Question about DIY hybrid EV

spinningmagnets

spinningmagnets

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I recall reading about how youtuber "Rich Rebuilds" took the 102V drivetrain from a wrecked Zero motorcycle, and adapted it to a light vintage hot rod with a 3-speed manual transmission.

He ended up using only two of the gears, but he reported that acceleration was very nice (and certainly "useable"). The video seems to verify it ran well.

Tesla gets great performance from one speed because it uses super high watts, but I wouldn't need high performance.

My theoretical proposal would be a small truck like a Chevy S-10, with a manual transmission. These have been converted before, so that's no problem, with many examples.

Meanwell power supplies can be daisy-chained to achieve the desired voltage when charging at home. My questions are about the system voltage and back-up generator. It's easy to find a generator that provides 220V and has a key-start. If I used four lithium golf cart 48V packs, the voltage would be 216-ish volts?

(54V max times four packs = 216V?) the nominal 48V would be 192V, and it "seems like" I could just turn the generator on when the voltage dips to 200V, and I could leave it on until I parked at home to plug in, or if the battery managed to gain voltage while the truck was running, I could turn the genset off at 210V?
 
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The Zero battery pack is 28S, so when fully charged to 4.2V its 117V, at an LVC of 3.0V its 84V, and nominal 3.7V is 103V

Two of them in series (or four 14S packs) would be 206V nominal...234V fully charged.

I'm wondering if I can use a common 220V generator set to keep the vehicle running when the battery gets low. A simple bridge rectifier can convert the 220V AC to DC, and it would lower the voltage a hair.

Once the battery gets down to 206V at the mid-point, can I turn on a 220V genset and keep it running until I get home to a proper charger for the custom voltage?

Would an output of 210V after the rectifier be enough voltage?
 
spinningmagnets said:
A simple bridge rectifier can convert the 220V AC to DC, and it would lower the voltage a hair.
Click to expand...
Typically when you do this, your DC output rectified voltage goes way up. Like you could be seeing 250-300v in this case. Depending on your source (a 220v generator in this case), when you apply it to the load of keeping your battery charged, it may go down, but you don't know, and it's not going to be a good idea to apply 300v to a battery that can only take a top charge of 234v. I guess what I'm saying is that your simply-rectified voltage from a 220v generator is going to be too unpredictable to safely charge a battery.

Plus you'd need a rectifier capable of handling that load.

Furthermore, say you get this running, your circuit would need a way to make sure it's not overcharging the battery.

So off the top of my head, I'd modify your idea as the following: 220v generator -> Meanwell power supply or battery charger with a max output DC voltage of your battery. You'd need to be sure that your battery is getting charged correctly.
 
Just google "rectifier goes bang" it is a bit of a meme.

Don't try for short cuts, often times they lead to smoke alarms and people lecturing you about burning the kitchen table, then the cat is just gone and you knew *nothing* about all that. Next thing ya know, tin shed in the backyard for all your tools...

Ok, maybe that was just me.
 
To see some of the problems with non-typical charging processes like you're looking at, you may want to look up "bad boy charging", both here and on DIY Electric Car forums.

The two main ones are probable overvoltage, and probable overcurrent, since you don't have any hardware limiting either one.

Also, the overcurrent may be too much available from the supply thus damaging the battery, or too much demand from the battery thus damaging the insufficiently-capable source.
 
amberwolf said:
Also, the overcurrent may be too much available from the supply thus damaging the battery, or too much demand from the battery thus damaging the insufficiently-capable source.
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As a final comment, rectifier based approaches also give you a very poor power factor, since you can only use the "top" of the AC waveform. This leads to (for example) a 10KW generator only able to provide 6KW (but using as much gas as a 10KW load would.)
 
JackFlorey said:
As a final comment, rectifier based approaches also give you a very poor power factor, since you can only use the "top" of the AC waveform. This leads to (for example) a 10KW generator only able to provide 6KW (but using as much gas as a 10KW load would.)
Click to expand...
When a standard 220V generator is used, what is the best way to convert it to DC? What would the resulting DC voltage be?
 
Just rectify it?

Or filter it, regulate it, current limit it, and or other safety features?

"best way" depends on exactly what you want to do with it, and how much you care about the source and the load and what could happen to them in various events.
 
spinningmagnets said:
When a standard 220V generator is used, what is the best way to convert it to DC? What would the resulting DC voltage be?
Click to expand...
You would get the most power from a power factor corrected charger or power supply.

If you are engine (not copper) limited, then you can do almost as well by using a plain old rectifier. A rectifier will give you 320 volts if you use a full bridge. It will be hard on the copper, but it will work.
 
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