Thread: lithium dual battery ideas

Not once anywhere have I said or shown it going 15v or over. Near, briefly, for a spike but never at or over and never for more than an instant. As an “automotive electrician with 40 years of experience” you should know what a voltage spike is and what can cause it. You interpret it how you want mate. You’ve show your true colours. I just wish I’d known your after sales support consisted of “the problem is with you and your car” before wasting the money.

Originally Posted by Macadamia

Not once anywhere have I said or shown it going 15v or over. Near, briefly, for a spike but never at or over and never for more than an instant. As an “automotive electrician with 40 years of experience” you should know what a voltage spike is and what can cause it. You interpret it how you want mate. You’ve show your true colours. I just wish I’d known your after sales support consisted of “the problem is with you and your car” before wasting the money.

You did not have a voltage spike.

A voltage spike will be of less than a second duration, and as such, any such spikes would be immediately absorbed by your cranking battery.

All alternators continually generate spikes of up to 60v, but they never get into the system because your cranking battery acts as a massive capacitor and suppresses these SPIKES.

You had a voltage SURGE, where your alternator raised the voltage to over 15.1v for more that 15 seconds and this caused your Traxide isolator to shutdown.

Your BM2 shows that on at least one occasion, when the voltage was sampled, it was at 14.93v.

But your BM2 only takes a sample once every 2 minutes, so we have no idea just how much higher the alternator voltage actually went, but as the USI-160 shutdown at that point, as according to your own post, so the alternators voltage had to be over 15.1v for at least 15 seconds to cause the USI-160 to shutdown. Thats a SURGE not a spike.

Facts are facts and these are the facts you posted up.

Maca, you have it in your head there is nothing wrong with your vehicle, so be it but the facts state otherwise.

Maca - a few questions for you to make sure you are getting the most out of your current setup (which should also help if you add a lithium battery to give you more storage capacity - keep an eye on what Tombie is up to in the “What happened to your D3/D4” thread as he just replaced two auxiliary batteries with a single ITECH120X lithium battery).

How is your solar panel charge controller connected to your batteries and have your checked it is all working correctly?

In the graphs you posted the only time I see your solar panel charging was when you isolated the auxiliary battery.

A faulty solar controller, or a failed diode on the solar panel could also cause problems and be draining the battery.

And is your dash-cam left permanently on? You mentioned the dash-cam draws 0.4A.

If the dash-cam is alway left on, then between the normal parasitic drain, the USI-160 (if not isolated), and the dash-cam you could be draining close to 0.8A - which over 24hrs is around 19Ah being consumed.

For comparison - this is the typical drain on my cranking battery overnight (D3 not D4) and daily recharge via 80W of solar panels that I see. I fully isolate the USI-160 when the engine is not running, which disconnects the auxiliary battery.



Not shown, but the auxiliary battery drops about 0.05v per week when isolated (with nothing connected to it other than the BM2 monitor).

Originally Posted by DiscoDB

How is your solar panel charge controller connected to your batteries and have your checked it is all working correctly?

In the graphs you posted the only time I see your solar panel charging was when you isolated the auxiliary battery.

A faulty solar controller, or a failed diode on the solar panel could also cause problems and be draining the battery.

It's connected to a renogy MPPT solar controller connected directly to the aux battery. unfortunately where I park my car gets absolutely no sun from about june to october (thanks Melbourne!). I actually disconnected it a couple of weeks ago concerned that it might be a small parasitic drain but it hasn't made a difference.

And is your dash-cam left permanently on? You mentioned the dash-cam draws 0.4A.

If the dash-cam is alway left on, then between the normal parasitic drain, the USI-160 (if not isolated), and the dash-cam you could be draining close to 0.8A - which over 24hrs is around 19Ah being consumed.

yes permanently on. the 0.4a is measured at the 70a fuse when the only things connected/on are the dash cam and AGB25. I'll log a few days with the battery shared and isolated and see if it makes a difference.

The next step I would be taking is to start disconnecting anything that has been added and revert back to the original set up - i.e. cranking battery only with nothing else added.

So no solar, no dash-cam left on, no Aux battery, and no USI-160 (disconnect the earth cable to power it down fully).

Then you will be able to confirm the alternator and cranking battery is all behaving as expected (watch for at least 3-4 days). At the same time see how the auxiliary battery holds voltage with no load on it over the same period.

Only then start adding extra’s one by one and monitor again for a few days each time you add one extra item back.

Personally - I think between the normal parasitic drain, the USI-160, and dash-cam you are already using up a large portion of your AUX battery storage capacity so everything needs to be in a good health just to handle this base load. And the 100W solar should be more than enough to cater for all of this.

Yes a lithium battery will give you more useable storage capacity, but I would want to confirm you don’t have another problem first (or at least better understand what true load you need to cater for).

By the way - I am also in Melbourne and my 80W solar set up performs perfectly fine over winter but where I park it gets full sun during the day. I probably only see 1 or 2 days a month it won’t recharge the battery fully.

Any USB ports etc in the vehicle?

Those and Dash cams are hard on batteries, it’s quite surprising.

And wouldn’t be the first time the HVT-70D has needed to be replaced whilst still under warranty.

Would be good to do a test on it to see how much capacity it has lost.

Tombie - what made you go with the ITECH120X?

I’ve read mixed reviews on the iTech products and their warranty policy where they reserve the right to deny any claim if they determine the battery was at end of life (even within the warranty period).