add a battery kit and onboard charger

[cambosoup99]

I've got 2 batteries wired in with my add a battery kit from blue sea systems and the system works great.

Recently, I added and onboard charger to maintain the batteries while away. protournament 100 by promariner. The charger works as advertised but with the add a battery kit installed the ACR kicks in and instead of charging 2 batteries separately. It combines them which defeats the purpose of my onboard charger features.

so I installed a switch that disconnects the ground from the ACR when i'm charging via the onboard charger. seems like problemed solved.

but now i have to deal with another switch to remember to turn on and off.
would a regular 30/40amp normally closed relay. do the job to automate this? I'm thinking it would but just want some opinions from everyone else.

 

[Silvertip]

Re: add a battery kit and onboard charger

Leave the system as it was. When the batteries are combined, so are the charger outputs and bridging them is perfectly acceptable as the isntruction sheet should indicate. The net result is the same charge rate so charging is not altered. There is no problem charging two batteries in parallel. The charger (or the engine regulator) cannot distinquish between the two batteries anyway as it monitors system voltage. No switch is necessary.

 

[cambosoup99]

Re: add a battery kit and onboard charger

this charger reads voltage from both batteries and allocates more charge for the weaker battery and less for the stronger battery. Which allows the batteries to get charged faster. And if the outputs are combined same charge will be going to both batteries. That why i was sayin it would defeat the purpose of using this charger with the ACR connected.

 

[Silvertip]

Re: add a battery kit and onboard charger

The load sharing feature is advantageous mainly in a 24 volt series) situation. The situation with your ACR is not an issue if left as is, and without the switch, since with the batteries paralleled, the charger outputs are bridged (paralleled) as well so the full output of the charger goes to the "system". As the ACR parallels the batteries they equalize quickly which again, the charger does what it is supposed to do -- dump the full charge to the both batteries. It cannot differentiate batteries in that scenario nor does it need to.

Look at it this way. The way YOU want and EXPECT the charger to operate is that when one battery is fully charged the charger output for that battery switches to help out the other. Both outputs are now working on one battery correct??? So when the ACR parallels the two batteries, they become one giant battery to the charger and both outputs are on that one giant battery just as they would be in your "expected" scenario.

I repeat -- leave the system alone and allow it to work as it is intended.

 

[cambosoup99]

Re: add a battery kit and onboard charger

yeah, i guess that makes sense to me now. I should have purchased a single charger then to save money.. thanks

 

[Silvertip]

Re: add a battery kit and onboard charger

That logic is also not valid. Had you bought a single output charger you likely would have bought one that has the output rating of just ONE of the outputs on your dual output charger. Using the dual output charger allows twice the charge rate of a single output when the two outputs are bridged. Therefore charging would take twice as long. Buying a single 20A charger is not much less expensive than a dual 10 amp. And the dual 10 amp charger allows use in a series (24 volt) system should the need ever arise.