24v Charging w/ dual 12v charger - BJ42 CAD spec (1 Viewer)

[essco1503]

Hi all
OK....I spent last night going in circles on here looking for simple charging/maintaining info on 24V NATO spec CAD 42s. Ive got two BJ42s. An 82 with 5spd conversion and an 84 with factory 5spd. BOTH are 24v. I am keeping BOTH at 24v especially the 84 as it is being rebuilt to factory new. I am happy to deal with the pain of finding 24v stuff and Ive got a good sparky that knows what he is doing here on the Island.
My question, that has just seemed to create more confusion and debate (haha) is, can I set up and use a dual 12V NOCO charger and charge/maintain my trucks WITHOUT having to disconnect any of the wiring between the two batts? Im hoping to permanently mount the eyelet connectors onto each battery in both trucks and have them just share a double 12v charger so I can just plug one truck in at a time. I usually drive the 82 fulltime as a daily and will have the 84 in storage for nice days Id like to be able to keep them plugged in especially in the winters although, Ill be hooking up a Planar coolant heater to both to make starting easier and healthier in the cold.
Does my plan sound ridiculous? Can I just leave all the battery wiring connected and plug my twin 12v charger up to both batts and leave it? I also was wondering what actual amperage you all recommend for top up and maintaining. Cheers all

 

[AirheadNut]

I would not recommend using a dual 12V charger for a 24V system as it is likely that both 12V outputs share a common supply within the charger. I am not sure how that would effect the charger or the batteries, but I suspect it would not be good for the electronics inside a NOCO unit. It would be safer to use two identical, separate single output 12V chargers for the two batteries.

 

[LDRF]

I would not recommend using a dual 12V charger for a 24V system as it is likely that both 12V outputs share a common supply within the charger. I am not sure how that would effect the charger or the batteries, but I suspect it would not be good for the electronics inside a NOCO unit. It would be safer to use two identical, separate single output 12V chargers for the two batteries.

If using two separate 12V chargers/maintainers, do you need to isolate the two batteries? Or, can you just hook the two chargers /mantainers up to the two batteries and start charging away?

Does it matter whether it's a charger or a maintainer?

I'm in the same boat as @essco1503 and his 42s; I'd like to keep my HZJ73 "fresh" as it's not my daily.

 

[essco1503]

I am looking at the NOCO specifically because it mentions it can do this Im more concerned about the neg link between the two batts and if i should maybe put a switch in that cable so i can just turn it off and charge them as individual 12v batts I have a feeling though that no matter what, the charger will only see each battery as a 12v because only the positive on the high side and negative on the low side are actually 24v if my grade 8 science memories serve me right? Charging this way should also keep the balance between the two batts fairly close because they are being charged individually. Again, I just want to make 110% sure that I do NOT need to disconnect the connection between the two batteries in any way before i plug in to charge or maintain for storage. Thanks so far everyone and LDRF hopefully we can clear it up once and for all on here!

 

[AirheadNut]

I am by no means an expert on 24v systems or NOCO chargers. I did find a 3rd party website selling NOCO products that claims the GEN5x2 can be used to charge 24v battery banks, but they don't mention if the batteries need to be disconnected from each other. NOCO doesn't mention anything about 24v use with any of their dual output chargers except the Pro line that has specific 24v settings. I would recommend contacting NOCO and seeing what they say about it.

A simple solution would be to make a quick disconnect on the cable between the two batteries.

 

[essco1503]

I am by no means an expert on 24v systems or NOCO chargers. I did find a 3rd party website selling NOCO products that claims the GEN5x2 can be used to charge 24v battery banks, but they don't mention if the batteries need to be disconnected from each other. NOCO doesn't mention anything about 24v use with any of their dual output chargers except the Pro line that has specific 24v settings. I would recommend contacting NOCO and seeing what they say about it.

A simple solution would be to make a quick disconnect on the cable between the two batteries.

Thats what Im thinking of doing. I just hate cutting things for the sake of cutting them haha.

 

[Greg_B]

I have a Victron mounted in the engine bay of my BJ74 and have been super happy with it thus far. That model comes in 12V and 24V versions. Bonus is you can have a load on (fridge) and it will act as power supply while charging and then maintaining the batteries. A number of the "smart" chargers will not.

I do have NOCO chargers and been happy with them. But I wanted something fulltime in the BJ74 that would work with a load cycling on and off.

EDIT and yes, you can hook up two 12V chargers the way you explained in your original post; Each charger will only see the one battery it is hooked up to. Double check with NOCO to make sure they will be happy with that for warranty purposes, if you do go NOCO.

hth's
gb

 

[greenbeast]

Good thread, we have a BJ45 24v and it’s always a hassle pulling batteries since my shop wasn’t complete.

 

[Freewheel]

+1

I've got the NOCO 2 bank 12v charger and it works fine without disconnecting the batteries.

 

[Freewheel]

And they stay balanced with the 2 12v, which they won't necessarily do if using the Noco 24 volt charger (which I also have, originally bought for 24v charging, but now mainly used for the 12v reconditioning function)

 

[essco1503]

You guys are absolute legends. Cant thank you enough. Yes Freewheel, part of the reason I want to go this way is to constantly be levelling voltages. If you got two good 12b batts you SHOULD have one great 24v system is my thinking. Now, the next part, getting me some good diesel fired coolant heaters from Planar. Nothing like a family of happy little Cruisers..

 

[LDRF]

@essco1503 - From what @Freewheel and @Greg_B have observed, the 2x12V NOCO should be good to go with no need to disconnect the two batteries. That's also described on the NOCO support page: NOCO - Series And Parallel Charging - Support - https://no.co/support/series-and-parallel-charging. Note, on the GENIUS2X2 page (NOCO - 2 Bank 4A Smart Battery Charger - GENIUS2X2 - https://no.co/genius2x2) it does say "For Genius Multi-Bank 2X2/2X4, each bank is isolated and functions independently.", so that's extra reassuring.

 

[essco1503]

@essco1503 - From what @Freewheel and @Greg_B have observed, the 2x12V NOCO should be good to go with no need to disconnect the two batteries. That's also described on the NOCO support page: NOCO - Series And Parallel Charging - Support - https://no.co/support/series-and-parallel-charging. Note, on the GENIUS2X2 page (NOCO - 2 Bank 4A Smart Battery Charger - GENIUS2X2 - https://no.co/genius2x2) it does say "For Genius Multi-Bank 2X2/2X4, each bank is isolated and functions independently.", so that's extra reassuring.

Yeah Im 100% good to go on it and I have the charger and some extra eyelet connector cables ordered and on their way. I think this will be a great solution and Im glad its 100% cleared up now on here too so anyone looking for the info in the future has it clearly laid out. I got the 2x10 amp unit cause the way these smart chargers operate I never need to worry about too much voltage going in at the wrong time but if I do have flat batteries Im not waiting forever to get them charged up and reconditioned.

 

[Greg_B]

A few more thoughts...

This threads been great at reminding me of my evolution with charging two 12V batteries in series. And it has been an evolution. The BJ74 now has solar, so the batteries are maintained all the time. Though at my latitude in the depths of the cloudy wet winter months it struggles if I don't drive it regularly and leave the converter hooked up (slow drain).

The two bank NOCO will be a great solution for the reasons mentioned in posts above. As long as you don't need power supply for a load, as well as battery maintenance. Of course this is accurate for only as long as the chargers abilities are not changed.

NOCO 24V charger versus NOCO two bank charger from Charging a 24V Battery System thread.

Medium/Long term battery storage maintenance from 24V Float/Maintenance Battery Charger thread.

hth's
gb