UPDATE: April 30, 2008 Please click here
This is a continuation of:
"Bank Charging" by charging in parallel, w/one charger.
The goal is to get the benefits of bank charging without the expense and bulk of having to use multiple chargers. This thread covers a much simpler way to do it than that covered previously. This is best done for lower-powered systems, because a large block of high-powered Anderson powerpoles would be difficult to connect/disconnect, and high-amperage fuses are more expensive. Plus, if you screw something up, your going to get a BIG spark, and possibly a fire or being burnt! Having smaller wire and smaller fuses to the charge connector is nice safety feature for a high-power system.
I had a discussion over PM with e-doggies, and he mentioned using a "jumper harness" in the charging connectors in the drawing (check above link) to wire the batteries in series. This eliminates the need for the high-power connectors in blue, provided the charge connector, and charging wiring can handle the high power when the EV is in operation.
I've seen mr_exon do this, and mf70 also mentions using a "series-parallel plug". Just to give credit where it's due; this is not my idea! I just wanted to help spread it, and incorporate some of my thoughts to help you all.
Here's the basic idea:
I'd upsize the wire from stock slightly. Here's what I would recommend:
Small scooter/ebike: 10 AWG, Anderson PP45 connectors
Large scooter: 8-6 AWG, Anderson PP75 connectors
I recommend using Anderson Powerpole connectors, because they are modular and each contact is completely isolated from the others with plastic. They can only connect when oriented 180 degrees opposite, so once the mating connector is constructed, it will only go in the right way. This makes it easy to use jumpers (see below) to reconfigure the pack on the fly as the connectors are universal. I got mine here: http://www.powerwerx.com .
It would be very helpful to label which connectors are to which batteries. And also label which connectors are to the main positive and negative of the pack. This is why I set them up so the positive and negative for each battery are adjacent to each other. This'll make it easy to measure each battery's voltage, or load test each battery.
Here are some advantages:
● All of those listed here(check bottom of post).
● Safer because just one connector can re-wire the batteries. Because the "ride" connector must be removed to insert the "charge" connector, than there's no risk of wiring the batteries in parallel and series at the same time, if the connectors are setup properly. This does not mean you can eliminate having one fuse per battery! All of them are necessary to protect each circuit from shorts!
● Easy and quick to rewire the batteries for charging or riding.
● Possible to load test each battery from the connector. This'll make it easy to find a bad battery. NOTE: be sure not to exceed the current that the fuses are rated for when doing this.
○ A convenient way to do a load test if your controller has no low-voltage cutout, is to remove the ride connector, and jumper one battery's positive and negative to the main positive and negative respectively. This will power the scooter from just that one battery.
○ If the charger is a smart type that can diagnose battery problems, than you can connect it to each individually battery and watch how the battery accepts charge, and for any codes.
● If you decide to increase the system voltage, than you won't need to buy another charger, just some more anderson powerpoles which can be added to the existing connectors.
● Easy to connect a range-extender battery pack.
● Easy to "break in" the batteries, as you can just connect the charge connector to power a 12v-120v inverter powering a lightbulb and clock. This way there won't be any risk of over-discharging the batteries because inverters usually have a low-voltage cutout, and when it does cutout you'll see by reading the clock.
● Easy to run with the batteries in parallel for a low-speed mode by just inserting the charging connector (or 1/2 voltage (see below)). This will also reduce the potential to damage the batteries when riding on low charge. This will probably not work if your controller has a low-voltage cutout. Beware: you can still damage the batteries by going below 10v/battery.
○ This can be done with a controller that has a low-voltage cutout, if you have a controller bypass contactor.
● Can bypass a battery on the road to get home if one battery dies. You can keep some "jumpers" to do this. The jumper would consist of a wire with two powerpoles on each end. You'll need N-1 jumpers as batteries, so that you can wire the other ones in the circuit as well. This will prevent the need to break up the run connector which wouldn't be so easy if it is nicely assembled with short and direct interconnects.
● In an "oh ****" situation when a controller fails closed (directly connecting the batteries to the motor) the connector can function as a disconnect if it is accessible when riding. Note: Only recommended for small scooters, as the larger powerpoles may be difficult to remove in a panic.
● Can charge from a range of DC-DC converters that have a 13.8v to 15v output. This makes it possible to charge more efficiently from batteries which store solar/wind energy, or from a larger ev which has a DC-DC converter.
● A 48v pack can have a connector wired to have two 2-battery strings in parallel for half voltage. A 72v system could have three 2-battery strings in parallel for 1/3 voltage, or two 3-battery strings in parallel for 1/2 voltage.
● If you've got an ebike with a bursh PM DC motor than you can insert the charge connector (or a 1/2 voltage connector (see last bullet), and install a contactor to bypass the controller to get regen! Best done if you've got a really steep hill to go down, and you've already used some charge from the batteries.
● If it turns out wiring the batteries in parallel to charge doesn't work for any reason, than you can easily traditionally bank charge with N number of chargers for N batteries.
● You can keep a small low-voltage emergency pack of NiMH, NiCads, or LiFePo4 to charge your scooter in an "oh ****, I'm out of charge" situation.
That's all I can think of for now; my brain needs a recharge.
PS: If your wondering why I spent so much time explaining this setup, it's because I clearly have no life. I also want to use this for myself and it helps me understand it.
PPS: I have no doubt parallel/series switching beats bank charging and that's why I'm doing it for my motorcycle and scooter.
Here is how I took my X-treme xb 600 from 48v and 21 mph to 60v and 30 mph. First, you will need to remove the battery pack and seat. Also, take the lid off of the battery pack and make sure all the connection screws are tight(some of mine were loose). Next, drill (2) 1/4" holes in the corner of the seat pan in the left front corner. See Below...
Now, cut the black wire coming from the last battery's negative post and attach a length of 12 ga. or better wire to each black wire long enough to reach up to the storage area under the seat. The wire coming from the 4th battery's negative will go to the 5th battery's positive post. The other wire will go from the 5th battery's negative post to the plug that the black wire we just cut went to. Then route the 2 new wires through the hole in the battery box beside the plug. See Below....
Now would be a good time to put a piece of black tape on the wire that will go from the 5th battery's negative wire to the plug. This will save confusion when wiring everything together later. Or you could use black wire on the negative which I didn't think of until now. LOL! When you have done these steps put your battery box lid back on and rout your wires along side the battery pack plug along the frame and pull them up to the seat area in front of the controller. See Below....
Now install your seat pushing the wires through the 2 holes you drilled in the start of this project.
Now, put a female spade connector on one wire and a male spade connector on the other wire so you can plug these 2 wires together to charge the 48v pack with your stock charger. Now it is time to wire the 5th battery. Use any length of wire with a female spade connector on one end(If your battery has this kind of post). You will need one for the negative terminal and one for the positive. Now, remember that piece of tape you put on your negative wire coming from the battery pack plug? Good. If you put a female terminal on the end of it, you will need to put a male spade connector on the end of the wire that plugs onto the 5th battery's negative terminal. Also, I suggest using black tape on the 5th battery's negative wire or black wire so you know which wire plugs onto which post, because you will have to remove them from the terminals to charge the 5th battery with a standard 12v battery charger. See Below....
Here is the $28 charger I bought at the local Wal- Mart to charge my 5th battery...
This is how you will connect the 2 wires coming up through the seat for charging the 48v pack with the stock charger...
Now, the fun begins.
If you used a Female spade connector on the positive wire coming from the 48v pack(the wire you didn't put black tape on) then you will need to put a Male spade connector on the wire coming from the 5th battery's positive terminal. Likewise, you will put a female spade connector on the 5th battery's negative wire. This way, you should be able to connect the 2 battery pack wires together AND connect the positive wire to the 5th battery's positive, and the negative pack wire to the 5th battery's negative when you are ready to ride in 60v. Now, let's wire it up for 60v.
With all of your spade connectors in place, connect the positive wire coming from the battery pack(yes, this is actually the wire coming from the 4th battery's negative) to the wire that connects to the 5th battery's positive terminal. Do the same on the negative.(Both wires that had black tape should be hooked together) See Below....
You are now running 60v on your 48v scooter. If you have already done the shunt mod on your controller (E-max Controller Mods - Shunt Resistor Trick) then you are about to have some real 30mph fun!! Actually if you haven't done the shunt mod I would suggest you stop right now, take off your controller, get out your soldering iron and drill, and do it first. As soon as I figure out how to get video off my cell phone and onto my pc I'll put a vid of my speedo as I'm going 30 mph up on youtube and link it here. Till then here's a pic of my latest mod. :)
I hope this thread will be useful for all who own xb 508s, xb 600s, or any other electric scooter. Post questions here and I'll do my best to answer them. Thanks for all the help I've gotten from this forum and I hope this helps someone in return.
I finally got around to documenting the process for those still unsure of the process. Hopefully this will help a few people out who still aren't sure of the procedure.