Problem Charging Aux Batteries with Smart Charger

The AGMs in the Thumper would not be the same as Optima because they are special. They are AGM but spiral wound instead of flat panels and much more robust with less problems on corrugations etc.

Bit hard to check the charger because I don't think it will work unless connected to a battery with sufficient voltage to get it going.

Did you notice it being the normal fairly hot temperature that the CTEKs run at or was it cold or really hot? Was the 14V still happening when you disconnected it or just when it started charging?

I would expect that the aux battery would have been feeding high current into the Thumper if it was hot and smelly so check that battery voltage first, if you haven't already. A 7A charger would probably not be able to provide all that much energy to the battery so perhaps it was the other battery that did the damage.

Hi D4206, from what you have posted, there are two possibilities, one has been covered by a few posters, and that is that the thumper battery was either stuffed when you connected the charger or failed while charging it.


In this case,because the charger is only a small current charger, the thumper battery simply pulled the charger and the other batteries down.


The other possibility is that the charger went over voltage ( I don’t thing this is the case ) and as the USI-160 has over voltage protection, it simply turned off when the voltage got too high.


Again, the first suggestion is most likely the case.


PS does the 4206 in your handle stand for anything specific?

Tim,

If the USI 160 turned off it just isolates the aux batteries from the starter battery so wouldn't affect the Thumper unless he also has a USI 160 between the two aux batteries??

Yep, I agree Bob, and that’s why I posted that the thumper battery is more than likely to problem.

Quote:

---

Originally Posted by drivesafe

Hi D4206, from what you have posted, there are two possibilities, one has been covered by a few posters, and that is that the thumper battery was either stuffed when you connected the charger or failed while charging it.


In this case,because the charger is only a small current charger, the thumper battery simply pulled the charger and the other batteries down.


The other possibility is that the charger went over voltage ( I don’t thing this is the case ) and as the USI-160 has over voltage protection, it simply turned off when the voltage got too high.


Again, the first suggestion is most likely the case.


PS does the 4206 in your handle stand for anything specific?

---

Thanks for the comments Tim.

Seems as though the thumper may have been the problem.

As far as I know the Optima is still ok. (It's only a few months old), so hopefully hasn't been damaged.

Would you suggest a higher output smart charger be used rather than the Ctek?

Can I replace it with another AGM battery...ie not another Optima, just a deep cycle AGM? The incompatibility question mentioned in a previous comment concerns me.

D4 =Disco, 206=house number.

Cheers,
Bill

Hi again Bill and no. The 7 amp charger is ideal for what you are doing.


It is actually healthier for lead acid batteries to be charged with low currents rather than high currents.


So again, stick with the charger you have, and your batteries will love you for doing so.

Just to help.. you can buy replacement batteries for the Thumper - $62ea
They are just an alarm battery BTW...

And do not be worried by the old "mixed battery type" statement... that's not an issue in these vehicles (LiThium excepted).

The AGM charging profile is higher than Normal mode (for Ca/Ca, MF and Gel) so you were running lower not higher...

https://www.aulro.com/afvb/images/im...017/03/641.jpg

C-Tek shouldn't have any problems at all charging this set-up if batteries are in good nick. [wink11]

I have almost the identical set-up in my D4. Traxide system installed, with Optima yellow top under the bonnet, and an Engel battery pack very similar to the Thumper in the back running the fridge. I plug a C-Tek charger or an 80W solar panel into the Anderson plug on the back of the vehicle every two or three months to bring everything back up to fully charged, and have never had a problem.

Coincidentally, I also have a stuffed Thumper out in the shed. It has never been in the D4, and was last used two or three years ago. I recently went to use it and it was dead flat. Pulled the top off and found a loose connection inside the box on the negative terminal post - fixed that, but it will not take a charge. I haven't checked yet if one or all four of the cells inside the box are stuffed - but I have been thinking about buying replacement/s as required. Thanks Mike - I had not got around to looking up the price of replacement cells yet. [biggrin]

I have cooked thumper batteries in the past too I think from too high charge current. If the batteries are discharged they can try to take more current than they can handle and the batteries inside will get hot and warp. I installed some ventilation holes into my thumper casing to give the batteries inside some ventilation. I think to charge the thumper AGM batteries you need to limit the current to less than 4A?

The batteries inside are just regular AGM batteries available from Battery World et al...

Thank you very much for all the responses....much appreciated [emoji16][emoji106]