Enginer kit proper break-in charging cycles

[rickw]

Originally Posted by ias513

Here's my 2 cents.

I have been running a 2kw system since mid Aug on a Gen I Prius.

I often run about a total 10 mile commute to work and back. I was plugging in every night. I am getting the feeling that maybe I should have only plugged in when my Enginer pack's cell voltages became a bit lower.

Although I did not record it, I think I was often recharging when the cells were a bit on the higher end of their range. (I seem to remember often seeing 3.2 and 3.3 readings.)

I have also been seeing the weak cell problem. When I get all my cells in good shape again from Jack, I'm going to try to charge them more on a milage basis that will not discharge them too deep, but at least allow them to discharged a bit more into their cycling range.

I'm just winging a number here for now, but I'm thinking once I see a cell drop down to around 3.000 V or lower, then I'll recharge.

I'm basing this on my kit and also helping a couple of other's with theirs.

In general, I think the cells are very sensitive to overcharging.

Anybody have an opinion on this?

Hello
I have the 4kw in a gen I prius charging batteries is a pain the problem is its a smart charger but it does not know the individual cell voltage but the total voltage of all cells combined. The balancer is suppose to keep the cell voltages equal. Thats why they start beeping near the end of charging to let you know a cell is over 3.7 volts above that is a bad thing for that cell. Ive been trying to improve the balance of charge by letting the batteries discharge until the red light comes on turn the unit off for 10 minutes let the balancer do its thing than turn the switch back on til the light comes on and repeat process. That way all cells end up equally discharged and should charge at a more even rate. I also am also using a timer to charge 2 minutes off 58 minutes to give the balancer time to equalize voltage. The first hour or 2 should be ok to constantly charge them. High cell voltage is going to shorten life of the battery.
You want to keep the lowestcells above 2.8v and the highest below 3.7v

[donalmilligan089]

I would like to know how concerned one needs to be when one reads of all the charging,balancing and all that goes with getting the enginer off to a proper start. There seems to be a lot of discussion about these things

[dan2l]

Originally Posted by donalmilligan089

I would like to know how concerned one needs to be when one reads of all the charging,balancing and all that goes with getting the enginer off to a proper start. There seems to be a lot of discussion about these things

Hi donalmilligan089,
Right now, I would say that the operator needs to stay within audile range of the balancers, 100% of the time, while charging. and then need to be sure to turnoff the charger if an allarm sounds. The rest of the discussion are important for knowing what is going on, but should not nessisarily need to be checked all the time. Having said this, I will remain vigalent for many charge cycles.

This is a quick answer. I hope it is to your point.

Thanks,
Dan

[Fibb222]

Originally Posted by dan2l

Hi donalmilligan089,
Right now, I would say that the operator needs to stay within audile range of the balancers, 100% of the time, while charging. and then need to be sure to turnoff the charger if an allarm sounds. The rest of the discussion are important for knowing what is going on, but should not nessisarily need to be checked all the time. Having said this, I will remain vigalent for many charge cycles.

This is a quick answer. I hope it is to your point.

Thanks,
Dan

This is correct. The charger can easily overcharge the cells. I think 1.5 hours on a count down might be more manageable, if you don't mind not fully charging your kit.

Also, let the cells balanced completely (d<0.010) after the kit is spent, before charging.

[minnesota_plugin!]

I just purchased a 6 KWH kit and am getting it installed next week. I am up north and its 0 degrees out now, and -10 at night and my garage is not attached, so a freezer with a car in it. I cannot stay out in the garage with my car for six hours every night, so i am buying a baby monitor so i can monitor my little baby balancers and tend to them when they cry, i mean beep

[adric22]

I'm going to be installing the kit into a Gen-1 Prius in a week or two (whenever the darned thing arrives) But I just have to wonder if there isn't a better solution. For example, a way to allow the battery balancer to turn off the charger in the event of a cell nearing a state of overcharge? Or maybe using shunts on each cell instead?

[Daox]

Unfortunately, unless you build something yourself, the kit is the way the kit is.

[minnesota_plugin!]

So, does my baby monitor idea sound like a solution? Does anyone else have any other ideas about how to monitor the balancers without freezing or even if it was summer, staying in my garage every night...Any other ideas anybody? Even if it involves buying a smaller charger or something....?

[ericbecky]

minnesota_plugin!,
I had the very same idea. I haven't implemented it, but it sounded cheap, fast, and would get the job done.
There are a few other ideas floating out there, like
- getting a less aggressive charger
- putting it on a multi-increment timer (charge a while, rest a while)
- using two sets of chargers, one for fast charging within your known safety zone and then switching to a trickle charger to top things off.

[dan2l]

Hello everyone,
Fisrt we need to do Buddy Cells. This does the most to save cells from extremes in curent flow and high or low voltages.

Second Enginer has turned down the Charger from 58v to57v. For my system this worked the first time with no allarms. I was close(90mv) but no allarm and the charger did shut down. I did get 2.5kwhr ito the batteries in 4 hours of charging.

I caution against cycling the charger. When I turned my charger back on with fully charged batteries I got 13amps going into batteries that should have been only taking a trickle. I do not know how fast the charger will cut back in the second charging cycle.

Next Jack is still working on a fix for this. Long term I think he is geting a 16 cell balancer with higher curent flows to be quicker at balancing. He knows that he needs to have this balancer shut down the charger. He is also woeking on a short term fix but I am not sure what that is.

In the mean time, The DB8 balancers we have now do have charger shutdown cappability. It is limited to 36v10a. So this will not work with todays charger. I plan to work on replacing the charger I have now with a pair of 30v10a chargers. I have not purchased parts yet, but I think powersupplies like this should be easy to get.



This is a wireing diagram that I think will work to have the Balancer stop the charging using 2 smaller chargers. Note that it does have Buddy cells.

I will get to this at some time in the future. But if one of you gets a chance to make this work sooner Please let us know how it goes.

Thanks,
Dan