Charging from a 12v battery + general charging issues

On site I use pro peak chargers and they do it all, they charge at any given rate and are foolproof, they work off a normal plug at home, and car battery so easy even I can do it, cost around £30 - £45 but well worth it if you have lots of batteries

Thanks for that - v. useful to know.

Obviously if I can make do with what I've got then I'd like to avoid spending more money.

Gotta agree with TJ, pro peak is the way to go if you want to run off 12v, a lot safer than buggering your batteries up. There`s always a few on fleabay..here`s one http://cgi.ebay.co.uk/Pro-Peak-2500-AC-DC-Delta-Peak-Fast-Charger-Ripmax_W0QQitemZ250291045775QQihZ015QQcategoryZ1200QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I use a pro Peak Charger....and again i highly recommend them.

Since there is nothing worse than a battery dying on you in the middle of a battle (and attempting a frantic swap, assuming you remembered to take a spare out with you) I have to agree with the chaps - be 100% sure of your battery condition and use the right kit.

I too have a ProPeak but have been using this £11.99 jobbie with great success for the past 18 months http://www.component-shop.co.uk/html/ra ... trol1.html It has a cig plug 12v option but you would want to use it charging on a journey rather than relying on the 'fast charge' option of the ProPeak to blat some life in a dead battery.

Strictly speaking of course (and the cheapest option if you don't want to spend cash needlessly - who does?) you should have carefully charged a couple of batteries prior to the game and have no need of charging kit in the car at all - nothing like being prepared, eh?

Thanks for all the input. Steve

Theoretically, that set up would work, but I'm guessing there'll be limited conditioning and no form of protection from overcharge, etc...

The Pro-Peaks rule, and I've had mine left over since my RC car/buggy racing. The only thing they don't do is 9.6V batts from a 12V source, but will do 9.6V batts from mains 240v.

Remember to get the VP one if you're charging Nimhs!!!

(Yes I've been using one as well for 4 years and its ace!)

Thanks again guys.

Theoretically, that set up would work, but I'm guessing there'll be..... no form of protection from overcharge, etc...

Hmmm ..... I'd overlooked overcharging - sure looks like Pro-Peaks rule!!

I would heartily recommend the Pro-Peak 2500 VariPulse, not the standard Pro-Peak 2500. I got mine when they first came out, they've been around for nearly 10 years now and they still keep that model on the production list. It's so very useful.

One thing which some might not realise is that it trickle charges at a current of 130mA exactly. The reason for this?

Well, to calculate the length of time to trickle charge a battery is the capacity of the battery (in Amps), divided by the charge current (in Amps), then multiplied by a charge constant "n".

(Battery[Amps] / Charge[Amps]) x n[constant] = ChargeTime[Hours]

If the entire electronic energy transfer system and batteries were 100% efficient, the value of the charge constant "n" would be '1'. But it's recognised that it never will be a 100% efficient transfer (due to heat production, distance voltage drop, etc...) and so people choose a value of between 1.2 (usually for
NiCD) and 1.4 (usually for NiMH) to counter-act/make-up for this . Due to trickle charging never being a precise science, picking between the extremes of 1.2 or 1.4 is just pedantic, so most use the constant 1.3 - It's fine for both NiMH and NiCD batteries. Now this is where the clever bit is. 130mA is 0.13Amps (see where this is going?), so the division by 1.3, and then multiply by 1.3 cancels out! Yes, if slow charging with a trickle charger that has a charge current of 130mA, then the charge time is the capacity of the battery in Amps!

For example, with a 1600mAh battery:
(Battery[Amps] / Charge[Amps]) x n[constant] = ChargeTime[Hours]
So;
(1.6AmpPerHour / 0.13Amps) x 1.3 = 16Hours
Cancel out those "1.3s" (taking into account the factor of ten);
1.6AmpPerHour = 16Hours [at a charge current of 0.13Amps (130mA)

No need to work out trickle charge times with a Pro-Peak, just look at your battery and the answer will be right in front of you! Neat, eh?

Now that is a most useful post!

McV, leading on from that - Is the trickle charge selection of the ProPeak under the 'delta peak' control or is it in effect a bog standard regular charger that needs to be calculated by time?
One of the reasons I chose an 'intelligent' charger was that you don't have to worry about the residual starting capacity or remember to turn the thing off at a specific time.
Incidentally, I have the ProPeak 2500 and was always unhappy about it's 3.5A fast charge as batteries got hot and I was convinced I wasn't getting maximum life out of batteries (this was when the cost a lot) and found 600mA charging with my £12 'intelligent' charger to be more satisfactory. I'm the sort of person who plans ahead and so never needed a panic charge on the morning of a skirmish 'cos I had forgotten to look after the most essential bit of kit, so can live without 'fast' charge!

McV, leading on from that - Is the trickle charge selection of the ProPeak under the 'delta peak' control or is it in effect a bog standard regular charger that needs to be calculated by time? One of the reasons I chose an 'intelligent' charger was that you don't have to worry about the residual starting capacity or remember to turn the thing off at a specific time.

With the Pro-Peak VariPulse, it's only the variable fast charge that has the dealt peak detection, really it's the only thing that needs it. With such a low trickle charge rate as 130mA (as compared to the usual slow charger current of ~ 500mA), it really isn't a precise art. Just turn it off around the hour. Even then trickle charging is not going to be totally precise due to the value of battery capacity not being an exact measurement either. It all has to be taken with a pinch of salt. If you feel your batteries getting warmer than 'warm' near the end of the charge time, take 'em off charge anyways, don't wait until the bitter end because the calculations say so.

do a 130mA Incidentally, I have the ProPeak 2500 and was always unhappy about it's 3.5A fast charge as batteries got hot and I was convinced I wasn't getting maximum life out of batteries (this was when the cost a lot) and found 600mA charging with my £12 'intelligent' charger to be more satisfactory. I'm the sort of person who plans ahead and so never needed a panic charge on the morning of a skirmish 'cos I had forgotten to look after the most essential bit of kit, so can live without 'fast' charge!

Yeah, I dislike the standard Pro-Peak 2500, that's why I recommend the Pro-Peak 2500 VariPulse. It has a little dial on the front which allows you to control the charge current when in fast charge mode. In part answer to your other question above, this dial does let you set the delta peak detection fast charge down to a charge current of 500mA! So, yes, it does effectively do a delta-peak detected 500mA trickle "fast charge".

I hardly ever use the fast charge on mine either, except when doing a 500mA delta-peak detection charge on new batteries when conditioning them. Other wise mine are all trickle charged via the 130mA route.

Additional info to anyone else about Pro-Preaks 2500 series (and probably other chargers they produce):
- To trickle charge at 130mA; connect up the battery and power as you would to fast charge, but just don't push the fast charge button, it'll trickle charge in this current state. It's not really explained very well in the manual.
- With the Vari-Pulse, do not turn the charge current dial over 1.5 times (max) the capacity of your battery. I usually don't go above 1 times (e.g: if you've got a 1600mAh battery, don't go charging it at 3Amps charge current, no more than 2.4Amps, but best charged at the lowest possible setting you can in the time restraints you face).

I got mine from DMS Racing http://www.dms-racing.com/ many moons ago (nearly 10 years?). They haven't really shifted in price. I'd recommend trying to buy one second hand. I've seen 'em got for under £20. Just make sure it still works fine!

MODS: Is it worth editing this thread down and making it a Pro-Peak sticky?

Nothing worse than a sticky pro peak

Thanks to all contributors for the advice

I too have a ProPeak but have been using this £11.99 jobbie with great success for the past 18 months http://www.component-shop.co.uk/html/ra ... trol1.html It has a cig plug 12v option but you would want to use it charging on a journey rather than relying on the 'fast charge' option of the ProPeak to blat some life in a dead battery.

I ummed and arrred over the ProPeak VP and the Component Shop jobby (see CW post) and finally settled on the latter. I've also ordered a new

NiMh 8.4V 1400mAh

to complement the

NiMh 8.4V 1050mAh
NiMh 8.4V 1000mAh
NiCd 8.4V 500mAH

batteries I already have which should give more me more than enough juice for a weekend's play (plus 12V charging back-up as a contingency).

This debate has prompted me to do a fair amount of reading on batteries and how to look after them (maybe, just maybe , I should have done that before ) but despite McVickers extensive explanations I can't quite get my head around how long I should be charging my batteries for.

Hopefully it will become clearer when the new charger arrives.

Thanks for the help so far.

Luckily, you won't need to worry as you now have an 'intelligent' charger. Set the left dial to 7 cells, the right dial to 600mA (or 300ma for the non-1400 batteries), switch on and plug your battery in. When the light turns green you are done! Don't worry about over charging either as it has now dropped to a really low trickle charge and safe to turn off when you are ready (heh, I don't mean after a four week cruise!).

When you come to have a go with the NiCd it will probably be worth pressing the little 'discharge' button once connected - this will run the battery down before charging to 'full'. This cycling is a better way to deal with the dreaded memory effect of NiCd's (although at the NiCd'd capacity I'm guessing it will be an emergency-emergency battery!).

Thanks CW - good advice and new technology make life so simple. Thanks.

(although at the NiCd'd capacity I'm guessing it will be an emergency-emergency battery!).

It's the one I'll lend to the wife!

Do not discharge any NiMHs you will ruin them.