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Looking for 50-60A 48V LiFePO4 battery charger


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I need a 48v battery charger (output up to at least 57v for LiFePO4) that can provide a constant charge to a LiFePO4 battery bank of up around 50 to 60 amps DC. In other words, I want to be able to inputting around 2500-3000 watts into the batteries. I will be drawing off these batteries with an inverter at the same time, so this charger needs to be able to run 24/7 (not shutting off after a preset number of hours/minutes).

 

For those of you who have shopped around quite a bit in Thailand, do you know of any sources of 48v battery chargers (or DC power supplies that can output up to 57-58v) at 50-60 amps? (I'm aiming at a limit of around 3.55v per LifePO4 cell, or 57 volts for the bank.) I've found some chargers that are rated at 10-12 amps, but some do not state the actual output voltage (I'm thinking some are made for Li-ion batteries and a max of around 54.6v), and I'm hesitant to buy 5-6 of those in hook them up in parallel to get the amperage I'm aiming for.

 

In case you are curious, at times I will be drawing up to 5000W via a hybrid inverter. My overall usage based on my power bills is less than 30kwh/day. So I'm thinking that an average of 2.5 - 3kw will keep the batteries charged provided I don't draw too heavy a load for too long a period at one time.  (Drawing more than 10-15 amps from the grid power incurs too great a voltage loss on the undersized low-voltage grid power line (which is 1km from light meter & transformer). The owner does not want to replace the undersized wire but build a system with solar power in mind for the future.

 

You might be wondering why I don't use my hybrid solar inverter to do the job. I wish I could but it appears to me that it's settings are such that the only time it charges the batteries from the grid is when it's NOT using the inverter (and passing grid power on to the output). In other words, it has three "priority" settings for the source of output power:

 

  • 1) "UTI": Use the inverter as a "UPS", passing grid power to the output unless the grid power goes outside an acceptable range (dropping below a selected voltage of 170V or 90V). While grid power is being passed to the output, it also charges the battery bank.
  • 2) "SOL": Solar power is the preferred source. If solar power is insufficient, the batteries will be drawn on as well. Grid power is not passed to the output unless solar power is not available (which is true in my case, since we don't have solar panels yet) or the battery level drops to the user-selectable value.
  • 3) "SBU": Solar/Battery/Utility: Grid (utility) power is used as first priority. Solar and battery power is used only when the grid power is not available.

 

My system is designed for the primary purpose of providing a reliable 220-230v, and secondarily to utilize solar power when it is added on. So, none of the above options works for my situation.

 

Using "UTI" means that I will still pass grid power to the output until it drops to 170v. To me that seems too low. There is another more serious reason not to use this setting: the only reason the grid power drops below 170v is because we are drawing too heavy a load. (There is no one else using this small line from our light meter.) So, if my inverter switches from grid power to battery power when the grid power drops too low, then after the inverter switches from using the grid, the grid power will jump back up to 220+volts. The inverter will sense that all is well with the grid again, and it will switch back to using grid power, which will cause grid voltage to drop again. (And I expect such a rapid cycle of switching between grid and battery power would quickly damage some equipment.)

 

If I use "SBU", I will be running off the inverter consistently, as long as the batteries can supply the need. When the battery voltage drops to the low limit I've set on the inverter, the inverter will switch to "UTI" mode (passing grid voltage on to the output while charging the batteries) until the batteries are charged up to my preset target voltage. Then it will switch back to the batteries.

 

My thinking is, if I keep the inverter in "SBU" mode, and add a battery charger to the system to provide a constant feed of at least 50 amps (DC) into the batteries, then my battery bank will not drop too low as long as the heavy loads do not last too long at one time. (If there is some situation where we have a heavy load for an extended time and the batteries are drawn down, then the inverter will switch over to charge the batteries until battery voltage recovers. During this time both the "regular" chargers and the hybrid inverter charger would be drawing from the grid as well as any other loads, so we would likely have a "brown out" until the inverter/batteries can be charged back to an acceptable level. If this situation occurs too much, we will have to consider (1) adding solar panels to supplement grid power and/or (2) increasing the size of the battery bank (currently 4.8kwh) to tide us over during heavy loads.)

 

Current equipment: Suoer 5KVA 48V Hybrid Inverter; 100AH Sinopoly LiFePO4 x 16 with Daly BMS

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12 minutes ago, Crossy said:

It might. One thing that concerns me: I see no mention of an input voltage, and the only amp rating (60A) is in the part of the description that talks about a 27v output (which doesn't make sense since you have 3 options for output voltage to select from when purchasing: 48, 53.5, and 58v). Makes me wonder if the input is 27V(dc?), and the output can be selected at 48, 53.5, or 58 volts. Of course, I need an input of 220v.

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7 minutes ago, SunshineHarvey7 said:

It might. One thing that concerns me: I see no mention of an input voltage, and the only amp rating (60A) is in the part of the description that talks about a 27v output (which doesn't make sense since you have 3 options for output voltage to select from when purchasing: 48, 53.5, and 58v). Makes me wonder if the input is 27V(dc?), and the output can be selected at 48, 53.5, or 58 volts. Of course, I need an input of 220v.

 

If you zoom in on the rating plate on the side it's 220V range.

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56 minutes ago, SunshineHarvey7 said:

Using "UTI" means that I will still pass grid power to the output until it drops to 170v. To me that seems too low. There is another more serious reason not to use this setting: the only reason the grid power drops below 170v is because we are drawing too heavy a load.

 

Why not put sensitive equipment on an AVR? Technically much easier than mucking about with chargers etc.

 

Our whole-house AVR regulates down to about 160V before shutting down "low voltage".

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1 hour ago, Crossy said:

 

If you zoom in on the rating plate on the side it's 220V range.

I was about to buy it, and then I realized that I really need a charger that has a wide operating voltage range. This one says 200-230(?) volts. If I'm charging 50v x 60A, that's 3000W, or around 13 amps. At that load, my grid voltage might drop below 170v, maybe around 150v. So I think I better look for a power supply that's not too fussy with input voltage. 😉

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1 hour ago, SunshineHarvey7 said:

3) "SBU": Solar/Battery/Utility: Grid (utility) power is used as first priority. Solar and battery power is used only when the grid power is not available.

For the record, I described this option incorrectly. When choosing SBU, solar power is used when it is sufficient. If not, then battery power will be used to make up the difference. Utility (grid) power is only used when the battery voltage drops too low.

 

The inverter also has priority options to select the source of power for charging the battery. With my inverter, I can choose a priority of solar or utility power, simultaneous use of both, or exclusively solar. In this section of the manual, I spotted the reason for my frustrations with this inverter (and probably many similar inverters under other brand names): "If this inverter/charger is working in Battery mode, only solar energy can charge battery. Solar energy will charge battery if it's available and sufficient."

 

Being that this inverter will take solar panel input in the voltage range of 60-110v, if my friend isn't ready to shell out the money for a bunch of solar panels sand set them up, it'd be tempting to buy a 90v dc switching power supply and feed it into the PV input. (Can't do that once our panels are hooked up, of course.) Then the hybrid inverter would manage the battery charging.

 

What do you think?

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1 hour ago, Crossy said:

 

Why not put sensitive equipment on an AVR? Technically much easier than mucking about with chargers etc.

I'd love to. Problem is, with the 1km supply wire from the grid being undersized, an AVR is just going to draw even more amps to make up for the voltage difference, which seems to be asking for trouble. Does that make sense? (I think most people would replace the 1km supply wire, but I sympathize with the owner, who wants to aim for solar instead of shelling out the money for bigger supply wire.)

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I think I would go for parallel off-grid inverters that can supply your peak load.

 

Charge the batteries from solar when it's available or your charger when the sun is hiding.

 

That isolates you from the iffy supply.

 

Size your batteries as appropriate (add more if necessary).

 

Add a change-over switch (manual) so you can use the grid in case the solar goes down.

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32 minutes ago, Crossy said:

I think I would go for parallel off-grid inverters that can supply your peak load.

 

Charge the batteries from solar when it's available or your charger when the sun is hiding.

 

That isolates you from the iffy supply.

 

Size your batteries as appropriate (add more if necessary).

 

Add a change-over switch (manual) so you can use the grid in case the solar goes down.

Yes, I think that's the direction I should go. I've just been learning that for times when solar isn't enough, I'll need a charger that's separate from the inverters. If I did it over again, I don't think there would be any reason to use a "hybrid" inverter for my situation. A standard off-grid inverter (that can work in parallel) should do.

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24 minutes ago, SunshineHarvey7 said:

What are the specs (output volts, amps, watts)?

I have made a suggestion using your post title only and not gone into the detail. Golf cart chargers are available in the voltage and current range you desire.

 

Eg 48V/50A 48V/100A 60V/50A and so on...

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25 minutes ago, SunshineHarvey7 said:

Yes, I think that's the direction I should go. I've just been learning that for times when solar isn't enough, I'll need a charger that's separate from the inverters. If I did it over again, I don't think there would be any reason to use a "hybrid" inverter for my situation. A standard off-grid inverter (that can work in parallel) should do.

 

You will need some sort of charge-level monitor to control the charger, should be a module available on Lazada / AliExpress.

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