Hook up to slave receptical

[Barrydumoulin]

I just purchased two new Diehard AGM batteries for my 77 A2. I have seen older video about installing a 24 volt Battery Tender for trickle charging, but noted another video where a Battery Saver was installed through the Slave Receptacle. Any issues in doing this? Thanks all.

[Hambone]

You should have no problem running your charging setup through the slave receptacle.

[Bonica]

If you are using 51R batteries and need mounting brackets I have them available for immediate shipment.
PM me for further info.

Fil Bonica

[kmam]

I pulled the innards out of the slave receptacle and replaced them with an anderson connector so I can connect my charger using the same connector I use on other items. That works fine and retains the original appearance when not in use.

[pvtwinger]

I was once given advice not to charge the two 12v batteries in series with a 24v charger. I don’t know if it is a good or bad idea. I think it has to do with possible uneven charging states of the individual batteries when charging them together in series, but I am not certain of this. Anyway, I purchased a Battery Tender® 2-Bank 12V, 1.25 Amp Battery Charger, which allows you to maintain two 12v batteries with a single Battery Tender. The Battery Tender is not a charger, but a battery maintainer, although it can charge a battery that is not totally dead.

I connected the two sets of leads from the Battery Tender to the two batteries permanently (not with alligator clips) and mounted the Battery Tender inside the battery compartment. I then ran the AC cord out of the battery box to the passenger side footwell and just plug it in to 110v AC when needed. This has always worked fine for my situation. Only drawback I see is that you can’t easily see the status lights on the Battery Tender unless you remove the battery box lid, but that has never been a problem for me.

[rickf]

Maintaining two 12 volt batteries in series is not as bad as charging them in series even though that is what is done in the original setup. As long as the batteries are both bought together and equal in charge there is no issue but if you get a battery that becomes weaker than the other then the good battery will be constantly be overcharged because the total voltage will show low. The system will charge at 28 volts but instead of each battery getting equal voltage the weak battery will be calling for 14.5 volts while the good battery will only need 13 volts. so hooking up to the slave connector will work fine, just keep an eye on the batteries and check them occasionally with a meter to be sure they are equal. And to do that you leave the ignition off and crank it for about ten seconds to take any surface charge off and then take your voltage readings, they should be equal. And I would just modify a spare slave connector to attach to the maintainer, that way if you ever need it to actually use as a slave connector to give or get a jump it is still available.

[Refit1701]

It was my thinking that when using a dual maintainer, you have to disconnect the interlink between the two batteries, is this so? When I use a full charger I disconnect them and charge them separately.

[svramselaar]

hi

if you take the slave plug to load and have a masterswitch it must be closed
normaly the connection cable must not be removed , with the loader they are two different circuits
Rick is right with the argument aboud the midle point voltage this is way you can not take 12 volt from one battery
use alwais a DC- DC converter
a AGM battery use a higher load voltage not 13,6- 14,4 volt but 14,6-14,8 volt
a MUTT generator( A1 ) stand at aboud 13.6 - 13.7 volt a alternator (A2 ) stands at aboud 27- 28.8 volt
wen the voltage at the MUTT must go over 29 volt the ignition and bulbs are at danger
at a older vehicle i alwais recommend the normal lead accid battery`s
below a nice explanation aboud the AGM battery`s

george

https://www.alpha-batteries.co.uk/blog/ ... batteries/

[Barrydumoulin]

Thanks everyone for the great responses. I noted that it is best on AGM's to NOT trickle charge, just once a month, interesting fact. This is a great site! I will see about altering or manufacture some pins to charge through the slave port.

[rickf]

If you are running two 12 volt chargers you do not have to disconnect anything. You need to only hook the leads of charger #1 to the positive and negative of the the battery #1 only. And the charger #2 goes to the positive and negative terminal of the other battery. Never hook the negative charger lead to the body! It will see 24 volts there. From terminal to terminal it is only reading/charging between those two points.