Another battery question

[Phancy]

I have 4 Trogen 6 volt 125 batteries that are 8 years old and are in great working order. I recently been given 2, new 6 volt U S AGM 2000 batteries. Is it ok to wire in the wet cells into the AGMs being they are to different types of batteries? We do a lot of off the grid camping the extra power would be nice. We have 280 watts of solar to help keep them charged.

Phancy

[time2roll]

The new AGM may wear out same time the older Trojans do. Otherwise no real harm.
I would not recommend this if spending money but for free.... go for it.

[Dirtclods]

In the past I've ran AMG battery with a wet cell no issues and no special charging system it worked fine!

[pianotuna]

Best practise would be to have switches to isolate the banks from each other during charging.

[Phancy]

Thanks for the information. I have 2 batteries in the battery compartment of the camper, i had to remove the drawer tray, I have 2more in the wheel well front drivers side and possibly put 2 more in the rear wheel well.
With what I have just read I may take the t 125s out, buy 2 more AGMs and install the AGMs. This will help with battery maintenance as I rarely take the camper off the truck.
Thanks again,
Phancy

[MEXICOWANDERER]

Where's my horsee with the disposable diaper when I need it?

It Depends...

A recharge voltage that can properly recharge the AGM batteries will not be high enough for the flooded batteries. So in recharging the AGM batteries will hog most of the charging as they have lower internal resistance.

If your time off-grid is limited to 1-2 weeks the batteries can suffer through it. Try and separate the two types when recharging. 14.4 volts for the AGM and 14.8 volts for the flooded batteries. Just realize that twi weeks is the absolute limit each time you do this and I would't do it more than a couple times a year at that duration.

I would recharge each type of battery immediately upon returning home. Depending on aging chemistry the batteries will get-along when paralleled from OK to poorly.

Take a chart along that explains proper run and charge voltage for each type of battery.

The 3-cell batteries can be measured individually whilr at rest. If you come across one that is .2 lower than other(s) then this is serious enough to need immediate corrective action. The 6-cell batteries cannot be checked while connected and at rest.

You have a lot of batteries to recharge I would start off with the flooded batteries first because they would encounter sulfation on a two week trip with deep discharges.

Separating the two types for recharging then reconnecting for use is the biggest headache. The age of the batteries - both types, was taken into consideration.

[Reddog1]

Moved to Tech Issues

Wayne
Moderator

[Crazy_Ray]

google 12volt side of life. read and learn

[Dakota98]

Artum Snowbird wrote:
I would think that you would want to separate the two sets of batteries with a switch so that you can use one set or the other for output. But at the same time you will also want to charge both sets of batteries. I think you can do this with a good switch and a few diodes that will only allow circuit flow in one direction.

This sounds like the best plan.

Both types of batteries actually have different charging profiles. The AGM's factory specs indicate maximum bulk charging of 14.4 - 15.0

The SLA's will require higher voltage for occasional equalization.

[jswharton]

Where do you have room for 6 batteries plus 2 more?

[Artum_Snowbird]

I would think that you would want to separate the two sets of batteries with a switch so that you can use one set or the other for output. But at the same time you will also want to charge both sets of batteries. I think you can do this with a good switch and a few diodes that will only allow circuit flow in one direction.

[cewillis]

One reason is that the 'stronger' (those that have a higher fully charged voltage) batteries will constantly be trying to charge the weaker ones - ie, the batteries will tend to equalize. Also, lead acid and AGM batteries have different charge rates, and max charging voltage.
That said, I might be tempted to try it in a carefully monitored situation to see what happens -- until someone reminds me of something that I'm forgetting.

[popeyemth]

Phancy wrote:
Why not ages?

It's my understanding new batteries have less internal resistance and most of the amperage will come from them at first and that shortens their life

[2oldman]

Your Trojans will be just fine with other stuff. I see people doing this kind of thing all the time and 'they' claim it works just fine.

[Phancy]

Why not ages?