I plan on replacing my Trojan T-125's with 3 (or 4) x Lifeline 12v AGM batteries @ 215 A/H for a total of 645 (or 860) A/Hs total. I want to use the 12V batteries since I dry camp 90% of the time and use an inverter - from what I understand the AGM 12v units withstand short heavy loads pretty well. I'll also have a full solar setup to support (1000 watts @ 24v, Bluepower MPPT 100 amp controller), but my question is about the converter/charger. The stock unit is a WFCO, so I want to replace it with either a Progressive Dynamics 9200 series, the Powermax or possibly the Parallax 5400 series. The Parallax is pricier, but offers auto temperature compensation. Question is, is it worth the investment given my usage pattern (will mostly be used in the driveway in between trips)?The Parallax 5475TC is roughly $525 Cdn vs $260 for the PowerMax or $400 for the PD9280/

9280 gets my recommendation. Parallax TC is OK but a bit muted to really count. The daily boost of the PD should keep your batteries tip top all Winter.

JMO, but if I were investing this many $$$$ in a new set of AGMs I'd insist on a charger that offers temp compensation, which most converters don't. The Parallax ParaMode is one of those exceptions. :B

If your solar charger has temp compensation, use that for the final 20% of charge. The first 80% or bulk charge doesn't really require temp compensation. You can use an adjustable power supply to manually bulk, or the cheaper Prog. Dyn. to get the batteries up to 80%; then let it drop out and leave the temp compensated solar to finish it properly.

Here is how I do it as learned from others on here with AGMs. Go camping run them down, do 50-90s same as with Wets, then go home.Now you get to recharge the AGMs properly to their "real full" the specs for my AGMs say to recharge at 14.8ish and to float at 13.7ishEverybody says the (only) way to tell if the AGMs are full so you can stop the recharge at the right time and not overcharge, is by watching the amps as they taper down to close to zip (under 1 percent of AH) and then drop to your Float voltage. After that the amps should be stable at near zero. So how to do that? You need a charger that you can control the voltage yourself to keep it at the charging voltage and then \drop it to the spec float (adjusted for temp of course--you know the temp and there are tables for the adjustment to voltage)And you need an ammeter to watch the amps as above. I use my Trimetric. The other thing to watch is the spec max amps for the AGMs. Mine say 27amps per 100AH batts so with my pair of 100s that is 54 but I use my --Yes!--55 amp PowerMax ADJUSTABLE voltage charger. (so I do not use the 100 amper or I would be way over spec amps unless I had a bank of four of these things)There is no way you can do the right thing without an adjustable voltage charger. If you do not do the right thing, your AGMs will not die in the first 5 minutes. So it is all about money--how often do you want to replace the AGMs vs how much to pay for a proper charger and an ammeter.

Direct ConnectionAs "Direct" As You Can Get. October test of 5-year old Lifeline, 104% capacity -- with attention paid to proper voltage for particular temperature.The link below takes you to where you can download and store Lifeline maintenance information. A ton of it."Lifeline Sez" then becomes your salutation on the forum...http://lifelinebatteries.com/knowledge-center/

Choice of converter for AGM batteries | Good Sam Community

Cydog15
Explorer
Nov 30, 2017
The Boondocker adjustable should be fine but I seen Bestconverter also has a 14.8 boost Progressive Dynamics unit too.

Progressive Dynamics 14.8 boost for Trojans
time2roll
Nomad
Nov 30, 2017
phemens wrote:
Any reason to pick the PM4 series over the PM3?
PM4 I believe adds the daily short boost of 14.6 volts similar to the PD. Yes if you get PowerMax you want this feature. The daily boost makes up for some of the other shortcomings of these converters. Does not seem to be available in MBA replacement board for WFCO or I would have one.
time2roll
Nomad
Nov 30, 2017
phemens wrote:
My solar controller does do temp compensation, so do I need it in both?
Not IMO.
time2roll
Nomad
Nov 30, 2017
While AGM does like a good speed charge I would not get all hung up on it.
Certainly do avoid the 5 amp trickle charger for bulk charging on a regular basis.
BFL13
Explorer II
Nov 30, 2017
time2roll wrote:
phemens wrote:
Any reason to pick the PM4 series over the PM3?
PM4 I believe adds the daily short boost of 14.6 volts similar to the PD. Yes if you get PowerMax you want this feature. The daily boost makes up for some of the other shortcomings of these converters. Does not seem to be available in MBA replacement board for WFCO or I would have one.

http://www.bestconverter.com/Boondocker-Main-Board-Assembly-for-WFCO-8955_c_196.html

I am not clear on how often it does the boost when in the "storage" stage. Have to ask Randy.
landyacht318
Explorer
Nov 30, 2017
I am firmly in the adjustable voltage manual camp. I keep thinking about how much of a pain in the butt it would be to have to worry about what stage some converter is trying to achieve and considering battery temperature, and how to determine when full actually occurrs, requiring absorption voltage and an ammeter.

Any automatic converter, without temp compensation is going to be outside ideal, quite often.

Spinning a dial after looking at a thermometer and ammeter is so simple and allows me to achieve the perfect absorption voltage, and the perfect float voltage, and it is simple, takes little to no time, offers a level of precise control no automatic source will ever allow.

And those automatic adjustable sources, how many hoops does one have to jump through to actually adjust it. 90 degrees one day and 50 the next, I spend 0.21 seconds spinning a dial.

The whole 'it has to be automatic' mindset regarding every aspect of life, is a sign of human devolution, in my opinion.

You could not pay me to use any automatic charger in my particular usage. It would be a nightmare of trying to trick it into doing its job, where as the adjustable voltage power supply is plug it into AC, adjust voltage to desired area, connect to DC. Watch how many amps flow to achieve desired voltage.

Cold battery, add a bit of voltage, hot battery reduce a bit, gonna suck up 40+ amps for a while, reduce voltage a bit, maybee.

Not going to be around when 0.5% capacity is reached at absorption voltage, then time to full is not a factor, set to float voltage.

My Meanwell rsp-500-15 is PFC too, and has thousands of hours on it, and emits flatulence in parallel with mine own at 'automatic'

Forum Discussion

Choice of converter for AGM batteries

About Technical Issues

Related Content

Replacement Battery Help/Choices/Opinions

Converter/Battery Charger

Tire choice

Chassis battery won’t charge from converter

replacing battery with converter