Inverter with bike battery?

I have 2 bike batteries that I would like to use with an inverter during power outages. I likely will only ever use 75W max, but my battery is 48V, and most small inverters use only 12V. Does it make sense to buy a voltage reducer and small 300W pure sine wave inverter for this purpose or is that just making things more complicated? I already have an EcoFlow for my refrigerator/sump pump, so this is just for lighting and small electronics.

I was watching a DIY Solar review of inverters on YouTube, and he showed how you have to use a resistor to charge the capacitors before attaching the battery to the inverters. Is this true of small inverters as well, or just the large ones with large “surge” ratings? I assume that all the 48v inverters will need this procedure, which would be a little inconvenient for emergency use because I was hoping to solder the wires to an adapter that plugs directly into the battery, but I suppose that I could have 2 sets of wires if necessary. The video also mentioned grounding…. Is that necessary if only running from a battery?

Anyway, I’m hoping that someone can provide some insight into the best method for using these batteries, as they seem like they would be great for emergency outages. In addition, I’d like to use the system in winter to condition the batteries when they are in storage. Thanks in advance!

What is the battery capacity rating?
75W on the AC output side of the inverter?

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Bud Martin said:

What is the battery capacity rating?
75W on the AC output side of the inverter?

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The batteries are 504Wh each. Yes, I think I’d easily stay under 75W on the AC side. Thanks for your insights.

DAC76 said:

The batteries are 504Wh each. Yes, I think I’d easily stay under 75W on the AC side. Thanks for your insights.

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75W/0.85 = about 88W on the DC side of the inverter.
It is not practical to convert 48V to 12V and then convert 12V to 120Vac, too much loss.
You can get 48V to 12V converter to run 12V devices and run 120V device on Ecoflow.
Example of buck converter: the 360W one should be able to supply enough power to run the 300W inverter.

Bud Martin said:

75W/0.85 = about 88W on the DC side of the inverter.
It is not practical to convert 48V to 12V and then convert 12V to 120Vac, too much loss.
You can get 48V to 12V converter to run 12V devices and run 120V device on Ecoflow.
Example of buck converter: the 360W one should be able to supply enough power to run the 300W inverter.

https://www.amazon.com/Pro-Chaser-Converter-Complementary-Connectors/dp/B07S9KDSQ5/ref=sr_1_1_sspa?

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I’m not real familiar with 12v devices. Would you then attach that buck converter to something like this, if sticking to dc:

https://smile.amazon.com/gp/aw/d/B0...d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWwp13NParams

The buck converter I show you in the Amz link is for converting 48VDC input into 12VDC output that you can connect anything that require 12Vdc to run, such as the one in your link, or 12VDC lamps, or the 300W imverter if you need to.

There are also some 48v inverters as well. Such as: https://smile.amazon.com/Victron-Energy-Phoenix-Inverter-VE-Direct/dp/B076TCJKN6 or https://smile.amazon.com/KRXNY-Inverter-Display-Output-Socket/dp/B082HJBM8L/ even some cheaper ones as well. But having the DC-DC converter to 12v allows you to use the inverter in a lot more useful ways like from your car.

Additionally you might could use the batteries to charge your Ecoflow a little bit.

DarrylG said:

There are also some 48v inverters as well. Such as: https://smile.amazon.com/Victron-Energy-Phoenix-Inverter-VE-Direct/dp/B076TCJKN6 or https://smile.amazon.com/KRXNY-Inverter-Display-Output-Socket/dp/B082HJBM8L/ even some cheaper ones as well. But having the DC-DC converter to 12v allows you to use the inverter in a lot more useful ways like from your car.

Additionally you might could use the batteries to charge your Ecoflow a little bit.

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Thanks for the info. Do you happen to know if the lower power inverters such as that Victron need to preload the capacitors to avoid sparking? I did not see anything in the manual in regards to this.

Also, I’m very new to this. Is there any safety precautions in regards to working on the DC side, or is this pretty harmless at these voltage levels? From what I read it sounds like it sounds like there is not much to worry about.

Your idea of charging the EcoFlow with the batteries is very interesting. I had not thought about that. I could easily charge via the 12V adapter if I were to just go the DC route.

I remember on probably the same video from Will talking about preloading the capacitors, he mentioned it was not necessarily needed on small inverters. Personally I have not had very large ones to connect and I did not preload.

48 volts is at the high end of low voltage. (<50v) In theory it does not shock you. However there are stories on here of people getting a shock from their 48v batteries. So just be careful,

As far as charging the ecoflow directly from the battery, you possibly could put the input through the MC4 solar connectors and it would pull the 48 volts directly the amperage would depend on your EcoFlow. A Delta Pro would pull about 15 amps or 720 watts of charging which may deplete the bike battery very quickly. So it may be better for other purposes.

DarrylG said:

I remember on probably the same video from Will talking about preloading the capacitors, he mentioned it was not necessarily needed on small inverters. Personally I have not had very large ones to connect and I did not preload.

48 volts is at the high end of low voltage. (<50v) In theory it does not shock you. However there are stories on here of people getting a shock from their 48v batteries. So just be careful,

As far as charging the ecoflow directly from the battery, you possibly could put the input through the MC4 solar connectors and it would pull the 48 volts directly the amperage would depend on your EcoFlow. A Delta Pro would pull about 15 amps or 720 watts of charging which may deplete the bike battery very quickly. So it may be better for other purposes.

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Thanks again for all the info. Hopefully just 2 more questions: does a small inverter with a single battery need to be grounded? And would you put a breaker between the battery and inverter, or just hook it directly together?

Watch Jehu Garcia on YouTube. He has videos of making powerwalls out of 36V batteries from scooters and he also sells 24V batteries meant to act as an expansion battery to EcoFlow devices. What EcoFlow model do you have?

I think a converter then an inverter is too much lost in the conversion. I think it would make more sense to buy a small 48V inverter. Keep in mind your Ebike battery is likely able to put out 20 maybe 30 amps so I’d stick with something under 1000 watts unless you plan on using it for a DIY home system. 48V is the standard for large loads in the 3-15k watt range.

MarcoWasRight said:

Watch Jehu Garcia on YouTube. He has videos of making powerwalls out of 36V batteries from scooters and he also sells 24V batteries meant to act as an expansion battery to EcoFlow devices. What EcoFlow model do you have?

I think a converter then an inverter is too much lost in the conversion. I think it would make more sense to buy a small 48V inverter. Keep in mind your Ebike battery is likely able to put out 20 maybe 30 amps so I’d stick with something under 1000 watts unless you plan on using it for a DIY home system. 48V is the standard for large loads in the 3-15k watt range.

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Nice, I’ll have to check out those videos. I have an EcoFlow Delta 2.

Yes, I’m looking at a really small inverter. I’m leaning towards the Victron that only does 400W peak. I like some of the other models that include a built-in battery gauges, but it sounds like the Victrons might be better quality. I’m sort of caught up on the topic mentioned above with possibly having to precharge the capacitors because this will be something that is connected/disconnected every time it’s used.

I like the idea of the inverter the best, but maybe just going the route of the buck converter and using 12V devices will be easier in terms of routine use?

DAC76 said:

Nice, I’ll have to check out those videos. I have an EcoFlow Delta 2.

Yes, I’m looking at a really small inverter. I’m leaning towards the Victron that only does 400W peak. I like some of the other models that include a built-in battery gauges, but it sounds like the Victrons might be better quality. I’m sort of caught up on the topic mentioned above with possibly having to precharge the capacitors because this will be something that is connected/disconnected every time it’s used.

I like the idea of the inverter the best, but maybe just going the route of the buck converter and using 12V devices will be easier in terms of routine use?

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You’re in luck. Your EcoFlow accepts Solar Input at 11-60V at either 13A or 15A, max 500W. Finding some conflicting info on the amperage.

What does this mean? Well Solar is DC. The MPPT has no way of knowing what’s providing the DC power, just as long as it falls within the parameters you’re fine. Your 48V Ebike battery whether it’s a 13S or 14S NMC is within that voltage range (and likely a perfect match for the best charging efficiency from the MPPT) and can be plugged into the solar input. Expect it to draw 50’ish volts at 9 or 10A when fully charged. 14S is 58.8V and 13S is 54.6V max. As long as the cells in the pack and your BMS can handle a 9-13A load it should be fine. I would pull it off before it’s completely empty as that’s when you’ll see the highest amperage because the voltage is low but the EcoFlow will still try to max out the wattage limit of 500.

*I don’t own an EcoFlow Delta 2 and have never attempted this, this is based off Jehu Garcia’s videos and common sense about how an MPPT works.

MarcoWasRight said:

You’re in luck. Your EcoFlow accepts Solar Input at 11-60V at either 13A or 15A, max 500W. Finding some conflicting info on the amperage.

What does this mean? Well Solar is DC. The MPPT has no way of knowing what’s providing the DC power, just as long as it falls within the parameters you’re fine. Your 48V Ebike battery whether it’s a 13S or 14S NMC is within that voltage range (and likely a perfect match for the best charging efficiency from the MPPT) and can be plugged into the solar input. Expect it to draw 50’ish volts at 9 or 10A when fully charged. 14S is 58.8V and 13S is 54.6V max. As long as the cells in the pack and your BMS can handle a 9-13A load it should be fine. I would pull it off before it’s completely empty as that’s when you’ll see the highest amperage because the voltage is low but the EcoFlow will still try to max out the wattage limit of 500.

*I don’t own an EcoFlow Delta 2 and have never attempted this, this is based off Jehu Garcia’s videos and common sense about how an MPPT works.

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That would be really nice. That might be a little advanced for me though. I don’t want to do anything that could damage the batteries as the primary function is still performing well as a bike battery.