Battery charging for dummies

[Mccool]

I'm hoping to get some advice on charging my trailer batteries.

The trailer has two 6v golf cart batteries run in series giving me 12v and 210ah capacity. They are running a 12v fridge and a string of led lights. Once fully charged, they can run the fridge and lights for ~12 days until they hit 11.7v which is when the fridge cuts off. I have the output side finished and working well.

Now I'm looking into the input side and how to charge the batteries. I would like a permanent "shore power" Input and eventually solar input. The trailer batteries receive no charge from the truck.

Can I buy a charger capable of handling both solar and shore power? If so, any suggestions?

For the solar, do I need a charger and a "controller"?

Thanks!

 

[dreadlocks]

You should just use separate chargers for solar and shore power, they do make all in one units but they are rather limiting and a single point of failure.

This is a rather nice one, though you could go bigger w/dual GC batteries: https://www.amazon.com/MINN-KOTA-1831100-MK110PC-Precision-Charger/dp/B00FM1W9V0/ or you could install what most travel trailers use, a converter/charger such as this: https://www.amazon.com/Progressive-Dynamics-PD9130V-Inteli-Power-Converter/dp/B002OR41J8/ but many of these are just basic dumb power supplies and not using charging profiles which can be a problem if your on shore power for anymore than a few days at a time, or want it to maintain batteries in off season.

and for solar you need a charger/controller (they are one in the same), I'd look at Victron MPPT, that will be sized depending on how much solar you can fit..

 

[Mccool]

Thank you! That clears things up for me. I was looking at the victron MPPT 100/20 for the solar but wasn't sure if I needed an additional controller to make it work.

I will keep them separate per your suggestion. For the shore power, is 10 or 15 Amps adequate? I wont have it hooked up more than a day or two as everything will be turned off when not in use, so the "dumb" charges may be sufficient for my uses.

 

[dreadlocks]

most deep cycle lead batteries Ive worked with seem to be good around 10A charge capability for each 100AH, they spend vast bulk of the charge at that or less.. If they are discharged enough they take more than 10A its only for a very short period.. less than that and your looking at longer charge times.. 10A each typically gets a 100AH 12v battery from 40% SOC to 100% soc in ~8h, with your two 6v 210AH I'd expect a full charge in ~16h.. which sounds rather reasonable unless your on a generator and have to work w/quiet hours.. then you might want a 20-30A charger so they charge as fast as they can.

Batteries dont like sitting unused for extended time, or being stored at anything but fully charged.. they will loose power on their own, and you can come back in spring to find batteries that have been flat for months and likely toast.. you need something that can properly maintain em when not in use.. you can either do this w/shore power and a smart charger, or if you park outside you could let the solar handle supplying a maintenance charge, but only if they are not covered in snow for months.

 

[Buddha.]

You should just use separate chargers for solar and shore power, they do make all in one units but they are rather limiting and a single point of failure.

This is a rather nice one, though you could go bigger w/dual GC batteries: https://www.amazon.com/MINN-KOTA-1831100-MK110PC-Precision-Charger/dp/B00FM1W9V0/ or you could install what most travel trailers use, a converter/charger such as this: https://www.amazon.com/Progressive-Dynamics-PD9130V-Inteli-Power-Converter/dp/B002OR41J8/ but many of these are just basic dumb power supplies and not using charging profiles which can be a problem if your on shore power for anymore than a few days at a time, or want it to maintain batteries in off season.

and for solar you need a charger/controller (they are one in the same), I'd look at Victron MPPT, that will be sized depending on how much solar you can fit..

I have that progressive dynamic with the "charge wizard" for my 210ah GC setup. Lived in the trailer all last summer and now it's been sitting unoccupied, plugged in all winter MN. Seems to do fine, fingers crossed its keeping my batteries' life up.

 

[dreadlocks]

yeah that charge wizard takes it from a dumb charger to a "smart" lead battery charger, basically you want it to go into a float charge when battery is fully charged and not just constantly dumping 14v out, dumb chargers will overcharge if left on, boiling away water and eventually wrecking the battery.. and if it sits in float for say a month they should go up to charge voltage for a few hours so all the cells stay balanced and other things.. Ive got a progressive dynamics converter in my trailer and its allright, does not output its rated power however.. I can only get about 27A out of my 45A lithium model despite oversized wiring.. so you might buy a lil bigger than you think you need to account for that.. Why I suggested a 30A for quickly charging dual GC batteries.

You still want to go check on em periodically, make sure they are not low on water, voltage is good and maintainer didnt get unplugged or just up and die on yeh.. once a month or every other month at least so you can catch it before it costs your battery bank.

 

[Buddha.]

I think mine is rated at 60a but I dont know if that's including the power the 12v systems are using; lights, fans etc.

 

[Mccool]

I would like to thank you fellas ( especially Dreadlocks) for all the advice. I have taken a few days to ingest it and do further research.

Unfortunately, after the initial advice I impatiently purchased a "battery tender" charger. I am unhappy with that purchase and in the process of returning it.

I'm trying to decide on a "shore power" charger to replace it. I'm looking at a 10 amp CTEK, a 15 amp Victron bluetooth charger, an IOTA 30 amp, and the Progressive Dynamics 30 amp.

from my understanding, all 4 of these are "smart" charges that will not only charge the batteries, but also maintain/float them while in storage.

is there a clear winner among these 4? They are all priced about the same, minus the CTEK which is cheaper.

 

[dreadlocks]

hard to go wrong w/Victron, and I find bluetooth is nice when your trailer is all locked down, covered in snow and you just wanna verify everything is good.. I pull open my BMV and check on it throughout the winter from the comfort of my warm bedroom.

 

[Mccool]

hard to go wrong w/Victron, and I find bluetooth is nice when your trailer is all locked down, covered in snow and you just wanna verify everything is good.. I pull open my BMV and check on it throughout the winter from the comfort of my warm bedroom.

that is reassuring, the victron was my top choice because the bluetooth features can be combined with the solar charger.

Last question (maybe), the 15 amp is going to be a smarter purchase than the 10 amp version for my situation, correct?

 

[dreadlocks]

yeah with dual GC batteries youd want the 15A, if you had a single battery it wouldn't hurt to have the 15A version, its just unlikely it'd ever output that very often, if at all.

 

[67cj5]

I'm hoping to get some advice on charging my trailer batteries.

The trailer has two 6v golf cart batteries run in series giving me 12v and 210ah capacity. They are running a 12v fridge and a string of led lights. Once fully charged, they can run the fridge and lights for ~12 days until they hit 11.7v which is when the fridge cuts off. I have the output side finished and working well.

Now I'm looking into the input side and how to charge the batteries. I would like a permanent "shore power" Input and eventually solar input. The trailer batteries receive no charge from the truck.

Can I buy a charger capable of handling both solar and shore power? If so, any suggestions?

For the solar, do I need a charger and a "controller"?

Thanks!

This past two weeks I have been testing 3 Chargers, As I want a mountable unit for the camper, The 3 Chargers are about the best money can Buy, If you want to charge those batteries at the correct rate then you need something around the 20/25 amp mark, I have been testing the NOCO G3500 (3.5A) and the NOCO G15000 (15A) and there biggest Charger the NOCO G26000 (26A), These Chargers are incredible and come with a 5 year Guarantee, These Chargers are the best I have ever tested,

Don't think that just because you have a large bank of batteries you need a big charger Because these NOCO chargers are that good there 15 Amp model will charge twice as fast as a 35amp linier type charger which are the old type chargers, I charged 2 115Amp 12v batteries side by side One on the 35amp linier charger and the other on the NOCO G15000 15amp Charger, And the NOCO Blitzed it Not only did the NOCO charge it's battery in under 2 and a half hours, But the Linier charger took over 4 hours and by the time it got close to being fully charged it had started to damage the battery, Because it had dropped the 800cca batteries CCA, When I put it on the Linier charger it was reading 563 and when I took it off the linier charger it was down to 416cca, So this was a good time to test NOCO's claim about charging and the Repair Mode.

After seeing how the NOCO G15000 performed on it's battery I place the 2nd battery on the NOCO and not only did it charge the battery Properly I then ran it's REPAIR MODE and Again in just over 2 hours It was charged and then I ran it's Repair Mode which NOCO state that it takes about 4 hours and sure enough It ran for 3Hrs 59mins and 49secs, I then rechecked the CCA and it was back up to 728cca, So I am truly impressed with how these 3 Chargers perform,

Even though I have the 3.5A and the 15A and the 26A, I tend to favour the G15000, It's very fast and efficient at Charging 115amp batteries and they have Bolt Holes as part of the body work so you can mount them Full Time in a Camper or RV etc. And you can remove or buy a new end piece for the leads and Screw them straight to your battery posts, It is impossible to over charge a battery with these chargers and they can be left on charger for Years on end without ever turning then off or removing the charger from the system, Another great feature is the larger models are Fan Cooled and they never get above room Temp,

They all Charge Normal wet batteries and AGM's and Calcium Batteries and Lithium Batteries so These Chargers are Future proof and the Larger models also have a Boost Start function that you can use twice in 24hrs, Why twice I don't know but that is what they say for some reason and every one of their Chargers have the Repair Mode, As they come to the end of their charging cycle the Voltage drops down to around 13.19/13.2 volts and then they go in to sleep mode until the batteries voltage drops a little then the Charger turns back on and tops up the battery and then shuts down again and it will keep doing that for ever or until you disconnect it, They Charge both 12v and 24v and the Larger G26000 can Charge 12v and 24v and it also Charges 16v AGM Racing Batteries and 16v Lithium Racing Batteries and it has a 30amp Boost Start function and the G15000 has a 20amp Boost Start function.,

If You had 4 of those batteries I'd say get the G26000, But I truly believe that the G15000 will more than do the job you want and it can charge Batteries up to 400amps as well as maintain bigger banks of batteries 24/7. But the G26000 can charge Batteries of up to 500amps as well as maintain bigger banks of batteries 24/7

These Chargers also have a 13.6v 5 Amp Supply Mode.

Hope that helps.

Here's the NOCO G15000

https://no.co/g15000

Here's the NOCO G26000

NOCO - 26A Battery Charger with Engine Start - G26000

The G26000 is a 26-amp 12V and 24V portable automatic car battery charger with engine starter designed to fully charge AGM and deep-cycle batteries.

no.co

 

[BigSwede]

Was comparing NOCO to a similar CTEK...twice as many one, two or three-star reviews for the NOCO 3500 on Amazon compared to the CTEK. But the CTEK doesn't do lithium, so...

 

[dreadlocks]

Victron has a 25A onboard charger that does lithium but its not made its way state side yet.. specs indicate they intend on releasing a 120v version but all that seems to be out there right now are 240v..

 

[67cj5]

Was comparing NOCO to a similar CTEK...twice as many one, two or three-star reviews for the NOCO 3500 on Amazon compared to the CTEK. But the CTEK doesn't do lithium, so...

They are very clever battery chargers, The little G3500 can do 6v and 12v and also has a low Amp setting for small 12v batteries, they claim it uses about 60watts but I just hooked it up to maintain a 110amp battery and in 26hrs 40mins it used 218 watts which equals about 8.17 watts per hour which is incredibly Low,

I normally use the G15000 for general charging but I thought I would try the G3500 and it managed to charge that 110A battery and maintain it which is awesome for such a small charger and it is rated for up to 120Amp, The big chargers are great too and can maintain batteries also but I thought a battery of this size was a good test for it because in theory it was almost at it's limit and it passed with flying colours.

Compared to CTek, NOCO are built like a Tank and have way more features and a 5 year warranty.