Battery Gr 31 AGM Unfamilar Territory

[MEXICOWANDERER]

This is where my age really shows.

Looks like the 55 amp WFCO didn't show. That leaves me with two CheapOWatts to recharge a group 31 AGM.

If that AGM can eat more than 60 amps at a helping, I need to come up with an alternative, when I head north next week.

Less than a sixty amp charge (bulk) rate and the imitation chargers can handle the situation. But even if I back them down voltage wise, high amperage is going to eat their lunch, or I'm going to need a cordless screwdriver to constantly tweak the pots.

Anyone out there force feed a 31 AGM to absorbsion voltage limit? I queried LifeLine and no answer for the last week. The other chargers will arrive 2nd or 3rd day after I leave.

Faint hope here of getting an answer but can't say I didn't ask...

[pnichols]

MEXICOWANDERER wrote:
Ain't life grand when someone reaches the age when nothing works right except what's between the ears?

I don't know which way to go on that: The DW and myself last fall went through the passing of her beloved mother ... who had a healthy body well into her 90's but a gradually deteriorating mind due to years and years of slowly advancing Alzheimer's. It was a long, long good-by and took a terrific toll on many loved ones who were involved in the situation. The IQs that be HAVE TO DO SOMETHING about that blasted Alzheimer's.

If one or the other has to go I'm of the opinion that a good mind right to the end is top priority, as it's our mind (and soul) that in fact make us "a person". I guess Stephen Hawking is an example of that taken to the extreme.

We can just do the best we can with what we have and hopefully help some others along their journeys till our last breath. 🙂

[MEXICOWANDERER]

It is indeed the humidifier causing the issue. Without it, I have major problems, and my AHI soars, my cardiologist roars, and I don't feel so hot during the day. The OMRON BP monitor confirms irregular heat beat. Ain't life grand when someone reaches the age when nothing works right except what's between the ears?

[pnichols]

My CPAP draws around an amp and a half powered from 12 volts, but it does no heating ... just pushes air on a setting of 10. Over several days use, mine hardly impacts our 200 amp hours of AGM battery capacity.

Why does your unit draw so much current? You might want to get an upgrade. I'm told that Medicare pays for a new one every five years. I'm about to look into the new little tiny one that automatically adapts to your needs by adjusting it's pressure to dynamically match your breathing. I'm not sure it operates off 12V though - still checking into it.

[MEXICOWANDERER]

Respironics 5.11 amperes @ 12.04 volts.

The GPL-31T is designed for charging amperages up to 262.5 amps or 250% of the rated Amp Hour Capacity due to low battery internal resistance.

If this came from Concorde battery they are contradicting themselves. The user manual recommended by Corcorde last week clearly states the battery can accept a 500 ampere charge rate and return from a 95% discharge (5% remaining) in less than an hour.
Document 6-0101 Revision D (2014)

Regardless, the battery is going to ultimately be fed with a mere 120 amperes. And I will increase charge lead size to 12AWG to throttle current proportionate to the charger's wattage potential limit.

[pnichols]

EsoxLucius wrote:
2013 LTV Unity MB Theater Seats
500 watts solar panels, 440 AH batteries, BlueSky Solar Boost 3024iL & IPN-Pro Remote, Magnum MS2000 & ME-RC50 remote
Koni Shocks F & R, Hellwig 7254, SumoSprings F & R
2012 Hyundai Accent SE, Blue Ox Aladdin/Patriot

Jay,

Off topic, but I notice that you're running Koni shocks on your LTV.

What Koni shocks are they?

I'm looking for performance inputs from motorhome owners with Koni FSD shocks on their rigs.

[EsoxLucius]

Lifeline GPL-31T Charging specifications
Bulk Charge Voltages: 14.20 - 14.60
Absorption Charge Voltages: 14.20 - 14.60
Float Charge Voltages: 13.10 - 13.40
The GPL-31T is designed for charging amperages up to 262.5 amps or 250% of the rated Amp Hour Capacity due to low battery internal resistance.

[pnichols]

Hmmm .... my CPAP (non-moisture-injection -> air pressure only) will operate many nights on our two Group 29 AGMs.

Trying to pump up to C/1 currents into your/any AGM can of course be done with plenty of super cooling while it's happening. How do you plan on throttling back those CheapOWatts versus battery temperature?

Sitting around watching a thermometer at the same as twittling a voltage control pot seems stressful and defeating the very purpose for having the CPAP in the first place. :h

[MEXICOWANDERER]

Yes it's a Lifeline. The original "plan" was to overwhelm charge acceptance with a bevy of CheapOWatts. Reality reared its ugly head and the 2nd batch was delayed. Plan B is in effect. Parts Store in USA. Six feet of 14 gauge fusible link wire (cross link insulation). The shottky pair will be connected, and both power supplies will share the misery. Don't see why I can't preset voltage while the units are operating open circuit, shut down, connect and then re-plug the power cord. I did bring along my Triplett meter. Load sharing, yadda, voltage yadda, Don't know if I needs fans or a power unit out of a Huey to keep these critters from Seppuku. Lose face, plunge knife in belly and yank upward.

[wa8yxm]

This is from Xantrex, and other sources

A group 31 non-optima is 130 amp hours (Optima abut 75)
Multiplying by 0.3 that means 39 amps is your max recommended recharge rate.

UNLESS, it is a lifeline, in which case that is the MINIMUM and you can hit it with like 300 amps for the bulk mode. (Source: Lifeline)

[landyacht318]

Ahh, you just need to teach your brain to twiddle the voltage pot in your sleep is all.
😉

So how are the cheapowatts to be engaged? Are you going to just set their voltage to Lifeline's 13.3v float at 77F?, and run cpap and other gizmo off inverter and AGM.

When power goes out battery depletes, when power comes back on, cheapowatts buzz away until Lifeline agm requires less than 72.4 amps? well plus inverter loads. how much is that? the inverter load powering the Cpap?

Depletion below that threshold might very well happen before the chreapowatts release the magic blue smoke.

I think my 27 Northstar might have lower resistance than the Lifeline, So I think it will gobble up more amperage than the 31 lifeline would, even if the lifeline weighs 6 Lbs more. Also my NS Agm Absv is 14.7v, My last read on the lifeline pdf said 14.3v at 77f AbsV.

I think you'll be okay. Extra fans /heatsinking couldn't hurt. I can help you out there when you next return stateside. I'm in North County SD.

Obviously rate of recharge will be slower after 13.3v is approached, but it should make it through the night. Then on awakening, if power has returned, you crank their pots to the max till battery reaches 14.3v, and 14 awg would then be your nemesis.

Not ideal, but certainly workable.

[MEXICOWANDERER]

I am away from home base. Danged near to the point of turning my pockets inside out. The battery is for my BiPAP. Heart goes out of rhythm when power goes off in the middle of the night. I am also picking up an alarm pulse oximeter along with many other items. Cardiologist warned me I was on thin ice so the battery is not optional. It goes near the bed. A couple times a week the power goes off. It may be off for five hours then return for a couple of hours then go away for half a day, or a day. Hence the AGM and fast recharge. But the CheapOWatts need to be three or more to make the load safe. Not going to happen this trip. Delivery delayed. Can't even get the big pot. So it's back to basics. Dang near thinking about using 14 gauge to throttle output...

One wire that looks silver is tinned copper in speaker cable. Guaranteed.

[landyacht318]

Amazon can be great like that. I've gotten a few things for free, but had them send me return shipping labels on things I thought they would just say keep and refund me the money, but somehow they get extra special shipping rates and still profit by having the product returned

Anyway it appears you doubled up on the 8awg to the Shunt. It would be a neat experiment to put a clamp on DC ammeter over the individual copper and aluminum wires to see how much current each is passing when in parallel and the MW is maxed out.

I did a similar experiment on two 4 awg wires, one which had steel ring terminals. 85 % of the current chose the cable with brass terminals instead.

[NinerBikes]

Amazon sided with me on it not being what I ordered from the vendor, and gave me a full refund and told me to keep the wire, too expensive for return shipping to the vendor in FL, and time intensive.

[landyacht318]

I ordered two ATC/ATO fuse holders that claimed to be 8awg, for a good price. When I cut the wire open and looked at the cross section, it was slightly narrower than known 10 awg and much narrower than my new Tinned Marine 8AWG. At least it is indeed copper

They came with 50 amp fuses though. The clear red insulation actually magnifies the appearance of the wire within. It looks like 6awg and impressive from the outside. the wire cutters revealed the illusion.