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Topic: How do you know when it's time to replace your Trojan T105 house batteries? (Read 706 times) previous topic - next topic
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How do you know when it's time to replace your Trojan T105 house batteries?
Hi everyone,

I have a 2008 26.5ft rear bath with standard 2 Trojan T105 batteries. I suspect the batteries may be the original ones (the previous owner had not replaced them since his ownership from back to 2012) and I'm wondering how to tell they need to be replaced. I keep them topped off and my battery meter indicates the solar panel it topping them off each day to 100%. On occasion, if I'm NOT on shore power it seems as though when I use my electric step the house batteries don't have enough juice to power the step in or out even it they show a full charge. Last night it was about 30 degrees and I went out to put a couple of items in the RV. When the electric step engaged, it moved very slowly and then the propane gas detector started beeping indicating it wasn't getting proper power and my interior light was flashing on and off. When I plugged in to shore power everything was good to go. It seems as though the step is drawing enough power to make the house batteries struggle. Any way to know they need to be changed out? I know that at 8 years at least I am on borrowed time with them but they haven't been pushed much over the years. The rig only has 20,000 miles on it. Appreciate any advice.
Joe B.
2008 26ft  grey/white Rear Bath
Family of 5 hitting the open road as much as we can.
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #1 –

From your description, you have a loose connection, or it is time for new batteries.
Fully charge the batteries (12 to 24 hours) with the appropriate trickle charger 14.5 to 15 volts combined, 7.25 to 7.5 separately. 
Amazon.com: Suuwer Automatic Trickle Battery Charger 6 Volt or 12 Volt 1.25...

Then check the Specific gravity of the acid in each cell with a battery hydrometer.  At full charge they should be about 1.275 and all should be close to each other.  A gravity reading of 1.00 is fully discharged or shorted cell.  Use this for Specific Gravity.  Amazon.com: Performance Tool W1657C Deluxe Battery Tester: Automotive

Then test each battery separately,  with a 100 amp load tester like this.
Amazon.com: Schumacher BT-100 100 Amp Capacity Battery Load Tester: Automotive
If it drops into the yellow or red zone, it is time for new batteries.



As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Rodney
1988 Mid Bath
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #2 –
I edited my post to indicate that when this low power seems to occur I am NOT on shore power. Just running off the house batteries.
Joe B.
2008 26ft  grey/white Rear Bath
Family of 5 hitting the open road as much as we can.
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #3 –
Do you have a way to monitor the voltage? 

I can tell I need new batteries when the voltage soon drops below 12.3 or so once disconnected from a charging source (no solar, engine and generator off, no shore power).

I usually see something in the 11.x range, indicating a shorted cell in the battery.

You can take the batteries to most auto parts places and have them tested for free.  After 10+ years, I would skip that step and just buy new ones.

Some people only buy Trojan brand.  In my area there are golf cart stores with competitive prices.  I buy the Costco or Sams club alternatives and have had decent luck. 

Rich
‘03 MB in NC
2003 MB
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #4 –
Quote from: rich  - 
Do you have a way to monitor the voltage? 

I can tell I need new batteries when the voltage soon drops below 12.3 or so once disconnected from a charging source (no solar, engine and generator off, no shore power).

I usually see something in the 11.x range, indicating a shorted cell in the battery.

You can take the batteries to most auto parts places and have them tested for free.  After 10+ years, I would skip that step and just buy new ones.

Some people only buy Trojan brand.  In my area there are golf cart stores with competitive prices.  I buy the Costco or Sams club alternatives and have had decent luck. 

Rich
‘03 MB in NC

Thanks for the info. I've contemplated trying the Costco brands but unsure of what battery is compatible. Would love to find a battery that was maintenance free but research seems to indicate its not as simple as a quick battery swap out.
Joe B.
2008 26ft  grey/white Rear Bath
Family of 5 hitting the open road as much as we can.
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #5 –
Ah battery talk ...... <smile>

A link with good infro about/on batteries.
Basic to Advanced Battery Information from Battery University

Replacement depends on what your plan is for the future use of you LD.   And <smile> the size of you wallet.  But as a rule of thumb Lithium is the most expensive up front but cheapest in the long run.   Lead Acid is the cheapest up front but most expensive in the long run.

glen

personal fine art photo stuff
TF Mack | Flickr
It's all good .......
2014 Twin King
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #6 –
The simple answer to the question posed in the OP is if your fully charged batteries get weak fast and fully recharge fast they have had it. The only glitch with this method is you have to have experience with new batteries to make this judgement call and if you are new to the game and come in to it in the middle to later part of a battery banks life  you won't have required perspective.
Discuss anything with anyone and disagree agreeably. Always be polite and respectful.
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #7 –
Quote from: brewersarcade  - 
I've contemplated trying the Costco brands but unsure of what battery is compatible.

The Costco locations I've seen only  stock 1 kind of 6v golf cart batteries.  That's the one you want!  (2 of them).

They're probably not as good as OEM, but they're not as expensive either.  Others have valid reasons for making a different choice. 

Rich
'03 MB in NC

2003 MB
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #8 –
Quote from: rodneyhelfrich  - 
From your description, you have a loose connection, or it is time for new batteries.

Then check the Specific gravity of the acid in each cell with a battery hydrometer.  At full charge they should be about 1.275 and all should be close to each other.  A gravity reading of 1.00 is fully discharged or shorted cell. 

Then test each battery separately,  with a 100 amp load tester like this.

Batteries that are at least light years old should be suspect, especially if you are noticing things working slowly or the voltage dropping quickly.
Costco batteries are OK,  Trojan batteries are a longer lasting but cost more. Either presents a better value than AGMs.
Lithium represent a large investment in batteries and a charger, fine if you expect to keep your LD for many more years

Other than reading the specific gravity of the batteries's electrolyte, testing deep cycle batteries is difficult due to the size of the load bank needed.  When I maintained generators and large battery banks, at LAX, we used a trailer-mounted load-bank to test large batteries, basically was a huge resistor with fan cooling.
Smaller, hand held testers cannot provide a large enough load, long enough for a useful reading without burning up.

Larry

Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #9 –
Quote from: Larry W  - 
Batteries that are at least light years old should be suspect, especially if you are noticing things working slowly or the voltage dropping quickly.
Costco batteries are OK,  Trojan batteries are a longer lasting but cost more. Either presents a better value than AGMs.
Lithium represent a large investment in batteries and a charger, fine if you expect to keep your LD for many more years

Other than reading the specific gravity of the batteries's electrolyte, testing deep cycle batteries is difficult due to the size of the load bank needed.  When I maintained generators and large battery banks, at LAX, we used a trailer-mounted load-bank to test large batteries, basically was a huge resistor with fan cooling.
Smaller, hand held testers cannot provide a large enough load, long enough for a useful reading without burning up.

Larry



Thanks Larry and gang. I think I need to budget for a new pair of Trojans after the winter freeze. Install should be pretty straight forward correct? Shut off the main power breaker and rewire in the new batteries? I would absolutely go Lithium becuase we plan on keeping our Lazy Daze a long time (we're in our late 30's with 3 small kids) but I don't quite understand what type of charger I need to get and if it's a DIY job or one I should let a RV shop handle.  Now, who knows the best place to get a dea on the T105sl!? :D

Thanks for the responses. I'm slowly learning the ropes and appreciate the years of expertise you all have!
Joe B.
2008 26ft  grey/white Rear Bath
Family of 5 hitting the open road as much as we can.
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #10 –
Without a way of electrically monitoring the batteries, it can be difficult to keep track of their condition. Batteries that use an excessive amount of water are getting old. Checking the battery voltage after dark (no shorepower) will tell you if there is a shorted cell. A reading then of 10.5 to 11.9 Volts means the batteries are down a cell even if a battery monitor is indicating full charge.

Steve
2004 FL
2013 Honda Fit
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #11 –
Quote from: brewersarcade  - 
I would absolutely go Lithium becuase we plan on keeping our Lazy Daze a long time (we're in our late 30's with 3 small kids) but I don't quite understand what type of charger I need to get and if it's a DIY job or one I should let a RV shop handle.

Lithium will require a complete rewire with new charger/converter and probably solar charge controller as well. One of those things where asking if it is DIY is an indication you need to find a pro to do the job... The learning curve will be steep.

Steve
2004 FL
2013 Honda Fit
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #12 –
Quote from: brewersarcade  - 
Thanks Larry and gang. I think I need to budget for a new pair of Trojans after the winter freeze. Install should be pretty straight forward correct? Shut off the main power breaker and rewire in the new batteries? I would absolutely go Lithium becuase we plan on keeping our Lazy Daze a long time (we're in our late 30's with 3 small kids) but I don't quite understand what type of charger I need to get and if it's a DIY job or one I should let a RV shop handle.  Now, who knows the best place to get a dea on the T105sl!? :D

Thanks for the responses. I'm slowly learning the ropes and appreciate the years of expertise you all have!

I am the original dufus when it comes to things electrical. I had to replace my Trojans in a parking lot in the middle of a trip. I found it very helpful to take a picture of the old batteries installation before disconnecting anything. I think I also taped notes to the various wires indicating to which terminal they were attached. Much relief after reassembling when everything worked properly. In addition to the breaker (or throwing the disconnect switch if one is installed), don’t forget to pull the solar fuse if you have panels. My Trojans are now 8 years old, so I might soon be repeating the process. — Jon
(Former) ‘06 TK “Albatross.” And (former) Vespa 250.   Alas, no more; both are gone.😕 Great memories remain! 😄
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #13 –
Quote from: Jon & Loni  - 
I am the original dufus when it comes to things electrical. I had to replace my Trojans in a parking lot in the middle of a trip. I found it very helpful to take a picture of the old batteries installation before disconnecting anything. I think I also taped notes to the various wires indicating to which terminal they were attached. Much relief after reassembling when everything worked properly. In addition to the breaker (or throwing the disconnect switch if one is installed), don’t forget to pull the solar fuse if you have panels. My Trojans are now 8 years old, so I might soon be repeating the process. — Jon

Thanks!! Need to check my fuse panel. Didn't think about the solar fuse. I was just going to shut off the main breaker. I assume the fuse for the factory panel is with the rest of the fuses. Thanks again! Found a dealer near me that sells the Trojans for $170 each and I assume there is a core fee. I'll hold off until the Spring but just another add to the expense list ;D
Joe B.
2008 26ft  grey/white Rear Bath
Family of 5 hitting the open road as much as we can.
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #14 –
I too have been thinking about batteries, in our case we have no solar. Our batteries are slightly swelled so I feel we are on borrowed time. I did install a watering system and water consumption I feel is about normal. In our case, I really can't justify the added cost of Lithium or AGM I feel the plain old T105's would do us just fine.

Jon
1994 MB
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #16 –
While we are still in Yosemite, I’ve been watching the OEM Battery Monitor like a hawk. I will let AM Solar install my recently purchased Victron monitor come July with our upgrade.

As much as I dislike running the generator to top off the batteries, there just isn’t enough sun to charge them.

I’ve seen the charge of the freshly topped 4 year old AGMs go from a healthy 12.8 to a low of 10.5 overnight with only the fridge running.

I am now leaning to a total of 4 Lithium batteries and a total of 5 100 watt solar panels. I feel very comforted by Lithium’s long life and useful Depth Of Discharge (DOD).

With the DOD of AGM batteries being 50% and their annual 10%  loss of useful charge capacity, Lithium’s just make more financial sense on top of the peace of mind and QCF (quiet campground factor) that comes with their installation.

Lithium’s are unlike Flooded batteries. From what AM Solar told me, Lithium’s require a completely different charge controller. They also require additional electronics between them and the chassis alternator.

All of this is above my pay grade so I’m letting the Pros do the work for me. Next years trips to Yellowstone and Yosemite I plan on listening to the squirrels and the creeks instead of my generator.

Kent

2015 27' RB "MissB.Haven"
 
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #17 –
Kent,
Why does your fridge drop the battery voltage overnight?  Mine runs on propane when I'm not hooked up, not 12v. The only 12v load at night is the furnace turning on and off, and the CPAP.

BTW, I have a 12v side by side fridge/freezer in the tug that draws off 4 6v Lifeline AGM's .  The fridge draws 4ah, runs pretty much continuously,  and that draws the battery voltage from 12.9 to 12.65v overnight with healthy batteries.

I'll be interested in where you go with this, since my AGM's are five years old in the LD.

Harold
2014 27 MB
Towd: Either the Jeep Wrangler or trailer containing the BMW R1200GS and 2 E-bicycles
Happy wife=Happy life
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #18 –
Quote from: Blueox25  - 
Why does your fridge drop the battery voltage overnight?  Mine runs on propane when I'm not hooked up, not 12v. The only 12v load at night is the furnace turning on and off, and the CPAP.

Actually, the fridge controls run on 12V, as do the defroster heaters that cycle on periodically, whether on propane or shorepower, drawing an amp or more. Still, a healthy fully-charged set of batteries should not drop that much in voltage unless there is an unknown parasitic load somewhere.

Steve
2004 FL
2013 Honda Fit
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #19 –
Steve,

Not to distract from the OPs post, but I’ve looked everywhere for random phantom power vampires but have found none. 👹

As recently as September while in Yellowstone, the voltage has remained fairly consistent from night till morning. I have had the occasional power usage after dark that has taken the AGM’s down to the 10.5 range so I’m thinking I have cursed them to loose power more quickly. I also wonder if the colder weather here in the Valley may be a factor.

Just charged the batts before heading for breakfast at Curry Village and I’m cringing at what the monitor will be reading when I get back to the rig.

Kent
2015 27' RB "MissB.Haven"
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #20 –
Kent,
Do you have a good shop that can do a load test? Putting a big load on the battery and watching the voltage drop will tell you a lot about your battery's  health.
2014 27 MB
Towd: Either the Jeep Wrangler or trailer containing the BMW R1200GS and 2 E-bicycles
Happy wife=Happy life
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #21 –
Quote from: Kent Heckethorn  - 
Just charged the batts before heading for breakfast at Curry Village and I’m cringing at what the monitor will be reading when I get back to the rig.

Kent, your batteries will likely not charge up that quickly through the converter. I don't recall if you have a battery monitor, but if so, you need to at least charge at about 14.3 V until the charge current drops to 1A to put most of the charge back. However, if you read 10.4 V in the morning, you probably have a shorted cell. If you have a voltmeter, check the voltage across each battery before charging. You will probably find one reads about 2 V higher than the other.

Steve
2004 FL
2013 Honda Fit
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #22 –
Quote from: Steve  - 
Actually, the fridge controls run on 12V, as do the defroster heaters that cycle on periodically, whether on propane or shorepower, drawing an amp or more.

The heaters around the perimeter of the doors are powered all the time, whenever the refrigerator is on. The control board does not have a defrost timer.  Premium replacement refrigerators have a 'high humidity' switch that turns the heaters on and off.
Our LD's refrigerator door heaters have been disconnected to lower the power draw, living in a dry climate, they are not all that useful.  If we lived east of the Rockies, they would still be connected.

FYI, For those not in the know, Dometic refrigerators have heating wires around the perimeter of the doors to dry any condensation that occurs under the gaskets. In humid climates, condensation evidently is an issue.
Older LDs refrigerators had a switch for the door heaters and one for leaving the refrigerator's interior light constantly on, used to provide heat, in very cold conditions, to prevent the refrigerator's contents from freezing.

Larry


Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #23 –
Quote from: rich  - 
I can tell I need new batteries when the voltage soon drops below 12.3 or so once disconnected from a charging source...

What do you mean by “soon?” One hour? Next morning?

I have two 4 years old 6 Volt lead batteries (Interstate GC2-XHD-UTL, 232 Ah) that are usually being charged by my 320 Watt solar system. Right now (at 1 pm in Southern California) the charge controller shows that they are charged to 14.0 Volt (see picture), tonight at 9 pm it will show between 12.9 and 12.6 Volt (using some lights, keeping my laptop and my mobile hotspot charged, having the 1500 Watt inverter on), and tomorrow morning - before using anything, just having had the inverter on over night - it will show 12.3 or 12.2 Volt (I had once only 12.1 Volt).

Can you (or someone else) tell me what this means in regards to my batteries? Are they good, kind of ok, or getting weak? Thanks!

Apart from this question I would also appreciate if someone could explain to me the numbers in the picture from the charge controller. I do not really understand them, especially not the second row with the Ampere numbers, and this is not foolproof enough explained in the manual. Thanks!

Klaus
2001 26.5 Mid-Bath
Re: How do you know when it's time to replace your Trojan T105 house batteries?
Reply #24 –
Your solar panels are connected in series, producing 31.2 V at 4.7 A (i.e. 146.64 Watts) into your charge controller, which is apparently an MPPT model which will keep its output at max power. So, 146.64 W / 14.0 V = 10.47 Amps to the batteries, pretty close to the 10.6 Amps indicated. The third symbol may be loads, drawing 0 Amps, so nothing turned on?

Steve
2004 FL
2013 Honda Fit