Golf Cart Battery Bank?

[CarlCruzin]

I have a golf cart with a pretty large battery compartment. It currently has 6x 8v lead acid.

An idea I am pondering is replacing the exiting batteries with a DIY 320AH 48v Lifepo4 battery pack, and making it accessible as the battery source for a home backup inverter (similar to the F150 Lighting concept)

Has anybody done something like this?

 

[Will Prowse]

Most BMS will be fried with that type of inductive load. Especially the regen voltage spikes across a fet bank. This is why most golf carts are implementing a braking resistor these days.

Or you could buy a roypow battery. It comes with a breaking resistor and build quality is fantastic. Even has a built-in t-class fuse. You won't be able to break it. Takes under an hour to do the full install.

 

[CarlCruzin]

Hmm.. I am not familiar with those nuances. It sounds like more research is in order. It has a 3-phase AC motor rated at 5kw, so I figured a 150-200A bms wouldn't break a sweat

 

[jberger]

If you actually log the amperage, you will see some serious draw from a stop, especially on a slope. I upgraded the controller in mine and it logs in real time. There are some BIG spikes in there from a stop. 200a I think is the reasonable starting point but it will need to allow to a higher amount for 3 seconds or so.

 

[Delmar]

Eagerly following as I have done everything but the LiPo retrofit. I measured my 48V Yamaha AC motor golf cart at acceleration around 120A. Then again it was done with a handheld clamp meter while driving, without a seat, so was difficult to multitask while attempting not to fall off. Steady speed was around 25A.

 

[CarlCruzin]

I suppose I can dissect my post into two portions:

1. Most interested if anybody who has a golf cart for casual transportation around their community, and also has a solar/inverter/battery setup, has used their golf cart's fairly large battery pack as a "mobile/removeable" energy storage source for their home (when connected). Such as using Anderson connectors to connect the golf cart to the inverter when the golf cart is not in use (95%+ of the time)

- Considering that most golf carts are not used extensively, the batteries are under-utilized and normally replacement is due to age and not use.

- Considering how many KWH of DIY batteries it looks like would fit in the same space as the lead acid ones, while not increasing weight or negatively effecting performance. My battery compartment is approximately 14" x 40", So I should be able to easily fit 16x 320AH eve cells for approximately 13kwh of useable storage.

2. Not quite as curious at the moment but still on the research list for this hypothetical project, is figuring out how to retrofit the LiFePO4 batteries. (simply due to the fact that I know lithium batteries can and have been retrofitted by others)

 

[Delmar]

1. Most interested if anybody who has a golf cart for casual transportation around their community, and also has a solar/inverter/battery setup, has used their golf cart's fairly large battery pack as a "mobile/removeable" energy storage source for their home (when connected). Such as using Anderson connectors to connect the golf cart to the inverter when the golf cart is not in use (95%+ of the time)

Yes. My setup backfeeds my breaker panel, with the main and all 240V breakers off. With the unknown-age 6x 8v lead acid I can get 8-10 hours of runtime (without solar). Ran my furnace blower through the 2021 Great Houston Freeze.

 

[CarlCruzin]

Yes. My setup backfeeds my breaker panel, with the main and all 240V breakers off. With the unknown-age 6x 8v lead acid I can get 8-10 hours of runtime (without solar). Ran my furnace blower through the 2021 Great Houston Freeze.

How did you run the cables for the battery pack? Quick-connect, or more permanent when needed?

 

[Will Prowse]

I suppose I can dissect my post into two portions:

1. Most interested if anybody who has a golf cart for casual transportation around their community, and also has a solar/inverter/battery setup, has used their golf cart's fairly large battery pack as a "mobile/removeable" energy storage source for their home (when connected). Such as using Anderson connectors to connect the golf cart to the inverter when the golf cart is not in use (95%+ of the time)

- Considering that most golf carts are not used extensively, the batteries are under-utilized and normally replacement is due to age and not use.

- Considering how many KWH of DIY batteries it looks like would fit in the same space as the lead acid ones, while not increasing weight or negatively effecting performance. My battery compartment is approximately 14" x 40", So I should be able to easily fit 16x 320AH eve cells for approximately 13kwh of useable storage.

2. Not quite as curious at the moment but still on the research list for this hypothetical project, is figuring out how to retrofit the LiFePO4 batteries. (simply due to the fact that I know lithium batteries can and have been retrofitted by others)

Yeah I just slap an all-in-one on top of the battery. I throw some panels on the ground next to my golf cart when I need to charge it. I charge it about once a month. And I have another golf cart with the solar panel on the roof that charges itself.

That battery is very big. All you need is 5 kW hours really. They'll give you 50 to 60 mi in most golf carts.

 

[Delmar]

How did you run the cables for the battery pack? Quick-connect, or more permanent when needed?

I plan to purchase the correct Anderson connector someday, however already had multiple sets of the UPS battery connectors. They were pinned for 2x 24V in series, but I repinned for 2x 48V in parallel. They work so I am in no hurry to replace. Just ignore the color codes.

 

[CarlCruzin]

Yeah I just slap an all-in-one on top of the battery. I throw some panels on the ground next to my golf cart when I need to charge it. I charge it about once a month. And I have another golf cart with the solar panel on the roof that charges itself.

That battery is very big. All you need is 5 kW hours really. They'll give you 50 to 60 mi in most golf carts.

I agree that it would be overkill for golf cart needs. My thought is that if I can fit a large enough battery pack in the golf cart, then it can serve as a substitute for a dedicated solar battery pack.

 

[MurphyGuy]

Most BMS will be fried with that type of inductive load. Especially the regen voltage spikes across a fet bank. This is why most golf carts are implementing a braking resistor these days.

Or you could buy a roypow battery. It comes with a breaking resistor and build quality is fantastic. Even has a built-in t-class fuse. You won't be able to break it. Takes under an hour to do the full install.

Did Roypow fix the BMS tripping problems? Last time I was active in the golf cart forums, they had a lot of problems with their BMS's tripping.

Specs on most golf cart batteries are 100 amps max discharge.. but if you put two or three adults on a car and head up a hill at full throttle, you'll be drawing a lot more than 100 amps... more like 150 or 170.. and the RoyPows were tripping because of it.

 

[MurphyGuy]

I have a golf cart with a pretty large battery compartment. It currently has 6x 8v lead acid.

An idea I am pondering is replacing the exiting batteries with a DIY 320AH 48v Lifepo4 battery pack, and making it accessible as the battery source for a home backup inverter (similar to the F150 Lighting concept)

Has anybody done something like this?

View attachment 162568

I have a 48 volt precedent and am waiting for my batteries to reach the end of their life. When that happens, I'll be building a new lithium pack for the cart.

You want to use a BMS with an external contactor relay.. I'd stay away from any BMS that passes motor current through itself. I'll most likely use a REC BMS or an Orion.

But yeah, no reason you couldn't have it do double duty as a spare off-grid battery...

 

[MurphyGuy]

I'd be vary cautious with any website selling batteries that has a "Shop Here" link which then takes you to more advertising.

When they hide the price, that's when you run away.

 

[SamDeleted]

2. Not quite as curious at the moment but still on the research list for this hypothetical project, is figuring out how to retrofit the LiFePO4 batteries. (simply due to the fact that I know lithium batteries can and have been retrofitted by others)

Out of interest, is there any particular reason you want to go lithium ?

Are the current lead acids not doing the trick?

 

[MurphyGuy]

Out of interest, is there any particular reason you want to go lithium ?

Are the current lead acids not doing the trick?

Lead acids have a few drawbacks.. None of them are show stoppers, but they are a pain in the rear.

1) You have to always check water.
2) (the big one) You can't just stop using the cart and leave it until the next day, it has to be charged every night.
3) They make the cart more top heavy. Ever pound removed stabilizes it.

 

[Delmar]

Lead acids have a few drawbacks.. None of them are show stoppers, but they are a pain in the rear.

1) You have to always check water.
2) (the big one) You can't just stop using the cart and leave it until the next day, it has to be charged every night.
3) They make the cart more top heavy. Ever pound removed stabilizes it.

1. I love my Trojan Hydrolink. Stick the hose in a jug, give the ball a squeeze or few and you are done.
2. Add solar panels and the cart charges as you use it and when parked. No connection to a wall charger.
3. The weight is low and makes a dandy ballast if you have solar panels. Remove the weight and cart will ride like a buckboard unless you soften the springs.

Plus no worries of charging when freezing, and the battery going nuclear and burning your house down.

 

[MurphyGuy]

1. I love my Trojan Hydrolink. Stick the hose in a jug, give the ball a squeeze or few and you are done.
2. Add solar panels and the cart charges as you use it and when parked. No connection to a wall charger.
3. The weight is low and makes a dandy ballast if you have solar panels. Remove the weight and cart will ride like a buckboard unless you soften the springs.

Plus no worries of charging when freezing, and the battery going nuclear and burning your house down.

1) Trojan makes the best lead acid battery you can buy.. Rolls is a close 2nd place, but that's arguable.
2) Not so much.. If your solar charger doesn't have enough horsepower and takes too long to charge the batteries, it can add to sulfation issues.
Deep cycle batteries at low SOC need a charger of a minimum size rating.. if it takes too long for them to charge, they will sulfate. I think the general idea is that they need to be (near) full charged within 5 hours.
3) For small people yes, for someone like myself who's 6'3" tall, I contain enough ballast myself.. (LOL) Reducing weight increases not only speed and acceleration, it also increases range.

One other concern for us folks in the colder climates is that lead acid batteries lose much of their capacity when it gets cold.. All battery chemistries lose capacity as temperature drops, but lithium is much better at it than lead acid is.

The fire thing is an issue..

 

[Rico360z28]

Most BMS will be fried with that type of inductive load. Especially the regen voltage spikes across a fet bank. This is why most golf carts are implementing a braking resistor these days.

Or you could buy a roypow battery. It comes with a breaking resistor and build quality is fantastic. Even has a built-in t-class fuse. You won't be able to break it. Takes under an hour to do the full install.

I just got a golf cart here myself and was wondering what the batteries were that you used on that video. Now I know. Thanks!

 

[raurre]

I have a golf cart with a pretty large battery compartment. It currently has 6x 8v lead acid.

An idea I am pondering is replacing the exiting batteries with a DIY 320AH 48v Lifepo4 battery pack, and making it accessible as the battery source for a home backup inverter (similar to the F150 Lighting concept)

Has anybody done something like this?

View attachment 162568

Thread 'DIY 230Ah EVE Mobile Battery (aka) EZGO Golf Cart' https://diysolarforum.com/threads/diy-230ah-eve-mobile-battery-aka-ezgo-golf-cart.40927/

This is what I built. I have it installed so it can run as part of my system.