48V Golf Cart Battery Bank to Inverter ??

grampadennis

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Sep 24, 2019
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Question, Can I use my 6 8v batteries series connected in my GOLF CART for emergency power by attaching a 48vdc to 120vac Inverter ? If so , what is the safest way of doing this. Thanks.
 

robaroni

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You can.
Make sure you vent the batteries, especially if you plan to add a charger and PV.

The inverter should have a low voltage cut off to keep the batteries from too low a state of charge.

Usually golf cart batteries are 105 to 110 aH. That means you get about half of that with a discharge level of 50% or about 2.4Kwh times the efficiency losses of the inverter (about 15%) or roughly 2Kwh of usable power.
Even though you're using 48 volts you should still keep your lines short, keep the inverter close to the cart.
You should also fuse the inverter line on both sides even if it has internal fusing.
The fuses should be relative to the inverter power. Let's say you have a 1,000 watt inverter. At 48 volts and 1,000 watts you should have about a 50 amp fuse. Usually inverters have a surge that is double their running power. at 48 volts you're drawing about 20 amps so I doubled it and added a little more, you can use a 40 amp fuse also just make sure to watch your power usage. I would get a P3 Kill A Watt and run all my appliances off it so I could see how much power I'm drawing from the inverter. This way you can keep it within the inverter's limits.
Rob
 

grampadennis

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Joined
Sep 24, 2019
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You can.
Make sure you vent the batteries, especially if you plan to add a charger and PV.

The inverter should have a low voltage cut off to keep the batteries from too low a state of charge.

Usually golf cart batteries are 105 to 110 aH. That means you get about half of that with a discharge level of 50% or about 2.4Kwh times the efficiency losses of the inverter (about 15%) or roughly 2Kwh of usable power.
Even though you're using 48 volts you should still keep your lines short, keep the inverter close to the cart.
You should also fuse the inverter line on both sides even if it has internal fusing.
The fuses should be relative to the inverter power. Let's say you have a 1,000 watt inverter. At 48 volts and 1,000 watts you should have about a 50 amp fuse. Usually inverters have a surge that is double their running power. at 48 volts you're drawing about 20 amps so I doubled it and added a little more, you can use a 40 amp fuse also just make sure to watch your power usage. I would get a P3 Kill A Watt and run all my appliances off it so I could see how much power I'm drawing from the inverter. This way you can keep it within the inverter's limits.
Rob
Thank You !! I actually understood most of what you said..........LOL . So , I guess, I am on the right track :cool:
 

grampadennis

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Joined
Sep 24, 2019
Messages
17
You can.
Make sure you vent the batteries, especially if you plan to add a charger and PV.

The inverter should have a low voltage cut off to keep the batteries from too low a state of charge.

Usually golf cart batteries are 105 to 110 aH. That means you get about half of that with a discharge level of 50% or about 2.4Kwh times the efficiency losses of the inverter (about 15%) or roughly 2Kwh of usable power.
Even though you're using 48 volts you should still keep your lines short, keep the inverter close to the cart.
You should also fuse the inverter line on both sides even if it has internal fusing.
The fuses should be relative to the inverter power. Let's say you have a 1,000 watt inverter. At 48 volts and 1,000 watts you should have about a 50 amp fuse. Usually inverters have a surge that is double their running power. at 48 volts you're drawing about 20 amps so I doubled it and added a little more, you can use a 40 amp fuse also just make sure to watch your power usage. I would get a P3 Kill A Watt and run all my appliances off it so I could see how much power I'm drawing from the inverter. This way you can keep it within the inverter's limits.
Rob

When you say "fuse the inverter line ON BOTH SIDES .........what does that mean ?? Would a 50amp breaker on the positive side do the same thing , like this one ..??.
 

robaroni

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When you say "fuse the inverter line ON BOTH SIDES .........what does that mean ?? Would a 50amp breaker on the positive side do the same thing , like this one ..??.

Good question sorry I didn't address it fully.

OK, let's say you have an inverter that can run continuously at 1,000 watts with a 2,000 watt peak for 3 seconds. Ideally what you want is to fuse it for those 2,000 watt surges plus just a little more.

Now let's say your inverter is 110 VAC out, 2,000 / 110 = ~18 amps, this is you peak 3 second surge current so I'd use something around a 20 amp fuse on the secondary (output of the inverter)

If you run 220 volt inverters just do 2,000 / 220 or whatever your output voltage is to get an idea of your current and fuse requirements.
 

robaroni

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Sep 30, 2019
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I am nervous about this so let me double check what you are saying , I should be able to add this breaker .................
https://www.amazon.com/gp/product/B07J5FBLKM/ref=ox_sc_act_title_1?smid=A2AF8XMIDUY3TS&psc=1 BETWEEN the positive of the battery and the positive of the Inverter and I am done. Nothing else is needed . Correct ??
That should work fine. Also make sure to have good connections to the battery and the inverter. AWG 6 (100 amps) or AWG 4 (135 amps) battery cable can be purchased with connectors on it if you can't do your own. They will cost a little more but you'll be sure of getting good terminals.

Something like this:

It won't hurt to use dielectric grease around all the connections either, dielectric grease is an insulator and it will keep moisture and corrosion out of the connections:

 

grampadennis

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Sep 24, 2019
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That should work fine. Also make sure to have good connections to the battery and the inverter. AWG 6 (100 amps) or AWG 4 (135 amps) battery cable can be purchased with connectors on it if you can't do your own. They will cost a little more but you'll be sure of getting good terminals.

Something like this:

It won't hurt to use dielectric grease around all the connections either, dielectric grease is an insulator and it will keep moisture and corrosion out of the connections:


THANK YOU !!!! time to buy some stuff !! ;-) ONE more goofy question, GROUNDING CABLE , what kind of cable would be best ???
 
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robaroni

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THANK YOU !!!! time to buy some stuff !! ;-) ONE more goofy question, GROUNDING CABLE , what kind of cable would be best ???
You can use battery cable the same AWG as your power cables. A simple solution is to get bare stranded ground cable at box stores like Home Depot.
 

grampadennis

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Sep 24, 2019
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once again ............THANK YOU !!! ............I ordered my AIMS inverter today...........more questions to follow ..........LOL
Hello,

I got my Inverter up and running. Ran a fan AND a full sized Refrigerator about 30 min as a test . All was fine. Nothing heated up. Question: Is it possible to run my inverter directly into my panel ?? . I have a 4 prong outlet on the wall then running into the panel. I know its probably not up to code . It doesn't use an official "transfer switch" so I would just have to make sure grid power is shut off AND all my 220's are off. What cable would I need to simply plug into one of the ac outlets on the inverter and run it to the WALL switch next to the panel ?? Thanks.
 

Supervstech

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Hello,

I got my Inverter up and running. Ran a fan AND a full sized Refrigerator about 30 min as a test . All was fine. Nothing heated up. Question: Is it possible to run my inverter directly into my panel ?? . I have a 4 prong outlet on the wall then running into the panel. I know its probably not up to code . It doesn't use an official "transfer switch" so I would just have to make sure grid power is shut off AND all my 220's are off. What cable would I need to simply plug into one of the ac outlets on the inverter and run it to the WALL switch next to the panel ?? Thanks.
If you hook to your panel, get a lockout on the main breaker. Home Depot has one ya just screw to your breaker panel, so you have to shut off the main in order to turn on the inverter.
 
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