UV-26 or Viper...

[gianaameri]

I have received a number of PMs asking the same questions... so I post the answers here.

The N19s I have both have "6S" LiPo batteries.

This is not the Viper version or upgrade.

The Viper has "7S" batteries and due to the higher voltage requires a voltage regulator which I did not want because I wanted to keep my scooters as simple as possible (certainly no software and processor and board in my scooters, if possible).

The trim is very good. I enclose a picture (click here http://www.rebreathermallorca.com/video/n19trim.jpg ) of the scooter in a salt water pool (it is neutral about 1/2 meter below the surface). For reference, the salt in the pool is a lot less than that in the sea (it is only to produce chlorine from salt).

[billyf]

I have received a number of PMs asking the same questions... so I post the answers here.

The N19s I have both have "6S" LiPo batteries.

This is not the Viper version or upgrade.

The Viper has "7S" batteries and due to the higher voltage requires a voltage regulator which I did not want because I wanted to keep my scooters as simple as possible (certainly no software and processor and board in my scooters, if possible).

The trim is very good. I enclose a picture (click here http://www.rebreathermallorca.com/video/n19trim.jpg ) of the scooter in a salt water pool (it is neutral about 1/2 meter below the surface). For reference, the salt in the pool is a lot less than that in the sea (it is only to produce chlorine from salt).

so you have a 22.2v pack for your 24v N19?

and a 25.9v pack for your 24v viper?

NO Battery Management System on either pack?????

how long have you been running these packs?

how do you determine when to stop burning the packs or stop charging them?

[gianaameri]

so you have a 22.2v pack for your 24v N19?

and a 25.9v pack for your 24v viper?

NO Battery Management System on either pack?????

how long have you been running these packs?

how do you determine when to stop burning the packs or stop charging them?

I do not have a Viper.

I have 2 N19s with 6S Li-po battery and the battery burn-time I use for reference is in post 22 on this thread.

One I park somewhere in the cave for spare when I do not tow it, and the other I run for 2 hrs. max. on each dive.

Then swap them around the next day. The primary after recharging becomes the backup, and the backup the primary.

[a64pilot]

I think maybe his point is that without a way of cell balancing and discontinuing the charge, your LIPO's will very likely catch fire and or have a short life expectancy. You almost certainly have a battery management system somewhere, possibly in the charger, if it's there, you will have a large plug with several wires that connect to the battery for charging, if only two wires, it's in the battery, and its electronic. There just really isn't much of any way of running a large LIPO battery without electronics

[billyf]

I think maybe his point is that without a way of cell balancing and discontinuing the charge, your LIPO's will very likely catch fire and or have a short life expectancy. You almost certainly have a battery management system somewhere, possibly in the charger, if it's there, you will have a large plug with several wires that connect to the battery for charging, if only two wires, it's in the battery, and its electronic. There just really isn't much of any way of running a large LIPO battery without electronics

well you can but if you plug in a charger without a BMS and walk a way and forget, you might come home to a pile of ashes.
you can search the forums and see lots of home builders that wound up with a fire.

I shorted a 18650 trying to solder it, hat to run out of the house with a flaming ball of fire!

after that I never soldered another battery, I built a CD welder.

also burning a Li pack below 2 volts will damage the cells and shorten the life cycle.

this past weekend one of the packs I built had an issue while on a dive.
a design flaw caused a short between the PCM (battery management system) and the motor.
the PCM burned out but protected the Cells and motor.

I figured out the design flaw and it was a simple over site on my part on just this pack, I ordered a new $45 part and will have the pack back up and running.

without the PCM both the pack and motor would have been toast.

[gianaameri]

As far as I know, the battery pack has no balancer. None of the LiPo packs by SS do. This means the individual cells (6 of them) are connected in a series and they are charged with two wires as a pack (not individually).

As a single cell deteriorates, not having a balancer circuit, that single cell will be the weak link and could cause a number of potential problems (theoretical ones). Practically, the pack performance will be reduced due to that single cell weakness/failure.

These packs do have a low voltage cut-off device (I believe). I do not know if the same circuit also provides overvoltage protection (it probably does).

Best person to answer these questions is SS.

The charger regulates the charging process. Personally, I charge the 30 amp pack with a 1 amp charger, outside the garage, away from any other combustible material, and in the shade. So, I charge very slowly. I think most of the fires problems (and short battery life) with LiPos are caused by the pack overheating during charging (or by high discharge rates).

A pack with a balancer for charging each cell individually would be definitely better though. I do not know of many/any scooters that do have one though.

[gianaameri]

As far as I know, the battery pack has no balancer. None of the LiPo packs by SS do. This means the individual cells (6 of them) are connected in a series and they are charged with two wires as a pack (not individually).

As a single cell deteriorates, not having a balancer circuit, that single cell will be the weak link and could cause a number of potential problems (theoretical ones). Practically, the pack performance will be reduced due to that single cell weakness/failure.

These packs do have a low voltage cut-off device (I believe). I do not know if the same circuit also provides overvoltage protection (it probably does).

Best person to answer these questions is SS.

The charger regulates the charging process. Personally, I charge the 30 amp pack with a 1 amp charger, outside the garage, away from any other combustible material, and in the shade. So, I charge very slowly. I think most of the fires problems (and short battery life) with LiPos are caused by the pack overheating during charging (or by high discharge rates).

A pack with a balancer for charging each cell individually would be definitely better though. I do not know of many/any scooters that do have one though.

The balancer could be inside the SS pack though. It is something I never discussed with SS, but it could be they put it inside the pack as a matter of course. It is something I'd definitely like to have in a LiPo pack as part of the charging process.

What I do not like which I was referring to in my earlier post is the output voltage regulator (a.k.a. Electronic Speed Control). As simple connection as possible between battery and motor is what I prefer.

Less to go wrong.

[gianaameri]

As far as I know, the battery pack has no balancer. None of the LiPo packs by SS do. This means the individual cells (6 of them) are connected in a series and they are charged with two wires as a pack (not individually).

As a single cell deteriorates, not having a balancer circuit, that single cell will be the weak link and could cause a number of potential problems (theoretical ones). Practically, the pack performance will be reduced due to that single cell weakness/failure.

These packs do have a low voltage cut-off device (I believe). I do not know if the same circuit also provides overvoltage protection (it probably does).

Best person to answer these questions is SS.

The charger regulates the charging process. Personally, I charge the 30 amp pack with a 1 amp charger, outside the garage, away from any other combustible material, and in the shade. So, I charge very slowly. I think most of the fires problems (and short battery life) with LiPos are caused by the pack overheating during charging (or by high discharge rates).

A pack with a balancer for charging each cell individually would be definitely better though. I do not know of many/any scooters that do have one though.

The balancer could be inside the SS pack though. It is something I never discussed with SS, but it could be they put it inside the pack as a matter of course. It is something I'd definitely like to have in a LiPo pack as part of the charging process.

What I do not like which I was referring to in my earlier post is the output voltage regulator (a.k.a. Electronic Speed Control). As simple connection as possible between battery and motor is what I prefer.

Less to go wrong.

...looking inside the battery pack box with difficulty and a mirror through a perspex transparent panel I can see something which could be a balancer board and 6 white wires in addition to the standard red and black wire.

It may be the balancer board for the charging of each of the individual 6 cells is inside the pack - which is good news!

I have asked confirmation from the supplier that there is a balancer inside.

[gianaameri]

...looking inside the battery pack box with difficulty and a mirror through a perspex transparent panel I can see something which could be a balancer board and 6 white wires in addition to the standard red and black wire.

It may be the balancer board for the charging of each of the individual 6 cells is inside the pack - which is good news!

I have asked confirmation from the supplier that there is a balancer inside.

So, there is an internal charging control/management board.

It takes care of overvoltage, undervoltage and has a basic balancer which operates provided the batteries are in close tolerance one with the other, plus it provides a host of other safety features to prevent fire/damage.

You can see in minute 3 of the following video my N19s in action:

http://www.youtube.com/watch?v=nfJRQ...1&feature=plcp

Patrick is using one, and I (the nutcase with 3 torches each side of the white helmet), use the other.