Clarity failed to start...

I cannot restate the generically useless information I already presented better than your summation @MrFixit. I am sure that Kentucky would agree that you can beat a horse to death, or "technically beat it to death" and either way it is still dead. I just could not resist the urge (ADHD/OCD) to input info regarding likely the most critical part of any battery maintenance, and that is temperature.

Here is the overriding best guidance I can give for any lead acid based battery system, keep it at 13-13.4 volts (which amazingly, you will note, is the approximate float voltage Honda chose to hold the 12 volt battery at while the HV battery is charging, although it is held at ~14 volts while the car is "on"). You will "rarely" harm any 12 volt lead acid battery at that voltage, regardless of design, and will certainly protect it from deterioration of self discharge and sulfation. This is against my fanatical attention to detail philosophy but will work for 90+%.

So yes, that means any regulated DC power supply capably of provinding at least the reserve capacity divided by 10 (C/10) current at 13 or so volts (more than 12.8, but less than 13.8) will suffice just fine for all the ambient temperatures we humans find reasonably endurable.

I will now bring the shovel, if you kind sir will help me clean up the raw glue material we have left in our wake!

Cheers,

Cash

 

Can't let the horse die so easily, now that you got so numerical on me.

I just went out to the garage and measured the voltage on the tractor battery (has been on a Deltran Battery Tender Plus for at least a month 24/7). Voltage is 13.18, Temperature in garage ~45 degrees.

Now, I can sleep again ?!

 

If the $300 tool was purchased to extend the life of a single $50 battery, that wouldn't make sense. However, the tool will last longer than the first battery. If the $300 tool doubled the life of a $50 battery, then it would pay for itself in 6 batteries, while reducing the number of batteries needing to be removed, carried, purchased, carried, installed, carried, and recycled. Are the Clarity's 12V batteries really just $50?

 

True, but who here with a Clarity drives it so infrequently that this kind of maintenance is necessary, or even beneficial?

 

Has anyone been removing their 12v battery for charging on a tender (in the house)?

(Covid19 problems)

 

Instead of having to go through the hassle is disconnecting the battery, I bought a very inexpensive quick disconnect (<$5). Then if I’m gone or not driving for extended periods, it’s easy peasy plug n play for the battery tender. It’s polarized and even has a nice cap on the end to keep it clean and not short anything out. Just Search eBay or Amazon.

 

@JustAnotherPoorDriver No I don't, still drive occasionally and it is charged anytime you are driving or charging the HV. It is also under very little load passively/parasitic. Removing it for any period of time will cause your car's systems to reset. This ranges from annoying to full on PITA. You will get the dash Christmas tree for several systems until you drive at low speed for a 20-30 seconds (TPMS, ACC/LKAS, and a few others are inop until you do). Your radio will disable but should re-enable with the power button hold to reset (if it doesn't you have to enter a code which unless you got from your dealer when you bought it, you have to go online or call to get). Although very very unlikely you "can" trigger imobilizer issues IF you have MIL/DTC problems you were unaware of before the battery was pulled. Stickware found that out the hard way (surprised a lot of us). The big issue "could be" if you are due any inspections. Especially with the low amount of driving. If you pull the battery all your environmental monitors will reset. You would have to drive it for a while in varying conditions and trigger the ICE a bit for the sensors to become valid so you can pass an emissions test (OBDII). May not be a deal, but worth knowing.

If your car is outside then I get the desire to take the battery in. However if in a garage, a small trickle charger would be fine. A word of sales caution, do not by a desulfator system unless you are willing to remove the battery. Regardless of what they may try to sell you, pulse frequency desulfators (which have some value) will not work on a battery "in-system" it has to be OCV.

Cheers,

Cash

 

Unfortunately, it's in a commercial garage where I have no access to power

 

@JustAnotherPoorDriver

That does change things, sorry forgot about where you are. If you will not be turning it on for over 3-4 weeks than yes, I would agree about removing the battery for charging. However, another option would be to just disconnect it if it is charged (after a drive or HV charge cycle). Again, it is a pain with all loss of system data and warnings I mentioned above (and inspection issues) I recommend at least disconnecting the negative off the battery, only if you are serious about 3-4 weeks of non-use. The battery "should" be fine, as long as you drive it and charge the HV at least once (for an hour) every 7-14 days. You should charge your HV pack to at least 60 percent, charge the 12 volt and then either remove it or disconnect it. Use a small towel or trash bag to wrap around the negative lead so it doesn't bump into anything. Those heavy wires tend to migrate back to where they normally sit (the battery post). Short of that and really better would be to install a battery disconnect. However considering the covid situation, your location (NYC) and everything else it may not be an option right now.

Another option is to do the PDI in reverse for the fuses. @KentuckyKen has shown repeatedly how valuable that little document is. You can remove the fuses and at least reduce parasitic drain a little bit as Honda did.

Best wishes,

Cash

 

FWIW: See post #31 of this thread.

The Clarity is currently starting it’s 6th week of abandonment, as we departed the rental house we keep in a Covid hotspot for work purposes, when work shut down. We took the other car to our residence in an undisclosed secure location.

When unnecessary travel is permitted, we may make the drive and swap vehicles. With all this excess fuel, it’s the least we can do to help out. If the battery is dead, I’ll use the Lithium jump pack.

 

I need to correct my earlier post about desulfation devices. There are good ones, and they are more expensive than regular battery tenders that just trickle charge the battery - and will work while connected. It is just less efficient, and there are a lot of caveats on them, so you have to read the manual to get the benefit. Another member messaged me to let me know he checked his (same brand I use) in circuit, and it is working well (checked with an oscilloscope). So, although my general recommendation for desulfation (generally flooded cell batteries only) with it open circuit, is still valid, it is not a restriction specifically. However, the best thing is to prevent battery aging/sulfation in the first place. Which any voltage source that holds the battery around 13.3 volts will do.

@Landshark has good experience on this. The assumption is the battery was fully charged before you stored it. If you made only short trips and short charges that may not be the case. However, you should be good for at least the month or two based on his experience. If not, as I have mentioned before, you need very little current to actually "jump start" a Clarity as it doesn't need to start an ICE, just close some large relays. Best wishes and good luck!

Cheers,

Cash

 

Mine has been in storage since our first snow storm in late October and remains there now since I am working from home and otherwise not driving anywhere due to state "stay at home" order. So it will have been sitting with a battery maintainer on the 12V battery continuously for going on 6 months by the time our state reopens. (Governor has already extended the statewide stay at home order until after Memorial Day.) I'll let you all know what happens when it finally comes out of storage.

 

If you are able to drive to the commercial garage, you can charge the 12V battery by simply “starting” the car. The HV battery will slap the paddles on it to the tune of ~14.6V. A half hour of this once a month would be more than adequate.

Now if someone would calculate how many times a fully charged HV battery could charge the 12V battery, our heads might explode.

In the mean time this is the perfect opportunity to pad the pockets of Mr Bezos and order one of those Lithium jump packs.

 

I put it in "on" (not accessory) mode for 1+ hours last week. Still black on the battery, not blue.

 

You have a few options.

1. Ignore and resign yourself to a dead battery...Buy a portable jump starter, jump it and drive it when the time comes, or have it towed to dealer or shop or auto parts store and just have it replaced when you’re ready to drive it again. Basically replace battery at that time, sitting this long in a low/discharged state without a proper charge is absolutely damaging the battery.

2. Take your battery out of the car, carry it into your home, put it in a proper charger and charge it fully. Ideally it’s done utilizing a smarter charger that measures health of the battery also, so you know whether you’re charging a battery worth saving or if you are charging a brick of useless junk that’s going to fail anyway.

3. It sounds as though the battery is weak, but still has the car able to fire up on its own as is. If so, just go for a LONG drive! Despite rumors, driving is NOT illegal and people are not getting pulled over for just driving safely and following laws. So get that car out of the garage and run it for like a 200+ mile road trip...I mean seriously drive it, use HV and/or HV charge mode the entire time so you stil come home with 60% in the traction battery. Wastefully burn thru a tank of gas. Get out of the city, go out to the country and see something different. Marvel at spring flowers and nature. Dedicate 4 to 6 hours and just go drive around to nowhere. This will be the healthiest thing you can do for the car, it will allow hours for the battery to recharge, and I suspect you’ll enjoy it too and come home feeling refreshed given the current situation. Obviously stay away from humans you don't live with. Pack some snacks, or hit a drive-thru fast food joint if you're feeling safe to do so (all drive-thru fast food restaurants are still open most places), burn thru a whole tank of gas, refill it before returning home, and wipe the pump handle down/wash your hands and take all measures as needed to stay safe. Consider bathroom stops from a COVID safety standpoint. Don't out drive your bladder, or be willing to pull over and pee on a tree in a rural forest somewhere. Not sure I'd be willing to venture into a public bathroom right now...but everyone is different. New York is a stunningly beautiful state. Get out of the city and go look at it, for the health of both you and your car.

Can you tell I'm lobbying for #3 above? There are probably other things you can do, but I'm so excited about #3 for you, I'd just choose that. Be well.

 

Did you happen to measure the voltage before you started? Or while the car was on?

Ideally you’d want to wait about an hour after charging to get an accurate resting voltage.

We must have different batteries as mine will apparently throw up a white flag when charging is required and a red flag when water must be added to the “maintenance free” battery.

 

The blue indicator can look black in color in some lighting. This is especially so when a flashlight is shined directly into the indicator. One test of the 12V battery SOC is to put the vehicle in accessory mode (two pushes of the on button without pressing the brake pedal). If the 12V battery is low, the red battery warning icon will show on the upper left of the driver's dash display.

LeoP

 

@leop - Are you sure about this?
I think the red battery icon is ON whenever you are in accessory mode. I just looked at mine (I'm sure my battery is fine) and both the red battery icon and the check-engine are illuminated. I think this just amounts to a lamp check, and does not indicate a low battery condition.

 

It means the 12V system is "not" charging and there is a discharge on the battery. It is a "charging" system indication only. It is triggered anytime current is flowing out of the 12volt battery with the vehicle systems on (second press of the power button for ACC level "2"). It will also illuminate as a MIL/DTC response if you are driving and the DC-DC converter fails or shuts off and your car is running on reserve 12 volt power out of the battery.

Manual pages attached. You can also hack in cool 12v battery monitoring things like this (one in vehicle ON, one in vehicle accessory while plugged in charging).

Cheers,

Cash

 

Yes, the dash battery indicator light does show if the 12V battery is not charging. I assume that this determination is made by measuring the 12V battery voltage. I make this assumption because "for my Clarity" the red indicator light sometimes turns off when the engine icon turns off in accessory mode. I say sometimes because if I have the head lights on or the 12V battery is not fully charged, the red battery light stays on. In accessory mode with the headlights off, I measure a 14A load on the 12V battery. This is reasonable given the computer and electronics in the Clarity. Even if the light red indicator light turns off initially, if I leave the vehicle in the accessory mode, the red battery indicator light turns on again within minutes. Measuring the voltage leads me to the belief that the set voltage for the red battery indicator light is about 12.5V volts.

For about a minute or so after I turn off the accessory mode, there is still a 5A discharge from the 12V battery as the electronics seem to be powering down slowly. I have not yet looked at the 12V battery discharge after turning off from the drive mode.

Can I assume that the 12V battery voltage shown on Cash's center display is a feature of Honda Hack?

LeoP