C Cab Hot Rod Power Advice

You know, sometimes I wonder where my brain is.

The block feels like pot metal. It's not plastic. Maybe aluminum. I'll check it with a magnet tomorrow.
Click to expand...

That's got to be one of the dumbest statements I've made in a very long time. Of course it can't be metal.
It's probably just a form of Bakelite.
 
The latest configuration picture looks not bad. The resistance between the two controllers should be low enough to play nice. Just keep in mind that if those terminals come loose, you will likely fry one of the controllers.

The throttle uses 3 wires. +5v, ground and signal. To combine the controllers pick either one and run all 3 wires to your throttle. Then run only the signal wire from the other controller to the throttle signal line and leave the +5 and ground disconnected. You could probably also connect the throttle grounds together, but not necessary. Best to have the throttle signal wires connected near the controllers, then run long wires to the throttle.
 
Here's a question posed to me.

curious?? how are you going to be sure BOTH MOTORS turn the SAME rpm?
maybe two sensors to monitor the rpm of both motor sprockets then slow down/speed up of specific motor.
Just using the motor controller would not be too reliable IMO
Click to expand...

I just figured that the motors were designed to work at a certain RPM, and both would work the same, maybe not?

Is this something I should be concerned with?
 
no real reason to worry about it. if you find that you have problems with one motor taking too much of the load (gets hot compared to the other one), you can put an adjustment pot into that side in series with the throttle signal, to turn down it's throttle relative to the other one, so they both produce the same power when driving in a straight line.


the rpm doesn't matter. they'll spin at the speed the loading on each one allows.
 
amberwolf said:
no real reason to worry about it. if you find that you have problems with one motor taking too much of the load (gets hot compared to the other one), you can put an adjustment pot into that side in series with the throttle signal, to turn down it's throttle relative to the other one, so they both produce the same power when driving in a straight line.


the rpm doesn't matter. they'll spin at the speed the loading on each one allows.
Click to expand...

Thanks, so I'll be moving on then.

Here's the latest wiring version. I've added ring terminals and rearranged where the wires go. Mainly due to the slot sizes.

Did away with the bulky jumper, and made buss bars instead. They are the same metal thickness, as the ring terminals.
It really made it much easier to button everything down.

 
Excellent. That should work great.

The motors will tend to go the same speed but if there was a problem where they were drastically different you would notice a pull in the steering.

You can try to check the speeds with the wheels off the ground when you get them going.
 
Great! Next step is to cut out a sheet metal bottom, that all those components can be secured to.

Before I screw everything down though, I would like to get the converter in.
Size does matter, and in this case , this unit looks to be right, for what I think I need.

I won't be intentionally driving this at night, so if the lights are a shade dim, not a problem, as long as they are on, and blink when asked to.

Basically, head, tail, turn, and brake lights. Enough amps to push a sound system for the engine audio.
Can't think of anything else. So the below unit is what I'm considering.

I'm ready to buy, if it seems the right unit.....what say you?

https://www.amazon.com/dp/B07S8H5JMR/ref=twister_B07T7GFGV5?_encoding=UTF8&psc=1
 
Just_Ed said:
I'm ready to buy, if it seems the right unit.....what say you?

https://www.amazon.com/dp/B07S8H5JMR/ref=twister_B07T7GFGV5?_encoding=UTF8&psc=1
Click to expand...

Yes, good.
 
Currently using a Pro Chaser 72V to 12V 30 amps for my lights, 6 months 2000 miles. Really only need a 10a or less.
Thinking about using a tool battery for the lights to cut down on the wiring.
 
25A is probably overkill, but they are very efficient so the only real drawback will be size/cost. With LED headlights, the light loads should be way less than the rating. Nice to have some extra capacity for future accessories. This one has a "key switch" line so the main wires can stay connected, just like the motor controllers.

One thing to note: I assume this converter is NOT isolated, which means the main battery will be connected to one of the output wires. As a result, I recommend NOT using the vehicle frame for running power. Run pairs of wires to the lights, etc. and leave the frame isolated. This provides additional safety in the event a wire makes contact with the frame accidentally.

Another fun accessory would be a 48v to 120 VAC inverter. I have one at home for power failures. Just something to consider for the future.

Meanwell 700w inverter.jpg
 
Thanks for the input.

I settled on a compromise, and ordered this unit. It's coming from just down the road.
I got mine for $22.99 and free shipping.

https://www.ebay.com/itm/DC-Golf-Cart-RV-Voltage-Reducer-36V-48V-Step-Down-Reduce-to-12V-240-Watt-20-Amp/223540427098?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D225074%26meid%3D72aa0ed56b6941ac8618a364ed790682%26pid%3D100005%26rk%3D3%26rkt%3D12%26mehot%3Dpf%26sd%3D223132127813%26itm%3D223540427098%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv5PairwiseWeb&_trksid=p2047675.c100005.m1851

Another fun accessory would be a 48v to 120 VAC inverter. I have one at home for power failures. Just something to consider for the future.
Click to expand...

I was wondering about using this battery pack out on some camping trips.
 
Your 12v converter looks just like one I have. So far no problems.

Yes, you could use the big battery and inverter just like a generator (without the noise and smoke). I have a bigger inverter that can power a microwave oven or just about anything else. Now you can bring the big screen TV and laptop computers camping.

During last summer's power shutdown, I ran my TV for about 10 hours off one of my 52v bike batteries which is much smaller than your pack.
 
fechter said:
Your 12v converter looks just like one I have. So far no problems.

Yes, you could use the big battery and inverter just like a generator (without the noise and smoke). I have a bigger inverter that can power a microwave oven or just about anything else. Now you can bring the big screen TV and laptop computers camping.

During last summer's power shutdown, I ran my TV for about 10 hours off one of my 52v bike batteries which is much smaller than your pack.
Click to expand...

Bit off subject, but you got me thinking. We aren't dry campers. We're more into 'glamping'. However our RV group likes to go dry camping at times. We don't have a generator, nor think we need one.

Can this battery pack be hooked directly to my existing SLA batteries, and used as back up through the on board inverter? (Not sure I asked that correctly)
 
'Belly Pan'?

Now it's wait for the converter to get here.
I need to make sure it will all fit into the same space, before screwing anything down.

So things are moving along nicely. all the drive components are in.
Soon there will be a function test.


 
You can't charge a lead-acid car battery using the 12v dc-dc converter. It doesn't have current limiting made for that so could overheat and self-destruct. They do make similar units that could be used to charge a battery. Something labeled CC-CV.
 
things like the meanwell hlg series led psus would work for that, as well as for the dc-dc. but they cost more. something like the hlg-150h-12a would probably do what you're after, at something like 11a-12a of output available. (they're also adjsutable output voltage, iirc that one goes up to 13.5v). if you need more current, there's the hlg-320h-12a or hlg-600h-12a, which would give more current than the 150h.


the other problem with a 12v dc dc even if it were current-limiting in the right way, if it is actually just 12.0v, is that it wont' charge a lead acid battery very far--takes 13.6-14v+ to fill them up.
 
OK, I guess that's not worth the effort then.

Lets look at it another way.

Only as a back up to the existing batteries.
Disconnecting the RV batteries, and using my battery pack instead.
Would I still need to use the 48v to 12v converter?
 
Just_Ed said:
Can this battery pack be hooked directly to my existing SLA batteries, and used as back up through the on board inverter?
Click to expand...
Are you saying you have an SLA pack in your RV ?...with an inverter to run AC equipment ?
If so, What voltage does your RV SLA pack run at ? , 12v, 24v, 36 or 48v ?
 
Hillhater said:
Just_Ed said:
Can this battery pack be hooked directly to my existing SLA batteries, and used as back up through the on board inverter?
Click to expand...
Are you saying you have an SLA pack in your RV ?...with an inverter to run AC equipment ?
If so, What voltage does your RV SLA pack run at ? , 12v, 24v, 36 or 48v ?
Click to expand...

My rig uses two 12 volt deep cycle batteries, to maintain the 12 volt system, with a (converter).
I use primarily the 50 AMP cord, with 30 AMP pigtail to the 30 AMP outlet, when I'm hooked up to shore power.
 
Just_Ed said:
Disconnecting the RV batteries, and using my battery pack instead.
Would I still need to use the 48v to 12v converter?
Click to expand...
if the rv is a 12v system (two 12v in parallel), then yes, otherwise the much much higher voltage of your 48v battery will damage or destroy anything unable to handle the higher voltage (lights will burn out, electronics will fail/blow up, etc).

if the rv is a 24v system (two 12v in series), you still need a converter for the same reasons (though the degree of damage could be less if you didn't, depending on the designs of stuff connected at the time).

so you have ot use a 12v (again, 13.6v would be better) (or 24v, really 27.2v) converter capable of at least as much current as the system will ever draw, at peak. so if there are motors or other things on the system (coolers or heaters, fridges, etc) the converter has to be able to handle the very high startup peak currents those may draw, and it must handle enough current to satisfy *all* of them at the same time, should it happen that they all ever turn on at once, by random chance, if they're on thermostats/etc.

if it can't handle the current, the cheap ones may just die. better ones will just shut off completely until they're reset (by taking all load off them, sometimes by turning the power input off and back on). depends on how they'r edesigned inside. a current-limting converter, like those meanwells, would just drop it's output voltage until the current limit equals the demand on it, or shut off if it can't drop any further.

a fuse on the output, rated for at most the max current the converter is rated for, would help prevent converter damage, if it blows fast enough.

if all you have is lights on the system, the converter you're getting is probably ok, as long as they don't total up to more current than the converter can output.

if you have high draw stuff on there, like refrigerators, air conditioners/heaters, stove/oven, etc., it can't handle those.
 
Just_Ed said:
Lets look at it another way.

Only as a back up to the existing batteries.
Disconnecting the RV batteries, and using my battery pack instead.
Would I still need to use the 48v to 12v converter?
Click to expand...

Yes, that could work. I'll bet the output of the converter is really more like 13.8v (mine was). There may actually be an adjustment inside for the output voltage. As long as your loads are less than 20A, it will be fine.
 
Thanks for the feedback.

I went looking for an alternative to my BP.

Found this one. And it's 48 pounds lighter.
Not sure how long 90Ah would be in reality.

https://www.techdirectclub.com/bmw-ev-lithium-ion-battery-12v-3s-90-ah-1kwh-solar-golf-cart-rv-back-up-power/

Haven't delved into the particulars, as I just thought about it, but maybe it could actually replace my existing batteries, when they finally fail. Like what the compatibility with the RV's electrical system, i.e. converter, charging, BMS etc. It's just a whim, so there's no desire to be changing anything, unless it's simple and inexpensive.
 
Just_Ed said:
Found this one. And it's 48 pounds lighter.
Not sure how long 90Ah would be in reality.
Click to expand...

It says it's 3 series cells. 12.6v fully charged (or maybe a little less). If you tried to charge it with the vehicle, it would get dangerously over charged.

For a 12 lead-acid replacement, 4 series LiFePO4 cells seems to work out better as you can charge it with the vehicle alternator safely. Downside of those is they are about 2x heavier and larger than Li-ion.
 
fechter said:
Just_Ed said:
Found this one. And it's 48 pounds lighter.
Not sure how long 90Ah would be in reality.
Click to expand...

It says it's 3 series cells. 12.6v fully charged (or maybe a little less). If you tried to charge it with the vehicle, it would get dangerously over charged.

For a 12 lead-acid replacement, 4 series LiFePO4 cells seems to work out better as you can charge it with the vehicle alternator safely. Downside of those is they are about 2x heavier and larger than Li-ion.
Click to expand...

OK. Not so simple, as pull and swap.
Time to put this idea on the back burner, and back to hot rod building.
Thanks for the insight. Maybe I will address this at a later date, when I've just got nothing better to do.
 
You must log in or register to reply here.
Back
Top