Dual battery systems?

Anyone ever had a "Thumper" system?

These appear to be about the same cost as a fixed dual battery system (amp for amp) in the vehicle, but could be a bit more versatile.

If anyone has got one or used one can you let us know the pro's and con's of them.

G'day, A mate of mine who lives full time in the bush travelling around the country uses a thumper for his power in his tent....Seems a good battery and does the job no worries but he is on his second battery as the first one blew up....(it was replaced under warranty tho)

Not sure that I would be using one of these in the vehicle as a second battery tho either, not really the right application for that job and at the price alone I would be thinking of a different road to go down too.

I have just set up a second battery in my bush rig and I have installed an AGM (optima) battery......
At half the price of a thumper I'm sure it will live longer too.

optima are just awesome batteries , you can be sure it will last a long time. They do cost a bit however!


themrburns

Te biggest con for a thumper is the cost....the biggest pro is being able to just buy one....Basically its just an AGM battery inside a box with a range of electrical fittings from 240v to 12v.
Much of it you can buy and install yourself as i have done, but went one better by opting to install it all in a plastic toolbox from bunnings $50. Totally portable and often used as a step....now jam packed full of electrical stuff from digital multimeter, 12v soldering iron, test light, cable ties, crimping tool, short extension lead with Anderson plug fitted with alligator ends, and spare everything i probably will never use.

I fitted mine out with all the goodies found in a thumper including USB charging port....except ATM im just using a maintenance free starter battery till such times i need the second AGM....and iv had to call upon it several times to jump start myself and others.
Iv also got a an inverter inside the box that was a gift from a friend should i need 240v.
ATM its connected to the starter battery of the vehicle from where it charges through a dual battery solenoid via Anderson plugs...protected both ends with dual 50A resettable circuit breakers. Fitted on the dash is an idiot switch with a big red LED to tell me its on. (User selectable)
All acc connected to the battery box are run through a separate 10Amp resettable circuit breaker.
Whats not seen in these pics is the wall now separating the battery from the sundries area.
Again, totally portable and able to be connected to my portable solar panel if used while stationary.

Total cost was well under what you would pay for a basic thumper.

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Hi mate,

I had a thumper and while it worked well, it blew up after only about 12 to 14 months. By blowing up I mean a couple of the cells inside swelled so much they cracked the external casing holding all the cells in place.
It's not one battery in a fancy case, it's about 4 smaller cells in a fancy case.

As Narrawa said, very expensive for what they are compared to a normal battery, but for me at the time it was the convieniance.

I since replaced it with a 120 ahr AGM battery from the same supplier and it's a beauty. Did simillar to what narrawa has done, by adding anderson plugs and cigarette lighter attatchements to a marine casing.
I will say the distributer is fantastic to deal with and I'll use him again if I ever need anything. He also is the distributor for the fridgemate range of fridges.

cheers,
steve

I hate clever people Narra

Robert

Is it clever people you hate???? or just tight arses.


At the end of the day...its a lot of money for a deep cycle battery.
Check out this model with a 90Ah battery and a 600W P/S inverter.
Criiiipes!!!i

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Thanks everyone for your input.

It appears out of the 2 Thumper systems known both have expired(GPX and Mad Tuna). Not exactly a good Kit Kat strike rate.

I'll do a bit more homework this week and let you know what happens.

To do it myself with 20amp 12v to 12 v charger, 100 amp battery and 600w sine inverter it should come in just under a grand with all the bits and pieces. Much like yourself Narrawa I'm a tight butt but you just have to buy quality items or they end up costing more in the long run.

Mad Tuna, those fridges look the goods, has yours survived okay?

Just livening up an old discussion
Just bought a camper trailer, that has 3 x 100 amp batts ..I have got a ctek convertor charging my second battery in the lux ..Which works brilliant, the engel ran the 2nd battery down .jump in the car n fire up ,how many times have I been caught b4
Do you think.
I,ll have any dramas tapping on to the 2nd battery,fuses etc , via Anderson plugs and 10mm cable..to the the trailer Anderson plug  (volt drop)
Mark 409

Mark, tell us a little more clearly your intentions.??
Length of cable ?..how the 3 batt are connected...just a little run down on the setup.
It might be just me, but i cant make out exactly what you want to do with your setup till i can get a better picture of how its setup.

Also, the ctek your using....is it the DC/DC converter charger type.?

morning Narrawa
Just reread my post it is a bit confusing..1 to many.
yes The charger I have is a ctek DC to Dc convertor in the car charging, my second battery and it works well..
The camper trailer has 3 x 100 ah batteries in parallel charged by a mains charger ,There is also a Anderson Plug from the trailer that feeds the batteries for when travelling ,I was going to take a feed from my 2nd battery in the car via the Anderson plug, to top up the 3 batteries in the rear..when travelling ..Total distance will be about 6metres. I will be using 2c 10mm Red/Black ... I was just wondering if there might be problems with the sensing of the batteries due to the volt drop, tho it should,nt be to bad, as the cable is a reasonable size.. I,ll be adding solar later as the ctek has the capability for it.
regards
Mark409
I like your power box above..

There is also a Anderson Plug from the trailer that feeds the batteries for when travelling ,I was going to take a feed from my 2nd battery in the car via the Anderson plug, to top up the 3 batteries in the rear..when travelling

Still a little unsure here.?..your charging the three batteries that are in parallel from the alternator while driving?... or the DC-DC charger via the Anderson plug while driving.?
Either way, your charging the rear batteries via a cable coming from the engine bay. If that cable is solid enough, no problems. (Pending that below)

If using the DC-DC charger, id have it in the camper trailer where it can lift the voltage regardless of the voltage drop through the cable length. However... I can't find literature to say its able to do that...which means mounted in the engine bay you'll run into two problems..
1. The temp sensor built into the charger will be running hot and adjusting the charge rate to the batteries falsely.
2. If it does not have the ability to take 12v and convert it up to 14.4v...it will undercharge if mounted close to the aux batteries while running from the alternator via the Anderson connection. UNLESS, the cable is of sufficient size to carry that voltage to the rear when the engine is running.??

Im assuming your using the DC-DC charger upfront to keep your dual batt in the engine bay charged, where you run your fridge from...hence the reason you need to start the engine to charge it up some....is this correct.?

Solar panels put out a much higher voltage than the alternator, the DC-DC converter charger can work with this by lowering it...but if its not able to up the voltage over long runs...its not going to do the job. Its good for about 20A...your alternator is able to put out much more Amps down that cable if its big enough.

Tapping into your aux batt from the engine bay, or back of your truck regardless of how its being charged will not help the 3 batt in the camper. The amount of time required to charge all 4 batt from a 5 stage charger ...is a very long time driving....Thats if iv assumed correctly, as im still a little unsure of the set up.???

Before you connect the trailer batts to the cars aux batt, make sure you have at least 50A circuit breaker / or fuse as close as possible to the cars Aux battery to prevent accidental meltdown fires.

If there is a short for what ever reason between the fuse in the engine bay and Anderson Plug at the trailer you may still have a aux batt that will not in smoke. 10mm cable is gonna carry serious amps if it shorts somewhere.

A CHARGING BATTERY CAN EXPLODE with just one spark nearby.

Voltage drop from the cars aux batt is proportional to current draw, cable dia (cross sectional area) and the internal resistance of the aux batt, so remember, so long as you aren't pulling heaps of amps on flat batteries screaming for a charge after a big wind down off recharge then voltage drop should be less of an issue once the trailer batteries come back to life after a few minutes running on on the cars alternator.

I wouldn't plug the trailer with a flat battery then drive at night though (unless your alternator can handle the extra current with the High Beam on) You could maybe just charge one battery on the trailer (with the others temporarily disconnected in turn)

Because the trailer is a temporary connection (while driving), charge regulators and mismatching batteries really is a non issue and over kill.

Sorry boys
appreciate the feedback ,,been a bit busy of late

Narrawa
If using the DC-DC charger, id have it in the camper trailer where it can lift the voltage regardless of the voltage drop through the cable length. However... I can't find literature to say its able to do that...which means mounted in the engine bay you'll run into two problems.. The converter is next to the car battery with the temp sensor on the car battery
1. The temp sensor built into the charger will be running hot and adjusting the charge rate to the batteries falsely.
2. If it does not have the ability to take 12v and convert it up to 14.4v...it will undercharge if mounted close to the aux batteries while running from the alternator via the Anderson connection. UNLESS, the cable is of sufficient size to carry that voltage to the rear when the engine is running.??
The ctek does pump the voltage up to about 14.4v (generally about .6v above alternator voltage..primary battery volts)..10mm cable ..should be plenty.

Im assuming your using the DC-DC charger upfront to keep your dual batt in the engine bay charged, where you run your fridge from...hence the reason you need to start the engine to charge it up some....is this correct.?
Correct..tho now the fridge will be in the back.

Its good for about 20A...your alternator is able to put out much more Amps down that cable if its big enough.
If I hook it up directly to the alternator I may lose the primary battery ,,and I don't want to use isolators when I stop..i know I,ll forget. The ctek is limited to 20Amps for Aux battery correct

Tapping into your aux batt from the engine bay, or back of your truck regardless of how its being charged will not help the 3 batt in the camper. The amount of time required to charge all 4 batt from a 5 stage charger ...is a very long time driving....
It is mainly for the intial trip just to keep the batteries maintained,i drive 2 days to get there ,hopefully ill get 3 or 4 days before I need the genny...


NuggieDreamer
All circuits will be fused 50A ..not a big one for cb,s .ive seen em weld together ,,
I wouldn't plug the trailer with a flat battery then drive at night though (unless your alternator can handle the extra current with the High Beam on) You could maybe just charge one battery on the trailer (with the others temporarily disconnected in turn
The ctek should limit the current draw to 20Amps..

Thanks boys  for the info,,I,m gonna give it a go anyway ,,I,ll let u know how it goes..  All the font colours may be different     
Mark 409

All good Mark, i use a simple 80A cheap solenoid setup for dual battery charging. With 2x 50A circuit breakers either side of the positive terminals.
Its wired to an idiot switch on the dash which i just leave turned on, while the ignition is on, the two batt are joined and charging. A little LED in the switch tells me their connected. When the ignition is turned off, they disconnect from one another. The AUX batt 105Ahr AGM sits in the rear next to the 40L Engal, its also being fed by a 60W polly panel above on the roof.

My c/van is independent of the vehicle when traveling. Its got a 130W panel and its own battery.

I'LL JUST STICK TO THE CAT MOTHER OF ALL BATTERIES wired to the solar panel via a regulator and the battery is independent of the car..

this thing feeds to fridge and lights in the recreational part of the vehicle--the business end of the car--motor etc has its own setup.

regards
oneday

Narrawa wrote:All good Mark, i use a simple 80A cheap solenoid setup for dual battery charging. With 2x 50A circuit breakers either side of the positive terminals.
Its wired to an idiot switch on the dash which i just leave turned on, while the ignition is on, the two batt are joined and charging. A little LED in the switch tells me their connected. When the ignition is turned off, they disconnect from one another. The AUX batt 105Ahr AGM sits in the rear next to the 40L Engal, its also being fed by a 60W polly panel above on the roof.

My c/van is independent of the vehicle when traveling.  Its got a 130W panel and its own battery.

My little box of tricks is very similar to Narrawa's however is under modification with a few extras.

Use a solonoid which is connected to the "run" on the ignition so the auxiliary battery is charged while driving. If I need power for accessories (two way etc) while stationary the ignition is switched to "accessories."
The box of tricks is connected to a third battery which can be charged via another solonoid which as Narrawa mentions has an idiot switch and light indication which is usually only on while travelling or cloudy days.
The modified box will have a greater output battery charger and analog voltage & amp gauges to show both solar and charger input. While stopped for the day detecting a portable 120W fold up solar panel keeps the third battery topped up to keep the Engels running.
Think there is already a photo of my old box here somewhere but here it is again, will include a new photo after the mods are done.

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