Lithium Recommendation; need torque, not range

[zeen]

Hi all. The FLA Trojans in my 2010 era RXV with Aco/Danaher controller finally gave up, and I'd like to upgrade to lithium. The cart is used mostly as a pick up truck, hauling stuff up and down the hill at my cottage. The hill has one steep spot of maybe 50', the rest is gentle. I've used the cart to tow a jet ski up the hill, but will be selling that. I did manage to have the cart shut down trying to drag a boat lift out of the water, but won't try that again. I believe the controller is rated at 230 amps max. I can't think of any scenario where I'd go more than 10 miles in a day.

I'm very happy with the 105ah EcoBattery kit I put in my wife's RXV, but want to get away as cheap as possible for this one. Anyone have recommendations for a kit with enough oomph to handle hills and come in under $1500?

[TheCartBoy]

If you're trying to save money, a DIY pack is the best way. And you can build it with cells that can provide enough amps for your high torque requirements.

[zeen]

Thanks for the reply. I'm handy enough to have DIY'd my wife's EcoBattery conversion, but building up the entire kit sounds a bit daunting. In either case, what is the minimal Ah battery I'll need to make it up the hill? I peaked at the last RXV I was in at a local golf course, and it had a 50Ah battery, so I assume that's enough. Would a 30Ah epoch 48v battery work, or would I need two of them?

[TheCartBoy]

I put a single epoch in an RXV, it's ok for flat ground, but tow something heavy and it will shutdown.

1 epoch is 60 amps continuous, and up to 100 amps time limited. You will need 2-3 units to ensure the BMS isn't the bottleneck. That's why I suggested a DIY unit, here's a good thread on one: https://www.buggiesgonewild.com/showthread.php?t=193259

[Pat911]

Originally Posted by zeen

Thanks for the reply. I'm handy enough to have DIY'd my wife's EcoBattery conversion, but building up the entire kit sounds a bit daunting. In either case, what is the minimal Ah battery I'll need to make it up the hill? I peaked at the last RXV I was in at a local golf course, and it had a 50Ah battery, so I assume that's enough. Would a 30Ah epoch 48v battery work, or would I need two of them?

You’re confusing specifications. You don’t need Ah to get up a hill, you need Amps, or more specifically, peak Amps. Ah’s are purely for range.

A 30Ah Epoch battery can provide 60A continuous and 100A, 10 second peak. I would suggest that one is not enough, especially if it takes longer than 10 seconds to get up that hill. You will need at least 2 for 120A continuous and 200A 10 second peak.

As a comparison, the 72Ah Eco Battery can provide 150A continuous, 300A for 30 seconds and 500A for 3 seconds.

[Volt_Ampere]

Torque == current! You need to spec a battery that can deliver the necessary current for your application. If you scimp on that you will not be satisfied with the results.

[zeen]

Now we're getting somewhere. I agree with all that. All I care about is amps, but the batteries are advertised by Ah. What is the cheapest way to deliver the amps I need, irrespective of total range capacity (Ah)?

[TheCartBoy]

Originally Posted by zeen

Now we're getting somewhere. I agree with all that. All I care about is amps, but the batteries are advertised by Ah. What is the cheapest way to deliver the amps I need, irrespective of total range capacity (Ah)?

Cheapest and least amount of work for whats on the market today, I would buy 2-3 of these units and replace the BMS myself.

https://batteryhookup.com/products/n...ifepo4-battery

Each unit, the cells are rated for 100 amps continuous. With 2, thats 200 amps continuous, and is very close to maxing out the motor controller limits. With 3, the controller would become the limiting factor.

[zeen]

Wow, one of those would probably do it. 200 amps for 15 seconds would get me up the steep part of the hill, 100 amps continuous should be fine. Two of them would be more than enough. Now all I need is an idiot proof BMS and install kit.

[Pat911]

The JK BMS JK-B2A24S20P. Look no further. Purchase it from the JK BMS store at AliExpress for the best price.