Best Blender/Combiner/Balancer for 48V+52V setup?

You need a blender because parelalleling batteries is dangerous. But why do you need to parallel the batteries? I see no compelling reason to do that, and many to avoid it.

Both my e-bikes have the battery in the frame along with the battery connection. They're both drop-n-lock. And at the end of the day I am trying to keep these things functionally fashionable without hanging wires and mounts everywhere. What part of the configurations concern you, the blender?

You don't necessarily need a ton of wires and stuff. I have an Ariel Rider X-Class with a 48V battery and 52V battery. Either battery can handle the full max discharge my controller is set to. I just have one fully potted ideal diode in front of the 48V battery:

And an ammeter in front and behind it that I sealed in transparent heat shrink after calibrating:

And then just a Y cable from two XT-60 connectors to an XT90S antispark connector to my motor. You could fit it all in the controller compartment above the bottom bracket (I zip tie it to a frame tube for better cooling, though).

I figure the only way I can mess up is if I drained the batteries completely, unplugged the 52V battery, charged only the 48V battery, then plugged everything together without checking the voltages. I don't really have any plans to ever unplug them, though.

My batteries have on/off switches, but there's plenty of ideal diodes with back to back FETs that let you have a tiny on/off switch if you want:


The on/off switch just controls power to the MOSFETs, so carries barely any current. It doesn't have to handle the full discharge amps.

That said, just a typical marine boat rotary battery selector switch rated for 60V 300A is only the size of the ideal diode alone:

So Glenn's suggestion isn't huge either.

Paralleling will give me more torque. When I was pondering a 52V addition I was hoping for more speed but pairing them was harder than pairing two batteries of the same 48 voltage. I need to unplug and charge all of my batteries separately, daily. My space will not permit my charging them on the bike. Is the blender the worry? It seems to resolve far greater worry. If the Phaserunner is set within the Blender and batteries' limits should this not run cool?

Never seen a blender that can actually parallel packs, so I don't think you'd get any more torque. You'd have to set max amps on your controller to only what one pack could handle or not use a blender. I tried previously with a blender and setting my max amps higher just tripped the over current fault on the BMS on a pack eventually.

One of the manufacturers was asked flat out in a thread and said it's true it doesn't parallel and rather just alternates back and forth:

I can think of about a dozen ICs that can combine two batteries like that, but only one that can share the load between them by only partially driving the FETs to compensate for differences in charge state and internal resistance in the two packs. Even then it only successfully shares the load when the packs are very closely matched in voltage. So the only case where it works is the same case where you just check the voltages are the same before plugging the packs together. Even then it generates more heat than the blenders that switch back and forth because the FETs aren't as efficient if they aren't being driven fully.

lnanek said:

One of the manufacturers was asked flat out in a thread and said it's true it doesn't parallel and rather just alternates back and forth:

Minshine dual battery balance dischargers, 20A-150A, 80V/100V

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Blenders being cooler is what I need. Guess I'll have to revel in distance alone. Thanks for lowering my expectations Were these Minshine blenders efficient and might they run cool with my proposed settings? Their wiring looks thinner than my pricey option.

The last link you shared had a model number DBB*. Isn't that a Minshine thing to distinguish their balance discharge model from the non-balance one?

Transit Artist said:

Both my e-bikes have the battery in the frame along with the battery connection. They're both drop-n-lock. And at the end of the day I am trying to keep these things functionally fashionable without hanging wires and mounts everywhere. What part of the configurations concern you, the blender?


View attachment 390094View attachment 390095

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No concern as such, I'm sure the product does what it says on the box, I'm just trying to understand your motivation for introducing complexity and electrical losses. I do now, and you definitely have a compelling reason - a blender permits a neater installation.

I'm not convinced that a manually operated battery switching arrangement couldn't be installed almost invisibly, but it's hard to make useful suggestions without being familiar with all the nooks and crannies of your bikes.

Generally, where there's a will there's a way, and a little bit of lateral thinking goes a long way. Using the blender is all good, so long as you considered alternatives and understand the compromise ... otherwise it's a lazy shortcut.

Do you really need the extra capacity for most rides? Or just occasionally? For an ICE vehicle the best reserve tank is a Jerry can. For an electric one I think the principle is no different - isolation and independence are important. You'd never merge two gas tanks. Why would you do it with batteries?

That's just the way I look at it. If you were using regen and/or parallel charging it'd be a very different situation - more akin to running a second car battery for powering a camping fridge, that you want charging from the alternator but unable to drain the starting battery.

glennb said:

For an ICE vehicle the best reserve tank is a Jerry can. For an electric one I think the principle is no different - isolation and independence are important. You'd never merge two gas tanks. Why would you do it with batteries?

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Simple Jerry can example not quite the same. I parallel two identical batteries, always Y-connected. Of course that provides (nearly) double the range without switchgear or reconfiguring. But: Main benefits you are ignoring? (Nearly) double the amperage, (nearly) half the voltage sag, less stress on the batteries.

I'm presuming the OP is looking for similar benefits, but is constrained by non-identical batteries, and non-single port BMSes.

I think the analogy holds well enough for the OPs use case. He's not paralleling them, so achieves none of those benefits. The blender will draw the 14S battery down by a quarter or so, then bounce back and forth between the two thereafter.

With equivalent cell series configurations the blender minimises depth of discharge by load sharing of sorts. That's a benefit. However it's non-applicable with non-equivalent batteries, in this case with the 14S battery being discharged more deeply.

So, what's left, convenience of auto vs manual switching, and neater installation. The neatness I'm not sold on, because I believe it's possible to fashion a hidden or aesthetically pleasing manual battery switching system.

Convenience? I will concede that point.

I saw a neat little DIY box on a German forum where you plug the batteries in and it connects them via a blender and also has two voltage readouts. Then you can flip a switch to parallel them directly.

That's a neat idea, Things are heading in the right direction. It'll be a while before there's a gizmo that optimises the draw, discharge, and charging (inch. regen) of, from, and to, any two power sources, but basic load sharing is not too much to ask.

Parallel dissimilar supplies optimally such that neither is overtaxed and the maximum combined current is available at all times. That's the task of a blender. There's no blending otherwise, merely alternating. "Blending" implies merging, and they don't do that.

How to discern acceptable tax rates? Presumably temperature smd voltage, but that's beyond my pay grade.

Thanks for hashing his out for me as I would not know the questions to raise. Is the 48V Samsung 50E the presumed 14S? Not that this fits anywhere on my bikes but If I were to switch that 10Ah for this 13S3P 48V 15Ah the blender would still keep the pair from providing a boost in amp output, correct?
That marine boat rotary battery selector switch is smaller than the throw switches I'd found. if i revert to a switch config rather than a blender with a 52V option from either of these packs would I need a CycleAnalyst to swap settings profiles? And am I even providing a difference given my 750W and 1000W Bafang G62 motors' limitations?

glennb said:

I think the analogy holds well enough for the OPs use case. He's not paralleling them, so achieves none of those benefits. The blender will draw the 14S battery down by a quarter or so, then bounce back and forth between the two thereafter.

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OK, fair enough, I misunderstood the OP's use case.