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[Alex Atkin UK]

Don't get me wrong, I understand the merit of having a battery dedicated to the 12V electronics, I just don't understand why it wouldn't have a fail-safe to keep it charged from the HV battery.  Nobody is going to expect to get a flat battery when the car is plugged into the wall.

[tiffy]

Don't get me wrong, I understand the merit of having a battery dedicated to the 12V electronics, I just don't understand why it wouldn't have a fail-safe to keep it charged from the HV battery.  Nobody is going to expect to get a flat battery when the car is plugged into the wall.

I agree, while having a lot of respect for the very clever Toyota hybrid technology, they were after all pioneers and the principle of their system has been adopted by a lot of other manufacturers, surely it would be feasible to monitor the 12 V. battery voltage while the vehicle was not in use and apply a periodic boost charge from the HV battery via the converter (the normal charge route) to sustain the LV battery charge.
Considering the capacity of the HV battery bank and the relatively low capacity of the 12 V. battery due to no engine cranking capability being required from the LV battery, would have thought that this would have the capability of considerably extending the 12 V. battery charge well beyond it's current predicted operational state while the vehicle is not in use.
Obviously, the HV battery state would be monitored also and further charging of the LV battery disabled at a pre determined point to preserve it's life.

For anyone contemplating purchase of a smart battery charger suitable for hybrid 12 V. batteries, have just ordered this:
https://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/343092
It's on discounted offer at present with an estimated 12 day stocking delivery, best price I've seen for a new unit.   

[tiffy]

Perhaps becoming somewhat paranoid about the charge state of the 12 V. battery in my Toyota CH-R Hybrid, I found this battery monitor:
Bluetooth Battery Monitor
The unit manual is available here Documents for anyone wishing to browse the spec's..

Note, for anyone contemplating purchase, there are a number of different brandings and price variations for what certainly appears to be the same device, the link supplied was the best price listing and is branded "Quicklynks".

Played around with the unit on the bench using a variable voltage PSU and an accurate Fluke DMM, established that the current consumption was indeed marginally greater than 1 ma. and the voltage indication as displayed on the Android phone app. was surprisingly accurate, no greater than 0.02 V. variation to the Fluke DMM.
Simulated the "crank" and "charge" tests with the PSU, both worked fully to spec..
Obviously the "crank" test will be hypothetical on my hybrid as the 12 V. battery does not actually crank the engine.
The short term (5 mins.) and long term voltage recording appeared to be working fully to spec..

Fitted the unit on the car this morning, only took a few minutes, ty-wrapped module to battery handle.
Would have liked an in line fuse, not supplied, will probably add one later, just in case!

Started off monitoring with a short charge run, "ready" mode on a hybrid with engine quite quickly kicking in, normal charge voltage with "charging" indication displayed.
Normal charging continued after the engine stopped as would be expected via the DC-DC converter from the HV battery as long as vehicle "ready" mode was maintained.
On "switching off" vehicle, was surprised at the fairly rapid rate of discharge down to approx. 12.44 V. (deemed to be 80% charge).
Use of the "auxiliary" mode (commonly used to enable radio) considerably accelerated the battery decay rate.
2 hours after initial testing with vehicle stopped and locked, battery voltage has decayed to approx. 12.30 V. (deemed to be 65 to 70% charge).
I do have a dash cam fitted but the "shock sensor" is disabled so produces no battery drain when idle.


Bluetooth range is more or less to expectation, can't access the monitor from house with vehicle in normal location, adjacent detached, closed garage.
Access around and within the vehicle is adequate and to expectation.

Early days, but very impressed with the capabilities of the monitor and the associated phone app., hope to establish if my 12 V. battery is below spec. and produce evidence should this be the case which should help with any negotation for a warranty replacement if I feel I have to go down that route.


I now have my Noco GB40 Lithium Ion battery jump pack on hand and fully charged which I intend to keep in the car at all times just in case!

Edit: Typo correction.

[tiffy]

For any of the forum hybrid owners who may still be interested:

Have noted that the perceived 12v battery issue is not unique to hybrid's, have read on line of instances with full EV's having the same issue. 

Having now received the TechMate OptiMate 4 smart charger, have completed a charge/maintain cycle on my C-HR, 45 AH battery while still connected to vehicle, results monitored and recorded via BM-2 monitor/Android phone app., phone screen shots attached.
Car remained locked throughout the charging operation, only known residual battery drain is the alarm system.

Shot-1 shows start of charge @ 15:25 hrs. after a few previous short journeys.
Shot-2 shows designated max. charge voltage being achieved @ 18:31 hrs. and progression to "test after charge" routine.
Shot-3 shows completion of "test after charge" routine @ 05:09 hrs. and beginning of maintain routine.

The battery maintain cycle now carries on at 30 min. intervals with a voltage swing of approx. 12.8 to 13.3v.

In theory the battery has passed the charger test and been designated as healthy, charger removed.
Battery charge voltage now being monitored and recorded to establish if abilty to hold charge under no usage conditions is any better than previous.

Edit: Attachments re-sized/re-formatted.

[tiffy]

I would be interested in a review of the GB40.

Apologies, just remembering about your request for review.

Did receive the unit last week from Halfords deliver to store, much faster than predicted.
Very sturdy and robust unit, looks like it could well withstand quite a bit of physical abuse.
The supplied soft storage bag is "just that", certainly won't offer much protection or keep the bits and pieces together very well.
Ordered the dedicated hard storage case from Amazon @ £14.00, more impressive, everything fits nicely all be it with the unit up side down due to the port covers retaining mouldings, not a big issue and still deemed worth the money.

On receipt, the unit was well discharged, took close to 6 hours at full 2 amp USB charge to reach full state, would guess must have been lying on Halfords shelf for quite a while.
Still, no current reason to believe the Lithium Ion battery has been damaged, idle charge is holding without any issues.
Have only checked operation to date on mobile phone charging, no occasion to use in earnest as yet!

The GB40, 1000 Amp unit is very likely overkill for my proposed application on the hybrid, the GB20, 500 Amp unit would be more than adequate for a hybrid or full EV as neither require cranking capability from the 12v battery (nothing to crank on a full EV), however, with price difference being only £20 thought the GB40 unit would be more versatile for general usage on conventional cars should the need ever arise.

So, just insurance really should the car 12v battery go flat again, who knows if I will ever have to use in earnest?

[tiffy]

Have now completed 2 complete charge cycles on the 12v battery using the previously mentioned smart charger (while still in situ & connected), the second cycle completed in a much shorter time than the first, a few very short local runs occured between the 2 charge cycles.

Again, after a few short local runs the car has been parked up and locked in the garage for 2 days, voltage has held at approx. 12.44v (deemed to be approx. 80% charge) after the initial quite sharp drop post usage, this if definately an improvement in battery performance from post (smart) charging exercise.
Battery voltage is being logged and recorded with the Bluetooth monitor and associated Android phone app. mentioned earlier.

The 12v battery voltage does still drop quite quickly with any activity, door locks, electric mirrors, power steering hydraulic pump, auxiliary system activation for radio usage etc., probably to expectation with such a low capacity battery (45 AH).
Not been in a position as yet to carry out a longer term (car idle) test to positively establish just how long a healthy 12v battery would hold up for before entry & starting would be inhibited, will still be carrying my Lithium jumper pack on board as insurance.

As a bonus, have "cycled & refreshed" the 12v sealed lead acid batteries in my UPS and house alarm system with the smart charger (both while disconnected), have had to replace both previously after a relatively short life which I believe could be due to constant charging with very rare discharging, may help to extend life, both indicated healthy after charging & testing cycles were completed.