How I'm combatting rising fuel prices with solar.

[Biggkidd]

@Wingnut
I just went and looked back I guess I didn't put the expected running voltage of the new battery bank on here. But I want them to operate between 50 and 53 volts all the time. I can push them higher or lower but to get the most longevity I think this will be the ticket. They can be pushed as high as 58.4 volts and taken down as low as 40 volts. 80% of the useable amp hours are in the listed range of 50-53 volts though.

 

[SheepDog]

You said you put all the cells in parallel.. that gives you 3.2 volts - how can you connect a 48 volt charger to that and not hurt the battery?

 

[Biggkidd]

You said you put all the cells in parallel.. that gives you 3.2 volts - how can you connect a 48 volt charger to that and not hurt the battery?

I also said I rewired them back in series before I put them on to charge.

 

[SheepDog]

I missed that! Sorry for the interruption.

 

[Biggkidd]

I missed that! Sorry for the interruption.

It's all good I'm glad people are checking out the thread. I don't think to many of us know much about these newer style batteries. The cost is prohibitive until I found out about DIY builds. DIY is the only way I could pull this project off. To go buy a 48 volt 100-105 AH LifePO4 battery would cost just about $2000 out the door. Once this is all said and done after all the little pieces and parts I'll have about $1300 maybe $1350 in to it. BUT I can buy a piece here and there I didn't have to shell out $2000 all at one time. It was going to cost almost to the penny the same amount of money to put lead acid batteries back in as doing it this way. Granted this is a bit more work and a lot more time but I live for stuff like this.

 

[SheepDog]

I am now sure that you know what you're doing.
As long as you enjoy it that takes the "work" out of it. Good on ya!

 

[Neb]

Your updates keep me thinking. Thank you.

Be careful it going with larger wheels with heavy loads. More voltage and current will only put more stress on the motor to turn larger wheels. Monitoring motor temp may be a good idea.

Ben

 

[Biggkidd]

@Neb Other than when I go riding for the joy of it or go visit with the neighbors 2 miles away this cart rarely sees more than a 1/2 mile at a time and usually only a 1/4 mile. It's that far to go feed the critters and handle the chores.

I'll put an infrared temp gun on my list of things to acquire but it'll be down the list aways.!

Correct me if I'm wrong here but doesn't higher voltage run at lower temps and with less amperage If everything else remains the same?

 

[Neb]

@Neb Other than when I go riding for the joy of it or go visit with the neighbors 2 miles away this cart rarely sees more than a 1/2 mile at a time and usually only a 1/4 mile. It's that far to go feed the critters and handle the chores.

I'll put an infrared temp gun on my list of things to acquire but it'll be down the list aways.!

Correct me if I'm wrong here but doesn't higher voltage run at lower temps and with less amperage If everything else remains the same?

If the power is constant then yes...

Power = voltage X current

Or

Power = current (squared) X resistance.

But with larger tires more torque is required to turn the wheel to achieve the same forward force to move the cart.

Ben

 

[Biggkidd]

I know and understand larger tires take more effort to get moving. But you did confirm what I always thought about volts & amps relation to power and heat, thanks. Isn't it also true that the number one cause of electric motor failure is low voltage under heavy loads? That's what my experience has taught me but I could have learned wrong.

Anyway the higher 48 volt system should work better with larger tires than the original 36 volt system would have correct? We are not talking about huge jumps in size here just from 18 inches to 23 inches.

Try and keep in mind when it comes to stuff like this life has been my teacher I haven't been to any classes for these sorts of things and I am certainly no rocket scientist!

 

[Neb]

I know and understand larger tires take more effort to get moving. But you did confirm what I always thought about volts & amps relation to power and heat, thanks. Isn't it also true that the number one cause of electric motor failure is low voltage under heavy loads? That's what my experience has taught me but I could have learned wrong.

Anyway the higher 48 volt system should work better with larger tires than the original 36 volt system would have correct? We are not talking about huge jumps in size here just from 18 inches to 23 inches.

Try and keep in mind when it comes to stuff like this life has been my teacher I haven't been to any classes for these sorts of things and I am certainly no rocket scientist!

I can't speak to most common electric motor failure but I have many AC induction motors that failed with signs of over heating. Does your cart have a DC motor?

Check the motor name plate that often had HP voltage and current specd. Alternatively look up the model number to find the specs.

Tire size

The motor and drive train delivers torque to turn the wheel. Torque is a turning force...

Torque = force X length ( from center to edge)

Assuming the wheel size you stated are diameter and making the math easier..

9 inch radius vs 12 inch radius

Skipping the math...

For the same forward force the motor will have to supply 30% more torque.

My cautions are that if you beef up the power to drive the motor and increase the torque required the weak link may be the motor.

Note
My electric motor training was in the Navy 45 years ago. My physics and electrical engineering degree didn't go into motor theory.

Didn't @Supervisor42 post that worked a lot on fork trucks? He may know more than I can offer.

Just trying help

Ben

 

[Biggkidd]

Thanks Ben we are on the same page. The motor is rated for 36 or 48 volts and for 90 amps continuous and often spikes to near double that when taking off up a hill with a load. AKA normal. IIRC it's 2hp at 36 volts and 2.5-3hp at 48 volts. It does use more wattage at the same amperage at 48 volts than it does at 36 volts. I know clear as mud right!

 

[Supervisor42]

Didn't @Supervisor42 post that worked a lot on fork trucks? He may know more than I can offer.

Just trying help

Naw, I ain't never said nuthin' about working on no folk trucks.
All of the ones made after 2005 actually had 3-phase AC motors in them that ran off of AC made by the controller from the 48vdc the battery provided.
The motors in them were huge indestructible beasts 24" dia. 3' long weighing over 300lbs.
Much greater stall torque than their DC ancestors and GONE were the carbon brushes that kept me busy replacing them for decades.
For mobile electric motors made in the last 15 years, the best advice I can offer is to pay attention to the cooling airflow thru the motor to assure that it is not blocked by dirt or mud buildup.
The controller will watch over the amp-draw and motor temp for you.
And if you are worried about the motor temp sensor not-working/failing, just disconnect it and see how slow 'limp-home' mode is.

 

[viking]

Thanks Ben we are on the same page. The motor is rated for 36 or 48 volts and for 90 amps continuous and often spikes to near double that when taking off up a hill with a load. AKA normal. IIRC it's 2hp at 36 volts and 2.5-3hp at 48 volts. It does use more wattage at the same amperage at 48 volts than it does at 36 volts. I know clear as mud right!

This is where you may need to consider lower gear ratios to reduce the amp load in using larger diameter tires. I have not worked on electric carts, what is the mode of connection between the motor and the drive axle, chain and sprockets? Motor winding wire size can be the limiting factor in consideration of overheating the motor

 

[Neb]

This is where you may need to consider lower gear ratios to reduce the amp load in using larger diameter tires. I have not worked on electric carts, what is the mode of connection between the motor and the drive axle, chain and sprockets? Motor winding wire size can be the limiting factor in consideration of overheating the motor

Agreed.

Monitoring the motor temp will offer a warning sign.

Ben

 

[Biggkidd]

Naw, I ain't never said nuthin' about working on no folk trucks.
All of the ones made after 2005 actually had 3-phase AC motors in them that ran off of AC made by the controller from the 48vdc the battery provided.
The motors in them were huge indestructible beasts 24" dia. 3' long weighing over 300lbs.
Much greater stall torque than their DC ancestors and GONE were the carbon brushes that kept me busy replacing them for decades.
For mobile electric motors made in the last 15 years, the best advice I can offer is to pay attention to the cooling airflow thru the motor to assure that it is not blocked by dirt or mud buildup.
The controller will watch over the amp-draw and motor temp for you.
And if you are worried about the motor temp sensor not-working/failing, just disconnect it and see how slow 'limp-home' mode is.

This an antique made in 1988 it was a 36 volt resistor cart. It's still a resistor cart but now it's been swapped to 48 volts. A LOT more pep now!

I'd like to have one of the AC motors but this old dinosaur is not going to be affected from random electrical impulses I wouldn't think and I bet that controllers & controller controlled motors would be. If I ever fall in to a pile of money maybe I can put all the pieces in a box on a shelf and swap it to an AC setup!

 

[Supervisor42]

This an antique made in 1988 it was a 36 volt resistor cart. It's still a resistor cart but now it's been swapped to 48 volts. A LOT more pep now!

I'd like to have one of the AC motors but this old dinosaur is not going to be affected from random electrical impulses I wouldn't think and I bet that controllers & controller controlled motors would be. If I ever fall in to a pile of money maybe I can put all the pieces in a box on a shelf and swap it to an AC setup!

Well, that changes everything!
Since it does not have a "controller" and it making more horsepower, monitoring the motor temp is the important part.
Even an old-timey bulb-sensor temp gauge attached to the top of motor with a pipe clamp would be a big help.

 

[Biggkidd]

Well, that changes everything!
Since it does not have a "controller", monitoring the motor temp (since it is making more horsepower) is the important part.
Even an old-timey bulb-sensor temp gauge attached to the top of motor with a pipe clamp would be a big help.

How hot should it run and how hot is to hot?

 

[Supervisor42]

How hot should it run and how hot is to hot?

That depends on the class of the motor. Given the year, I wouldn't run it over 250°F.
The hotter it gets, the more resistance in the field wiring, and the more heat they make.

 

[Wingnut]

Ah, the discussion has become more technical since I last visited this thread... good points made, though, that's for sure. I wasn't implying that BK would burn rubber with those larger tires, I was thinking more of top-end speed, lol. This is an interesting thread, although some of the electrical discussion is beyond me... y'all know more about that subject than I do. However, all who enjoy tinkering with machines will certainly like this thread, the challenges and the creativity involved.

I still hold with my previous assessment: get the batteries dialed in the way you want 'em, then tackle the other challenges. Maybe you'll have to mount slightly smaller tires for best overall performance... that hill-climbing in the mud would be a good example, I've been thinking along lines of mostly level terrain. However, taller tires might also affect safety on slopes by placing the CG higher: the cart would then be easier to roll while traversing those slopes, wouldn't it? If a tire 'tripped' over an obstacle?

You already have the lift kit installed, right? Maybe I need to rethink that taller tire number, go with something a little lower in profile or use smaller rims. You don't want your cart to turn into a 'lifted disco truck' (a.k.a. rollover special, lol). And you're using this cart more for utilitarian purposes than, say, racing purposes... though it'd be nice if the cart had a little pep to it for fun. Somehow, this line of thought brings back memories of the IACC boats in the America's Cup Series...

An astute Cup Class pro once commented that the perfectly-designed IACC boat would literally fall apart as it crossed the finish line... those large yet fast monohulls were on the cutting edge of development, employing lightweight space-age materials and high-tech design to attain maximum boat speed. The 110' tall rigs generated heaps of drive, so all those fancy components were stress-tested to the max during races, and even during practice things were broken or torn, lol.

That's why spectators witnessed some crazy events, like John Bertrand's boat oneAustralia going to the bottom... boat sank like a stone after her carbon fiber hull cracked, the lead in her keel dragging her down pronto. You can probably find that video on the web, it's pretty funny... no loss of life, just loss of dignity as John Bertrand was forced to leap overboard to safety. I like John Bertrand, he's one helluva sailor, and his classy response to the sinking just made him that much more likable, lol.

Anyway, my point is this: you'll be messing with this cart for a bit to bring it up to speed, and also to make the most out of it as a utilitarian vehicle. But you've ALREADY made great progress, same way those Cup Class designers and sailors figured out ways to improve their boats. Hey, look at the bright side, your cart (and its mods) cost one helluva lot less than an IACC boat, which went for at least $5M back in the day, not counting the associated costs of each racing syndicate.

So you're ahead of the game, lol... and now the America's Cup involves fast cats which are unbelievable in terms of acceleration & boat speed. The crews now wear helmets, if that gives ya any clue... can you imagine photo-shopping helmets into old historic black-and-white pictures of America's Cup racing? With crews from the 1800s and early 1900s wearing helmets? Ridiculous... and humorous too. Meh, I'm done here, just keep up the good work, aye? You da man!!!

Edit: Found a video of oneAustralia sinking, the commentator is clueless but the video says it all, lol. Nice 'Billionaire Boys Club' logo on the hull & main, those rich wanks never felt the loss, lol.

oneAustralia going down...

Edit #2: This video seems dated now that I watch it again, but at the time, those racing syndicates were pushing the envelope for monohull performance... and even though they were using materials like carbon fiber and titanium, gear and equipment still FAILED under enormous forces, stresses, etc. Look at the cats used in today's racing, and those craft are astounding in their performance... just outright astounding.

 

[Biggkidd]

That depends on the class of the motor. Given the year, I wouldn't run it over 250°F.
The hotter it gets, the more resistance in the field wiring, and the more heat they make.

I want to say I read it is a class H motor or heat rating. I've read so much stuff. It's great to be able to talk to someone who knows!

@viking said something about rewinding with heavier wire. Now that's probably something I could do IF I knew what to use and which parts to do. I couldn't believe youtube let me down bad when I searched for info there a month or two ago when I first thought of it. I remember doing things like that 35 years ago but the memory isn't that good for something I only did 2 or 3 maybe 4 times tops. Heck I didn't even have my drivers license yet.

@Supervisor42
Maybe this will help and if I'm lucky this is one you know ALL about! Lol

 

[Biggkidd]

Ah, the discussion has become more technical since I last visited this thread... good points made, though, that's for sure. I wasn't implying that BK would burn rubber with those larger tires, I was thinking more of top-end speed, lol. This is an interesting thread, although some of the electrical discussion is beyond me... y'all know more about that subject than I do. However, all who enjoy tinkering with machines will certainly like this thread, the challenges and the creativity involved.

I still hold with my previous assessment: get the batteries dialed in the way you want 'em, then tackle the other challenges. Maybe you'll have to mount slightly smaller tires for best overall performance... that hill-climbing in the mud would be a good example, I've been thinking along lines of mostly level terrain. However, taller tires might also affect safety on slopes by placing the CG higher: the cart would then be easier to roll while traversing those slopes, wouldn't it? If a tire 'tripped' over an obstacle?

You already have the lift kit installed, right? Maybe I need to rethink that taller tire number, go with something a little lower in profile or use smaller rims. You don't want your cart to turn into a 'lifted disco truck' (a.k.a. rollover special, lol). And you're using this cart more for utilitarian purposes than, say, racing purposes... though it'd be nice if the cart had a little pep to it for fun. Somehow, this line of thought brings back memories of the IACC boats in the America's Cup Series...

An astute Cup Class pro once commented that the perfectly-designed IACC boat would literally fall apart as it crossed the finish line... those large yet fast monohulls were on the cutting edge of development, employing lightweight space-age materials and high-tech design to attain maximum boat speed. The 110' tall rigs generated heaps of drive, so all those fancy components were stress-tested to the max during races, and even during practice things were broken or torn, lol.

That's why spectators witnessed some crazy events, like John Bertrand's boat oneAustralia going to the bottom... boat sank like a stone after her carbon fiber hull cracked, the lead in her keel dragging her down pronto. You can probably find that video on the web, it's pretty funny... no loss of life, just loss of dignity as John Bertrand was forced to leap overboard to safety. I like John Bertrand, he's one helluva sailor, and his classy response to the sinking just made him that much more likable, lol.

Anyway, my point is this: you'll be messing with this cart for a bit to bring it up to speed, and also to make the most out of it as a utilitarian vehicle. But you've ALREADY made great progress, same way those Cup Class designers and sailors figured out ways to improve their boats. Hey, look at the bright side, your cart (and its mods) cost one helluva lot less than an IACC boat, which went for at least $5M back in the day, not counting the associated costs of each racing syndicate.

So you're ahead of the game, lol... and now the America's Cup involves fast cats which are unbelievable in terms of acceleration & boat speed. The crews now wear helmets, if that gives ya any clue... can you imagine photo-shopping helmets into old historic black-and-white pictures of America's Cup racing? With crews from the 1800s and early 1900s wearing helmets? Ridiculous... and humorous too. Meh, I'm done here, just keep up the good work, aye? You da man!!!

Edit: Found a video of oneAustralia sinking, the commentator is clueless but the video says it all, lol. Nice 'Billionaire Boys Club' logo on the hull & main, those rich wanks never felt the loss, lol.

oneAustralia going down...

Edit #2: This video seems dated now that I watch it again, but at the time, those racing syndicates were pushing the envelope for monohull performance... and even though they were using materials like carbon fiber and titanium, gear and equipment still FAILED under enormous forces, stresses, etc. Look at the cats used in today's racing, and those craft are astounding in their performance... just outright astounding.

Wow that thing may as well have flown to the bottom. I've never seen anything go down that fast!

 

[Neb]

Ah, the discussion has become more technical since I last visited this thread... good points made, though, that's for sure. I wasn't implying that BK would burn rubber with those larger tires, I was thinking more of top-end speed, lol. This is an interesting thread, although some of the electrical discussion is beyond me... y'all know more about that subject than I do. However, all who enjoy tinkering with machines will certainly like this thread, the challenges and the creativity involved.

I still hold with my previous assessment: get the batteries dialed in the way you want 'em, then tackle the other challenges. Maybe you'll have to mount slightly smaller tires for best overall performance... that hill-climbing in the mud would be a good example, I've been thinking along lines of mostly level terrain. However, taller tires might also affect safety on slopes by placing the CG higher: the cart would then be easier to roll while traversing those slopes, wouldn't it? If a tire 'tripped' over an obstacle?

....

outright astounding.

Good point on 5he CG.

Please excuse the equations. I provide them only to help others understand the challenges. I generally do the math for you.

Give a man a(n) fish(answer) he is ok for now.
Teaching a man to fish(determine an answer) he is ok forever.

Ben

 

[Wingnut]

Yeah, BK, she had the Titanic beat, lol... and I've been reading Horatio Hornblower novels all weekend, C. S. Forester was one heck of an author. One of my favorites, in fact, so maybe that's why the nautical theme prevailed in my post, lol. I'm actually working my way through the entire Hornblower series, it beats watching TV, that's for sure. A short list of my favorite authors will always include:

C. S. Forester

Nevil Shute

Arthur Conan Doyle

Robert Louis Stevenson

Henry Rider Haggard

Nevil Shute is my all-time favorite author, but Robert Louis Stevenson's TREASURE ISLAND is my all-time favorite book. Doyle, Forester & Rider Haggard don't suck either, lol. For American authors, I go with these guys:

Edgar Allan Poe

Jack London

Mark Twain (or Samuel Langhorne Clemens)

Herman Melville

James Fenimore Cooper

That's enough good literature to keep anybody busy for a while, lol...

Enough thread-jacking, I'm back to my cold beer...

 

[Supervisor42]

I want to say I read it is a class H motor or heat rating. I've read so much stuff. It's great to be able to talk to someone who knows!

@viking said something about rewinding with heavier wire. .

@Supervisor42
Maybe this will help and if I'm lucky this is one you know ALL about! Lol
View attachment 87255

Nope, I never seen one of those.
The good news, no cooling air flow to get clogged, which is also the 'not-so-good-news'.
It relies on thermal transfer to the gear case by being bolted on to it.
Rewinding the fields with heavier wire: if it was a 48v cart and you were converting it to 36v, then maybe.
I'd just rig a temp gauge on the motor and let it ride. If it fails, it is likely because it is how many years old? (2022-1988=34).
If you changed the batteries from flooded to lifepo? think about the charge max-amps and float volts. Not all charge controllers know how many, or what kind of batteries they are connected to.
Now, back to the list of my favorite authors!

 

[Biggkidd]

Nope, I never seen one of those.
The good news, no cooling air flow to get clogged, which is also the 'not-so-good-news'.
It relies on thermal transfer to the gear case by being bolted on.
Rewinding the fields with heavier wire: if it was a 48v cart and you were converting it to 36v, then maybe.
I'd just rig a temp gauge on the motor let it ride. If it fails, it is likely because it is how many years old? (2022-1988=34).
If you changed the batteries from flooded to lifepo? think about the charge max-amps and float volts. Not all charge controllers know how many or what kind of battery they are connected to.
Now, back to the list of my favorite authors!

Okay just a couple comments and I will quit bugging you about this. Thank for your insight!

Thermal transfer so KEEP IT CLEAN STUPID don't let it stay all covered in mud as often happens around here. GOT IT!!! Good tip too. thanks again! I hadn't even thought about the motor heating up or overheating. Then again I haven't really pushed it any yet, I'm sure I will. You know I could give it some cooling fins if need be so it could radiate heat easier.

No worries on the charge controller it's solar and settable. It's a solar powered golf cart. We do live off grid so giving it it's own solar panel seemed sensible. This way it charges everyday.

 

[Neb]

Nope, I never seen one of those.
The good news, no cooling air flow to get clogged, which is also the 'not-so-good-news'.
It relies on thermal transfer to the gear case by being bolted on to it.
Rewinding the fields with heavier wire: if it was a 48v cart and you were converting it to 36v, then maybe.
I'd just rig a temp gauge on the motor let it ride. If it fails, it is likely because it is how many years old? (2022-1988=34).
If you changed the batteries from flooded to lifepo? think about the charge max-amps and float volts. Not all charge controllers know how many or what kind of battery they are connected to.
Now, back to the list of my favorite authors!

Ok

I will post my favorite authors list elsewhere.

How hot is too hot?

Find the motor specs. We don't want do any destructive testing now do we?

But before doing much else get a baseline measurements. Get an idea how the temp of 5he motor behaves now.

Ben

 

[Biggkidd]

I'll have to dig out the old gage I've got exactly like the one he posted. It's moved with me twice and never been used I bet I bought it as part of a set at least 25 years ago and probably longer. I saw it not long ago WHERE is the question.

 

[Neb]

I'll have to dig out the old gage I've got exactly like the one he posted. It's moved with me twice and never been used I bet I bought it as part of a set at least 25 years ago and probably longer. I saw it not long ago WHERE is the question.

A wise man goes into his storehouse and brings forth treasures both old and new.

Somewhere in Proverbs

Ben

 

[Biggkidd]

This is where you may need to consider lower gear ratios to reduce the amp load in using larger diameter tires. I have not worked on electric carts, what is the mode of connection between the motor and the drive axle, chain and sprockets? Motor winding wire size can be the limiting factor in consideration of overheating the motor

Direct drive into the gear box from the motor.

What I'd really like to do is swap in a set of speed gears after putting a torque converter on it like they use on gas engines. One similar to this. First link I came to. lol They triple the torque and some of the better ones even give about 10% overdrive on the high side.

https://www.amazon.com/MOOSUN-GO-KA...=sr_1_2?keywords=TAV-30&qid=1654017117&sr=8-2
Then you would have all the torque you need and higher speed too! Maybe 40-45 Sure would make it a lot more fun especially with the flat torque of a DC motor. I'm still trying to figure out how to couple it all together to make it work. There's NO doubt in my mind it would not only work but work very well!

@Wingnut
Thought you might want to read that bit and that you might have some ideas?

Wish I had a rear end out of a gas golf cart they already have 1/2 of that as part of the rear end.