UPDATE 1 on 23 Dec postUPDATE 2 on 25 Dec post----------Mex is driving me crazy! He said do not mix my used 12s (Scrubber batteries, he calls them--humph! They are respectable golf car batteries I'll have you know. Humph!) with my regular bank of 6s or they would evilly interact, and I would ruin my good 6s. I asked if that were still true if they were all on a Float charge. Mex said they would still have evil interactions even when all on a Float. So I have gone ahead at some inconvenience to keep the used 12s and the good 6s apart. Now all of a sudden, Mex pipes up in another thread with this!!!MEXICOWANDERER wrote:Batteries should be separated after the charging protocol. Connect all batteries together and apply 1 nominal 14.2 charging volts and there is no way any of the batteries can detect it one battery or a hundred are online, or the chemistry of any of them. The only requirement made of a charging system is that it not under or overcharge the battery. Voltage requiments for flooded 5% antimony batteries and pure lead AGM is similar enough for multiple warhead work.It's when the charging ceases that the problems arise.So go ahead and use a smart solenoid to parallel charge the batteries. I have done this too many times to count.What is going on here? Are there evil interactions or not as long as they are charging or on a float? Does this leave the time they are discharging together as when the evil interactions get going?If they are banked on solar, they discharge at night and charge during the day. So the evil interactions come out after dark? Can I just call Ghost Busters?

I think the difference is you were talking of a float charge which would be charging at a low current and is used to maintain a charge, not charge from an uncharged state. He is speaking of 14.2 volts at a hgiher current which can overcome the tendency of the batteries to drain voltage from one another and is used to return a battery from an uncharged condition to charged.

I was proposing to bank them all together while camping off grid, sometimes for weeks at a time, where they would be discharging and charging together. They would get solar and converter charging as required, never getting to 100% and not going below 50% either, then going home and separating them to get ("recover") each to 100% individually.Then they would go on a Float together or separately (I have several float chargers) till the next camping session.Mex said that was bad. Has he changed his story? Did I not understand the Oracle the first time? This really matters for how I set up the trailer with wiring etc.

If they are all wet cell and you have solar... I would just connect them and let it run.No separate charges upon return. No reconfiguring while camping. Just let the solar do it's magic.Of course if you have insufficient sun for a few weeks to get up into absorption then apply a float.That is how I roll.

smkettner wrote:If they are all wet cell and you have solar... I would just connect them and let it run.No separate charges upon return. No reconfiguring while camping. Just let the solar do it's magic.Of course if you have insufficient sun for a few weeks to get up into absorption then apply a float.That is how I roll.X2.If you want to join them and may want to separate them later, use a master disconnect switch.

Hi,My limited understanding is that the mix of the different chemistries plus the difference in require ideal float voltage leads to weakest bank becoming a parasite on the others once they are fully charged up.

Mixing Batteries on Float-- Mex Test Update 2

50 Replies

Pipeman
Explorer
Dec 18, 2013
Quoting Mex "It's when the charging ceases that the problems arise." I get charge them together and then disconnect them from one another after charged!!!!
pianotuna
Nomad III
Dec 18, 2013
Hi mena,

No, it doesn't matter if the batteries are all new. In an ideal world they need to be as near twins of each other as possible. Mixing a 6 volt bank, with 12 volt jars simply is not optimal.
pianotuna
Nomad III
Dec 18, 2013
Hi BFL13,

It may help to think of alternator charging at the end of a long wire. The alternator tends to "see" the chassis battery--and shuts down leaving the battery on the long wire less than fully charged (or even not doing any charging at all).

A similar process may be going on with dissimilar chemistries and voltages. The six volt in series, because of their external series link needs must always have slightly lower voltage due to increased resistance from the connections, so charging voltage, for them, needs to be "tweaked" upwards to overcome the resistance--but that means the 12 volt jars would be receiving higher than optimal voltage and possibly tending towards overcharging.

It was interesting to see my house batteries being "thirsty" after 4 days of 13.2 volts in cold weather (-20 to -30 C), with little in the way of solar charging. I did remember to push the button to get to 14.4 a couple of times, but mostly I forgot.
mena661
Explorer
Dec 18, 2013
MEX meant that your bad batteries would prey on your good one's. That's why he saying not to connect them together. I think if your T1275's were new they would be ok to connect together while camping. There is interaction between them especially when they're on float. I saw this for myself recently when I found the bad wiring connection and one of the 6V wasn't getting fully charged. One battery was at baseline, two were above baseline and the not fully charged one was showing just that. Fixing the bad wire didn't allow a full charge on that low battery either with them all connected together (believe me I wasted a week on trying to do just that). I had to separate them all and charge that 6V individually. OT, it seems that topping them off (finish charging) individually is a pretty fast process.
BFL13
Explorer II
Dec 18, 2013
For the time I would be camping with them banked, they would never get to 100% anyway. They only get to 100% when taken there separately at home (or if I ever did the split bank trick with solar)

So that leaves keeping them on Float at home as the only time they might be prevented from staying at 100% if connected mixed after being "recovered", from what PT mentions. If they are all at 13.4v will one set eat the other?

I am trying to understand if there is some sort of evil interaction current eddying nasty business that goes on that harms them during normal discharges and recharges and on Float. I don't care if one set only gets to 97% while the other set gets to 98% on a day's worth of solar. That gets fixed when doing the 100% recovery they all get later separately.
pianotuna
Nomad III
Dec 18, 2013
Hi,

My limited understanding is that the mix of the different chemistries plus the difference in require ideal float voltage leads to weakest bank becoming a parasite on the others once they are fully charged up.
westend
Explorer
Dec 18, 2013
smkettner wrote:
If they are all wet cell and you have solar... I would just connect them and let it run.
No separate charges upon return. No reconfiguring while camping. Just let the solar do it's magic.
Of course if you have insufficient sun for a few weeks to get up into absorption then apply a float.
That is how I roll.

X2.
If you want to join them and may want to separate them later, use a master disconnect switch.
time2roll
Nomad
Dec 18, 2013
If they are all wet cell and you have solar... I would just connect them and let it run.
No separate charges upon return. No reconfiguring while camping. Just let the solar do it's magic.
Of course if you have insufficient sun for a few weeks to get up into absorption then apply a float.
That is how I roll.
BFL13
Explorer II
Dec 17, 2013
I was proposing to bank them all together while camping off grid, sometimes for weeks at a time, where they would be discharging and charging together.

They would get solar and converter charging as required, never getting to 100% and not going below 50% either, then going home and separating them to get ("recover") each to 100% individually.

Then they would go on a Float together or separately (I have several float chargers) till the next camping session.

Mex said that was bad. Has he changed his story? Did I not understand the Oracle the first time? This really matters for how I set up the trailer with wiring etc.
Sloop_Smitten
Explorer
Dec 17, 2013
I think the difference is you were talking of a float charge which would be charging at a low current and is used to maintain a charge, not charge from an uncharged state. He is speaking of 14.2 volts at a hgiher current which can overcome the tendency of the batteries to drain voltage from one another and is used to return a battery from an uncharged condition to charged.

Forum Discussion

Mixing Batteries on Float-- Mex Test Update 2

50 Replies

About Technical Issues

Related Content

Mixing battery types??

Lifepo4 float setting?

LFP battery absorption and float - report

Mixed Messages

Flooded Batteries on Float