Backup charger

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raysun
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Posts: 11415
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Backup charger

Post by raysun »

Added a new backup battery charger to the stable.
20240704_155628.jpg
It's a 48V single stage charger rated at 100A. I've set it to 75A as I don't care to run equipment to its maximum rating. Especially gear with parts made from Chinesium.
Guts wise, its a pair of bog-standard telcom charging modules. A pretty good choice if one is looking for parts that get a lot of runtime in the field.
The manufacturer has added a rudimentary control interface, which is OK, as there aren't many parameters to adjust. Also added some operating features that are fairly novel like a "soft start" charging algorithm that starts at 0A, and slowly ramps up 0.1A at a time until reaching the set output value (75A in my case).
It has "smarts" to commicate with certain lithium BMS for closed-loop charging. It also has a dry contact relay and simple AGS logic. 2 minute generator cooldown is part of the AGS library. I don't use any of these features so can't comment on how well they work.
I ran it briefly from my EU7000is at 240V and it presented a stable load. Startup was much less abrupt than the Meanwell industrial charger I put in. It will also run (at reduced output) from 120V, which is a nice "fallback" should the backup-backup generator need to be pressed into service.
The unit came with a power cable and 4AWG battery cables. The cables attach to the chassis with some plastic-housed connectors that look a bit prone to damage. They may be easily removable once connected - at least the battery cables were. I couldn't unlock the power cable, but maybe that takes some kung-fu I haven't learned. It was easy to mount on the wall, and I secured the cabling with cable clamps to minimize stress. The other end of the battery cables have 5/16" tinned copper ring terminals, pretty standard for 4AWG, but my bus bars need 3/8". I had to ream out the holes to fit. I'll have to get some dressing on the copper that's exposed, or maybe I'll fire up a solder pot and re-tin them.

I have a feeling this AC charger may be more efficient, and less quirky, than the dual FXR chargers. I'm going to run a few tests, and if that proves to be the case, I may use it in lieu of the inverters for backup battery charging.
Last edited by raysun on Mon Jul 08, 2024 3:07 pm, edited 2 times in total.
chrisski
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My RE system: 8048 Radian w/ Load Center
Mate 3
Flex max 100 afci X 2
Fortress eFlex 5.1 kWh Battery X 4
TP1000 for Internet Connectivity
Location: Central AZ, lowland desert

Re: Backup charger

Post by chrisski »

I appreciate the review on Outback equipment.

I hear this can also be used with a 120 volt generator, did you notice the option'?

Also the ramping up the amperage is supposed to be good for generators that may not be clean enough to synch with other chargers.

I have an RV with a 13 kWh battery. If this were available in 24 volts, I’d consider it. For my home system, the radian charging at 7 kW has worked for me.
raysun
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Posts: 11415
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Backup charger

Post by raysun »

chrisski wrote: Thu Jul 04, 2024 8:33 pm I appreciate the review on Outback equipment.

I hear this can also be used with a 120 volt generator, did you notice the option'?

Also the ramping up the amperage is supposed to be good for generators that may not be clean enough to synch with other chargers.

I have an RV with a 13 kWh battery. If this were available in 24 volts, I’d consider it. For my home system, the radian charging at 7 kW has worked for me.
The 120V input is simply connecting to the L1-G terminals on the power plug, so any 'dog bone' adapter wired for that will do the trick.
Since it's only constant current, it will only be usable for lithium charging.
I wouldn't be spending so much time on this were it not for some weirdness in the dual FXR architecture that shows up on AC Input and charging. I could never run the problem to ground (and that may contribute to the problem ☺️), so decided to put in a work-around should it be needed.
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sodamo
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Re: Backup charger

Post by sodamo »

Good addition, Raysun. I{ve got the previous, Yellow version. Running it off my EU7000 and a single FX3048.
Pleased so far.
David
raysun
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Posts: 11415
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Backup charger

Post by raysun »

First run at full output (75A).
The charger appears to be about 92% efficient. That's pretty good.
The charger is set to 55.2V which, along with the FM80s set to 54.8V, complete the "Absorb" phase in 11 minutes. The FM80s drop out in "Charged" status when the AC charger raises the voltage above their setpoint.
By the time 55.2V has been reached, the charge current drops to (near) zero. The charger, however, maintains its charge voltage on the battery bus. The charger is designed to stop charging by removing the AC source (stopping the generator in my case.) The charger has SoC and Battery Voltage logic to control the AC generator via AGS, but my Honda is manual start.
raysun
Forum Overlord
Posts: 11415
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Backup charger

Post by raysun »

Why mess with yet another charger? (Making a total of 7 in my menagerie: 2 FXR, 2 FM80, 120V and a 240V Meanwell chargers, and the EG4.)
Why indeed. I don't like single points of failure, or classes of failure. If our battery can't be charged in a timely manner, we are SOL.
Having an external AC charger to backstop the Outback units is just prudent "defence in depth".
The dual FXRs on an FP2 have always presented some "fail-like" behaviors that seem endemic to the inverter design. For myself, and others, it manifests with AC Input.
The N.A. dual inverters can be configured in parallel (120V single phase) or series (240V split phase). However, in parallel with AC Input, the inverter pair had a hard time balancing current draw, often overloading the generator, or tripping grid breaker. In series, a similar issue would crop up, as well as another odd effect. The result is charging with dual inverters is problematic.
My work-around is in the form of an external AC charger capable of meeting, and exceeding, the inverters' maximum charge current. Instead of connecting the generator to the inverters, it now feeds the AC charger only. The inverters are relegated to simply inverting.
The net result so far is the generator runs at a consistent throttle, no changes due to loads. The charging is set to 75A, more than enough for charging and our daytime loads. If loads should exceed that, the remainder is drawn from the battery. The inverters never switch between charging and inverting, because they are only inverting.
The infrequent call for AC charging on my system makes this an occasional service, but if it continues to smooth out operations I'm going to stick with it. The AC charger even has a rudimentary AGS I'm planning on implementing with my Honda, though generally, manual start will be employed.
Now, I just need to get an external gas tank for the generator...
Last edited by raysun on Mon Jul 08, 2024 3:13 pm, edited 1 time in total.
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sodamo
Forum Emperor
Posts: 1401
Joined: Mon Apr 03, 2006 1:55 am
My RE system: Totally off grid - Hamakua side, Big Island, Hi

36 Trina 280 & 16 Phono 250 in 48 volt array (fixed) 14080w
Adding 12 Hyundai 365 (4380) 18460w total
Radians GG8048A/GS4048A w GSLCs
4 FM 80 charge controllers
Hub 10.3
FNDC w/3 shunts
Mate 3s
OpticsRE - MMKL - Ninole Hi
15 SimpliPhi 3.8 (57kw) (1125 AH)
14Kw Kohler 14RESA Propane

Charging Only
2FX3048T
Hub
FNDC. - shared shunt feeds from Radian FNDC
Mate 3s
EG4 Chargeverter
10Kw MEP 803a Military gen

Honda EU7000i
Starlink w Eero Pro 6e network
Davis VantagePro2 Wx Station
On line at: https://www.wunderground.com/dashboard/pws/KHININOL2
Location: Ninole, Hi

Re: Backup charger

Post by sodamo »

I take the somewhat complementary approach with my FX/EG4/Honda setup. Charge only, my FX isn’t connected for any AC load. Main purpose of my FX is to trigger AGS. Suppose I could get educated as I believe this could be FNDC function?
David
raysun
Forum Overlord
Posts: 11415
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Backup charger

Post by raysun »

sodamo wrote: Mon Jul 08, 2024 2:21 pm I take the somewhat complementary approach with my FX/EG4/Honda setup. Charge only, my FX isn’t connected for any AC load. Main purpose of my FX is to trigger AGS. Suppose I could get educated as I believe this could be FNDC function?
Actually the solo FX / AGS / Charger / [No AC OUT] is a quite flexible and reliable device. One could scarcely do better.

Hamakua rain down here right now. Start the genny and run for cover.
Screenshot_20240708_114722_Chrome.jpg
External AC charger on shunt C.
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