LiFePO4 Supplier

[Jerry Carducci]

I use the FrSky FAS100 ADV for current consumption, battery voltage and Ah used (via a LUA script).

----I just ordered one of those. Where does the script run? What events does it listen for or is it strictly on a timer?- I've used other languages but not LUA

You can also use the FLVS ADV to monitor up to 8 cells in a LiFePO4 battery, if you have access to the BMS balance entry point.

----That's the rub - getting access to that junction - I hate to crack open a case to solder a JST plug in...
Adrian.

[Paul Sparkes]

Just out of interest has anyone had any telemetry readings from a JT under different running conditions?
(A bit lighter than Chieftain? )

The most I have seen is 35amps on telemetry with the JT

[Gerhard Michel]

My heaviest tank is my King Tiger with Porsche turret at about 160 kgs. It consumes up to 65 amps (in combination with 250 watts of sound).

E.g. here is a 60 amps BMS. Its peak terminating current is 220 amps:

https://www.i-tecc.de/shop/bmspcm/bms-l ... a-24v?c=37

If this should furthermore be insufficient, you could use this one with 150 amps. Its peak terminating current is 500 amps. This should be enough even for a quarter scale model up to 500 kgs and more:

https://www.i-tecc.de/shop/bmspcm/bms-l ... a-24v?c=37

[John Clarke]

Hi Greg, sorry if the topic skews, it's an emotive subject that could be a very expensive investment that may not go as planned.
I'm not a tech boffin, but I do try to look at the facts I can understand. Listening experienced modellers is really important.

I understand it's a heavy model, I understand the model may run under different running conditions, which may or may not draw a lot of current.
If it stops for any reason. Not only is it a dead load, but a feeling of embarrassment as one trys to figure out what went wrong.

I have tried to workout what sort of tech Armortek has supplied with the Red boxes and based my needs on that.
I believe the main motors are protected by a twin 30 amp speed controller, which should shut down if continuous currents rise above 30amps on either drive, or more than 60amps combined.

And I'm not even adding the other current drawing elements that could be drawing anything up to 8- 10amps.

So with my very limited knowledge, If I was looking for a LIFePO4 battery it would be with the highest rated battery and BMS that fits.

If not, the battery could shut down way earlier before the main drive Red box system registers any problems if there were any in first place.
AGM's don't have a BMS and leaves the protection of the Model to the Red boxes.

I love the idea of LiFePO4 battery and its benefits, (off the shelf with BMS). But each time I look at the facts I just shy away.

[Jerry Carducci]

I've seen a few questions lately regarding batteries. As I've just finished testing out the setup for my KT electronics and radio system my
focus now turns to the battery selection. I've been using two 12 volt LiFePo4 packs that I've had for a while. These seem good to me except that
both packs have an internal BMS. I believe the BMS units are not ideal for using the 2 packs in series and as I recall the BMS units can cause a real problem when charging 2 packs in series; possibly causing out of balance conditions. Be kind!

My question is this. The two packs as 12 volt 30Ah and I'm considering taking them apart to re-use the individual cells to make one 24 volt pack
at which time I may or may not decide to use a new BMS to watch over the combined pack. I read that several of you have made your own packs
from new cell but has anyone disassembled a back to reuse the cells to make a different, combined 24 volt pack?

I also recall reading that some of you avoid BMS units altogether relying on telemetry to monitor voltage. In that case I want to ask are you only monitoring overall pack voltage or are you watching individual cells as well as with a LiPo pack?

I've got these packs so they're here to stay but I'm questioning their long term utility as they are.

Thoughts?

Jerry

[Adrian Harris]

I'm using two 12V 40Ah packs made from 32700 LiFePO4 cells with no problems during running or charging. They charge from the same points as main power lines, so as long as your chargers have floating outputs (such as NoCo or Ctek) then there's no issue with the batteries being in series.

You can use a FrSky telemetry unit to monitor the individual "cells" within the pack. Take care though, as there are different models, some are floating some are not, so check the specs!

Each of my battery packs is 4S6P, to give the storage and current capacity. I've not broken one of these packs down, but it would be possible to change it to an 8S3P configuration, giving twice the voltage but half the storage and current capacity. These 32700 cells are rated at 3C continuous discharge current, so that's 54A continuous and 108A peak from a 24V pack.

Adrian.

[Jerry Carducci]

I'm using two 12V 40Ah packs made from 32700 LiFePO4 cells with no problems during running or charging. They charge from the same points as main power lines, so as long as your chargers have floating outputs (such as NoCo or Ctek) then there's no issue with the batteries being in series.

You can use a FrSky telemetry unit to monitor the individual "cells" within the pack. Take care though, as there are different models, some are floating some are not, so check the specs!

Each of my battery packs is 4S6P, to give the storage and current capacity. I've not broken one of these packs down, but it would be possible to change it to an 8S3P configuration, giving twice the voltage but half the storage and current capacity. These 32700 cells are rated at 3C continuous discharge current, so that's 54A continuous and 108A peak from a 24V pack.

Adrian.

Thanks Adrian. I ended up removing the BMS units in my two packs and I'll give them a go that way. The balance connector is still there but the plug is somewhat larger and therefore not compatible with either the FrSky LiPo charger nor the balance connector of my chargers. To reverse the operation and re-install the BMS units would not be very difficult should I determine this was a bad idea. I've ordered one of the other FrSky in-line voltage/current sensors. The previous one I had was a bit overkill at 150A.I would have liked to monitor all individual cells however that will take a bit more work.

I've also ordered some 50Ah cells to experiment with; to make up my own pack with.

I believe my charger is up to the task. I have an iCharger 4010 Duo and a Meanwell RSP-2000-48 power supply to drive it. At the normal 120v line it can deliver 48volts at 31A and if I want to run it at 220v it can deliver 48v at 42A for the charger.

Jerry

[Gerhard Michel]

Hi Jerry,

I also use the iCharger 4010 Duo with best results. The charging limit of 40 A per channel is enough for most applications; only my 280 Ah backup battery uses the combined supply of the 2 channels.

[Gian Marco Menozzi]

hi Jerry,
I don't use the bms on my PZIII,
I rely on telemetry,
unfortunately the Flysky radio only has voltage detection,
on a Panther G turret yes, because I don't have telemetry.
I have 2 4s 22 Ah life po4 batteries connected in series,
I made the connection for the balanced charge,
I use an Icharge X8 as a charger, I find it excellent,
I have 2 other chargers that I use on batteries with lower capacity (Ah).
I don't know what kind of connectors/plugs your batteries have,
but you can either make an adapter or replace the plugs,
being very careful.
if Flysky is going to do single cell and current draw telemetry I will definitely buy and mount it.
Marco
P.s.
I do not use BMS and I am aware of the risks and benefits of not using them,
if you are inexperienced,
I recommend using BMS.

[Gerhard Michel]

I'm using my good old Graupner / JR equipment from model flight (R/C, sensor Electric Air). Up to 14 LiFe cells, 150 amps, consumed battery capacity since starting, temperature values, free choice of alert values; e.g. low voltage and so on.