Leisure battery drain issue

[smithm11]

So I recently done a DIY install on my transit using a renogy 100ah lithium batt and 40a dc/dc charger. this is connected to my heated seat (comes on with ignition). It charges the battery fine and have no issues with that. I bought the popular switch on ebay for around £20. it shows the batt level on a little small LED screen. I then have this connected to lights and a USB. I am trying to get my head around why after around 4-6 days of no driving, the battery goes completely dead, even though there has been nothing on apart from the tiny little LED reader. I have attached how I have wired it up. before anyone asks, there is fuses between all the major connections, just couldn't be bothered putting them in drawing. Battery when full reads 12.6v
Any suggestions would be much appreciated!

 

[Guigsy]

I assume you've charged up, pulled the fuse on various circuits and confirmed that the battery doesn't discharge?

Also, battery voltage is not a good way to measure charge level for lithium batteries. Their charge-voltage curve is almost flat, so voltage level can be very misleading. Does the battery have a BMS with an app?

 

[smithm11]

I assume you've charged up, pulled the fuse on various circuits and confirmed that the battery doesn't discharge?

Also, battery voltage is not a good way to measure charge level for lithium batteries. Their charge-voltage curve is almost flat, so voltage level can be very misleading. Does the battery have a BMS with an app?

I dont have BMS. I have a voltmeter, but not really sure what setting to use. everything just says 12.65v or nothing. I'm assuming this is an amp measurement I need to try and find?

 

[Guigsy]

Your lithium battery does have a BMS, but it might not have an app to tell you what's going on.

The best way to measure battery charge is with a shunt. It measures current (amps) in and out of the battery over time to add up how much energy you've used. It'll also tell you what the draw is at any time. Many people use a Victron Smartshunt. There are much cheaper alternatives on Amazon that'll still be fairly accurate, just make sure they measure current both charge and discharge current.

 

[ivorantony]

Is it actually dead? Or just showing that on the voltmeter,

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[smithm11]

Is it actually dead? Or just showing that on the voltmeter,

well the reader is off and no lights come on, i'm assuming that means its dead...

 

[smithm11]

Your lithium battery does have a BMS, but it might not have an app to tell you what's going on.

The best way to measure battery charge is with a shunt. It measures current (amps) in and out of the battery over time to add up how much energy you've used. It'll also tell you what the draw is at any time. Many people use a Victron Smartshunt. There are much cheaper alternatives on Amazon that'll still be fairly accurate, just make sure they measure current both charge and discharge current.

is there no way to do it witha voltmeter?

 

[Tombola]

reads 12.6v when full...?
no, should be 13.6 or more, are you sure its getting a good full charge

 

[Guigsy]

is there no way to do it witha voltmeter?

Unlike a traditional lead acid battery, where the voltage drops off with charge level, lithium chemistry means it's pretty constant except when it's 95% full, or pretty much dead.

reads 12.6v when full...?
no, should be 13.6 or more, are you sure its getting a good full charge

Yeah. 100Ah is a fair amount. What are you charging it with? 12.6v (measured at the battery) is pretty low.

 

[Kannon Fodda]

As Tombola which battery are you actually monitoring? The engine battery lead acid type would be 12.6V when charged. Lithium leisure will be 13.6V.

Is your DC charger set correctly so it's only running when engine running?

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[steve69]

A surprisingly common problem.
I have never got to the bottom of my battery drain. I ended up installing an extra battery isolating switch that I activate at the end of each trip.

 

[Tombola]

reads 12.6v when full...?
no, should be 13.6 or more, are you sure its getting a good full charge

oh and dont be fooled, by the led thing permanent you'd be surprised...and whats happening with the heated seat?? is that a cuplrit somewhere maybe
first things first, get it a full charge with a proper 3 stage charger

 

[Guigsy]

A surprisingly common problem.
I have never got to the bottom of my battery drain. I ended up installing an extra battery isolating switch that I activate at the end of each trip.

I've got a pretty hefty parasitic battery drain. But a 100Ah battery should still last more then a few days. It'd suggest something is continuously pulling about 10 watts or a couple of amps. Which is a lot when everything should be off.

 

[StillGoing]

Can you post a link to the switch you’re using.

 

[smithm11]

Unlike a traditional lead acid battery, where the voltage drops off with charge level, lithium chemistry means it's pretty constant except when it's 95% full, or pretty much dead.

Yeah. 100Ah is a fair amount. What are you charging it with? 12.6v (measured at the battery) is pretty low.

i am charging it with this

12V 40A DC to DC Battery Charger

The 40A 12V DC to DC charger charges the 12v dc battery by 3-stage charging. The DC to DC battery charger prevents over-discharge and protect the generator.

uk.renogy.com

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[smithm11]

Can you post a link to the switch you’re using.

5 Gang 12V LED Light Switch Control Panel Camper Van RV Voltmeter 2 USB Charger | eBay

5 Gang 12V/24V Inline Fuse Box LED Switch Panel Dual USB Car Boat Truck Camperâ¨. 15A Inline Fuse Box Holder. Rear with 15A fuse protection function. Easy to replace, protect panel from over-heating, over-currents, over charging and short circuit.

www.ebay.co.uk

 

[Guigsy]

i am charging it with this

12V 40A DC to DC Battery Charger

The 40A 12V DC to DC charger charges the 12v dc battery by 3-stage charging. The DC to DC battery charger prevents over-discharge and protect the generator.

uk.renogy.com

You'd need to drive around for about 3 hours to get the battery fully charged. Have you got a mains charger?

 

[stevewagner]

i am charging it with this

12V 40A DC to DC Battery Charger

The 40A 12V DC to DC charger charges the 12v dc battery by 3-stage charging. The DC to DC battery charger prevents over-discharge and protect the generator.

uk.renogy.com

Are you sure it’s working. I had. Renogy dc to dc charger which failed. After a lot of faffing around they eventually changed it. Two weeks later that failed.

 

[oldiesontour]

Charge your battery fully by mains or engine.
Switch everything off, disconnect a battery lead and then flash it on and off battery terminal preferably in a poorly lit place and look /listen for a spark this will give a good indication of a parasitic drain in the absence of an amp meter.Dont put a lot of faith in the led voltmeter they are not that accurate I had 2 that differed by as much as .5 volts

 

[Tombola]

You are going to run out of free posts soon if not already..it's worth subscribing.
You need to get or borrow a good mains charger and fill her up..

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[pappajohn]

Your pic shows ignition switch.... Is that the D+ connection or just a switched live?

 

[autorouter]

To find out if there is a parasitic drain on the battery, you need something that measures amps. The easiest way to measure amps is with a DC clamp meter. It clips around the wire and measures the amps by sensing the magnetic field that all current flow generates.

The alternative method of measuring amps involves disconnecting a wire connecting so that the amps flows through the meter. This is usually a pain to do for many different wires, and also tends to disturb the devices that are disconnected and you may have to wait for them to settle down again. A clamp meter avoids all that faff.

Unfortunately many (most) clamp meters won't measure DC amps, they usually only measure AC amps. Even when the ad says 'AC/DC Clamp Meter' you usually find in the small print it measures AC and DC Volts, but only AC Amps. So if you are buying a DC clamp meter you need to be careful.

I have a Uni-T UT210E, which measures DC amps up to 100A, and has a low 2A range useful for tracing small drain currents. It's a good meter, that also has sockets for probes to measure Volts, Resistance and Continuity, and is the one I always keep in the motorhome. The only thing I don't like about it is, when you first turn it on to amps, it goes into AC amps mode, and you have to press the blue button to change to DC amps. But that's a very minor niggle.

If you're buying one, be sure to get the E model, The A, B and C models only do AC amps. The D model does DC amps, but doesn't have the low 2A range that's useful for tracing parasitic drains.

UNI-T UT210E Handheld RMS AC/DC Mini Digital Clamp Meter Resistance Capacitan ⊕I | eBay

Capacitance (F). Jaw opening. AC current (A). DC current (A). Resistance (Ω). VFC, low pass filter. Auto power off, low battery indication. 39.3mm x 26.5mm.

www.ebay.co.uk