[ishlinea7260]

This Lock down has led to a battery issue in my Fortuner.
The battery was 3.5 years old and it might have been time for a new one, but this has made me ponder over purchasing a battery charger.

In this post lock down scenario since travelling is restricted to only essential cases, I know a couple of my cars will not be driven for couple of weeks at least. And if they are driven on short trips that may have a deleterious effect on the batteries.
I want to ask various members who are already using battery chargers.

1.Which one to go for Bosch C7 or C3?

2. Do I need to take out the car's battery to trickle charge it or can that be done with the battery in place in the engine bay?

3. Can the charger be left attached continuously for weeks?

4. Is there a fail-safe method in case of power surges?

[shaheenazk]

Originally Posted by ishlinea7260

This Lock down has led to a battery issue in my Fortuner.
The battery was 3.5 years old and it might have been time for a new one, but this has made me ponder over purchasing a battery charger.

In this post lock down scenario since travelling is restricted to only essential cases, I know a couple of my cars will not be driven for couple of weeks at least. And if they are driven on short trips that may have a deleterious effect on the batteries.
I want to ask various members who are already using battery chargers.

1.Which one to go for Bosch C7 or C3?

2. Do I need to take out the car's battery to trickle charge it or can that be done with the battery in place in the engine bay?

3. Can the charger be left attached continuously for weeks?

4. Is there a fail-safe method in case of power surges?

1. Opting for C7 is better as it can supply power to dead battery which is helpful in starting the car immediately. C3 does not have this feature.

2. No its not required. The battery can stay put in the engine bay.

3. Yes it can be. It will trickle charge the battery thus keeping it in optimal condition.

4. It protects from over charging but not sure of fail-safe method feature.

https://in.bosch-automotive.com/en/p...___c7_chargers

[saket77]

Bought the C3 and it was delivered today. My old transformer based charger was blown up by my apartment guard; I don’t know how. So, had to get a new and reliable charger and I opted for the C3. Honestly in my view, both C3 and the C7 are over priced for being a 3.8A and 7A charger respectively especially when based on SMPS technology. Here are some shots of C3. In the meanwhile, I repaired by old charger by getting a new 15v- 5Amp transformer and completed the set up by adding a couple of heavy duty 6A diodes and an ampere meter. Installed fuses on both input and output side to safeguard it to reasonable levels. Earlier the charger didn’t have a fuse. As part of my DIY experiments, I’ve made an auto cutoff circuit for the charger and shall shortly build a reverse polarity protection kit too along with variable volt and amp settings. Hopefully it will be a very good system once I integrate everything in it. Here are a few pictures of it too in action.








Work in progress- The old charger- now renewed. 14.6V at 5Amps.

[prithm]

Originally Posted by ishlinea7260

1.Which one to go for Bosch C7 or C3?

I would say for the premium that you are paying, go for C7. Features in it will help with your future battery upgrades too.

Originally Posted by saket77

Bought the C3 and it was delivered today. ...
Work in progress- The old charger- now renewed. 14.6V at 5Amps.

If I had time I would surely gone for a local brand, but circumstances forced me to opt for tried and tested. Just wondering, how are you planning to do a battery desulfation with your set up ? Don't you need higher Amps to help you with ?

[saket77]

Originally Posted by prithm

If I had time I would surely gone for a local brand, but circumstances forced me to opt for tried and tested. Just wondering, how are you planning to do a battery desulfation with your set up ? Don't you need higher Amps to help you with ?

Hi,

I think more than amps, battery desulphation would require higher voltage. Something in between 15-16v for three to four hours. But I’m not too interested to have it. But still, since I’ve used a 15v transformer, I can tap 15v DC out easily. If that is not sufficient and still if I’m keen on having a regeneration mode, I can design a DC booster kit.

Regards.

[saket77]

Originally Posted by shaheenazk

1. Opting for C7 is better as it can supply power to dead battery which is helpful in starting the car immediately. C3 does not have this feature.

Are you sure about this? In my opinion, this is not possible with a normal battery charger. A starter motor draws a large amount of current which at least the C7 can’t deliver.

Regards.

[shaheenazk]

Originally Posted by saket77

Are you sure about this? In my opinion, this is not possible with a normal battery charger. A starter motor draws a large amount of current which at least the C7 can’t deliver.

Regards.

My bad. I misunderstood the power function of the C7 battery charger. I have provided user manual explaining what exactly the power function does. Thanks for pointing out the misinformation. My apologies.

https://images-na.ssl-images-amazon....1eM0Iz4vQS.pdf

[sgiitk]

With more and more car vendors going for a 'locked' battery our chargers will be only for use with cases like battery going down. No more use for dead batteries per se.

In most cases a set of jumpers will do. So we have to 'think'.

[prithm]

Originally Posted by sgiitk

With more and more car vendors going for a 'locked' battery our chargers will be only for use with cases like battery going down. No more use for dead batteries per se.

In most cases a set of jumpers will do. So we have to 'think'.

True. I am not sure how they do it, but even motorcycle batteries are following suit.

I tried every trick in the book to get my bike battery alive after it drained out during lockdown and it is dead as a door nail now. Earlier, we used to somehow get them revived by electrolyte replenish or brute force charging, nowadays it just won't budge.

[KarthikK]

Originally Posted by saket77

Are you sure about this? In my opinion, this is not possible with a normal battery charger. A starter motor draws a large amount of current which at least the C7 can’t deliver.

Regards.

I have both the C7 and the C3, the C7 just has something called a dead battery revival mode with pulse charging for deeply discharged batteries. Like you said, it is impossible for the car to start merely by connecting it to a wired C7 To do something like that, one will need something like a jump start power bank from Anker or similar which can support the high current needs of the starter

Something like this is a good addition to the DIY recovery kit along with puncture repair stuff


There are many variations and brands depending on the car, budget and current required.

[RMN]

Does anyone know if its possible to purchase extras "Charging cable with cable lug" that comes with the C7? I would like to have them for each of my vehicle so that its easier to get them charged.

[vsathyap]

I got a C3 Charger, thanks to the lockdown, and to the fact that I need to maintain charge for more than 1 vehicle and scooter at home. The 2+ year old Exide 35Ah battery on my Alto was nearly dead and was barely able to crank the engine to life and I decided to bench charge the battery overnight. While removing the battery, I saw a lot of white crystals on the base of the battery plate and some bluish Copper Sulphate crystals on the Positive Terminal, which I thoroughly cleaned with Baking soda paste and a tooth brush.

There are 3 colour indicators on the battery - pasted as a sticker on the top, right next to the "eye"/ window of the battery. Green means all is well, transparent/clear means the battery needs charging and a red indicator means that the battery is low on electrolyte and needs distilled water to be added.

I could see that the battery eye had a clear colour and the sticker on the battery mentioned that if its clear, the battery needs charging. So, even after the overnight bench charging, and the C3 showing that its now in maintenance/trickle charge mode at 12.90V, the battery window is still clear /transparent and not green.

Does this mean that I need to add any distilled water? How much should I add? Unfortunately, there are no "MIN/MAX" levels on any side of the battery and it looks like its a sealed/maintenance free battery, although I can see a small plastic flap that can be pulled out to reveal 6 cell screw-caps underneath.

I also went to the extent of doing a timelapse recording of the C3's charging voltage v/s time and plotting it as a graph to see how the charger works. I checked that the battery is able to hold a charge of 12.6V for over 24 hours after disconnecting from the C3 - which means that the battery is still good.



So, coming back to my question:

1. How do i know that my battery needs distilled water?
2. If I need to add some, how much do I add?
3. What happens if I overfill it?

Thanks in Advance!

Mods - please move this to a relevant thread under battery maintenance if its not related to this thread. I posted here since there are a lot of C3 vs C7 discussions going on and I wanted to share details about the C3's charging characteristics as well.

[R2D2]

Originally Posted by vsathyap

While removing the battery, I saw a lot of white crystals on the base of the battery plate and some bluish Copper Sulphate crystals on the Positive Terminal, which I thoroughly cleaned with Baking soda paste and a tooth brush.

The crystal deposits on the terminals generally indicates overfilling of distilled water OR high charging voltage. You need to ascertain which one it is.

There are 3 colour indicators on the battery - pasted as a sticker on the top, right next to the "eye"/ window of the battery. Green means all is well, transparent/clear means the battery needs charging and a red indicator means that the battery is low on electrolyte and needs distilled water to be added.

Please remember the "Magic eye" as it's called indicates the condition of only one of the cells. When the eye is white it shows a low Sp Gr which in turn necessitates charging and/or checking.

Does this mean that I need to add any distilled water? How much should I add? Unfortunately, there are no "MIN/MAX" levels on any side of the battery and it looks like its a sealed/maintenance free battery, although I can see a small plastic flap that can be pulled out to reveal 6 cell screw-caps underneath.

If you can remove the caps please do so and check the electrolyte level.

How do i know that my battery needs distilled water?

A visual check is the best. Remember, the eye is an estimation of health that too only in 1 cell

]If I need to add some, how much do I add?

Fill till the bottom of the vent tube, no more. There should be ~2-3 cm gap between the surface of the electrolyte and top of the vent plug which sits flush with the battery top.

What happens if I overfill it?

Acid fumes will corrode terminal clamps and you will see salt accumulation around the metal parts. Make sure you use vaseline to coat the clamps.

[saket77]

So the C3 smart charger acts too smart. Somehow my Civic’s battery went into deep discharge. Read 5.5 volts. Connected it to the C3 and it detected it as a 6V battery: courtesy it’s over smart inbuilt logic which you cannot manually override. As a result, C3 showed it ‘ok’ and wouldn’t charge.

I’ll share with you guys a work around for C3 that actually works in such cases.

Connect your C3 to the discharged battery. If the battery voltage is less than 8V, C3 will see it as a 6V battery. It will either automatically go into 6V battery charging mode or even if you try to select manually any mode, it will only and only get into the 6V mode. Now connect an external power supply or another battery in parallel to the discharged battery while keeping the C3 connected. Care to connect the right polarities; i.e..+ to + and - to -
As soon as you apply the voltage on the terminals and the aggregate voltage surpasses the 8-9V threshold, C3 will now automatically shift to 12v battery mode. Now disconnect the external power supply/ battery as soon as proper charging mode is detected by the charger. Once the charger identifies the battery, amazingly it will charge it further normally. Even if there is a power cut at this or any stage, the memory function in the charger will save you the effort of doing the gymnastics all over.

I tested the above multiple times and it worked everytime. But what I did was something different. If you scroll above a few posts, I posted about a DIY old fashioned dumb transformer based charger. I have named it as ‘Virus charger’. Those who have watched a certain movie named ‘3 Idiots’ will be able to relate. Technically, this charger outputs 14.6 to 15V @5A, which is a good specification. Theoretically, this can charge a 30A car battery in 6-7 hours flat; from flat.
I connected this charger for about half an hour and post this exercise, the discharged battery now measured 11.8V. Now I connected the C3 again and it detected the battery properly and started normal charging.

Now, the main issue lingering in my mind is that why the two year old battery discharged so deeply. The car ran well during the last trip some 10 days back. Will check after I connect the battery back.

Trust that will help a C3 owner. Pictures in the order of post.

Regards.

[Roy.S]

Originally Posted by saket77

So the C3 smart charger acts too smart....

Exactly the same thing happened to me when I tried recharging a friend's car battery last month. We just couldn't figure out why the C3 would identify the battery from a Yeti as a 6V.
Thanks for the useful tip. Will use your suggestion next time I run into a similar problem. I've been using the C3 for a couple of years now and it always felt like it was programmed to err of the side of caution. As an experiment I'm going to try and recharge an almost completely discharged 150Ah UPS battery this weekend.