WFCO converter was charging at 13.67v yesterday. Then I saw THIS sticker on the power center

We dry camped perhaps 10-12 nights last year on weekender trips.
Four or five trips ranging 4-7 nights at family resorts & screaming kids parks with electric.

Should I worry about the 3 stage WFCO when it's less than a dozen nights without shore power per year?

I am thinking before I spend $200 on a good 4 stage converter I will just throw the shop charger into the pickup bed and charge the batteries that way.

If I do should I flip the battery disconnect on the TT so 14.7v volts dont harm my trailer?

12.65V is full charge on most all flooded cell batteries. Trojans are 12.72V. Specific gravity is a better indication than OCV.