LiPo Starter Battery

[Levent Suberk]

Voltage can be adjusted to 1.5 Volts with that step down converter. It can handle up to 5 Amperes.

https://m.banggood.com/XL4015-5A-DC-DC-Step-Down-Adjustable-Power-Supply-Module-p-945599.html

Firstly I fixed the heatsink on IC with supplied double sided adhesive tape and soldered a suitable connector to board input for changing LiPo battery when necessary. I opened a hole on top of starter box and soldered the glow plug clip cables directly on board output. Bolts and nuts can also be used on box top for glow plug clip connection instead of this. I adjusted 7.4 Volts 1350 mAh LiPo battery output voltage to 1.5 Volts with trimpot. Board has been fixed on battery with hook and loop strips. Whole assembly easily fits in Cox battery box. Foam blocks can be placed in box for packing.

[extra slim]

Thats a really nice idea, I like it. Have been using one of these for a few years... very good... dial it down for Cox 1.5v and can turn it up for other glows slightly... Lipo glow lead

[Martin Harris - Moderator]

I liked it so much I just ordered one along with a digital volt/ammeter. I wonder how quickly it will arrive with everything going on at the moment...

[Martin Harris - Moderator]

...and the answer is that they arrived yesterday morning. Not bad with the 2 Cs - Christmas and Covid.

I've knocked up a case on my 3D printer and after a little messing about with the wiring while the printer was going about its business, got it working well.

The first problem was that the meter display wouldn't work but I realised that having set the output to @1.5v it was below the meter's minimum supply voltage. A 9v PP3 and small wiring modification to power the meter module cured that (and luckily squeezed in the carefully minimised casing) and all looked fine.

The next thing to test was a glowplug. No glow and the voltage display dropped to zero. Some calculations suggested the output current should be in the order of 2 - 4 Amps (difficult to measure the resistance accurately) so well within the 5A capability (and claimed 75W power rating).

Mine didn't come with any secondary heatsink so I wondered if it was significant but surely it would have needed a few seconds to overheat and shut down, so my thoughts turned to the supply voltage - perhaps the dropping circuit was trying to dissipate too much energy and some protection circuitry was cutting in?

I'd based it on an old 1300mAh 3S pack so I tried a 2S and bingo!

Edited By Martin Harris - Moderator on 31/12/2020 22:43:25

[Levent Suberk]

Good news Martin

[Brian Cooper]

I bought one of these earlier this year. . . I ran it on a 2s lipo, and it worked beautifully for the first ten seconds, and then died.

Useless piece of kit. . But at least the "money back guarantee" worked well.

Happy New Year, everyone.

[Martin Harris - Moderator]

For £2.27 it would have been rude not to give it a try! Still working after the 3S abuse but then they are rated to 38 volts on the input side so it's not a big surprise. The internal protection circuitry seems very effective so I'm a little surprised yours went bang.

Happy New Year.

Edited By Martin Harris - Moderator on 31/12/2020 21:55:54

[Roger Jones 3]

As a starter battery I just use a 2200 3S lipo taped to my Kavan starter. Works fine on my OS120 four stroke and my OS105 two stroke heli engine, which are the biggest engines I've got.

And a 'C' size NiMh cell (from B&Q) for the glow.

Simple, low cost, no electronics to go wrong, and no wires in front to get sucked into the propellor..

[FlyinFlynn]

Posted by Martin Harris - Moderator on 31/12/2020 20:29:57:

The first problem was that the meter display wouldn't work but I realised that having set the output to @1.5v it was below the meter's minimum supply voltage. A 9v PP3 and small wiring modification to power the meter module cured that (and luckily squeezed in the carefully minimised casing) and all looked fine.

Edited By Martin Harris - Moderator on 31/12/2020 22:43:25

I'm not sure I understand this Martin, these combined ammeter/voltmeter displays work down to ~4V so if you power it from the 2S LiPo that should work OK..all you have to do is separate the display power supply from the sense wire (which goes to the regulator output) and it should read the ~1.5V ok.

[Nigel R]

Snap, Roger.

I do still carry my glow panel as a backup to the Glow stick. I use the fuel pump lipo to drive it.

Best move was ditching the gel cell and replacing it with a couple of old 3s 2000 packs, one in the starter and the backup one on the fuel pump and plug driver. I can swap them over if the starter drains its pack.

[Roger Jones 3]

Posted by Nigel R on 01/01/2021 11:55:43:

Snap, Roger.

I do still carry my glow panel as a backup to the Glow stick. I use the fuel pump lipo to drive it.

Best move was ditching the gel cell and replacing it with a couple of old 3s 2000 packs, one in the starter and the backup one on the fuel pump and plug driver. I can swap them over if the starter drains its pack.

Yeah.

My view is "Why do it complicated when you can do it simple?"

I do have a problem with fuel pumps. I had a couple of those 12 volt 'orange with a cream front' pumps. They are sold as fuel pumps in model shops but are actually windscreen washer pumps and only last a few months when used with glow fuel. Now I have one of those hand cranked 'egg shaped' blue things but it leaks, resulting in fuel dripping off my elbow, I have taken it apart and failed to see why it leaks. If left overnight on the one gallon fuel container it also siphons the whole lot onto the shed floor.

These things are sent to try us

[Phil McCavity]

Would a genuine LG 18650 be a better and cheaper power source for this?

 

 

Edited By Phil McCavity on 01/01/2021 16:50:21

[Martin Harris - Moderator]

(a) probably - although pushing it a bit on the minimum voltage and (b) no cheaper than using an elderly LiPo from my collection!

My main motivation is avoiding the self discharge liability of my glow sticks.

Edited By Martin Harris - Moderator on 01/01/2021 16:39:16

[Levent Suberk]

Posted by Phil McCavity on 01/01/2021 16:29:10:

Would a genuine Panasonic 18650 be a better and cheaper power source for this?

Edited By Phil McCavity on 01/01/2021 16:32:19

Phil, of course any battery can be used, if battery voltage is in input range of circuit.

[Levent Suberk]

The power output of LiPo battery is steady throughout the discharge, but the power output of NiMH batteries starts to decrease after charging. Also amperage of NiMh battery instantly drops while using. So a LiPo battery has longer drive time and better performance for a good hot glow for glow plugs. Also LiPo batteries have an instant high current output.

Edited By Levent Suberk on 01/01/2021 16:39:53

[Levent Suberk]

Posted by Martin Harris - Moderator on 01/01/2021 16:36:09:

My main motivation is avoiding the self discharge liability of my glow sticks.

Martin, you are right about this self discharge, a negative side of NiMh batteries.

[Phil McCavity]

Thank you for the reply, I have no Lipo batteries new or used so I will need to purchase something other than NiMH.

[Martin Harris - Moderator]

Posted by FlyinFlynn on 01/01/2021 11:26:56:

Posted by Martin Harris - Moderator on 31/12/2020 20:29:57:

 

The first problem was that the meter display wouldn't work but I realised that having set the output to @1.5v it was below the meter's minimum supply voltage. A 9v PP3 and small wiring modification to power the meter module cured that (and luckily squeezed in the carefully minimised casing) and all looked fine.

 

Edited By Martin Harris - Moderator on 31/12/2020 22:43:25

 

I'm not sure I understand this Martin, these combined ammeter/voltmeter displays work down to ~4V so if you power it from the 2S LiPo that should work OK..all you have to do is separate the display power supply from the sense wire (which goes to the regulator output) and it should read the ~1.5V ok.

What I failed to mention in my earlier post was that I tried this arrangement (or what I thought was the same) very briefly - after seeing instantaneous smoke I disconnected the battery rather smartly and could see no sign of any component damage and it worked fine after wiring in the PP3. Maybe a bit of wire getting hot? Perhaps I made an error but I'm happy enough with the PP3 which will probably last until its shelf-life expiry as it should only be powering the meter circuitry for short periods.

Have you actually tried this yourself successfully or is this a diagram you've found somewhere? The information from Banggood was sketchy at most...

P.S. That's a slightly different unit - there are 2 pots on it whereas mine only has one.

 

Edited By Martin Harris - Moderator on 01/01/2021 16:58:42

[FlyinFlynn]

In the early days of these meters there were some about that could not utilise the same power supply as the one you were trying to measure, I thought they were long gone now though. I have used one of these meters in this configuration and it did measure down below 1v. Are you sure you didn't mix up the thicker and thinner wires?

It is just an image off the web....and there are plenty of other examples, all showing the same basic configuration, the thin red and black are power to the meter displays, above ~4V, the yellow is the voltage sense wire and the thicker red and black are delivering the output power to the meters internal shunt to measure the current.

The regulator shown will be voltage and current regulated - hence the extra pot.

If you are ok with a 9v then this is all superfluous.

[Martin Harris - Moderator]

Well, the PP3 finally died yesterday so I revisited this and yes, it will self-power so I must have made a wiring error in the depths of the casing when I tried it before. It's now rewired and running happily.