Powerbank instead of Batteries for Roland FR1

[Tafaner]

I'm new here, so sorry if this has been well covered (I did search, but found nothing...)

I'm a jazz/latin player of many years (flute, 7-string nylon guitar mostly) but am just starting out on a CBA adventure - as a complete beginner! And since I haven't grown up with the sounds of acoustic accordions, it's quite natural for me to start with a ROLAND FR1XB for all its documented advantages. I have a lot of stage/audio kit already, so the ability to just "plug in" is a huge advantage for me. And if I ever get good enough to play on stage, I can use my existing wireless rig to move around freely on stage without tripping over wires.

But I have to say that the BATTERY arrangement on these accordions is very poor! Removing a stack of AA cells and recharging every ~5 hours is a step too far for me. So I've instead adopted a POWERBANK of the kind used for powering guitar pedals - basically a Lithium pack with controlling electronics in a small case that can be recharged in situ. My blurry photo shows this attached to the instrument - basically fastened to the outside of the battery door using 3M Dual Lock (a kind of industrial super-velcro). Note that is glued only to the battery door, which is a cheap plastic replaceable part. The instrument is unchanged.

The powerbank I used is a Harley Benton from Thomann, which I already had. It actually produces 2 x 9v which I had to join together (hence the 2 wires). In theory, the max output is only 1.2 amps, while the Roland power adaptor is rated for 2 amps - but my tests show that the instrument never draws more than 1 amp even at full volume with loads of notes pressed. Lithium powerbanks have a significantly higher capacity than AA cells of a given size/weight, and I calculate this should give me 8+ hours with speakers on, or 14 hours on headphones - for a weight of 220g.

Note there are other power banks, designed for driving phones and laptops, that look even better than the one I chose - in particular those that support the PD 3.0 (Power delivery) protocol. The way PD works is that you buy a special cable that contains a chip in the USB-C connector that "negotiates" the voltage required - 9v in this case. This looks like a brilliant solution BUT two of these that I tried had the same problem, namely that the 9 volts would not re-establish on power on! You had to physically unplug and reconnect the 9v cable to trigger the negotiation (the "plug and play" idea). So I used my Harley Benton one which produces an old-fashioned "fixed" 9 volts.

Now I just have to learn the bloody instrument!

 

[Ventura]

on background

the Rolands are somewhat sensitive to Voltages outside their engineering
design parameters, and have had problems and breakdowns linked to
incorrect voltage

the Rolands also are very good at hiding kill switches so that battery
covers need to be in place and power jacks need to be protected
from stress

the nominal correct power for the Fr1 series is 9 volts, with a design
that obviously accepts 9.6 volts (8 fully charged NiMh cells @ 1.2 volts each)
and has software in the accordion to show battery capacity as the cells
deplete and lose some voltage during use

now there are no combinations of LiPo batteries that give a natural 9.6
voltage except for a 3 cell pack near exhaustion.. fully charged 3 cell
LiPo gives you 12.6 volts.. clearly beyond the design parameters.

so do this at your own risk

in particular, charging a LiPo pack in situ and connected to the
FR1xb will definitely swing a voltage level above design limits..
do not be suprized if you fry something and negate the warranty..
remember, the main on-off switch is a software controlled device

there ARE some regulators on the market you can use and adjust to
take 4 LiPo cells in a power pack ranging from 16.8 to 12.8 volts
and give you a steady controlled output of 9 or even 9.6 volts at
a guaranteed constant current suitable for a V-Accordion, and this
would be the safe way to improve on the 8 NiMh default system

there is no need to get funny with the battery compartment, just
leave it empty, wire a right angle power cord to your substitute pack
and plug it in to the normal power jack same as you would the
PSB1u power adapter

you can build several packs to swap out

MOST LiPo power banks are only vaguely rated for a voltage, and
unless they specifically guarantee a constant steady output voltage
you cannot assume it. Some multi-output models will guarantee the
5 volt or 9 volt but the 12 volt is unregulated

 

[Tafaner]

on background

the Rolands are somewhat sensitive to Voltages outside their engineering
design parameters, and have had problems and breakdowns linked to
incorrect voltage

the Rolands also are very good at hiding kill switches so that battery
covers need to be in place and power jacks need to be protected
from stress

the nominal correct power for the Fr1 series is 9 volts, with a design
that obviously accepts 9.6 volts (8 fully charged NiMh cells @ 1.2 volts each)
and has software in the accordion to show battery capacity as the cells
deplete and lose some voltage during use

now there are no combinations of LiPo batteries that give a natural 9.6
voltage except for a 3 cell pack near exhaustion.. fully charged 3 cell
LiPo gives you 12.6 volts.. clearly beyond the design parameters.

so do this at your own risk

in particular, charging a LiPo pack in situ and connected to the
FR1xb will definitely swing a voltage level above design limits..
do not be suprized if you fry something and negate the warranty..
remember, the main on-off switch is a software controlled device

there ARE some regulators on the market you can use and adjust to
take 4 LiPo cells in a power pack ranging from 16.8 to 12.8 volts
and give you a steady controlled output of 9 or even 9.6 volts at
a guaranteed constant current suitable for a V-Accordion, and this
would be the safe way to improve on the 8 NiMh default system

there is no need to get funny with the battery compartment, just
leave it empty, wire a right angle power cord to your substitute pack
and plug it in to the normal power jack same as you would the
PSB1u power adapter

you can build several packs to swap out

MOST LiPo power banks are only vaguely rated for a voltage, and
unless they specifically guarantee a constant steady output voltage
you cannot assume it. Some multi-output models will guarantee the
5 volt or 9 volt but the 12 volt is unregulated

Very useful info, thanks ! But I'm not doing what you appear to think...

The Harley Benton powerbank (and others like it) is NOT just a pack of raw LiPo cells. Internally, it's a single cell of 3.7v but with inverter circuitry to produce the 2 stabilised 9v outputs. Because these are designed to drive guitar pedals that are themselves sensitive to voltage variation and to potential noise created by the inverter (which typically clocks at 50 KHz) the regulation and filtering are super important. Reports from many users indicate that these work - and don't ever over-voltage or introduce noise. The 2 x 9v outputs are also fully independent and floating (pretty standard with inverters, AIUI, as they use transformers and PWM via opto-couplers to regulate). So the 2 x 9v outputs are "quiet" and super stable and it's OK to connect them in parallel, as many other users have done successfully.

The charging function is a completely separate input to the power bank that uses a (slow) 5v USB charger, so there's no question of overloading the Roland 9v inputs. The Roland doesn't even know when the powerbank is being charged.

Because the Powerbank is a 9v regulated device, the state of charge is not evident from the voltage - and as the internal cell discharges, the 9v output will die suddenly. Because of this, the makers build-in a state-of-charge indicator, in this case a row of 4 LEDs. I would have preferred a %FULL display as some powerbanks have, but as I say, the ones I tried had other problems.

Good point about using a right-angled jack. As the pic shows, I've done this, and also lashed it to the neighbouring strap mount point to (hopefully) prevent it being pulled out.

So I *think* what I've done is OK technically - but time will tell !

 

[Ventura]

yes, i see, then the Benton product covers all the bases..

the only other thing you might consider then, if you ever
spot a used one for the right price, to rebuild one with
twice as many LiPo cells (in parallel) for a longer run-time..

you might use slim/wide laptop type cells and then just slip
it under the backpad to hold it in place

the bike and scooter battery packs are massively parallel
designs and do not seem to exhibit the kind of between-cell
crosschatter that drains NiMh and Lead-acid types

it got me curious to see what else they have in power
but the brand is owned by Thomann, and it appears
everything in the line is in support of the guitar stuff

 

[Tafaner]

It's true that the Harley Benton product doesn't have as much capacity as we would like! Based on their figures, I calculate 1.75 times the capacity of the NIMH AA cells that Roland suggest. They do actually make a bigger one (Mk 2) in the same range, but it is really deep and would probably stick in your ribs ! It's also twice the price. DIY adding another cell in parallel is an interesting idea, but I wonder if that would confuse the charging circuitry and the state-of charge LEDs ?

I don't like the fact that Harley Benton it's an anonymous Chinese offering, supplied to Thomann only. That's what got me thinking about PD 3.0 powerbanks, which are available cheaply everywhere and can have a LOT more capacity. The way these work is that they can support variable voltages that are "negotiated" by whatever you plug into them - often 5, 9, 12, 15, or 20 volts - all from the same device. To power a 9v device like the Roland, you buy a "9 volt cable" that has (extraordinarily!) a chip that negotiates the 9 volts built into the plug (see pic #1)

I thought this was a brilliant idea, but I hit 2 problems: the first unit I ordered would SHUT DOWN if there wasn't a minimum current flowing. The second one I tried (excellent in most respects, see pic #2) didn't have this problem - but would only negotiate the 9 volts required if you unplugged and reconnected the cable. Otherwise, it would default to a safe (but useless) 5 volts. I gather most if not all "PD" banks are like this because they are really designed as utility "plug and play" chargers, and not for permanent installation. And I didn't want to have to unplug and reconnect it every time I used the accordion.

So I reverted to the imperfect but reliable Harley Benton one. 10 hours on full power is good enough for me! And 220g is slightly lighter than the original AA cells (8 x 30g)

Thanks for your feedback!

 

[knobby]

the nominal correct power for the Fr1 series is 9 volts, with a design
that obviously accepts 9.6 volts (8 fully charged NiMh cells @ 1.2 volts each)
and has software in the accordion to show battery capacity as the cells
deplete and lose some voltage during use

now there are no combinations of LiPo batteries that give a natural 9.6
voltage except for a 3 cell pack near exhaustion.. fully charged 3 cell
LiPo gives you 12.6 volts.. clearly beyond the design parameters.

I'm so glad I read this thread the other day!
I just bought an FR1X yesterday, and when I got it home and checked the batteries I found that they previous owner had installed 8 AA Alkaline batteries @ 1.5v each instead of rechargables. I removed them and replaced them with rechargeables so hope the brief spell running with 12v hasn't done any permanent damage.

 

[Tafaner]

A few days after crowing about my installation of the HARLEY BENTON Powerbank on my FR1xb, I hit a problem ! The powerbank mysteriously shut down on me ! It seemed completely dead - but came back to life when I connected it to a USB charger. It then showed 75+% full, so had not gone flat as supposed. I can only guess that the max 1.2A output is not enough in rare circumstances, and the powerbank reacts by hanging !

So I revisited the alternative INIU "PD" powerbank I mention above. This is superior in almost every respect to the Harley Benton:
+ It has ~70WH capacity, so should last 3.5 times longer than AA cells (for ~200g extra weight!)
+ even the weaker OUT2 is rated 36W, ie 4 amps at 9v
+ It has a % FULL display so you have plenty of notice when it comes to charging
+ It fast-charges from a PD adaptor (via IN/OUT1) in an hour or so
+ It could potentially also power other devices (computers/tablets/phones) via a suitable cable, eg when travelling

The only thing I didn't like (apart from the cost!) was that I would have to unplug and reconnect the USB-C cable every time I wanted to use the accordion, to trigger the 9v negotiation. How long would the connector last ?

The answer turns out to be "a very long time" ! USB-C connectors are apparently designed for 10,000+ insertions according to Wikipedia. At once per day, this would be 27 years. I expect to be accompanying a choir of angels by then...

So here's my new setup in pictures. Time will tell if it's a good idea or not !

 

[dak]

The answer turns out to be "a very long time" ! USB-C connectors are apparently designed for 10,000+ insertions according to Wikipedia. At once per day, this would be 27 years. I expect to be accompanying a choir of angels by then...

The FR-1Xb doesn't have harp patches, so it would probably have to be a choir of Hell's Angels.

 

[JerryPH]

While I am glad to see that it works, this just looks uncomfortable... so while maybe it could keep it playing for 10 hours, how many hours can you play with that battery pack poking you in the chest before it starts to get annoying and interfering with your playing?

 

[Tafaner]

While I am glad to see that it works, this just looks uncomfortable... so while maybe it could keep it playing for 10 hours, how many hours can you play with that battery pack poking you in the chest before it starts to get annoying and interfering with your playing?

Fair point. I haven't yet tried standing up and playing for hours, but I'm not initially aware of it sticking into me. The back of the accordion isn't exactly body-shaped anyway, and the power bank is barely an inch thick and with rounded edges.

We shall see! But it's a relief not to have to remove and recharge all those cells - and also to know what % of charge remains.

 

[oldbayan]

When do you need to play 5+ continuous hours? Just curious! I have used a FR-1xb and a FR-18 for many years, and a FR-3xb since a year, just using internal AA NiMH batteries and never ran out of juice during a gig! I use 2500 MAh batteries. At home I plug the A/C adapter for infinite playing time. I would not risk ruining my instruments with home-made power packs with the wrong voltage. The FR-1 batteries are easy to remove and install, unlike the FR-3 that has 10 batteries kept into a separate holder.

 

[Ventura]

most of the gigs i have done over the decades were 4 sets
of 45 minutes over 4 hours with three 20 minute breaks

back in the day on weekends we had 3 gigs on Saturday/Sunday
quite often, and during the week too, though weekday lunch-gigs
were only 2 hours/sets

i simply will not use any equipment that is battery limited
(such as wireless Tx with built in rechargeables) or battery
packs that are difficult to rely upon for 2 sets before swapping out

i have vastly more important things to give my attention to,
so distractions that can be engineered out of existence by
customizing and improving the gear is always a worthy goal

hence , the big fat original FR7 battery packs are worthy and
predictable and reliable and i have 5 in rotation.. i found
NiMh 10 packs to be annoying with unpredictable 1 weak cell of 10
being a pain and distraction, and is why i moved to LiPo 1.5 volt virtual AA
8 packs as they are reasonably predictable over time

accordions/keys/arrangers/wireless with batteries you cannot swap out easily ?
not approved for professional use in my book

 

[Tafaner]

When do you need to play 5+ continuous hours? Just curious! I have used a FR-1xb and a FR-18 for many years, and a FR-3xb since a year, just using internal AA NiMH batteries and never ran out of juice during a gig! I use 2500 MAh batteries. At home I plug the A/C adapter for infinite playing time. I would not risk ruining my instruments with home-made power packs with the wrong voltage. The FR-1 batteries are easy to remove and install, unlike the FR-3 that has 10 batteries kept into a separate holder.

Opinions are bound to vary on this, but for me, it's not the 5 hours that's the problem, rather the inconvenience of removal and replacement every time. I imagine Roland did it this way because they designed it ~15 years ago, when rechargeable tech was more rudimentary. They also will have had an eye on costs. If your mobile phone required you to do this every day, would you not think twice about it?
As for the risk if over-voltage, I accept that batteries are intrinsically safe - but what about the provided mains adaptor? That's a conventional switched-mode device with voltage controlled by Pulse Width Modulation. Is it inconceivable that this might over-voltage? Would you trust this more than a modern PD 3.0 device? Not sure I would !

 

[dak]

Opinions are bound to vary on this, but for me, it's not the 5 hours that's the problem, rather the inconvenience of removal and replacement every time. I imagine Roland did it this way because they designed it ~15 years ago, when rechargeable tech was more rudimentary. They also will have had an eye on costs. If your mobile phone required you to do this every day, would you not think twice about it?
As for the risk if over-voltage, I accept that batteries are intrinsically safe - but what about the provided mains adaptor? That's a conventional switched-mode device with voltage controlled by Pulse Width Modulation. Is it inconceivable that this might over-voltage? Would you trust this more than a modern PD 3.0 device? Not sure I would !

You are overlooking the elephant in the room. Liability. If Roland blows up some generic AA-batteries (and I commend them for using generic batteries here) while charging them through a V-accordion, they will be on the line for repairing/replacing the accordion. Then any kind of fast charging requires monitoring voltage and heat of the individual cells. Even timer-based dumb charging needs to get rid of all the heat it generates.

The most convenient tech are complete battery packs with cells that cannot be replaced by the user (and thus can be guaranteed to be in comparatively similar state), have temperature control and can be attached to an external fast charger. But then you lose the easy availability of AA batteries.

Liability also is the deciding factor between trusting a "conventional switched-mode device controlled by PWM" and included by Roland over a "modern PD 3.0 device" that costs probably about a buck (if at all) to produce and where you have nobody you can sue for the damage on your instrument if someone decided that heatsink specifications and power limits are overrated. By the way: the modern PD 3.0 device does not regulate voltage level by magic but by using conventional switched-mode regulation.

 

[Tafaner]

Hi Dak

Well, I did say that opinions on this are bound to vary! I could reply at length, but am concerned that we, as techies, risk boring eveyone stupid in what is supposed to be an accordion forum. Let me say above all, that I recognise all the points you make - but just evaluate them differently.

I can't resist a couple of points in detail though.

When I referred to "Modern PD 3.0" device, I should have stressed MODERN. An engineering friend of mine was recently commissioned to build a PS for a customer guitar amp, producing 24V at 2Kw ! He had all the knowledge and materials needed, but still spent weeks blowing up MOSFETs on a daily basis. These things are capricious, and worse still, tend to fail CLOSED-CIRCUIT, with consequences you can imagine. He got there in the end, but the point is that SMPSs have been in evolution for decades to combat problems like this. So I would instinctively prefer a MODERN design over a 15 year old one (even if over-voltaging is rare in reality). But you are obviously right that PD 3.0 sits on top of the same SMPS tech as the Roland one.

You talk about "battery packs", ie multiple cells connected in series and parallel (in some cases). We've all grown up with this idea, so tend to assume it's the only way to go. The attached screenshot shows where this leads to, further down the road. This is the status display from the battery pack I use to power my Ebike. It has 56 cells, 4 in parallel x 14 in series. To control things "properly", every cell has a safety fuse and the BMS (that produces this status through bluetooth) monitors the voltages of all 14 of the cell 4-packs and the overall temperature. To prevent imbalances worsening, when charging, it even redistributes the charge according to the needs of each cell pack ! Obviously the battery packs you are talking about are rather simpler, but my point is - why go down the multi-cell route at all, if capacity doesn't demand it ? Most small powerbanks, like the one I have chosen, use a SINGLE CELL. They turn this into the voltage you need using an invertor - similar technology to the SMPS we use to charge them (an oscillator, a mini-transformer, switching MOSFET and an optocoupler for the PWM). Why prefer a battery pack over a single cell ?

We disagree, clearly, but thanks for your comments anyway!

 

[Rosie C]

Opinions are bound to vary on this, but for me, it's not the 5 hours that's the problem, rather the inconvenience of removal and replacement every time. I imagine Roland did it this way because they designed it ~15 years ago, when rechargeable tech was more rudimentary. They also will have had an eye on costs. If your mobile phone required you to do this every day, would you not think twice about it?

I have an Orange busking amp which despite being relatively new, still uses AA rechargeables. Otherwise it's a great amp, but changing batteries takes a few minutes. If only it had a battery magazine, or built in rechargeable lithium cells. Presumably it's all about keeping the cost down. There is a "19v DC" input jack which is likely to be interfaced to an 18v lithium drill battery someday soon!