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· IMA Enthusiast
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Discussion Starter · #161 ·
So discharging using autostop and then charging by driving won’t do anything for the useable capacity or does it help a bit?

After re-reading this thread (since I have too much spare time due to a lockdown in the Netherlands), one thing was unclear to me. In the beginning of this thread, it was stated that disconnecting the 12V battery resets the IMA battery, if I am not mistaken. Does this (slightly) bump the useable capacity? If so, would it be smart to do this once a month for example and how does disconnecting the 12V bump the useable capacity?

Unfortunately, performing the (dis)charge cycle is not an option for me. My car is parked in the underground parking of the appartment building I live in. So I am looking for different/easy ways to bump the useable capacity that are easily done in an underground parking without power supplies. Do you have any recommendations, maybe one of the above two things (discharge via autostop or disconnecting 12V)?
Discharging using austop etc then drive charging will have minimal (possibly zero) effect on recovering battery capacity etc.

Sorry. You need to grid charge and discharge properly.

Disconnecting the 12v battery clears several systems, not just the IMA, and is not recommended repeatedly.
 

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The final voltage depends a little on the battery temperature, a hot Nimh battery will have a slightly lower temperature than a cold one.
Mine was at about 118V. I need to check the tap voltages to see how well balanced the pack is.

The cheap led power supplies don't come in less than 250ma or so constant current output.
CC (Constant current) is the important bit.
If you have a posh CC power supply that can deliver less current then cooling will be less of an issue, but balancing will take longer.

Whatever CC power supply you get it must also have sufficient voltage capability to charge the pack.
About 130V or so is fine for the Nimh CRZ.

When the pack is completely full the cells burn off the energy as heat.
That equates to about 36W of power with the supplies I used that has to be absorbed/dissipated in the confined battery space.
The little fan is the simple solution to stop heat buildup. Especially if the ambient temperature is higher than the chilly UK.
The final voltage depends a little on the battery temperature, a hot Nimh battery will have a slightly lower temperature than a cold one.
Mine was at about 118V. I need to check the tap voltages to see how well balanced the pack is.

The cheap led power supplies don't come in less than 250ma or so constant current output.
CC (Constant current) is the important bit.
If you have a posh CC power supply that can deliver less current then cooling will be less of an issue, but balancing will take longer.

Whatever CC power supply you get it must also have sufficient voltage capability to charge the pack.
About 130V or so is fine for the Nimh CRZ.

When the pack is completely full the cells burn off the energy as heat.
That equates to about 36W of power with the supplies I used that has to be absorbed/dissipated in the confined battery space.
The little fan is the simple solution to stop heat buildup. Especially if the ambient temperature is higher than the chilly UK.
I've moved my fan as you'd suggested Peter and started charging again today, now I can feel cool airflow from the exit vent. Temperatures sensors remain low 20s, although I keep feeling like I'm noticing a slight smoke smell. Might be placebo, will keep an eye on it.

A pic of my charging set up:
View attachment 63121
Please open your led driver, i wanna see circuit
.
 

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Lets only take the IMA apart once! (y)

Adding a power cable connector for future easy IMA battery access.


Notes.

Rubber gloves. (To be worn at all times.)


Switch the IMA battery off before installing.
Use a proper 150-200V rated connector with shrouded pins etc. I use the Sp13 series connectors.
Use decent double insulated cable and heat shrink the connections.
Switch the IMA battery off before plugging or unplugging the charger or discharging bulb.

SP13-2 2 pin waterproof connector Power Cable Connectors IP68 Plug Socket WH W2 | eBay

View attachment 62955
Great, this was exactly what I was ruminating about.
I may buy a nice CR-Z very soon, and doing sometime a plug-charge was an idea. Some users in a group reported me that the IMA motor tend to never fully recharge well the battery, in the normal use.

What about a faster charge option? Maybe after this Nimh rebalance process.
If I understood the IMA motor can send up to 75A, 100v energy to the battery, using the inverter.


:cool: I will can flex the CR-Z to the ZEV charging station, using a formerly owned Type 2 to Schuko adapter
 

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Don't get the wrong idea about this, the grid charge is a procedure intended to rejuvenate a tired IMA pack and is not for regular use. It will not make rhe CRZ a plug-in hybrid and the car is NOT compatible with any standard EV charging systems.
 

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Don't get the wrong idea about this, the grid charge is a procedure intended to rejuvenate a tired IMA pack and is not for regular use. It will not make rhe CRZ a plug-in hybrid and the car is NOT compatible with any standard EV charging systems.
Ok! Anyway the input is not more than a standard 220v electricity via Schuko standard.
It was an idea about doing some periodic full charge of the IMA battery.
 

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I may just be over thinking this.. no safety related question is a dumb question right??

Okay, so regarding the rubber gloves; would medical (standard blue type) nitrile gloves be sufficient protection or they must be specifically made of rubber material?

On Amazon, the rubber ones are mostly $30+ and look like dishwashing gloves on steroids also seems like overkill.

Other gloves don't seem to provide full hand protection and look to be made of some fabric material but with the anterior portions (the fingers and palm areas) dipped in rubber/nitrile(?) material and un-dipped posterior portions (back of hand and fingers) open.



A merch link would greatly help!

Thank you.
 

· IMA Enthusiast
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Discussion Starter · #176 · (Edited)
Yes it matters.

Charging first re-balances the pack and prevents any low cell/s being grossly over/reverse discharged

1) Charge first (to balance pack)
2) Then discharge (to reactivate dormant cell material)
3) Then charge again (to fill it up and balance again).

Repeat steps 2 & 3 for extra cycles if desired.
 

· IMA Enthusiast
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Discussion Starter · #178 · (Edited)
What about a faster charge option? Maybe after this Nimh rebalance process.
If I understood the IMA motor can send up to 75A, 100v energy to the battery, using the inverter.
:cool: I will can flex the CR-Z to the ZEV charging station, using a formerly owned Type 2 to Schuko adapter
This is an interesting and perfectly logical question.

Yes the car can recharge at fairly high power levels for short periods when running.
But getting the car (standard Nimh IMA battery) to accept power from a high power external source is extremely difficult to do safely and of very limited practical value.

1) The standard IMA battery contains a tiny amount of useable energy < less than 600wh. (A 60kw (60,000wh) charger could charge it from 20-80% Soc in <10 seconds!)
2) The car will not accept power from an external source when on without throwing multiple error codes unless you do some very clever/difficult electronic fooling.
3) Force charging the battery at very high power levels when the car is off would require accurate additional (expensive) cell voltage, temperature monitoring and fan control.
4) Fooling a high power public charge point into actually turning on and delivering controllable power at the right voltage/current to a non OEM setup would not be trivial. :eek:
5) After charging you would need to use an OBDIIC&C to set the car SOC to high 75% or the car would simply think the SOC was still at it's previous level.
6) You also need to arrive at the charger down at 20% Soc, but the car won't let you do that without more hacks.

Of course it's an interesting project idea and even more tricky with an inflammable Lithium car :unsure:
In practical terms though, the amount of energy you would gain, let's say ~0.5kwh (10 cents) is simply not worth the time/effort/expense to implement.
Unless of course you have the skills, are in lockdown, stuck at home and you like tinkering. (y)

Using a home 1-7kw option could be possible but again the $$$ return on investment and technical difficulty is very much negative!
In the UK a 3kw domestic charger could do 20-80% Soc (Roughly 4Ah) in about 10 minutes.
 

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To put things in perspective-
In the case of a full EV or plug-in hybrid which has a large battery pack that actually powers the car on its own, the charger is adding miles of range.
In the CRZ which is a mild/assist hybrid with a MUCH smaller pack, charging adds seconds of assist. Hence the onboard IMA system which dynamically charges the pack as needed, as we drive.
So it's a matter of scale where you'd have to go to an awful lot of trouble to use an EV charger on a CRZ with little to be gained.
 
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