stops charging

Discussion about the MX60 Charge Controller

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raysun
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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
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Re: stops charging

Post by raysun »

The solar array charges my batteries up to 29.7v then starts float mode. When power is low I switch on the generator and it brings up power to 24.8v and will not increase past no matter how long it runs.
Has the system always exhibited this behavior?
jitterz
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Joined: Mon Sep 25, 2023 9:10 am
My RE system: 6 x 250w LDK panels
Outback flexmax60 CC
Aims 24V inverter
8x6v discovery batteries 400ah
24v 800ah battery bank

Re: stops charging

Post by jitterz »

raysun wrote: Sun Oct 01, 2023 9:23 am
The solar array charges my batteries up to 29.7v then starts float mode. When power is low I switch on the generator and it brings up power to 24.8v and will not increase past no matter how long it runs.
Has the system always exhibited this behavior?
Not sure, I only ran the generator last year before I closed the property down for the winter. This year I've not run it at all until now. The batteries were charging up to 29 in the summer and I was just looking to do a final charge to close it down for the season.
jitterz
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Posts: 18
Joined: Mon Sep 25, 2023 9:10 am
My RE system: 6 x 250w LDK panels
Outback flexmax60 CC
Aims 24V inverter
8x6v discovery batteries 400ah
24v 800ah battery bank

Re: stops charging

Post by jitterz »

Crap, I just checked the history on the flexmax. Batteries dropped way down to 20.9 one day. Looks like there was a full week of 24 highs and 21 lows when i wasn't here. Seems I mucked up the batteries badly.
raysun
Forum Overlord
Posts: 11087
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: stops charging

Post by raysun »

It sounds like they are substantially discharged. Not necessarily the end of the world, as long as they are recharged ASAP.
If on-site, I'd suggest running the generator. The inverter charger is rated at 40A (max) so recharging fully will take a great deal of time. If the battery is drawn to 50% SoC, the recharge could take 10 - 12 hours. If more deeply discharged, it can take even longer.

For future consideration. The 24V@800AH is a large battery (19.2kWH) The charging sources - Solar: 1.5kW, and inverter charger 0.96kW are relatively small by comparison. Solar is subject to availability of the sun, of course. But using r hours "full sun" daily equivalent would allow 6kW of replenishment. You might want to check back through the system logs (Optics make that easy) to see if that is around the average. The inverter charger is a bit more problematic. It's maximum charging power is 960 Watts. The 13kW generator will run all house loads and the charger, but its likely, unless it has electronic engine throttle control, that a good deal of gas is wasted as the total loads are somewhat less than the generator's capacity. It suggests that a separate, external AC charger could, and should, be added to the mix. Since the battery specs call for a charge rate of 80A - 200A, (40A - 100A per bank) a charger that falls within that range would help the situation out.
jitterz
Forum Member
Posts: 18
Joined: Mon Sep 25, 2023 9:10 am
My RE system: 6 x 250w LDK panels
Outback flexmax60 CC
Aims 24V inverter
8x6v discovery batteries 400ah
24v 800ah battery bank

Re: stops charging

Post by jitterz »

raysun wrote: Sun Oct 01, 2023 12:57 pm It sounds like they are substantially discharged. Not necessarily the end of the world, as long as they are recharged ASAP.
If on-site, I'd suggest running the generator. The inverter charger is rated at 40A (max) so recharging fully will take a great deal of time. If the battery is drawn to 50% SoC, the recharge could take 10 - 12 hours. If more deeply discharged, it can take even longer.

For future consideration. The 24V@800AH is a large battery (19.2kWH) The charging sources - Solar: 1.5kW, and inverter charger 0.96kW are relatively small by comparison.
Ok, that might explain alot. Not only is the array small but it's pointing west rather than south. I had to leave the property this morning, i ran the generator for a few hours. I've shut down the inverter to stop any draw from the batteries and it's supposed to be a few sunny days. It was sitting at 23.9 when I left. I'll be back up on Friday. Hopefully it gets better. I was given another charge controller a renogy 40A rover. It's 24v rating would allow another 1000w. I'm try and grab some panels and bring them up this weekend and point them south to direct sun. Do you mind if I pick your brain on that or start a new chat?
raysun
Forum Overlord
Posts: 11087
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: stops charging

Post by raysun »

No problem.
jitterz
Forum Member
Posts: 18
Joined: Mon Sep 25, 2023 9:10 am
My RE system: 6 x 250w LDK panels
Outback flexmax60 CC
Aims 24V inverter
8x6v discovery batteries 400ah
24v 800ah battery bank

Re: stops charging

Post by jitterz »

I've been wanting to grab some panels for the new charge controller for some time. I'm looking at 4 used 250w panels (i know new would be ideal but money is a factor). Given the charging issue I'm facing what would be the best way to wire them parallel or series or a form of series parallel?

Also how safe is it to do this if I can't get a hold of my solar electrician?
raysun
Forum Overlord
Posts: 11087
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: stops charging

Post by raysun »

jitterz wrote: Sun Oct 01, 2023 2:16 pm I've been wanting to grab some panels for the new charge controller for some time. I'm looking at 4 used 250w panels (i know new would be ideal but money is a factor). Given the charging issue I'm facing what would be the best way to wire them parallel or series or a form of series parallel?

Also how safe is it to do this if I can't get a hold of my solar electrician?
It's easy to hook up 4 250W panels. When you have them, there will be a foil sticker on the back with electrical specs. They will dictate (along with the charge controller's input voltage rating) how the array is to be wired. Most likely two series strings in parallel.
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