Running a 48v battery back in a 42v powered cart

[LizardCart]

Originally Posted by sthreatt

No, not the starter solenoid, the "main contactor" solenoid. The main valve for all the power from those seven batteries.

Okay.. I guess I need to look at a few more components. Thanks.

[Reddawg454]

This should be good.

[LizardCart]

Originally Posted by Reddawg454

This should be good.

I'm sure there will be a couple stumbling blocks, now I'm wondering the parameters withing the speed controller as an example, but I'm sure I can get it to work on a 48v system.

The use case for this bad boy is expanding.. I have another project going to put solar on my house and then have an off-grid backup battery pack for the house in the event the power goes out. I live in fire prone area of California and of course we have rolling blackouts in the summer/fall often these days... Anyhow, I'd like to make the cart be part of my backup power source for the house.

[LizardCart]

Okay.. I dug in a bit here.. I found the solenoid which was recommended I replace. it's a 36v solenoid which to me seems a bit weird, given it's a 42v system, but I'm sure it makes sense to you more buggy astute folks. Thanks for that tip @kgsc!

Pictures below. Can anyone recommend a solenoid that can be dropped right in here?

Fun stuff!

[kgsc]

Well that is a PDS controller so originally 36 volts that someone bumped to 42. Doubt it will take 48 long and is non programmable

[LizardCart]

Originally Posted by kgsc

Well that is a PDS controller so originally 36 volts that someone bumped to 42. Doubt it will take 48 long and is non programmable

Thanks KGSC.. when you say doubt it will take 48 long, does that mean you doubt I can fit a 48v solenoid in that space due to it's length?

Correct, there's nothing programmable on this bad boy other than the charger...

by the way, this is a 2006 Golf and Country Western cart.. It currently has 7 6v trojan 105s.

[kgsc]

The controller is made originally for 36 volts as well as solenoid. Neither will take 48 long.

[LizardCart]

hey folks.. got 8x 12v 108ah Lion LifPo4 batteries in with an Alltrax XCT400PDS controller and new 48v solenoid. I wired the batteries in a 4s2p configuration. I also installed a Victron BMV 712 Battery Monitor so I can get a true sense of state of charge, amps going out, amps going in, voltage drop when full throttle, etc. Also^2 upgraded the wiring on the batteries to 2 awg. Always good to get value out of the hydraulic crimper I bought a while back. Also^3.. put in a 48v to 12v converter rather than just going off one of the 12v batteries for accessory/light power. Battery balance can be a bit more important and difficult to maintain with LifePo4 batteries, so I wanted to draw off the entire circuit. Also^4 installed an Aimes 48v 1500 watt continuous 3000 watt peak inverter to power some large speakers and a refrigerator and pretty much anything else not requiring too much power (not that 1500/3000 watts is a small amount).

Man! the thing burns rubber off the line and topped out at 27mph! Almost feels dangerous at full speed.. Will need to be careful out there.

The only difficult parts were figuring out the best battery configuration to be properly balanced and be able to mount the stock wiring onto the new battery terminal locations, and the supplied wiring diagram from cartsunlimited.net for the alltrax controller was incorrect and I had to swap the f1 and f2 wires. Given the previous batt configuration/count was 7 batteries, I also had to be creative in how to install the 7th and 8th batteries.

Regarding the wiring diagram from cu.net.. I found some threads on here that they know about this and they had updated the wiring diagram to be correct for Exgo carts, but looks like it matches the Alltrax diagram so they must had reverted back as most carts need it wired as Alltrax suggests and mine happens to be one of the controllers where it needs to be reversed??

I do have a question, which hopefully makes sense to someone out there.. And honestly I guess I don't understand 100% how these controllers work yet.. On my stock Curtis controller the b+ connection side was wired differently than how cartsunlimited/alltrax suggests. From the factory it was wired such that the b+/a2 wire going to the motor was coming off the solenoid, not the b+ terminal on the controller. So on the motor side of the solenoid you had a thinner gauge wire (I'd say like 6awg or so) coming from the B+ terminal on the controller, and then a thicker gauge wire, (I think 4awg) going to the motor. I've now wired it per the diagram supplied by cu.net/alltrax where there's a wire going from the non battery side of the solenoid (this is now 6awg) to the b+ terminal and then the 4 awg wire comes off the b+ terminal to the motor. Assuming the controller doesn't care where that wire lands, given the 6awg vs 4 awg wire, it seems better to wire like it came from the factory compared to the supplied wiring diagram.?.?.?.? Anyone out there care to shed some light on this?

Another note.. my battery weight went from 434lbs (7x 62lbs) to 184lbs!!! Yes, under half the battery weight and I added an additional battery!

Anyhow, fun project, I'm still tidying up some wiring and things. Once i get it all buttoned up I'll post up some pictures.

This sucker pulls down the road pretty amazing now and should do well at the burn this year!

[golfboy64]

hey: I ran across this old discussion and am interested in converting my 2006 western 42v to 48.... Looks like you got a new controller new solenoid wiring, etc., but you are using the stock motor. Are things still OK???

Just wondering

[jasonojordan]

Originally Posted by golfboy64

hey: I ran across this old discussion and am interested in converting my 2006 western 42v to 48.... Looks like you got a new controller new solenoid wiring, etc., but you are using the stock motor. Are things still OK???

Just wondering

Probably not going to have much luck hearing from the OP. He was last on back in 2021 when he was working through his conversion. Has not been seen on the forum since according to his profile.