Solar System 2-Battery System - trickle engine battery?

[Dellmassive]

The manufacturers quote it has a current range of 0-2A. That implies a current limiting circuit.

Or are they just saying that they have a 7.5 ohm resistor so a a 15.6V leisure battery (worse case) to a 0V completely flat start battery (worse case) would result in 2A flow.

That would however result in 30W of heat that would need dissipating and a large 30W resistor. Something doesn't stack up between the hardware and the spec. You can make other assumptions about max and min voltages of course but there must be something more to limit current to 2A in that case.

Like to see the inside of one of these........

I haven't got one myself . . . . . but straight away i though something was up as there was no ground connection or 0v reference....?

so how could the circuit/charger work if it had no ground or 0v connection . . . . . it cant (unless it was just a passive pass through device)

so i done some digging and saw this review on Amazon . . . which confirmed my suspicion that it is just a passive pass-through device. (just a diode and a couple of current limiting resistors)

and yes me to, i would like to see one cut open . . . . . but i bet they have used potting compound to hide the contents?




https://www.amazon.co.uk/Votronic-b...2a+12v+dc+to+dc+battery&qid=1572188952&sr=8-3


John Smith
1.0 out of 5 starsMisleading
30 December 2018
Verified Purchase
Do not buy this device. Inside the plastic box is a single small diode and two resistors. This is not a charger in the normal sense of the word, simply a current limiting resistor and a diode to prevent reverse current flow when two batteries are connected together. It is absurdly overpriced.

 

[Dellmassive]

Someone has to crack one of these open . . . . . . . . .

@andys are you up for the challenge?

looks like 4x screws on the back, and the other guy must have got into it to say it only had 3x components....

i think he may be right, but am always happy to be proved wrong. =]

looks like through hole components on a PCB maybe?

 

[Dilbert]

but straight away i though something was up as there was no ground connection or 0v reference

You can current limit with active circuitry to a predetermined value with no reference to ground but this needs a minimum of around 4V potential different between the source and load. This obviously won't work in this scenario so, as you say, it has to be passive.

I am thinking the 2A is rather ambitious.

 

[Dellmassive]

lets see if @andys is up for opening his up to see the guts . . . . . =]

and some component values . . .

 

[andys]

Someone has to crack one of these open . . . . . . . . .

@andys are you up for the challenge?

looks like 4x screws on the back, and the other guy must have got into it to say it only had 3x components....

i think he may be right, but am always happy to be proved wrong. =]

looks like through hole components on a PCB maybe?





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No. Not when I’m obviously sitting on an asset that has appreciated by 50% in a year

I have actually seen it pass 2A on the Victron app

 

[andys]

I’ll open it up next time I have the seat out for any reason.

 

[Scylla]

Found a grommet ... under drivers seat.... happy now

 

[Ads_Essex]

Found a grommet ... under drivers seat.... happy now

This one?


A bit late now, but on taking that same route, I clipped my EHU cable in to empty pipe retainers (that supported the fuel lines between filter and tank). Worked a treat.

 

[Scylla]

This one?
View attachment 53503

A bit late now, but on taking that same route, I clipped my EHU cable in to empty pipe retainers (that supported the fuel lines between filter and tank). Worked a treat.

Yep that's the one

 

[Phil_G]

...on taking that same route, I clipped my EHU cable in to empty pipe retainers (that supported the fuel lines between filter and tank). Worked a treat.

I need to do the same thing for my lads T5, anyone know if theres a similar convenient grommet please?
(Cant check the T5, its not here)
Ta
Phil

 

[Ads_Essex]

I need to do the same thing for my lads T5, anyone know if theres a similar convenient grommet please?
(Cant check the T5, its not here)
Ta
Phil

There’s a grommet underneath each seat, and then there’s the grommet in the firewall between the glovebox and the battery tray (assuming that’s what you’re talking about)

 

[Scylla]

Yep I just used the grommet under passenger seat...and then ran the cable under the rubber mat to drivers seat ( via one of the channels) to the battery... then going forward to the engine battery on the t6 undid two screws holding the plastic under tray and fed the cable forward then up into the engine bay...

 

[travelvolts]

I’ll open it up next time I have the seat out for any reason.

I'm expecting a pukka one from Ablemail any time now.

 

[Dilbert]

I’ll open it up next time I have the seat out for any reason.

Anyone been inside one of the Votronic standby chargers yet?

I'm expecting a pukka one from Ablemail any time now.

Any news on this device?

Cheers.