two type chargers connected to one battery

[dbarrett]

I have an onboard Onan generator and access to shore power for storage. I have two chargers: a 55Amp no float type for boon docking and a 2stage 13Amp house charger. While boon docking, I want to use the 55Amp charger. What is the best way to hook up both these chargers? Can one charger damage the other if they are both hooked up but only one charging. Would switches be needed on the AC and/or DC side of the chargers? I need to keep it visually simple so that my less technical support can figure out what they need to do if I'm not there. Thanks for your expertise and help. Dino

[Chuck_thehammer]

westend wrote:

Chuck_thehammer wrote:
use 2 pole double throw power switches.. one or the other ..

NEVER Both at the same time... not designed for it..

if one is set at 13.5 and another is set at 13.7.. where do you think the difference will go.. into the lower voltage one and burn it up..

chargers put OUT and Never accept "IN"... and this is what will happen.

my opinion.

This is not how the two would operate together. Both chargers will start to push less amperage as the stored current in the battery increases or as current is supplied by an added charger. Since battery chargers are usually capacitor coupled and diode protected at the output, it is nearly impossible to "burn it up" with another charger. If it was possible, every time a charger was connected to a battery with higher voltage or current stored, the charger would fail. That is not the case.

For controlling the chargers, if the OP had a box with two AC switches, one marked "boost" and the other "float", it may be the most intuitive arrangement.

I guess my working at Triplett as a repair technician is no longer valid. some years ago. I will on longer offer advice on chargers/inverters

Have a good day.

[dbarrett]

Cowboy et al: Thank you for your knowledge and support. I now have a much better understanding of how battery chargers work. I like the simplicity of an illuminated double pole double throw switch idea with the labeling of boost and float. Great group here. Dino

[westend]

Chuck_thehammer wrote:
use 2 pole double throw power switches.. one or the other ..

NEVER Both at the same time... not designed for it..

if one is set at 13.5 and another is set at 13.7.. where do you think the difference will go.. into the lower voltage one and burn it up..

chargers put OUT and Never accept "IN"... and this is what will happen.

my opinion.

This is not how the two would operate together. Both chargers will start to push less amperage as the stored current in the battery increases or as current is supplied by an added charger. Since battery chargers are usually capacitor coupled and diode protected at the output, it is nearly impossible to "burn it up" with another charger. If it was possible, every time a charger was connected to a battery with higher voltage or current stored, the charger would fail. That is not the case.

For controlling the chargers, if the OP had a box with two AC switches, one marked "boost" and the other "float", it may be the most intuitive arrangement.

[K_Charles]

I don't know about your charger but I have had two chargers on one battery a few times and never had a charger go bad.

[pianotuna]

BFL13 has used up to 4 chargers on one battery bank at the same time.

[Chuck_thehammer]

use 2 pole double throw power switches.. one or the other ..

NEVER Both at the same time... not designed for it..

if one is set at 13.5 and another is set at 13.7.. where do you think the difference will go.. into the lower voltage one and burn it up..

chargers put OUT and Never accept "IN"... and this is what will happen.

my opinion.

[dbarrett]

Pianotuna: How would you know if the 2 chargers played well together? Observe line voltage? Do I want to operate the 55Amp no float charger for more than 2 hours? I'm thinking about water loss when it charges to 14.8V. Dino

[pianotuna]

Hook them both up. Apply power. They may play well together, or they may not. I would not fear damage to either.