[shobhitk]

Originally Posted by R2D2

Yes, it doesn't switch back to trickle charge so one could assume it to be a fault OR a gap between the functionality/program written in the smart charger's chip and the instruction manual....

It seems to be a fault because there could be minor deviations in the actual working of the charger as compared to the procedure mentioned in the instructions manual...that is normal. If suppose after completion of the regeneration process the charger would have come back to the standby mode (ie. the blue light on) then that would have been normal.


But in our case, after completion of the regeneration process the charger is not only not starting the normal charging procedure but it is also incorrectly showing that the battery is still at 0-25% of charge. So i believe that there is something wrong in the charger itself.

It would be nice if other users of C7 could also throw some light on this issue.

[R2D2]

Originally Posted by shobhitk

But in our case, after completion of the regeneration process the charger is not only not starting the normal charging procedure but it is also incorrectly showing that the battery is still at 0-25% of charge. So i believe that there is something wrong in the charger itself

Yes it should go back to standby if not trickle charge. Take it to the dealer and have Bosch examine it. I'd like to know what Bosch has to say.

Again for the benefit of other charger owners - please do not use the recondition/regeneration mode on AGM batteries. It will destroy them. AGMs are used in most lux cars and placed in the trunk.

[prithm]

Originally Posted by R2D2

I have put the C7 and C3 to the test. Took the battery out of the car and set it up for charging 24x7 first using the C7 for 2 days with a desulphator and then switched to the C3 this evening. Gotta test these things, no?

R2D2-san,

Hope things are OK at your end. I had to go AWOL for sometime.

I am currently in market looking for a dependable battery charger as well as maintenance kit due to new arrivals in our stable.

Narrowed down to C7 and very much interested in its Deep Discharged battery revival feature. How did you manage to do it for your battery ?

Can I use this for revival and maintenance of Home Inverter Batteries too ?

[R2D2]

Originally Posted by prithm

R2D2-san, Hope things are OK at your end. I had to go AWOL for sometime.

Yeah, I've been wondering where you are. Trust all is well.

Narrowed down to C7 and very much interested in its Deep Discharged battery revival feature. How did you manage to do it for your battery ?
Can I use this for revival and maintenance of Home Inverter Batteries too ?

The process is to make the connections, power on the charger and switch the mode of operation to Mode 4. The charger does the rest at 16 VDC and 1500 mA for about 4 hours after which it switches to a normal charge mode. Why limited to 4 hours? Because continual high voltage charging can destroy plates. Before charging:

a) I would recommend topping off the water in the cells (up to the bottom of the vent barrel. Do not overfill as electrolyte will bubble out.
c) Leave the vent caps on but do not tighten fully
d) Ensure good ventilation in the area. Charging at high voltages causes excessive gassing.
e) Please wear protective goggles and gloves.
f) Monitor the regeneration process. If something goes wrong for e.g. a power failure the timer is reset (I think) and the charge may continue for another 4 hours. This can damage the battery. Also if the battery gets hot during this process please switch off the charger at the mains. Do not disconnect the clamps before cutting power.

You can use it on any battery automotive or inverter. Once again never use this mode on gel cell, AGM/VRLA batteries.

[Leoshashi]

Originally Posted by prithm

Can I use this for revival and maintenance of Home Inverter Batteries too ?

Originally Posted by R2D2

You can use it on any battery automotive or inverter.

Reminds me of a mischievous jugaad I did last year.

We had replaced an inverter battery, and the old battery was lying downstairs awaiting pickup by scrap dealers. One fine day I was working on something in our parking, and we had a long power failure. I always wanted to have a reliable light source for such occasions, so took this opportunity to do this jugaad. Took some scrap wires lying around, an old switch, couple of connector pins, a scrap HL assembly and made this contraption:







The battery still had enough juice to do the intended job, and I charge the battery with my C7 once every month.

Regards,
Shashi

PS: This battery is more than 12 years old now, was installed in 2007, later used by caretaker for lighting his own quarter, and eventually is lighting up a small 60W HL Bulb. Regarrding maintenance, nothing was done except timely topping up with distilled water.

[prithm]

Originally Posted by R2D2

Yeah, I've been wondering where you are. Trust all is well.

All is well sir. Cannot complain.

Originally Posted by R2D2

f) Monitor the regeneration process. If something goes wrong for e.g. a power failure the timer is reset (I think) and the charge may continue for another 4 hours.

One thing about C7 that they are using to up sell is the feature of memory. It starts exactly where it left, not sure though how it can jog or validate the battery that it was charging before the outage event.

Originally Posted by Leoshashi

The battery still had enough juice to do the intended job, and I charge the battery with my C7 once every month.

Glad to see you back in action Shashi.

There is one thing that battery guru's recommended me (after much prodding and picking their brain) when I was discussing this at the local battery shop was that for home inverters the sulfation was higher and it requires one round of desulfation every 6 months. Their standard reply was that if your battery is older than 3 years or if there is significant corrosion in the terminals, or badly maintained - change it immediately to get good exchange cash. Further delay will only hurt the pocket.

When I told them that I was ready to pay them for getting the acid and electrolyte changed in a bad battery, they bluntly refused. Not sure if they were saying out of commercial interest. When I told them about Desulfation, their face went pale and said its something only specialists do and success rate was bare minimal. Though they were more interested to know how I knew about this.

In your situation, did you happen to do desulphation, recharge the liquids and then charge for regeneration or any other way ?

[R2D2]

Originally Posted by prithm

One thing about C7 that they are using to up sell is the feature of memory. It starts exactly where it left, not sure though how it can jog or validate the battery that it was charging before the outage event.

I am not sure if that resume after power failure applies to the regen mode. IIRC there are 2 mode differences you need to be aware of

a) Regeneration is basically coaxing any sulphate crystals on the plates back into the acid. Deeply discharged batteries can suffer from this issue.

b) Pulse charge - some call it a series of desulphation steps using electrical pulses and without using high voltage. It also does the same thing - breaks crystals away from the plate and back into the solution enhancing the battery's life and power. This is automatic. So, instead of relying on the battery's judgement I attach a separate desulphator to the battery whilst charging. Better still I use one of my CTEK chargers that permit manual setting of desulphation during the charging process.

About acid stratification - happens when acid with higher Sp Gr settles towards the bottom of the battery and DW on top. It leads to plate damage over time. Inverter batteries are susceptible to it. therefore it is essential to discharge about 10-20% of capacity (i.e battery at a 80-90% SOC) and recharge them thereafter. Do this regularly at least once a fortnight. Gassing during the recharge process mixes the acid and water preventing stratification.

Note - lost capacity cannot be recovered. The problem is with the plate deterioration. Do not change the electrolyte unless someone has added too much DW or heavens forbid acid.

Originally Posted by Leoshashi

The battery still had enough juice to do the intended job, and I charge the battery with my C7 once every month.

That's an eco-friendly step and repurposing of old batteries should be encouraged. The C7 can handle batteries up to 230 AH so that covers a large number of inverter batteries models including the highest capacity home inverter battery one I know of - Exide Invatubular 230 AH IT850.

As mains power supply gets more reliable, as it has in many parts of the country including Pune (we had regular 12 hour blackouts in 2005!), I believe we won't need such large models. A 100-150AH should present a nice balance of performance and cost. Therefore I am still wondering whether I should downgrade to 150 AH when it comes to replacing my current near 6 year old IT750 200 AH batteries. I am given to understand they generally last for 6-8 years if well maintained which is a given with me.

[wolf_lone]

On a C7 Charger trickle mode is activated once battery is charged with normal charging (12v car battery in this case). How long does it remain active ?

Can I remove charging once its activated? Its not mentioned in the manual..

[prithm]

Trickle charging is only to keep the charge on till you remove after full. Usually, its best to remove / disconnect as soon as C7 indicates completion. Recently I tried charging my UPS batteries and forgot to disconnect which invariably shifted to trickle after full charge. C7 was warm and I had to cool it before starting next session just to make sure I don't melt it.

Not advisable to keep in trickle for long duration.

[Leoshashi]

My C7 does get considerably warm when left in regeneration mode. But it's nothing alarming. It remains better than some of the modern smartphones we know.

Have left car batteries in trickle charging mode overnight, the charger stays absolutely cool.

[manim]

Originally Posted by prithm

Not advisable to keep in trickle for long duration.

I think trickle-charging by definition means it could be left on for an infinite period of time.

I use my Bosch-C7 one hour in the morning and a hour in the evening on my car batteries during this lock-down. But my Cruze 2 KVa UPS has two big 200Ah batteries which are on charge 24x7.

Trickle-charge will hold the battery fully-charged at just the right amount of its natural-discharge if left alone.

The only downside I see is that it consumes power. However my Cruze 2 KVa consumes 40 watts, and the Bosch-C7 6w at trickle, a small price to pay.

[prithm]

Originally Posted by Leoshashi

Have left car batteries in trickle charging mode overnight, the charger stays absolutely cool.

Originally Posted by manim

I think trickle-charging by definition means it could be left on for an infinite period of time.
....Trickle-charge will hold the battery fully-charged at just the right amount of its natural-discharge if left alone.

I agree with both of you on this about the intended purpose. But I am really not sure if it can be left alone for anything greater than a day. I left mine to trickle charge (due to my laziness & going by the book) the inverter battery for one whole day and it did become uncomfortably warm.

The instructions which made me even more lazy (from the C7 manual).

Originally Posted by manim

I use my Bosch-C7 one hour in the morning and a hour in the evening on my car batteries during this lock-down.

Do car batteries really need 2 hours of charging during standstill ? Folks here were advocating to run the car in idle for few minutes every few days.

[manim]

Originally Posted by prithm

Do car batteries really need 2 hours of charging during standstill ? Folks here were advocating to run the car in idle for few minutes every few days.

I agree it is overkill to do it two hours a day, but since the car is unused, I have connected the charger permanently, no harm in overdoing it

[wolf_lone]

Originally Posted by manim

I agree it is overkill to do it two hours a day, but since the car is unused, I have connected the charger permanently, no harm in overdoing it

I am using it for my HONDA City which gets out once a month or maybe once in 2 month... I charge the batteries every three months & it always go to 50% discharge as per C7.

Next time will disconnect when trickle charge is activated. As for warming it gets slightly warm & I bypass it by putting it on marble floor or on metal grill of window sill which dissipates the heat like a heatsink while its charging.

[R2D2]

Originally Posted by manim

I agree it is overkill to do it two hours a day, but since the car is unused, I have connected the charger permanently, no harm in overdoing it

Originally Posted by wolf_lone

I am using it for my HONDA City which gets out once a month or maybe once in 2 month... I charge the batteries every three months & it always go to 50% discharge as per C7. Next time will disconnect when trickle charge is activated. As for warming it gets slightly warm & I bypass it by putting it on marble floor or on metal grill of window sill which dissipates the heat like a heatsink while its charging.

These chargers are designed to be connected for extended periods of time. However, you need to check the battery regularly for electrolyte levels and of course the charger itself. As an electrical/electronic item, these chargers should not be considered fool proof or fail proof over the long term. Be cautious when dealing with batteries and chargers. A battery on charge can at best be warm to the touch. It wont be damaged. A really hot battery can mean one of more of the following:

a) EOL i.e there's a plate short or it's sulphated beyond hope of recovery.

b) Charging voltage is too high

c) Electrolyte level is low. This is a dangerous situation. Battery can explode. Switch off charger and top up ASAP.