Am I overcharging/ cooking my batteries?

[Gapper2]

Just got my solar mostly finished in May.  I have two Odiyssey PC-2150 batteries hooked in parallel .  One thing has been bugging me since I've had these batteries,  the way I read the manual on required maintenance is to hold absorption until .001C at the ten hour rate.  Which if I'm reading it correctly, is 9 mA and then go to float.  This seems totally unrealistic especially if you are relying on solar for topping off.  I'm pretty new at this twelve volt stuff and would appreciate any advice.

I believe the pertinent info is on page 10 and 15 of this manual:




I really have never had them that low but with my low usage sometimes they are taken to .2 amps per battery at 14.7v before going to float.  Is this overcharging?  I do try to charge at 80 amp min in bulk mode when the batteries will take it.

thanks in advance

[sternwake]

Quit charging when both group 31 in parallel accept 1 amp at 14.7v at 77f

While amps can taper below this with more time it is likely overcharging them to.do.so.

If you cycle them often to the 50% range these tppl agms crave high recharge currents. No less than 40.amps.per.each of your group 31.

[Gapper2]

Thanks Sternwake,  That is what I was holding them to before I got my solar hooked up.  Time to change the absorption time.  I have only taken them to 55% SOC twice. Still in sticks and bricks.  They don't have any trouble accepting all the amps I can throw at it.  The most that I've been able to muster up is ~134 amps.

[sternwake]

TPPL AGMs are impressive in how many amps.they can accept before.reaching absorption voltage when depleted. My single group.27 North star was taking 95 to.106 alternator.amps for.5+ minutes when my 140 amp circuit breaker.tripped

Two group .31s. In parallel could likely accept.250 for.several minutes when depleted below.50%.

Huge recharging currents appear.to be restorative to them when they start showing lesser voltages than expected during discharge.i can only muster 65 amps.of.plug in charger.

[Gapper2]

After I found out that these batteries required a minimum of 40 amps each from a bulk state it has cost way too much $$.   I first monitored the stock alternator output for over a year.  While the voltage regulator would reach 14.7v from a discharge battery, the amount of time it would hold that was very unpredictable.  Got frustrated and purchased a Sterling B2B 60 amp.  Got a good deal at $255 but my stock 108 amp alternator just couldn't produce.  So then got aftermarket 200 amp alternator and can see as much as 54 amps at a 14.7 profile until the overheat on the B2B reduces the current in half.  I've got plans for an external fan to aid the probably tiny fan in the B2B itself.   I also took one of your ideas I read about and glued a temp sensor to the stator of the alternator with guage on dash.  The B2B has a 12v switch input for manual control of the unit also.

Before the build got started, I bought the manual 100 amp PowerMax charger to keep the batteries happy.  The first unit they sent was defective and would only output 12.2vdc.  The one I have now only ouputs 15.7vdc.  Would like the 16.2 v you've written about before for equalizing wet cell batteriees.  I've taken it apart a couple of times trying to get that output voltage up but have been unsuccessful.  In fact I've stripped the output circuit board connectors that run the ouput to the batteries.  Not sure what they're called.  Unable to locate.  I use extra tight tie wraps and can only get ~74 amps from it now.  But at least it works.   Everything is lithium compatible.  But no where ready to go there yet.

Thanks for all your helpful advice over the years.  (three deep bows and a I'm not worthy)

[sternwake]

The powermax dc output terminal design did not.impress me. My friend ordered one and there was all sorts.of.issues. the first being a 75 amp model.with 100 amp.stickers. then the larger heavi3r 100 amp model.showed uo.with no.voltage adjustment. Then the 100.amp.adjustable.model.fan would.come.on loud with minimal loads at float.voltage.

The project.died. not.sure.what became.of.the powermax. We were going.to.add a fan for.push/ pull. I think voltage maxex.out around 15.5 iirc.

I posted an inexpensive.150 watt dc to dc converter which can 16.2 volt.flooded batteries in a recent thread.

Look.into delta fans. Well made and some.have rather extreme.rpm. not familiar with the sterling.

Luckily my alternator.is.externally regulated. I jus had to.trick.engine.computer with resistor. And use an.adjustable.regulator