Configure 2 battery packs for Serial, Parallel and Split use

I have two 36V20Ah Headway Packs (with the 38120 10Ah cells (5C), each pack with its own BMS) configured as 72v20Ah.

I'd like to be able to use the packs three ways:

1. Series - 72V20Ah - for
2. Parallel - 36V40Ah - for increased range
3. Single Pack - 36V20Ah - for lighter load

I'm using a Xlyte 7240 12-fet controller with a X5 rear hub.

Have you seen anyone with this? (I've read through the "Circuit Schematics" thread and came up empty)
What recommendations do you have on how to accomplish this setup?

Thanks.

It's pretty straight forward, Ryan. Put Anderson Powerpole connectors on both Headway packs. A red one for the positive lead and one black one for the negative lead (obviously)

Then put double Anderson Powerpole connectors on the controller end.

Then when you want to connect the packs in parallel for 36V 40AH capability, just connect both packs directly to the controller. If you want 72V 20AH power, then connect the first pack's + lead to one of the controller's positive battery connection, connect that first battery's - lead to the positive lead of the second pack and then connect the second pack's - lead to the negative lead on the controller's battery connection.

Easy. The only tricky part is doubling the connectors on the controller.

Hope this helps.
Ambrose

Just make some y connectors, like I mentioned on another thread just now. so two wires go into one for paralell connecting. To series connect, seperate the pairs of andersons on the packs, and you can connect serial style. Or, you can make a different kind of y connector, that makes up a serial connection if you don't want to risk mixing up the wires when connecting up.

What kind of cells does Ping use? I emailed him about doing something similar and he recommended that I not because "the cells won't like it". Do headway cells respond ok to switched // or series configurations?

Rian, I found the "Circuit Schematics" you need :wink:

That serie-parallel battery switch has been discussed a while here :wink:

You just need a DPDT high current switch.. also availlable at ebay for about 5$

Back in time... 2007.. here is the original thread about that :wink:

http://endless-sphere.com/forums/viewtopic.php?f=2&t=2728&hilit=dpdt+serie+parallel

http://endless-sphere.com/forums/viewtopic.php?f=2&t=1530&hilit=dpdt+serie+parallel

I used that for almost 1 year without any problem.

Doc

The use of diodes is allways a good idea. The original ping bms ( v1, v2 ) needed diodes to protect the bms in series connections. You'd have to ask headway about thier bms, and what it can handle.

In paralell connections, the diode is needed so that one pack does not charge the other. Two reasons, the bms doesn't like reverse flow of current, so if one charger was on and the other not, the current would flow into the other pack through the wrong circuit of the bms. The cells themselves could get stressed if a discharged pack was connected to a charged one, that is if the bms didn't smoke first.

Diodes are explained in the tech reference section.

Can anyone confirm for me please if using 1N5404 or 6A4/6A10 as bms protection diodes would be suitable to series 48v10a + 24v10a lifepo4 packs running with a 60a peak controller. thanks

1N5404 are only like 3A diodes, so you'd have to parallel quite a few to get enough current thru them to run a bike. At least 5 and probably more like 10-20, depending on your sustained and burst currents.

The 6A10 are 6A, so you might only need half as many, but they're like twice as fat.

I thought the peak rating of 250A for the 6A10 must be what to look at since nothing else at DSE or Jaycar looks more suitable.
I've read a lot of posts on here about placing diodes for series packs but there's no mention of a part number, and I can't find any in shops or online that are rated 100v 100A like as mentioned in this thread http://endless-sphere.com/forums/viewtopic.php?f=14&t=11738&start=0#p178375.
What are some commonly available types that have a suitable maximum average rating?

The peak rating is only going to be good for very tiny bursts. Typically only a few milliseconds, and I can guarantee that many ebike setups will draw much more than 6A for at least a few seconds at startups from a stop. The diode could probably take a significant overcurrent for a short period if it is heatsinked well enough, but repeatedly doing that frequently may not let it cool enough.

Trying to run more than the 6A continuous max rating will cook it even if it is heatsinked, eventually. How long that eventually is depends. What's ambient temp? What is the heatsink's ability to remove heat? How long does the core of the part stay hot? (one rating I saw was that 6A is only at 75C and lower, so the hotter it gets the less it can handle, too).

You're probably going to want to search for "ideal diode" here on ES using the google site search. Otherwise, you could look for diodes that are packaged in metal bolt-on types. Kind of like this:
http://www.tme.eu/katalog_pics/1/7/5/1750d999710585cbd17690e2e8fbe82c/d22-10-10.jpg
Those can be threaded right into a heatsink (or metal mounting plate), and generally are designed for very high currents.

I am not sure, but I think Ping directly sells the 100V 100A diodes (thought I read that somewhere in a similar thread).