[Aviator18]

Hello,

I am currently pulling my 1st Gen Insight's transmission to replace the input shaft bearing. Since I'm still in school and very busy with work and applications, the car will be sitting in my garage for the better part of a month. The IMA system is currently disabled and I'm worried about the battery's health during storage. Is there anything I need to do, or will the battery be ok sitting idle? I would rather not have to purchase a new battery as this one has been treating me well and I'd rather not spend money unnecessarily.

Thanks

 

[retepsnikrep]

Get, beg, borrow or build a grid charger and charge the IMA for 24hrs just before you put it back on the road.

If you want to recover some capacity and perhaps improve the pack as well get a 60w bulb and do some battery cycling while the car is off road.

Time it so your pack fiddling ends at the expected date of the cars return to use.

 

[insightbuyer]

I believe with the NIMH sticks, if you let the pack just self discharge, the sticks will get close to 0 volts but it isn't that detrimental to the sticks. I once bought sticks that were fully self discharged near 0 volts and they tested almost as good as new sticks in both self discharge over time and capacity.

 

[retepsnikrep]

I believe with the NIMH sticks, if you let the pack just self discharge, the sticks will get close to 0 volts but it isn't that detrimental to the sticks. I once bought sticks that were fully self discharged near 0 volts and they tested almost as good as new sticks in both self discharge over time and capacity.

Allowing sticks to self discharge to zero volts is fine, but that will not happen to them all in one month.
The OP's 4/6 weeks of down time is very bad for imbalance in a pack.

 

[insightbuyer]

Will letting the car sit for a month really drop the voltage down anywhere near zero? A month is a very short period of time. I actually thought he was going to let it sit for a year or more.

I would think a month is not a big deal at all.

 

[retepsnikrep]

I would think a month is not a big deal at all.

Unfortunately that is wrong.

It's not about them dropping to zero volts which takes a very long time.

It's about 120 cells self discharging to 120 different SOC levels in a month.

One might discharge to 50% SOC one 75%, one 80%, twenty to 45% etc etc etc.

 

[eq1]

It would have been best to drain the pack by driving and using a lot of assist before the layover. But it sounds like that ship has sailed. Might be good to do some kind of very slow, gentle discharge while the car's sitting, then grid charge before driving.

 

[insightbuyer]

This is why I decided to convert to lithium Ion because you can't win with NiMH. Its a nightmare dealing with these issues, and it gets worse if you try and replace some sticks with unmatched sticks.

 

[Jonny69]

Best thing you can do is give it a good long saturation grid charge before you use it again, to make sure everything is fully charged. As Peter said, if you can use the time while it’s off the road it’s a good time to run a few charge/discharge cycles as it’ll also improve the performance of the battery.

Basically, what it won’t like is if you just flick the switch and start it up, because some of the cells will be out of balance. The grid charge will make sure they’re all fully charged before you start. Cycling it will restore some capacity that has been lost over the lifetime of the battery due to memory effect.

 

[Aviator18]

Luckily the previous owner of the car installed a grid charger and gave me everything I need to charge, discharge. I'll try to do a few cycles before the first start. Thank you for the help!

 

[Aviator18]

I'll be sure to research charging/discharging first as I don't want to mess anything up.

 

[Aviator18]

Allowing sticks to self discharge to zero volts is fine, but that will not happen to them all in one month.
The OP's 4/6 weeks of down time is very bad for imbalance in a pack.

Update: I'm finally almost finished with the work. School and work have gotten in the way and held me up for quite a while. The car has been sitting for almost 3 months now, will the sticks have had enough time to self discharge to where I only need a single grid charge before going on my merry way? Should I do a few grid charge/discharge cycles? I've been planning on doing three charge/discharge cycles over the weekend after connecting everything up top this afternoon, but I want to run it by people who know what they're doing first. Also, can the battery pack be switched off while grid charging, or do I have to flip the "circuit breaker" on?

 

[Balto]

Update: I'm finally almost finished with the work. School and work have gotten in the way and held me up for quite a while. The car has been sitting for almost 3 months now, will the sticks have had enough time to self discharge to where I only need a single grid charge before going on my merry way? Should I do a few grid charge/discharge cycles? I've been planning on doing three charge/discharge cycles over the weekend after connecting everything up top this afternoon, but I want to run it by people who know what they're doing first. Also, can the battery pack be switched off while grid charging, or do I have to flip the "circuit breaker" on?

I would highly recommend at least one discharge/charge cycle.

 

[eq1]

The car has been sitting for almost 3 months now, will the sticks have had enough time to self discharge to where I only need a single grid charge before going on my merry way?

You may be misunderstanding the purpose of the 'grid charge b4 driving' thing. Whether your sticks have had 'enough time to self discharge' or not isn't the main concern or question. The main concern is that the cells probably have uneven self discharge, so sitting for extended period, like a month to 3 months like yours has, likely results in charge-imbalanced cells. The grid charge before driving is supposed to balance the amount that the cells are charged.

If during your layover, one cell totally self discharged (not uncommon) while most of the rest only self discharged say 10%, you'll run into problems, the pack won't work well, much, for very long, etc.

I guess a or the secondary concern is the palliative impact that a full discharge can have on the...performance/chemistry of the cells. That's something you'd have to achieve purposefully - as in, unless your pack sat for a year, probably more, you could never be sure that all the cells were fully discharged. The rate of self discharge in old, used cells can be highly variable. You just never know how long it could take for all of them to self discharge completely... So, you generally have to do a manual discharge on your own.

Should I do a few grid charge/discharge cycles? I've been planning on doing three charge/discharge cycles over the weekend after connecting everything up top this afternoon, but I want to run it by people who know what they're doing first. Also, can the battery pack be switched off while grid charging, or do I have to flip the "circuit breaker" on?

Pack switch needs to be ON to charge and discharge... In lieu of not doing other, better but more complicated and time consuming alternatives, probably best to do a full grid charge, followed by some kind of discharge/charge regime.

 

[olrowdy01]

Update: I'm finally almost finished with the work. School and work have gotten in the way and held me up for quite a while. The car has been sitting for almost 3 months now, will the sticks have had enough time to self discharge to where I only need a single grid charge before going on my merry way?

Not likely.

Should I do a few grid charge/discharge cycles?

Yes. This is a good time to make sure the battery is balanced and made as good as you can get it to be.

I've been planning on doing three charge/discharge cycles over the weekend after connecting everything up top this afternoon, but I want to run it by people who know what they're doing first. Also, can the battery pack be switched off while grid charging, or do I have to flip the "circuit breaker" on?

The battery switch has to be ON or the battery can't be charged or discharged. When the switch is OFF it disconnects the series connected cells.

It will take 4 or 5 days to do 3 charge/discharge cycles. The charge cycles alone can take 24 to 35 hours -each-. Make sure the first charge cycle gets the battery full. At 86° F the battery voltage will be ~174 volts. Warm ambient temperatures raise the voltage, low temperatures will lower the battery voltage.

You can get more info about this by going to my website and reading the V2 charger article. Click on the CRX area below this post to get to my website.

 

[Aviator18]

I understand the whole unbalance of the cells thing, although I certainly have a lot to learn regarding the IMA system. I'll do a few charge cycles before getting back out on the road. I can't wait to drive my Insight again, I miss it. olrowdy0, I'll be sure to check out your website. Thank you all for your input! This forum has been a huge help.