Hello all. This is my first post here. I have read till my head spins the Megawatt and CPS-1620 charging threads. Read the 40 page maintenance thread. Lot's of great information you can't get from the manufacturer.I'm looking for advice on purchasing the CPS-1620, Megawatt or this on Ebay: Ebay power supplyOn my Toyhauler I have two new Interstate GC2-RD batteries in series (the Costco golf cart batteries). 208ah. Most of our camping is boondocking. I have the built in Onan 4000w generator and build in 160w solar panel. I am changing the solar charge controller to a Blue Sky Sun Charger 30 that I can adjust for specific voltage and absorption time. My converter for now is the WFCO 55a that won't go into bulk mode. I may upgrade that to the PD with the charge wizard if I find the solar isn't getting the batteries fully charged.I have a decent voltmeter and hydrometer. I am going to buy the Freas hydrometer recommended by MexicoWanderer. I will also by a clamp amp meter and probably install a Trimetric monitor.I want to get a power supply so I can fine tune my batteries. Top off charges and equalization. I want these batteries to last but my main objective is to learn how to properly maintain real deep cycle batteries for down the road in retirement when I will have an off the grip home with a large and expensive battery bank.Interstate recommends a c/10 charging rate for my batteries which is roughly 20amps. I believe MexicoWanderer recommends a 5% of total ah rate (c/20) for top off and equalization which would be closer to 10 amp.I'm intrigued by the CPS-1620 for it's small size. However, from my experience heavier is usually better in the electronics world (at least with audio equipment). The Ebay supply weighs 6 lbs 2.6 lbs for the CPS-1620Thanks for any advice.

That linked charger is listed at a good price, and has a dial for current control as well, which is something the Meanwell/megawatts do not have.It should be good for top charging a pair of GC's and Equalizing them too, but not a bigger capacity bank.I wonder what the maximum voltage it can allow is.

Unless I am reading it incorrectly 30v max (0-30v adjustable).Oh and it weighs 6 lbs, not 17 lbs.

If it were me I would replace the WFCO 55AMP WF8955 converter/charger unit only with the PD9260C charger unit and be done with it.The PD9260C will fit in the same location of the WFCO 8900 series Power Distribution bottom compartment. Just hook up the DC output wiring and plug the 120VAC plug into a 120VAC Receptacle. You can also strip off the 120VAC plug and add ring terminals on the 120VAC side and connect directly to the WF8900series circuit breaker where the WF8955 Comverter unit was connected if you like.The PD9260C smart mode 60AMP unit will automatically perform all of the required smart charging modes your two GC2 6VDC batteries connected in series will need.You can confirm all of this with Randy at BEST CONVERTERS when you purchase the PD9260C unit.This is what I would do at any rate... The PD9260C will recharge your two GC2 6VDC Batteries connected in series in about three hours time using the smart mode charging techniques. The only maintenance you will need to perform is maybe check the fluid levels every two to three weeks.Just my thoughtsRoy Ken

Hammick - I bought Meanwell SE-200-15 for $38 for the same purpose, only for a car battery - to bring it back in shape after long absence. My RV bank is taken care of by solar, works like a charm. This my 10A Minny will be adequate for what you want - top charging and equalization, since you are not looking for high current and/or charging a big bank from the scratch. I'm not sure that a 30A Meanwell/Megawatt for $60 is any better in this case, since you don't need a lot of amps.What nobody told me is that Meanwell/Megawatt is a barebone system. You get what you see - no voltmeter, no cables, no handy knobs. Not even legs - you know, those small bumps or plastic washers at the bottom, so it won't be sitting with its hot ass on a wooden bench. I attached an old lamp cord, and a cord with crocodiles from a dead charger. I wrote about this already - tiny adjustment knob on Meanwell (the knob on Megawatt looks similar) is not for playing with it very often. It is small and flimsy, requires a careful handling with a small screwdriver, checking on multimeter after every micro-movement of your wrist to make sure that it's 13.7V and not 13.9, or whatever you need it to be. That Ebay charger looks more user friendly than Meanwell/Megawatt. But I don't know who and how makes them. Voltmeter and ammeter - I don't know how good they are. Have a 4-digit voltmeter from Amazon (2 decimal points), it works with 0.3V error which makes it pretty much useless. Mean/Mega are made well, this I know.Converters - they work as long as your batteries are in a trailer. If you remove them to some garage for long-term storage, converter won't be much useful.

GC2 batteries: help me pick power supply for maintenance

42 Replies

MEXICOWANDERER
Explorer
Apr 18, 2015
Hurricane lamps, smokeless campfire, kettle tripod, 2-man buck saw, wedgie maul, rifle and ammo and somone to wake me up out of this daydream...
hammick
Explorer
Apr 18, 2015
Almot wrote:
Ok, different chemistry in AGM. I think this is not that they are more sensitive to overcharging, but (read it somewhere) that they get into Abs and drop current to 1%C when they are CLOSER to 100% than flooded. So they can get the remaining few % of charge in Float mode, while flooded can't. And - yes, flooded you really want to boil for some time.

It's still better to have a CC with more features. You are more "in control" then. If I morph from semi-permanent to permanent living in a trailer and get a pair of GC, I can disable the current-triggered end of Abs stage by setting it very low. Then the timer expires first and overrides the current-trigger. CC log will tell me in the evening (or next day, or data for several days) whether the timer expired.
Though, have a gut feeling that with real fulltime living I will want a shore power.

No shore power for me. The ideal boondocking for me is nobody else around but the wife and dog, stunning mountain views and lots of wildlife. If the cell phones have no coverage even better. All I need in the evening are my binoculars and bourbon. OK and maybe my hydrometer :B
Almot
Explorer III
Apr 17, 2015
Ok, different chemistry in AGM. I think this is not that they are more sensitive to overcharging, but (read it somewhere) that they get into Abs and drop current to 1%C when they are CLOSER to 100% than flooded. So they can get the remaining few % of charge in Float mode, while flooded can't. And - yes, flooded you really want to boil for some time.

It's still better to have a CC with more features. You are more "in control" then. If I morph from semi-permanent to permanent living in a trailer and get a pair of GC, I can disable the current-triggered end of Abs stage by setting it very low. Then the timer expires first and overrides the current-trigger. CC log will tell me in the evening (or next day, or data for several days) whether the timer expired.
Though, have a gut feeling that with real fulltime living I will want a shore power.
MEXICOWANDERER
Explorer
Apr 17, 2015
Almot I surely worked with definitive reports a lot and when a definitive notation is included in this case it clearly shows the referal note means the OEM. Declaritive statements need to point exactly as the source of reference - in this case I have not read any OEM material who disputes the 1% AH claim. I agree with the claim.

And the fact is flooded batteries are a whole other story.

Trends & Tendencies

Makes the world go round.
hammick
Explorer
Apr 17, 2015
Almot wrote:

In the similar scenario with flooded, i.e. current dropped to 1%C - would you suggest keeping Absorption forcefully for another 20-25 minutes?

Yes at least that amount of time. Lead acid batteries need to bubble to get fully charged, especially GC2 batteries. Your AGMs are a different animal. They need a more delicate touch and don't like over charging.
Almot
Explorer III
Apr 17, 2015
MEXICOWANDERER wrote:
Using the AGM battery manufacturer's value for absorbsion charging voltage limit

And correcting that for temperarure...

When the charging amperage slumps to ONE PERCENT of total amp hour bank rating...

The batteries are considered 100% charged.

You surely worked with lawyers a lot. I like this "... considered ;) 100% charged". Seriously though, with AGM this is as far as you can go, without lengthy load tests.

So my AGM are full at the end of Absorption. Then they go to Float and suck in another 5-6 AH per 100AH battery before current drops lower yet, to zero or to the level of parasitic loads, which makes it 105% full, but let's not go there yet. My point was that when they have been floating for a few days, this current-triggered end of Absorption occurs (usually) a few minutes after it started, and frying them at high voltage any longer wouldn't be necessary.

In the similar scenario with flooded, i.e. current dropped to 1%C - would you suggest keeping Absorption forcefully for another 20-25 minutes?
MEXICOWANDERER
Explorer
Apr 16, 2015
Using the AGM battery manufacturer's value for absorbsion charging voltage limit

And correcting that for temperarure...

When the charging amperage slumps to ONE PERCENT of total amp hour bank rating...

The batteries are considered 100% charged.
Almot
Explorer III
Apr 16, 2015
hammick wrote:
MEXICOWANDERER wrote:
BTW

"FULL" means when the hydrometer indicates "full" not when some Looney Tunes meter gizmo dartboards a guess.

Exactly. Part of the reason whey I chose the BS SC30 controller. It doesn't guess when the batteries are full. It let's me tell it exactly what to do and for how long.

I think senor Mex meant bean-counting feature of battery monitors - determining SOC by counting AH in-out.

He is right, this is merely an estimate. Can be useful to estimate SOC in less than Full stages. This is why it isn't very useful to me, as my solar brings batts to Full in the evening 9 days out of 10, and CC itself keeps a log. No hydrometer, AGM won't take it. If log says that it exited Abs after 5 minutes - because the current dropped to 2.5A for 300AH bank - and then spend 5 hours in Float, it's as close to Full as it can be said about this black box. Or - if current is zero when fridge isn't cycling.

Telling CC what to do is fine as long as you know what to do. 30-minutes time for Abs in storage, taken off the top of your (and their engineer's) head is a guestimate. I would observe it for a few days, making notes how soon the current drops to, say, 2-2.5A for 225 AH bank. If it's 3 or 5 minutes, then set it so. A bit of pain to do this manually, but with this CC seems like you have no choice.
hammick
Explorer
Apr 16, 2015
MEXICOWANDERER wrote:
BTW

"FULL" means when the hydrometer indicates "full" not when some Looney Tunes meter gizmo dartboards a guess.

Exactly. Part of the reason whey I chose the BS SC30 controller. It doesn't guess when the batteries are full. It let's me tell it exactly what to do and for how long. I guess the drawback is electrolyte loss if you don't know what your are doing. It only takes seconds to reconfigure so I think I will be happy with it. Plus it filled the hole cut in the bedroom wall and was fairly inexpensive compared to other fully adjustable CCs.

I'll report back on how it hands abs time each day.
MEXICOWANDERER
Explorer
Apr 16, 2015
BTW

"FULL" means when the hydrometer indicates "full" not when some Looney Tunes meter gizmo dartboards a guess.

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GC2 batteries: help me pick power supply for maintenance

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