[R2D2]

Originally Posted by Roy.S

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.

TBH the C3 is a rather buggy piece of equipment (for want of a more acceptable word) it has issues in identifying batteries that are AGM and flooded for example, plus the state of charge "calculation" is a bit off the mark. TBH I am not exactly enthused by the C3. The C7 OTOH has better firmware.

I would recommend a C7 for a 150 AH inverter battery. The C3 will require a lot of patience.

[saket77]

Originally Posted by Roy.S

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.

With the tip, it will surely identify the battery but consider the time you’ll spend charging a 150Ah battery with a charger that puts out only 3.8A at max

Regards.

[Roy.S]

Originally Posted by saket77

... consider the time you’ll spend charging a 150Ah battery with a charger that puts out only 3.8A at max

Regards.

I'm doing this only because I'm bored and have too much time on my hands. The UPS battery is not being used lies forgotten in a corner. I'm curious to see what will happen if I try the C3 on it. Basically, this is what passes for entertainment these days.

[R2D2]

Originally Posted by Roy.S

I'm doing this only because I'm bored and have too much time on my hands. The UPS battery is not being used lies forgotten in a corner. I'm curious to see what will happen if I try the C3 on it. Basically, this is what passes for entertainment these days.

IIRC the C3 is rated to charge batteries from 1.2 to 120 AH. Not sure if it will complete the charge on a 150 AH or higher because these "smart" chargers have a timer. If a charge doesn't complete within the timeout period in the firmware the battery is presumed to be faulty.

I would recommend a C3 only for 2 wheeler and small automobile batteries upto a max of 50 AH. For larger batteries the C7 is the answer. I have use for both smart and manual or semi automatic chargers. The latter to be used when the smart chargers get oversmart (thanks to the built in safety routines) and cannot do the job. I could revive my car battery only via a semi automatic model, the Bosch C7, forget the C3, was quite useless. Sometimes you need sheer amperage and time to get a battery to accept a charge.

[sagarpadaki]

Originally Posted by saket77

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.

What external power supply can be used? Like a 12V adapter what we get from local electrical shops is sufficient?

[R2D2]

Originally Posted by sagarpadaki

What external power supply can be used? Like a 12V adapter what we get from local electrical shops is sufficient?

Any adapter outputting a constant 12V preferably 4-5A or more, for eg an external USB HDD power adapter can be used to bring the battery to about 30-40% SoC after which use a smart charger. Another good option is a Tata Sky HD+ box adapter It outputs 12V 5A IIRC. You need to check the polarity and ensure that the connections from the adapter to the battery are firm. I'd suggest cutting off the adapter jack and soldering the wires to a pair of crocodile clips again checking polarity. You also need to monitor the charging process at regular intervals

[saket77]

Originally Posted by sagarpadaki

What external power supply can be used? Like a 12V adapter what we get from local electrical shops is sufficient?

First I used a 12V 1A per supply. The charger shifted to proper charging mode and again back to 6V mode indicating it wanted little more power. I connected another power supply with 5A and it did the trick. I think anything over 2-3 amps with 12-15V DC will suffice.

Regards.

[anandpadhye]

I am looking to buy the C3 or C7 charger. However, there is no 230V wall socket in the parking and does not make sense to lay wires all the way from my meter to parking just for a trickle charger. Is there any good portable power supply (a portable inverter with built in battery) that I can buy? And what should be the capacity? I mean, what will be total power consumption of the C7 charger if it needs to charge my car battery which is showing 12V when engjne is off (i.e. the battery is 75% discharged)?

[pcpranav]

Originally Posted by anandpadhye

I am looking to buy the C3 or C7 charger. However, there is no 230V wall socket in the parking and does not make sense to lay wires all the way from my meter to parking just for a trickle charger. Is there any good portable power supply (a portable inverter with built in battery) that I can buy? And what should be the capacity? I mean, what will be total power consumption of the C7 charger if it needs to charge my car battery which is showing 12V when engjne is off (i.e. the battery is 75% discharged)?

Hi.
my take on this situation - it'll be better to buy a good jump-starter battery powerbank. It'll be portable, handy and very convenient to use. I have seen few on Amazon.in (and few foreign portals), but got to hear mix reviews. Also the battery within that such powerbank itself may not last long, and over period go bad - as it happens with most batteries.

Few months back I was thinking on same lines, and thought if any such powerbank came with a capacitor (super-capacitor), rather than a traditional battery. A bit of google lead me to https://www.autowit.com/products/aut...2-jump-starter : looking at the videos and technology they used, it seems very impressive.
I have not purchased it yet, but in future would try to get this - maybe hand carried by someone in US, so that lesser cost to me! Such a device can be carried on my car / bike trips, I have seen cases wherein battery went bad in middle of trip !!

on the main topic of this thread, I do like Bosch C7 design, but I dont have power outlet in my open parking, and it isnt feasible to carry battery to home.

For current situations when extended time vehicle is unused, I disconnect the negative terminal of battery, so as to preserve the battery charge for longer time - this is a 5 min task with a simple wrench. To make this even simple, I have ordered a cheapo battery disconnect switch from one of CN foreign portal - expecting delivery. With that, just a screw to disconnect the contacts on terminals - 1 min task.


regards,
Pranav

[RMN]

Has anyone been able to purchase the quick connector for the Bosch C7? It comes with just 1! I wanted to have the quick connectors connected to multiple vehicle so that I can easily charge them when needed rather than having to dissemble anything.

They dont come with the standard SAE connectors like the battery tender either. Any idea what is the name of the connector they use? Thinking of buying the adapters and making a harness my self.

[GTO]

Hey guys, based on the reviews, I've gotten the C7. With the media cars now coming in and restaurants shut, the usage of my cars is bare minimum.

1. What settings to put for my BMW 530d? It has an AGM battery.

2. What settings to put for my Jeeps regular battery?

3. I want to mount it outside on the wall next to my open parking spots. Is there any ready waterproof lockable box I can buy to house this? Or call the carpenter?

Thanks

[Leoshashi]

Originally Posted by GTO

Hey guys, based on the reviews, I've gotten the C7. With the media cars now coming in and restaurants shut, the usage of my cars is bare minimum.

1. What settings to put for my BMW 530d? It has an AGM battery.

2. What settings to put for my Jeeps regular battery?

3. I want to mount it outside on the wall next to my open parking spots. Is there any ready waterproof lockable box I can buy to house this? Or call the carpenter?

Thanks

1. Using "mode" button(this is the only pressable button), you can toggle between modes. Keep hitting the button till AGM's LED gets on.

2. For Normal flooded battery, there are two modes, trickle charging and regeneration. Trickle charging is what you need 99% of the time. Again using that single mode button, keep pressing till only 12V LED is on and the circular LED around Mode button starts flashing in 75-100% range. That's Trickle charging mode.

For regeneration, again use the mode button and keep pressing till the R LED turns on. That gives a high voltage (15-16V) and is mostly use to fix near dead batteries. This mode shouldn't be used regularly. Once or twice a year is more than enough. Also while I do this, I keep the battery away from any other thing and keep it's vent caps open since the electrolyte tends to boil a bit.

3. Better consult your carpenter, I'm not aware of any lockable box for C7.

Regards,
Shashi

[androdev]

Just to add to what Shashi said: center button is the only control. It starts in standby mode when the centre button has a ring lit up in blue colour. Press once: you get flooded battery mode. Press again: you get AGM mode. If press beyond this point, keep pressing till it cycles through other less common modes and returns to the first mode. It restarts in the last used mode after any power cut/resume. It's safe to leave it plugged in for any length of time. I never drive my cars for battery top up etc. Served great during pandemic.

You might already know this about your BMW, the charging can be done using the positive terminal under the front hood (negative terminal can be any metal portion of the frame) and there is no need to access the battery in the rear trunk for charging/jumpstart.

[GTO]

Thanks a ton guys.

Can I place it like this? Does it get too hot? Bonnet closes easily and this would protect it from theft and rains.

[androdev]

It doesn't get hot but remeber the Murphy's law! I normally close the hood (but don't fully close and latch) by leaving enough gap for the cable. I leave the charger outside as I use it in a closed garage and sometimes I forget to unplug for days. On the rare occasion of using it in the open area, I keep the charger brick under the car to keep it away from the sun. If you see the demo cars in showrooms, they route the cable from underneath the car and keep the hood fully closed etc. It is also possible to charge it through cigarette lighter socket if you manage to get cables hooked to cigarette lighter pin - in this case you can leave the charger inside the cabin and lock the doors. The charger also comes with clip-on mechanism which can be permanently screwed to the terminals and have the quick release plug strapped near the wiper area so that you can plug and unplug the charger without opening the hood - hence the location of the positive terminal is placed closer to the wipers in most German cars. Ideal if you have a single car to charge. Too many options :-) but it's very well made and robust and doesn't heat up during charging mode. No sure about other modes.