Costco GC2 Batts

[jake2250]

Well, One of my 4 year 4 month old GC2s from Costco just coughed up a cell during a cold Coast camp trip!! Sure I could buy another $86 Batt,, but I would still have a 4+ year old one..
Ordered two T105 Trojans,,, hopefully I wont report back for five or more years!!

[wa8yxm]

Costco are either Johnson Controls or US Battery from what I understand.

All good brands.. All good batteries.. I have no complaints about my Factory Interstarte (Johnson) and actual praise for the DEKA's that replaxed 'em..

[MEXICOWANDERER]

The duty cycle of a golf car...

Sent out every day to be returned when the batteries reach 50% state of charge

Every day

The duty cycle of an off grid battery

The to be recharged (daily?) when state of charge reaches 50%

Being sent out on a few weekends per year for a nine hole zot is not in the cards for a commercial golf car battery.

So RV duty for almost all GC batteries is like sending the Delta Force out to write parking tickets. Toss in Gomer Pyle and Beetle Bailey and they perform just as good as Delta Force personnel.

Reverse the duty and you will need two body bags.

[brulaz]

Thanks for that.
Good info.
Beginning to think I'm too cautious with my GC2s.

[landyacht318]

I was trying to find a different thread, to find out exactly when I installed some Costco interstate GC-2s in my neighbor's RV, replacing some group 29 wally world marine batteries.

I remember when they were new, the SG was still a bit low and took a while before they responded to a higher voltage massage even requiring a shallow cycle before they did respond.

There was some debate whether these were relabelled trojan T- 605s as the weight was the same and there were such rumors floating around. I honestly do not know who made them for interstate.

I will guess they have been in there 14 to 15 months.

Their only charging sources are a distant ford Alternator, and An Iota DLS-45 with the iq4.

These batteries likely have seen 30 deep cycles to the sub 11 volt range, and perhaps 50 cycles to the sub 12.2 range and perhaps an equal amount of cycles to the sub 12.45v range.

After the owner gets home I told him to plug it in for 3 days, then turn off the master of switch I installed at batteries, but no doubt that switch has been left on numerous times and the parasitic draws did their thing over unknown amounts of time to unknown levels of depletion, before the Iota got some 120vac juice to do its thing.

Anyway They are going on a multistate excursion and I told them I will check the batteries before they go.

It has been plugged in for a day.

SG was 1.265 +/- .005 on each of the 6 cells. No watering at all required.

I attached my Meanwell rsp-500-15 to it, dialed it upto 14.8v and amps quickly tapered to 2.3.

I let it go for a half hour then came back and twisted the voltage dial until they batteries were accepting 10.5 amps. This happened to be at 15.73v.

I walked away and some 15 minutes later saw amps had Tapered to 4.78 and dialed it up to 16v.

Batteries were accepting 6.1 amps at 16v so I dialed it upto 16.2v and they were taking 9 amps.

Came back some 20 minutes later they were still acepting 9 amps and bubbling vigorously, dipped the hydrometer on all 6 cells, All were at 1.275 +/- 0.003. Electrolyte still clear.

Disconnected Meanwell moved it to another neighbor's battery sealed maintenance free flooded 1.5 years old, that was down at 5.78v, taken down there over ~ a week by domelights.

Those costco interstate GC-2's are sure a different experience than the screwy31 whose SG was always low and varied widely, and the Iota seems to be doing a good job.

Hard to really say just how much abuse the batteries have endured, but it is safe to say the owner will use them until inverter starts screaming, and even the LEDs look dim before he will fire up the Generator.
The 50% rule is not even the slightest consideration to the owners.

[MEXICOWANDERER]

eBay search 500AMP SCHOTTKY RECTIFIER. Dual 250's. Anode bolt. Base is cathode. My recommendation for base insulator is Sil Pad 2000 and use silver based heatsink grease. Base holes are 1/4" diameter. 45 PIV. Mine are incredible .189 Vf static and .253 @ 47 amperes rectifiers in parallel. I heartily recommend 1000 watt 17 volt avalanche TVSs on both sides of the rectifier for ultimate lifespan when connected to an inductive load.

Hope this helps

[westend]

Mex,
What rectifier did you use for the Borg? I'm using some cased Schottky rectifiers in the bigger class A amps I build. IIRC, they are rated to 40 amps or so but their bigger brothers handle a lot more. These rectifiers run cool and voltage drop isn't that bad. I can pass along the parts numbers if you're interested.

I hope you and Mr Wiz can publish your power supply tutorials so some folks can get onboard with the manual charging.

BTW, I'm still working on getting some heat sinks down there to you. I haven't forgotten. My kids and their manageability take up a lot of my time, recently.

[MEXICOWANDERER]

Electro-chemical battery process is like baking a cake:

Success is not baking a cake at 700F for 15 minutes

Nor 3 hours at 177F

[MEXICOWANDERER]

The BORG uses (3) each 12 gauge "split ends" cables on POS and NEG terminals. These power supplies use individual circuit traces as seen in their printed circuit boards. Hopefully the images and text up the upcoming M&M articles will show images and text. I dumped the 3 12's into a six gauge distance four inches. This has seen 93 amps with negligable voltage drop. 3 12's = 9 gauge to handle 46 amperes. The M&M's really should be modified for extensive running all-out. 80 amp rectifiers and Panasonic low ESR capacitors plus max ventilation. Yes even the RSP can use the upgrades. The stuff is waiting in my delivery box. Landy the 80 amp rectifiers dropped Vf by almost a half volt in the Megawatt and that is not peanuts. But again this is for extensive all-out maximum charge rate. That's a lot different than using the M&M's to augment the existing onboard converter. Hopped-Up the M&M's become Mean little mothers. Rambo grade units. But hah (!) Maybe 1% of M&M users want or need that kind of snot. Dialed back to 80 really reduces heat as evidenced by hand over louvers.

[MrWizard]

that link doesn't work for me

try this one

https://www.amazon.com/GT-Power-Analyzer-Consumption-Performance/dp/B00C1BZSYO

[landyacht318]

I use 8 AWG between 40 amp meanwell and Blueseas 6007m battery switch studs, and then 4awg to battery.

There is voltage drop at 40 amps, so I often dial voltage higher than 14.7v, so it stays at max output a little longer, then dial it down later, when amps start tapering and voltage drop becomes less of an issue to keep voltage from rising above 14.7v, but a tenth of a volt is not going to fukushima the battery either.

Also when in parallel with my 25 amp schumacher charger, I need to dial it upto 15.3v or higher to keep meanwell at 40 amps until 65 amps gets my battery to 14.7v.

I twiddled my potentiometer a whole lot today, charging other's batteries.

The GTpower meter proved quite useful when deciding how long to hold 14.xx volts.

edit: bad link removed

[MEXICOWANDERER]

FOURTEEN

POINT

EIGHT

VOLTS

The forget the power supply even has an adjustment. When batteries start to bubble lightly note the charging amperage and how long it took. "How Long" is the key. Use a wind up timer like it the upcoming articles. This is easy stuff. My 11-year old granddaughter wags her finger at me when I trying pulling a fast one on her. She learned so fast it was scary. I figure you Home Improvement guys could keep up. 🙂

[BFL13]

hammick wrote:
Pretty sure I am going to order the 30a Megawatt. Most of my charging will be from 75 SOC or higher so a higher amp charger probably just wasted money.

The interstate specs are for 14.4v bulk charge and 15.3v absorption. Shall I just set the megawatt to 15.3v and charge until the current tapers to 20a? (my bank is 208ah).

Would setting it to 14.4v during bulk be any better for the batteries? In reality aren't the voltage settings for bulk and absorb always the same?

My goal is to set the Megawatt voltage and not jack with it. During the summer all charging will likely be from my solar which is temp compensated. Periodic equalization will also be done with solar.

So if you "don't want to jack with it" you don't really want an adjustable voltage charger. You just want a single voltage charger at the right voltage.

That is what I do with my "main charger" which is a PowerMax PM3-100 regular charger installed in the 5er. (Instead of using the adjustable voltage one set up as a portable charger) I have simply modified this one so it does not do "3 stages" anymore, just one voltage as set by the internal voltage pot.

You just take the lid off the unit, set the little blue pot to the desired voltage (14.8 for me) using your voltmeter in the output--- and snip R1 if it one of those newer ones with that 15 minute thing-- and put the lid back on.

To operate it, just wire it up to the batts or clamp it on as a portable, however you like to use it, and it will keep the charger voltage at 14.8 or whatever you chose, forever, until you unplug it. That will take the battery through two stages: bulk and absorption. You choose when to unplug it and stop the recharge.

Off-grid on generator, you stop at say 90% SOC, and when at home on shore power you can leave it on longer till the hydrometer says the SG is back to "baseline" full. (Maybe 1.300 depending on the temperature)

Not so expensive for the higher amp versions that way:

http://www.boatandrvaccessories.com/powermax-pm3-75-12-volt-75-amp-converter-charger.html

BTW I have extra PowerMax converters because my first ones blew their thermistors and they sent me their newer model ones with better thermistor designs as replacements, then I found out how to replace a thermistor so that got the first ones going again. (Not sure for how long with my unskilled work) so for now I have several 🙂 Never mind--but it might have been confusing some folks.

[3_tons]

I went to a Batteries+Plus store today and noticed that they had 230 a/hr Duracell GC's (gray cases) for $109.00 with a 1 yr warranty...

3 tons

[hammick]

Pretty sure I am going to order the 30a Megawatt. Most of my charging will be from 75 SOC or higher so a higher amp charger probably just wasted money.

The interstate specs are for 14.4v bulk charge and 15.3v absorption. Shall I just set the megawatt to 15.3v and charge until the current tapers to 20a? (my bank is 208ah).

Would setting it to 14.4v during bulk be any better for the batteries? In reality aren't the voltage settings for bulk and absorb always the same?

My goal is to set the Megawatt voltage and not jack with it. During the summer all charging will likely be from my solar which is temp compensated. Periodic equalization will also be done with solar.