Volto -- anyone try one of these out?

[RobA]

Has anyone tried one of this? What did you think?
http://www.pedaltrain.com/products/power/volto.php

[Govmnt_Lacky]

With 2A of output current.... why did they limit it to only 2 9V outputs? 

[RobA]

It looks like it daisy chains like the one spots. One of the constraints would be the amp-hour rating, which I don't see them specifying in any of the docs. They say something like 5 pedals for 36 hours. So, assuming about 20mA per pedal, that'll be around 3600mAh, which seems pretty reasonable for the size -- could be more too if I've underestimated the per pedal current they're implying.

[jkokura]

I want to, but I've read way too many issues they've had, and the release was delayed so often. I believe there is either design or quality control issues.

Jacob

[Mich P]

Do it yourself !
http://mike-bland.com/2013/01/11/rechargeable-9v-power-supply.html#rechargeable-9v-fire-it-up
Mich P.

[jkokura]

Mich, I'm super stoked right now. I think I'm going to be building one or two of those.

What I love most about it is that you can actually replace the 9V batteries out of it when they're done and worn out. I know that it will take a while, but I can't fathom buying a Volto for $100 knowing that the technology will wear out after X recharge cyclees.

Jacob

[RobA]

I want to, but I've read way too many issues they've had, and the release was delayed so often. I believe there is either design or quality control issues.

Jacob

Hmm, that's good to know. I was wondering why it had been announced almost a year ago but I hadn't seen it anywhere.

...
What I love most about it is that you can actually replace the 9V batteries out of it when they're done and worn out. I know that it will take a while, but I can't fathom buying a Volto for $100 knowing that the technology will wear out after X recharge cyclees.

Jacob

The recharge cycles on the Li-ion or Li-Po batteries should be much better than the NiMH. We use the NiMH rechargeables in my son's insulin pump controller. They do work, but it only takes a couple of charge cycles before you have to charge them twice just to get them back to about 3/4's full. They then drop to about 50% chargable level after a couple of months. At $20 for the eight you need to build a 9V pack, I think that you are going to end up spending more on them than you would on Volto.

On the good side, you wouldn't have any clock issues since you can get 9V right off the pack.

I've been working on an idea that is kind of a mix of the two. You can get 2-10Ah USB battery packs now for around 10 to 20 bucks (US) that are Li-Po based. I've been playing with some isolated boost circuits that would easily get 9V to 15V outputs (more if needed really) out of them. That way, you could do the replaceable battery with the advantages of using the Li-Po packs.   

[derevaun]

I've built a couple datasheet circuits for SLA chargers. I'm thinking that a 12v  SLA will feed a 9v regulator with plenty of available current (in fact, some fuse protection will probably be needed). An 11v battery for hobby/RC vehicles might work as well (dunno how noisy an LDR is), and they tend to be smaller/flatter. There are also nifty gas gauge ICs for batteries.

[pickdropper]

I want to, but I've read way too many issues they've had, and the release was delayed so often. I believe there is either design or quality control issues.

Jacob

Hmm, that's good to know. I was wondering why it had been announced almost a year ago but I hadn't seen it anywhere.

...
What I love most about it is that you can actually replace the 9V batteries out of it when they're done and worn out. I know that it will take a while, but I can't fathom buying a Volto for $100 knowing that the technology will wear out after X recharge cyclees.

Jacob

The recharge cycles on the Li-ion or Li-Po batteries should be much better than the NiMH. We use the NiMH rechargeables in my son's insulin pump controller. They do work, but it only takes a couple of charge cycles before you have to charge them twice just to get them back to about 3/4's full. They then drop to about 50% chargable level after a couple of months. At $20 for the eight you need to build a 9V pack, I think that you are going to end up spending more on them than you would on Volto.

On the good side, you wouldn't have any clock issues since you can get 9V right off the pack.

I've been working on an idea that is kind of a mix of the two. You can get 2-10Ah USB battery packs now for around 10 to 20 bucks (US) that are Li-Po based. I've been playing with some isolated boost circuits that would easily get 9V to 15V outputs (more if needed really) out of them. That way, you could do the replaceable battery with the advantages of using the Li-Po packs.   

That sounds like a much better plan to me.  Li-Po batteries aren't without their problems, but their upside is still better than NiMH.  For most Li-Po batteries, you should get 500-1000 charge cycles before they deteriorate (depending on life and storage conditions of course).

I have dealt with some Li-Po vendors.  We could do a group buy if we can get enough people to consume 8k batteries.  :-)

[jkokura]

One real benefit to the Volto product is the recharging - no need to disassemble and use a seperate battery charging unit - you can just plug it into a standard adapter and charge it up. Any hope of including a similar idea with the DIY version?

Jacob

[pickdropper]

One real benefit to the Volto product is the recharging - no need to disassemble and use a seperate battery charging unit - you can just plug it into a standard adapter and charge it up. Any hope of including a similar idea with the DIY version?

Jacob

I don't see any reason why not.  You just need to put in the appropriate charging circuit for the batteries used.

[derevaun]

A DIY version could easily include a charger on board. They're designed to be left in circuit, but it's probably best to disconnect the DC source when powering pedals, because the charger will try to share the load and its switching frequency might be audible--especially with other switching DC devices.

[RobA]

Yeah, it's pretty easy to include an onboard charger. This is the little IC I've been using to prototype with, http://ww1.microchip.com/downloads/en/DeviceDoc/20001984F.pdf

I've been using the Li-Po packs that Sparkfun and Adafruit carry. They are pretty cheap and include the control circuits to protect from over draining the battery and such. When looking for the batteries one of the things to watch out for is that the RC vehicle packs don't seen to have these. From what I've read, this is by design because it's more important to the users to have all the available current than it is to protect the battery. I don't think that's going to be the case with us.

The main thing I have left to do is to select a working boost circuit. I've played with a few, but I'm not really happy with them yet because none of them are isolated. I've got a few more IC's on order from Mouser that I should be able to test out pretty soon. But, at this point, I don't know if any of them will do the job well.

[derevaun]

That's good to know--I'd assumed the RC car batteries had that feature.

I've been using a BQ2031 lead acid charger chip from TI, to charge a 12v battery, which is run into a standard 7809 regulator. The battery is kind of bulky, and it will dump a lot of current into a short, so some polarity protection schemes are better than others.  The circuit for the chip is pretty elaborate, especially compared to simply trickle charging with a LM317.

I have a sample BQ2054 chip for Li-Ion/LiPo batteries that I haven't fiddled with yet. It seems promising--it's designed for more than one cell, and it's in a through hole package. But also a busy datasheet circuit.

[RobA]

I was surprised by the lack of protection circuit on the RC packs too. But, it does align with what I've seen at Sparkfun for the RC vehicle packs. I think the discussion I saw was on the Adafruit site. The reasoning was that the risk of damage to the battery pack was worth the additional protection for not having an RC plane fall out of the air. Makes, sense to me .

Thanks for the link to the BQ2054. I will check that one out too.