Battery Charging - 16 hour "special charge mode"?

rdalemercer · Post by **rdalemercer** » October 27th, 2007, 9:47 am

OK. I just received my 570 last night and eargerly opened the box and put Rooma on the docking station to charge after pulling the battery "tab" - resisting the temptation to let it clean. The manual (<-- I'll type a separate post on that one) states that "When charging for the first time .... Roomba will initiate a special 16 hour charge cycle" .... this is indicated on the Roomba with an Amber "flashing" lamp on Roomba.

My experience is not in keeping with the manual: I put Roomba on charge after pulling the tab and the Amber light "pulsed" signifying a normal charging cycle. Approximately 2 hours later the Green Fully Charged light turned on and seemed to be waiting for me to place it into servitude.

I resisted and have waited the suggested 16 hours before using Roomba. Was this necessary? Is Roomba "pre-charged" from the factory thus negating the need to charge Roomba for the inititating 16 hours? ... and if that is the case, then why doesn't the manual state as much?

Hmmmmm.....

Post by **Fraggboy** » October 27th, 2007, 11:39 am

Even though the clean button turned green after a few hours, the battery receives a trickle charge, which is needed to condition your new battery for a long life. Your battery will last longer cause you performed the 16 hour charge.

rdalemercer · Post by **rdalemercer** » October 27th, 2007, 1:19 pm

Thanks FraggBoy. I have a follow-up comment / question...
I just finished running the 570 for the first time and it did NOT make it back to the charging station.
Area 1 is the living/dining room: it took 50 minutes to complete it before the LH let it into the kitchen (area 2).
Area 2 is the kitchen: it ran for 45 minutes before it stopped and played it's "I'm out of battery" song. At 35 minutes it started flashing the "dock" light and was searching for the charging station, but as it approached the LH, it could not go past it back into Area 1.
I have removed and re-installed the batteries in the LH.....
Anything else that I need to do?

ovev · Post by **ovev** » October 27th, 2007, 2:00 pm

Did you start it from the home base or at least from the same zone as the home base is located in?
It seems that this is neeeded in order for the lighthouses to be able to guide the roomba back to its home base.

fancyfreewv · Post by **fancyfreewv** » October 27th, 2007, 2:05 pm

It will take a week or two of charging cycles to fully get it up to maxium. Then it should have no trouble making it back. My 550 took about 10 days and now runs for 2 hours.

rdalemercer · Post by **rdalemercer** » October 27th, 2007, 2:09 pm

OVEV,
Yes, it started from "area 1" which is where the home base is located.

It's charging now, so I'll have to wait to try it again, but hopefully resetting the LH worked.

How do I reset Roomba? <--- is there a "tips and tricks" section that I missed?

vic7767 · Post by **vic7767** » October 27th, 2007, 4:59 pm

You can reset you Roomba by holding down the Spot and Dock buttons at the same time for about 15 seconds. When you release them the Roomba should play a reset tune.

ovev · Post by **ovev** » October 27th, 2007, 6:43 pm

Please also check this topic 550 - lighthouse stops Roomba from docking

The 550 and 570 are basicly the same roombas so they should behave in the same manner

rdalemercer · Post by **rdalemercer** » October 27th, 2007, 10:36 pm

Thanks ovev.
I had seen that post and read it - but it always helps to re-read them and pick up new insights that had been missed the first time through.

I guess I will need to play with the location of the LH and the base to make sure that they are placed correctly in relation to each other. That is a point that I was wanting to investigate - and that is: Does it matter "where" the base/home/charging station is in relation to the LAST zone that Rooma is supposed to be cleaning prior to going back for a re-charge?

<edit> I guess I should clarify my thinking: "IF" Roomba can "see" the base/home/charging station FROM the last zone that it is in, then maybe the LH will be willing to let it pass to go back to charge? Mine was NOT visible to Roomba and may have caused it to not find the "beacon" from the base/home/charging station in order to get back to it.

I will move it, reset both Roomba and the LH's and try again tomorrow.

stanner · Post by **stanner** » November 18th, 2007, 6:15 pm

I had this same experience, and I'm still confused.

1) Has anyone actually seen the "amber flashing" which indicates the 16 hour refresh? Many people seem to have seen new roombas do the "amber pulsing" for a couple of hours before the "Green solid" turns on. If this is normal behavior, the manual needs to be changed.

2) If this is normal behavior (i.e. the green light comes on, but after only a couple of hours), how are you supposed to know when it's ok to use the machine?

3) How do you force it to undergo the 16 hour refresh, if it won't do it on its own?

fancyfreewv · Post by **fancyfreewv** » November 18th, 2007, 6:46 pm

I'm not the expert on batteries here however IRobot told me that it was okay to use it anytime the green light was on. On the 5xx series this happens quite quickly and you are correct that you don't see the orange for long.

That being said, the "experts" here have a different opinion on what constitutes a "full" trickle charge to all the cells in the battery pack. Just because it's green, doesn't mean the charge to all the cells is optimized. There are a lot of people who are very knowledgeable and have years of experience with these Roombas.

So, it has been recommended that you leave it on the charger to assure it gets a maxiumum charge.

As you use it and keep it on the charger, it has a better battery life. Mine does about 120 minutes routinely. There has to be something to the thinking process about giving it a better charge.

deparson · Post by **deparson** » November 18th, 2007, 10:13 pm

You only get the 16 hour cycle if the battery is very deeply discharged; much more discharged than you would get under normal use.

A battery that has nearly no voltage left can't be fast charged so the charger applies a very low charge over a long time to get it back to normal. You might see this with a unit that has been on the shelf for a year or so but not with new stock.

Bottom line is you don't need to charge for 16 hours if the unit goes green. Just use it and be clean

THX-1138 · Post by **THX-1138** » November 18th, 2007, 11:07 pm

Yes, you can go ahead and run your Roomba when the light turns green. If you wish to really extend the life of your expensive R500 series NiMH battery (at this moment US$90+S/H) and have it run efficiently then I suggest you check out this thread instead:

Roomba and Trickle Charging

glo69 · Post by **glo69** » November 18th, 2007, 11:27 pm

fancyfreewv is correct.

The best thing you can do for your battery is start it off with a 16 hr. charge. The light turning green just means that the fast charging has terminated. It doesn't indicate that all the cells in the battery are full and balanced. If the battery has been freshly, properly charged before you receive it, then it doesn't need it. But you don't know whether it has or not, so the safe thing to do is give it the full charge. 72 hrs. would be better, but I think iRobot knows how hard it is for some people to have patience, so they take what they can get.

Plenty of trickle charging time is important to all batteries. In order to save a lot of typing, I'm going to copy an old post of mine that goes into a lot of detail.

Trickle charging performs two important functions. One is to replace any battery discharge due to self discharge or stand-by power used by the robot.

The other is to balance the charges in the individual cells. A robot battery is not a single battery, but a series of 12 individual cells. Due to characteristics of each cell, caused by minute differences in the cell chemistry during manufacture, each cell charges and discharges at varying rates. When you discharge the battery, you end up with a group of cells that indicate a total voltage, but each of which has a different amount of charge remaining.

When you then recharge, the charger cannot see the charges in the individual cells, and treats the battery as a whole. What basically happens is that when the least discharged cell gets full, charging stops and the robot shows green. (Just to save a lot of posts, yes I know that this is a simplstic explanation, and there can be a lot of variations, but the general idea is accurate).

However, there are still cells that are not full. Since a cell that is not full has less resistance to accepting more charge, a slow trickle charge is used to bring the emptier cells up to full.

Trickle charge rates are very difficult to set. Trickle charge too fast and you will overcharge the full cells, which will add charge if the rate is high, and the low cells, if left on the charger to long. (See Scooba 5XXX battery charging)

Trickle charge too slow and the cell imbalance gets worse. The low cells are the ones that discharge the fastest, and when they haven't been given time to catch up, they start out low and get lower. Eventually you have a dysfunctional battery.

This, and cell crystallization (memory), is why iRobot's recommended battery reconditioning cycle is a Max run followed by a 72 hr. charge. The Max run depletes the battery more than normal and breaks up the crystallization, and then the 72 hr. charge gives the trickle charge a lot of time to rebalance the individual cells.

When you receive a battery from iRobot, they don't know how long the battery has been sitting around. The self discharge of the cells is also variable, and if a battery has been sitting, the cells can be out of balance. The 16 hrs. is just giving the trickle charge a little time to balance the cells. The full 72 hrs. would be better yet, but the odds are that the battery isn't very far out of balance, and iRobot knows they will be lucky if people will even wait 16 hrs. before running their bots.

The fact that some bots do the 16 hr. cycle and some don't would seem to indicate that the charging system makes a determination, possibly based on starting voltage, on whether the battery needs balancing or not. It may be programmed to follow a *If the voltage is low, the battery has been sitting around and needs it, if the voltage is high, the battery is fresh and doesn't need it* idea, but that's just a guess, and wouldn't really be an accurate indicator of individual cell balance anyway.

Will skipping the 16 hrs. ruin your battery? Who knows? If your cells are balanced, it won't hurt it at all. If they are badly out of balance, it probably won't ruin it immediately, but it could shorten it's lifespan.

In high quality battery packs the manufacturers test the individual cells and sell balanced packs. In cheap battery packs they just take the cells off of the assembly line and solder them together. So everybody can just decide for themselves which kind of pack iRobot sells, and decide whether you want to wait 16 hrs. or not.